const _ = require('underscore-plus')
const path = require('path')
const fs = require('fs-plus')
const Grim = require('grim')
const dedent = require('dedent')
const {CompositeDisposable, Disposable, Emitter} = require('event-kit')
const TextBuffer = require('text-buffer')
const {Point, Range} = TextBuffer
const DecorationManager = require('./decoration-manager')
const Cursor = require('./cursor')
const Selection = require('./selection')
const NullGrammar = require('./null-grammar')
const TextMateLanguageMode = require('./text-mate-language-mode')
const ScopeDescriptor = require('./scope-descriptor')

const TextMateScopeSelector = require('first-mate').ScopeSelector
const GutterContainer = require('./gutter-container')
let TextEditorComponent = null
let TextEditorElement = null
const {isDoubleWidthCharacter, isHalfWidthCharacter, isKoreanCharacter, isWrapBoundary} = require('./text-utils')

const SERIALIZATION_VERSION = 1
const NON_WHITESPACE_REGEXP = /\S/
const ZERO_WIDTH_NBSP = '\ufeff'
let nextId = 0

const DEFAULT_NON_WORD_CHARACTERS = "/\\()\"':,.;<>~!@#$%^&*|+=[]{}`?-…"

// Essential: This class represents all essential editing state for a single
// {TextBuffer}, including cursor and selection positions, folds, and soft wraps.
// If you're manipulating the state of an editor, use this class.
//
// A single {TextBuffer} can belong to multiple editors. For example, if the
// same file is open in two different panes, Atom creates a separate editor for
// each pane. If the buffer is manipulated the changes are reflected in both
// editors, but each maintains its own cursor position, folded lines, etc.
//
// ## Accessing TextEditor Instances
//
// The easiest way to get hold of `TextEditor` objects is by registering a callback
// with `::observeTextEditors` on the `atom.workspace` global. Your callback will
// then be called with all current editor instances and also when any editor is
// created in the future.
//
// ```js
// atom.workspace.observeTextEditors(editor => {
//   editor.insertText('Hello World')
// })
// ```
//
// ## Buffer vs. Screen Coordinates
//
// Because editors support folds and soft-wrapping, the lines on screen don't
// always match the lines in the buffer. For example, a long line that soft wraps
// twice renders as three lines on screen, but only represents one line in the
// buffer. Similarly, if rows 5-10 are folded, then row 6 on screen corresponds
// to row 11 in the buffer.
//
// Your choice of coordinates systems will depend on what you're trying to
// achieve. For example, if you're writing a command that jumps the cursor up or
// down by 10 lines, you'll want to use screen coordinates because the user
// probably wants to skip lines *on screen*. However, if you're writing a package
// that jumps between method definitions, you'll want to work in buffer
// coordinates.
//
// **When in doubt, just default to buffer coordinates**, then experiment with
// soft wraps and folds to ensure your code interacts with them correctly.
module.exports =
class TextEditor {
  static setClipboard (clipboard) {
    this.clipboard = clipboard
  }

  static setScheduler (scheduler) {
    if (TextEditorComponent == null) { TextEditorComponent = require('./text-editor-component') }
    return TextEditorComponent.setScheduler(scheduler)
  }

  static didUpdateStyles () {
    if (TextEditorComponent == null) { TextEditorComponent = require('./text-editor-component') }
    return TextEditorComponent.didUpdateStyles()
  }

  static didUpdateScrollbarStyles () {
    if (TextEditorComponent == null) { TextEditorComponent = require('./text-editor-component') }
    return TextEditorComponent.didUpdateScrollbarStyles()
  }

  static viewForItem (item) { return item.element || item }

  static deserialize (state, atomEnvironment) {
    if (state.version !== SERIALIZATION_VERSION) return null

    let bufferId = state.tokenizedBuffer
      ? state.tokenizedBuffer.bufferId
      : state.bufferId

    try {
      state.buffer = atomEnvironment.project.bufferForIdSync(bufferId)
      if (!state.buffer) return null
    } catch (error) {
      if (error.syscall === 'read') {
        return // Error reading the file, don't deserialize an editor for it
      } else {
        throw error
      }
    }

    state.assert = atomEnvironment.assert.bind(atomEnvironment)

    // Semantics of the readOnly flag have changed since its introduction.
    // Only respect readOnly2, which has been set with the current readOnly semantics.
    delete state.readOnly
    state.readOnly = state.readOnly2
    delete state.readOnly2

    const editor = new TextEditor(state)
    if (state.registered) {
      const disposable = atomEnvironment.textEditors.add(editor)
      editor.onDidDestroy(() => disposable.dispose())
    }
    return editor
  }

  constructor (params = {}) {
    if (this.constructor.clipboard == null) {
      throw new Error('Must call TextEditor.setClipboard at least once before creating TextEditor instances')
    }

    this.id = params.id != null ? params.id : nextId++
    if (this.id >= nextId) {
      // Ensure that new editors get unique ids:
      nextId = this.id + 1
    }
    this.initialScrollTopRow = params.initialScrollTopRow
    this.initialScrollLeftColumn = params.initialScrollLeftColumn
    this.decorationManager = params.decorationManager
    this.selectionsMarkerLayer = params.selectionsMarkerLayer
    this.mini = (params.mini != null) ? params.mini : false
    this.keyboardInputEnabled = (params.keyboardInputEnabled != null) ? params.keyboardInputEnabled : true
    this.readOnly = (params.readOnly != null) ? params.readOnly : false
    this.placeholderText = params.placeholderText
    this.showLineNumbers = params.showLineNumbers
    this.assert = params.assert || (condition => condition)
    this.showInvisibles = (params.showInvisibles != null) ? params.showInvisibles : true
    this.autoHeight = params.autoHeight
    this.autoWidth = params.autoWidth
    this.scrollPastEnd = (params.scrollPastEnd != null) ? params.scrollPastEnd : false
    this.scrollSensitivity = (params.scrollSensitivity != null) ? params.scrollSensitivity : 40
    this.editorWidthInChars = params.editorWidthInChars
    this.invisibles = params.invisibles
    this.showIndentGuide = params.showIndentGuide
    this.softWrapped = params.softWrapped
    this.softWrapAtPreferredLineLength = params.softWrapAtPreferredLineLength
    this.preferredLineLength = params.preferredLineLength
    this.showCursorOnSelection = (params.showCursorOnSelection != null) ? params.showCursorOnSelection : true
    this.maxScreenLineLength = params.maxScreenLineLength
    this.softTabs = (params.softTabs != null) ? params.softTabs : true
    this.autoIndent = (params.autoIndent != null) ? params.autoIndent : true
    this.autoIndentOnPaste = (params.autoIndentOnPaste != null) ? params.autoIndentOnPaste : true
    this.undoGroupingInterval = (params.undoGroupingInterval != null) ? params.undoGroupingInterval : 300
    this.softWrapped = (params.softWrapped != null) ? params.softWrapped : false
    this.softWrapAtPreferredLineLength = (params.softWrapAtPreferredLineLength != null) ? params.softWrapAtPreferredLineLength : false
    this.preferredLineLength = (params.preferredLineLength != null) ? params.preferredLineLength : 80
    this.maxScreenLineLength = (params.maxScreenLineLength != null) ? params.maxScreenLineLength : 500
    this.showLineNumbers = (params.showLineNumbers != null) ? params.showLineNumbers : true
    const {tabLength = 2} = params

    this.alive = true
    this.doBackgroundWork = this.doBackgroundWork.bind(this)
    this.serializationVersion = 1
    this.suppressSelectionMerging = false
    this.selectionFlashDuration = 500
    this.gutterContainer = null
    this.verticalScrollMargin = 2
    this.horizontalScrollMargin = 6
    this.lineHeightInPixels = null
    this.defaultCharWidth = null
    this.height = null
    this.width = null
    this.registered = false
    this.atomicSoftTabs = true
    this.emitter = new Emitter()
    this.disposables = new CompositeDisposable()
    this.cursors = []
    this.cursorsByMarkerId = new Map()
    this.selections = []
    this.hasTerminatedPendingState = false

    if (params.buffer) {
      this.buffer = params.buffer
    } else {
      this.buffer = new TextBuffer({
        shouldDestroyOnFileDelete () { return atom.config.get('core.closeDeletedFileTabs') }
      })
      this.buffer.setLanguageMode(new TextMateLanguageMode({buffer: this.buffer, config: atom.config}))
    }

    const languageMode = this.buffer.getLanguageMode()
    this.languageModeSubscription = languageMode.onDidTokenize && languageMode.onDidTokenize(() => {
      this.emitter.emit('did-tokenize')
    })
    if (this.languageModeSubscription) this.disposables.add(this.languageModeSubscription)

    if (params.displayLayer) {
      this.displayLayer = params.displayLayer
    } else {
      const displayLayerParams = {
        invisibles: this.getInvisibles(),
        softWrapColumn: this.getSoftWrapColumn(),
        showIndentGuides: this.doesShowIndentGuide(),
        atomicSoftTabs: params.atomicSoftTabs != null ? params.atomicSoftTabs : true,
        tabLength,
        ratioForCharacter: this.ratioForCharacter.bind(this),
        isWrapBoundary,
        foldCharacter: ZERO_WIDTH_NBSP,
        softWrapHangingIndent: params.softWrapHangingIndentLength != null ? params.softWrapHangingIndentLength : 0
      }

      this.displayLayer = this.buffer.getDisplayLayer(params.displayLayerId)
      if (this.displayLayer) {
        this.displayLayer.reset(displayLayerParams)
        this.selectionsMarkerLayer = this.displayLayer.getMarkerLayer(params.selectionsMarkerLayerId)
      } else {
        this.displayLayer = this.buffer.addDisplayLayer(displayLayerParams)
      }
    }

    this.backgroundWorkHandle = requestIdleCallback(this.doBackgroundWork)
    this.disposables.add(new Disposable(() => {
      if (this.backgroundWorkHandle != null) return cancelIdleCallback(this.backgroundWorkHandle)
    }))

    this.defaultMarkerLayer = this.displayLayer.addMarkerLayer()
    if (!this.selectionsMarkerLayer) {
      this.selectionsMarkerLayer = this.addMarkerLayer({maintainHistory: true, persistent: true, role: 'selections'})
    }

    this.decorationManager = new DecorationManager(this)
    this.decorateMarkerLayer(this.selectionsMarkerLayer, {type: 'cursor'})
    if (!this.isMini()) this.decorateCursorLine()

    this.decorateMarkerLayer(this.displayLayer.foldsMarkerLayer, {type: 'line-number', class: 'folded'})

    for (let marker of this.selectionsMarkerLayer.getMarkers()) {
      this.addSelection(marker)
    }

    this.subscribeToBuffer()
    this.subscribeToDisplayLayer()

    if (this.cursors.length === 0 && !params.suppressCursorCreation) {
      const initialLine = Math.max(parseInt(params.initialLine) || 0, 0)
      const initialColumn = Math.max(parseInt(params.initialColumn) || 0, 0)
      this.addCursorAtBufferPosition([initialLine, initialColumn])
    }

    this.gutterContainer = new GutterContainer(this)
    this.lineNumberGutter = this.gutterContainer.addGutter({
      name: 'line-number',
      priority: 0,
      visible: params.lineNumberGutterVisible
    })
  }

  get element () {
    return this.getElement()
  }

  get editorElement () {
    Grim.deprecate(dedent`\
      \`TextEditor.prototype.editorElement\` has always been private, but now
      it is gone. Reading the \`editorElement\` property still returns a
      reference to the editor element but this field will be removed in a
      later version of Atom, so we recommend using the \`element\` property instead.\
    `)

    return this.getElement()
  }

  get displayBuffer () {
    Grim.deprecate(dedent`\
      \`TextEditor.prototype.displayBuffer\` has always been private, but now
      it is gone. Reading the \`displayBuffer\` property now returns a reference
      to the containing \`TextEditor\`, which now provides *some* of the API of
      the defunct \`DisplayBuffer\` class.\
    `)
    return this
  }

  get languageMode () { return this.buffer.getLanguageMode() }
  get tokenizedBuffer () { return this.buffer.getLanguageMode() }

  get rowsPerPage () {
    return this.getRowsPerPage()
  }

  decorateCursorLine () {
    this.cursorLineDecorations = [
      this.decorateMarkerLayer(this.selectionsMarkerLayer, {type: 'line', class: 'cursor-line', onlyEmpty: true}),
      this.decorateMarkerLayer(this.selectionsMarkerLayer, {type: 'line-number', class: 'cursor-line'}),
      this.decorateMarkerLayer(this.selectionsMarkerLayer, {type: 'line-number', class: 'cursor-line-no-selection', onlyHead: true, onlyEmpty: true})
    ]
  }

  doBackgroundWork (deadline) {
    const previousLongestRow = this.getApproximateLongestScreenRow()
    if (this.displayLayer.doBackgroundWork(deadline)) {
      this.backgroundWorkHandle = requestIdleCallback(this.doBackgroundWork)
    } else {
      this.backgroundWorkHandle = null
    }

    if (this.component && this.getApproximateLongestScreenRow() !== previousLongestRow) {
      this.component.scheduleUpdate()
    }
  }

  update (params) {
    const displayLayerParams = {}

    for (let param of Object.keys(params)) {
      const value = params[param]

      switch (param) {
        case 'autoIndent':
          this.autoIndent = value
          break

        case 'autoIndentOnPaste':
          this.autoIndentOnPaste = value
          break

        case 'undoGroupingInterval':
          this.undoGroupingInterval = value
          break

        case 'scrollSensitivity':
          this.scrollSensitivity = value
          break

        case 'encoding':
          this.buffer.setEncoding(value)
          break

        case 'softTabs':
          if (value !== this.softTabs) {
            this.softTabs = value
          }
          break

        case 'atomicSoftTabs':
          if (value !== this.displayLayer.atomicSoftTabs) {
            displayLayerParams.atomicSoftTabs = value
          }
          break

        case 'tabLength':
          if (value > 0 && value !== this.displayLayer.tabLength) {
            displayLayerParams.tabLength = value
          }
          break

        case 'softWrapped':
          if (value !== this.softWrapped) {
            this.softWrapped = value
            displayLayerParams.softWrapColumn = this.getSoftWrapColumn()
            this.emitter.emit('did-change-soft-wrapped', this.isSoftWrapped())
          }
          break

        case 'softWrapHangingIndentLength':
          if (value !== this.displayLayer.softWrapHangingIndent) {
            displayLayerParams.softWrapHangingIndent = value
          }
          break

        case 'softWrapAtPreferredLineLength':
          if (value !== this.softWrapAtPreferredLineLength) {
            this.softWrapAtPreferredLineLength = value
            displayLayerParams.softWrapColumn = this.getSoftWrapColumn()
          }
          break

        case 'preferredLineLength':
          if (value !== this.preferredLineLength) {
            this.preferredLineLength = value
            displayLayerParams.softWrapColumn = this.getSoftWrapColumn()
          }
          break

        case 'maxScreenLineLength':
          if (value !== this.maxScreenLineLength) {
            this.maxScreenLineLength = value
            displayLayerParams.softWrapColumn = this.getSoftWrapColumn()
          }
          break

        case 'mini':
          if (value !== this.mini) {
            this.mini = value
            this.emitter.emit('did-change-mini', value)
            displayLayerParams.invisibles = this.getInvisibles()
            displayLayerParams.softWrapColumn = this.getSoftWrapColumn()
            displayLayerParams.showIndentGuides = this.doesShowIndentGuide()
            if (this.mini) {
              for (let decoration of this.cursorLineDecorations) { decoration.destroy() }
              this.cursorLineDecorations = null
            } else {
              this.decorateCursorLine()
            }
            if (this.component != null) {
              this.component.scheduleUpdate()
            }
          }
          break

        case 'readOnly':
          if (value !== this.readOnly) {
            this.readOnly = value
            if (this.component != null) {
              this.component.scheduleUpdate()
            }
          }
          break

        case 'keyboardInputEnabled':
          if (value !== this.keyboardInputEnabled) {
            this.keyboardInputEnabled = value
            if (this.component != null) {
              this.component.scheduleUpdate()
            }
          }
          break

        case 'placeholderText':
          if (value !== this.placeholderText) {
            this.placeholderText = value
            this.emitter.emit('did-change-placeholder-text', value)
          }
          break

        case 'lineNumberGutterVisible':
          if (value !== this.lineNumberGutterVisible) {
            if (value) {
              this.lineNumberGutter.show()
            } else {
              this.lineNumberGutter.hide()
            }
            this.emitter.emit('did-change-line-number-gutter-visible', this.lineNumberGutter.isVisible())
          }
          break

        case 'showIndentGuide':
          if (value !== this.showIndentGuide) {
            this.showIndentGuide = value
            displayLayerParams.showIndentGuides = this.doesShowIndentGuide()
          }
          break

        case 'showLineNumbers':
          if (value !== this.showLineNumbers) {
            this.showLineNumbers = value
            if (this.component != null) {
              this.component.scheduleUpdate()
            }
          }
          break

        case 'showInvisibles':
          if (value !== this.showInvisibles) {
            this.showInvisibles = value
            displayLayerParams.invisibles = this.getInvisibles()
          }
          break

        case 'invisibles':
          if (!_.isEqual(value, this.invisibles)) {
            this.invisibles = value
            displayLayerParams.invisibles = this.getInvisibles()
          }
          break

        case 'editorWidthInChars':
          if (value > 0 && value !== this.editorWidthInChars) {
            this.editorWidthInChars = value
            displayLayerParams.softWrapColumn = this.getSoftWrapColumn()
          }
          break

        case 'width':
          if (value !== this.width) {
            this.width = value
            displayLayerParams.softWrapColumn = this.getSoftWrapColumn()
          }
          break

        case 'scrollPastEnd':
          if (value !== this.scrollPastEnd) {
            this.scrollPastEnd = value
            if (this.component) this.component.scheduleUpdate()
          }
          break

        case 'autoHeight':
          if (value !== this.autoHeight) {
            this.autoHeight = value
          }
          break

        case 'autoWidth':
          if (value !== this.autoWidth) {
            this.autoWidth = value
          }
          break

        case 'showCursorOnSelection':
          if (value !== this.showCursorOnSelection) {
            this.showCursorOnSelection = value
            if (this.component) this.component.scheduleUpdate()
          }
          break

        default:
          if (param !== 'ref' && param !== 'key') {
            throw new TypeError(`Invalid TextEditor parameter: '${param}'`)
          }
      }
    }

    this.displayLayer.reset(displayLayerParams)

    if (this.component) {
      return this.component.getNextUpdatePromise()
    } else {
      return Promise.resolve()
    }
  }

  scheduleComponentUpdate () {
    if (this.component) this.component.scheduleUpdate()
  }

  serialize () {
    return {
      deserializer: 'TextEditor',
      version: SERIALIZATION_VERSION,

      displayLayerId: this.displayLayer.id,
      selectionsMarkerLayerId: this.selectionsMarkerLayer.id,

      initialScrollTopRow: this.getScrollTopRow(),
      initialScrollLeftColumn: this.getScrollLeftColumn(),

      tabLength: this.displayLayer.tabLength,
      atomicSoftTabs: this.displayLayer.atomicSoftTabs,
      softWrapHangingIndentLength: this.displayLayer.softWrapHangingIndent,

      id: this.id,
      bufferId: this.buffer.id,
      softTabs: this.softTabs,
      softWrapped: this.softWrapped,
      softWrapAtPreferredLineLength: this.softWrapAtPreferredLineLength,
      preferredLineLength: this.preferredLineLength,
      mini: this.mini,
      readOnly2: this.readOnly, // readOnly encompassed both readOnly and keyboardInputEnabled
      keyboardInputEnabled: this.keyboardInputEnabled,
      editorWidthInChars: this.editorWidthInChars,
      width: this.width,
      maxScreenLineLength: this.maxScreenLineLength,
      registered: this.registered,
      invisibles: this.invisibles,
      showInvisibles: this.showInvisibles,
      showIndentGuide: this.showIndentGuide,
      autoHeight: this.autoHeight,
      autoWidth: this.autoWidth
    }
  }

  subscribeToBuffer () {
    this.buffer.retain()
    this.disposables.add(this.buffer.onDidChangeLanguageMode(this.handleLanguageModeChange.bind(this)))
    this.disposables.add(this.buffer.onDidChangePath(() => {
      this.emitter.emit('did-change-title', this.getTitle())
      this.emitter.emit('did-change-path', this.getPath())
    }))
    this.disposables.add(this.buffer.onDidChangeEncoding(() => {
      this.emitter.emit('did-change-encoding', this.getEncoding())
    }))
    this.disposables.add(this.buffer.onDidDestroy(() => this.destroy()))
    this.disposables.add(this.buffer.onDidChangeModified(() => {
      if (!this.hasTerminatedPendingState && this.buffer.isModified()) this.terminatePendingState()
    }))
  }

  terminatePendingState () {
    if (!this.hasTerminatedPendingState) this.emitter.emit('did-terminate-pending-state')
    this.hasTerminatedPendingState = true
  }

  onDidTerminatePendingState (callback) {
    return this.emitter.on('did-terminate-pending-state', callback)
  }

  subscribeToDisplayLayer () {
    this.disposables.add(this.displayLayer.onDidChange(changes => {
      this.mergeIntersectingSelections()
      if (this.component) this.component.didChangeDisplayLayer(changes)
      this.emitter.emit('did-change', changes.map(change => new ChangeEvent(change)))
    }))
    this.disposables.add(this.displayLayer.onDidReset(() => {
      this.mergeIntersectingSelections()
      if (this.component) this.component.didResetDisplayLayer()
      this.emitter.emit('did-change', {})
    }))
    this.disposables.add(this.selectionsMarkerLayer.onDidCreateMarker(this.addSelection.bind(this)))
    return this.disposables.add(this.selectionsMarkerLayer.onDidUpdate(() => (this.component != null ? this.component.didUpdateSelections() : undefined)))
  }

  destroy () {
    if (!this.alive) return
    this.alive = false
    this.disposables.dispose()
    this.displayLayer.destroy()
    for (let selection of this.selections.slice()) {
      selection.destroy()
    }
    this.buffer.release()
    this.gutterContainer.destroy()
    this.emitter.emit('did-destroy')
    this.emitter.clear()
    if (this.component) this.component.element.component = null
    this.component = null
    this.lineNumberGutter.element = null
  }

  isAlive () { return this.alive }

  isDestroyed () { return !this.alive }

  /*
  Section: Event Subscription
  */

  // Essential: Calls your `callback` when the buffer's title has changed.
  //
  // * `callback` {Function}
  //
  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
  onDidChangeTitle (callback) {
    return this.emitter.on('did-change-title', callback)
  }

  // Essential: Calls your `callback` when the buffer's path, and therefore title, has changed.
  //
  // * `callback` {Function}
  //
  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
  onDidChangePath (callback) {
    return this.emitter.on('did-change-path', callback)
  }

  // Essential: Invoke the given callback synchronously when the content of the
  // buffer changes.
  //
  // Because observers are invoked synchronously, it's important not to perform
  // any expensive operations via this method. Consider {::onDidStopChanging} to
  // delay expensive operations until after changes stop occurring.
  //
  // * `callback` {Function}
  //
  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
  onDidChange (callback) {
    return this.emitter.on('did-change', callback)
  }

  // Essential: Invoke `callback` when the buffer's contents change. It is
  // emit asynchronously 300ms after the last buffer change. This is a good place
  // to handle changes to the buffer without compromising typing performance.
  //
  // * `callback` {Function}
  //
  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
  onDidStopChanging (callback) {
    return this.getBuffer().onDidStopChanging(callback)
  }

  // Essential: Calls your `callback` when a {Cursor} is moved. If there are
  // multiple cursors, your callback will be called for each cursor.
  //
  // * `callback` {Function}
  //   * `event` {Object}
  //     * `oldBufferPosition` {Point}
  //     * `oldScreenPosition` {Point}
  //     * `newBufferPosition` {Point}
  //     * `newScreenPosition` {Point}
  //     * `textChanged` {Boolean}
  //     * `cursor` {Cursor} that triggered the event
  //
  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
  onDidChangeCursorPosition (callback) {
    return this.emitter.on('did-change-cursor-position', callback)
  }

  // Essential: Calls your `callback` when a selection's screen range changes.
  //
  // * `callback` {Function}
  //   * `event` {Object}
  //     * `oldBufferRange` {Range}
  //     * `oldScreenRange` {Range}
  //     * `newBufferRange` {Range}
  //     * `newScreenRange` {Range}
  //     * `selection` {Selection} that triggered the event
  //
  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
  onDidChangeSelectionRange (callback) {
    return this.emitter.on('did-change-selection-range', callback)
  }

  // Extended: Calls your `callback` when soft wrap was enabled or disabled.
  //
  // * `callback` {Function}
  //
  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
  onDidChangeSoftWrapped (callback) {
    return this.emitter.on('did-change-soft-wrapped', callback)
  }

  // Extended: Calls your `callback` when the buffer's encoding has changed.
  //
  // * `callback` {Function}
  //
  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
  onDidChangeEncoding (callback) {
    return this.emitter.on('did-change-encoding', callback)
  }

  // Extended: Calls your `callback` when the grammar that interprets and
  // colorizes the text has been changed. Immediately calls your callback with
  // the current grammar.
  //
  // * `callback` {Function}
  //   * `grammar` {Grammar}
  //
  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
  observeGrammar (callback) {
    callback(this.getGrammar())
    return this.onDidChangeGrammar(callback)
  }

  // Extended: Calls your `callback` when the grammar that interprets and
  // colorizes the text has been changed.
  //
  // * `callback` {Function}
  //   * `grammar` {Grammar}
  //
  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
  onDidChangeGrammar (callback) {
    return this.buffer.onDidChangeLanguageMode(() => {
      callback(this.buffer.getLanguageMode().grammar)
    })
  }

  // Extended: Calls your `callback` when the result of {::isModified} changes.
  //
  // * `callback` {Function}
  //
  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
  onDidChangeModified (callback) {
    return this.getBuffer().onDidChangeModified(callback)
  }

  // Extended: Calls your `callback` when the buffer's underlying file changes on
  // disk at a moment when the result of {::isModified} is true.
  //
  // * `callback` {Function}
  //
  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
  onDidConflict (callback) {
    return this.getBuffer().onDidConflict(callback)
  }

  // Extended: Calls your `callback` before text has been inserted.
  //
  // * `callback` {Function}
  //   * `event` event {Object}
  //     * `text` {String} text to be inserted
  //     * `cancel` {Function} Call to prevent the text from being inserted
  //
  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
  onWillInsertText (callback) {
    return this.emitter.on('will-insert-text', callback)
  }

  // Extended: Calls your `callback` after text has been inserted.
  //
  // * `callback` {Function}
  //   * `event` event {Object}
  //     * `text` {String} text to be inserted
  //
  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
  onDidInsertText (callback) {
    return this.emitter.on('did-insert-text', callback)
  }

  // Essential: Invoke the given callback after the buffer is saved to disk.
  //
  // * `callback` {Function} to be called after the buffer is saved.
  //   * `event` {Object} with the following keys:
  //     * `path` The path to which the buffer was saved.
  //
  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
  onDidSave (callback) {
    return this.getBuffer().onDidSave(callback)
  }

  // Essential: Invoke the given callback when the editor is destroyed.
  //
  // * `callback` {Function} to be called when the editor is destroyed.
  //
  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
  onDidDestroy (callback) {
    return this.emitter.once('did-destroy', callback)
  }

  // Extended: Calls your `callback` when a {Cursor} is added to the editor.
  // Immediately calls your callback for each existing cursor.
  //
  // * `callback` {Function}
  //   * `cursor` {Cursor} that was added
  //
  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
  observeCursors (callback) {
    this.getCursors().forEach(callback)
    return this.onDidAddCursor(callback)
  }

  // Extended: Calls your `callback` when a {Cursor} is added to the editor.
  //
  // * `callback` {Function}
  //   * `cursor` {Cursor} that was added
  //
  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
  onDidAddCursor (callback) {
    return this.emitter.on('did-add-cursor', callback)
  }

  // Extended: Calls your `callback` when a {Cursor} is removed from the editor.
  //
  // * `callback` {Function}
  //   * `cursor` {Cursor} that was removed
  //
  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
  onDidRemoveCursor (callback) {
    return this.emitter.on('did-remove-cursor', callback)
  }

  // Extended: Calls your `callback` when a {Selection} is added to the editor.
  // Immediately calls your callback for each existing selection.
  //
  // * `callback` {Function}
  //   * `selection` {Selection} that was added
  //
  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
  observeSelections (callback) {
    this.getSelections().forEach(callback)
    return this.onDidAddSelection(callback)
  }

  // Extended: Calls your `callback` when a {Selection} is added to the editor.
  //
  // * `callback` {Function}
  //   * `selection` {Selection} that was added
  //
  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
  onDidAddSelection (callback) {
    return this.emitter.on('did-add-selection', callback)
  }

  // Extended: Calls your `callback` when a {Selection} is removed from the editor.
  //
  // * `callback` {Function}
  //   * `selection` {Selection} that was removed
  //
  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
  onDidRemoveSelection (callback) {
    return this.emitter.on('did-remove-selection', callback)
  }

  // Extended: Calls your `callback` with each {Decoration} added to the editor.
  // Calls your `callback` immediately for any existing decorations.
  //
  // * `callback` {Function}
  //   * `decoration` {Decoration}
  //
  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
  observeDecorations (callback) {
    return this.decorationManager.observeDecorations(callback)
  }

  // Extended: Calls your `callback` when a {Decoration} is added to the editor.
  //
  // * `callback` {Function}
  //   * `decoration` {Decoration} that was added
  //
  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
  onDidAddDecoration (callback) {
    return this.decorationManager.onDidAddDecoration(callback)
  }

  // Extended: Calls your `callback` when a {Decoration} is removed from the editor.
  //
  // * `callback` {Function}
  //   * `decoration` {Decoration} that was removed
  //
  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
  onDidRemoveDecoration (callback) {
    return this.decorationManager.onDidRemoveDecoration(callback)
  }

  // Called by DecorationManager when a decoration is added.
  didAddDecoration (decoration) {
    if (this.component && decoration.isType('block')) {
      this.component.addBlockDecoration(decoration)
    }
  }

  // Extended: Calls your `callback` when the placeholder text is changed.
  //
  // * `callback` {Function}
  //   * `placeholderText` {String} new text
  //
  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
  onDidChangePlaceholderText (callback) {
    return this.emitter.on('did-change-placeholder-text', callback)
  }

  onDidChangeScrollTop (callback) {
    Grim.deprecate('This is now a view method. Call TextEditorElement::onDidChangeScrollTop instead.')
    return this.getElement().onDidChangeScrollTop(callback)
  }

  onDidChangeScrollLeft (callback) {
    Grim.deprecate('This is now a view method. Call TextEditorElement::onDidChangeScrollLeft instead.')
    return this.getElement().onDidChangeScrollLeft(callback)
  }

  onDidRequestAutoscroll (callback) {
    return this.emitter.on('did-request-autoscroll', callback)
  }

  // TODO Remove once the tabs package no longer uses .on subscriptions
  onDidChangeIcon (callback) {
    return this.emitter.on('did-change-icon', callback)
  }

  onDidUpdateDecorations (callback) {
    return this.decorationManager.onDidUpdateDecorations(callback)
  }

  // Essential: Retrieves the current {TextBuffer}.
  getBuffer () { return this.buffer }

  // Retrieves the current buffer's URI.
  getURI () { return this.buffer.getUri() }

  // Create an {TextEditor} with its initial state based on this object
  copy () {
    const displayLayer = this.displayLayer.copy()
    const selectionsMarkerLayer = displayLayer.getMarkerLayer(this.buffer.getMarkerLayer(this.selectionsMarkerLayer.id).copy().id)
    const softTabs = this.getSoftTabs()
    return new TextEditor({
      buffer: this.buffer,
      selectionsMarkerLayer,
      softTabs,
      suppressCursorCreation: true,
      tabLength: this.getTabLength(),
      initialScrollTopRow: this.getScrollTopRow(),
      initialScrollLeftColumn: this.getScrollLeftColumn(),
      assert: this.assert,
      displayLayer,
      grammar: this.getGrammar(),
      autoWidth: this.autoWidth,
      autoHeight: this.autoHeight,
      showCursorOnSelection: this.showCursorOnSelection
    })
  }

  // Controls visibility based on the given {Boolean}.
  setVisible (visible) {
    if (visible) {
      const languageMode = this.buffer.getLanguageMode()
      if (languageMode.startTokenizing) languageMode.startTokenizing()
    }
  }

  setMini (mini) {
    this.update({mini})
  }

  isMini () { return this.mini }

  setReadOnly (readOnly) {
    this.update({readOnly})
  }

  isReadOnly () { return this.readOnly }

  enableKeyboardInput (enabled) {
    this.update({keyboardInputEnabled: enabled})
  }

  isKeyboardInputEnabled () { return this.keyboardInputEnabled }

  onDidChangeMini (callback) {
    return this.emitter.on('did-change-mini', callback)
  }

  setLineNumberGutterVisible (lineNumberGutterVisible) { this.update({lineNumberGutterVisible}) }

  isLineNumberGutterVisible () { return this.lineNumberGutter.isVisible() }

  onDidChangeLineNumberGutterVisible (callback) {
    return this.emitter.on('did-change-line-number-gutter-visible', callback)
  }

  // Essential: Calls your `callback` when a {Gutter} is added to the editor.
  // Immediately calls your callback for each existing gutter.
  //
  // * `callback` {Function}
  //   * `gutter` {Gutter} that currently exists/was added.
  //
  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
  observeGutters (callback) {
    return this.gutterContainer.observeGutters(callback)
  }

  // Essential: Calls your `callback` when a {Gutter} is added to the editor.
  //
  // * `callback` {Function}
  //   * `gutter` {Gutter} that was added.
  //
  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
  onDidAddGutter (callback) {
    return this.gutterContainer.onDidAddGutter(callback)
  }

  // Essential: Calls your `callback` when a {Gutter} is removed from the editor.
  //
  // * `callback` {Function}
  //   * `name` The name of the {Gutter} that was removed.
  //
  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
  onDidRemoveGutter (callback) {
    return this.gutterContainer.onDidRemoveGutter(callback)
  }

  // Set the number of characters that can be displayed horizontally in the
  // editor.
  //
  // * `editorWidthInChars` A {Number} representing the width of the
  // {TextEditorElement} in characters.
  setEditorWidthInChars (editorWidthInChars) { this.update({editorWidthInChars}) }

  // Returns the editor width in characters.
  getEditorWidthInChars () {
    if (this.width != null && this.defaultCharWidth > 0) {
      return Math.max(0, Math.floor(this.width / this.defaultCharWidth))
    } else {
      return this.editorWidthInChars
    }
  }

  /*
  Section: File Details
  */

  // Essential: Get the editor's title for display in other parts of the
  // UI such as the tabs.
  //
  // If the editor's buffer is saved, its title is the file name. If it is
  // unsaved, its title is "untitled".
  //
  // Returns a {String}.
  getTitle () {
    return this.getFileName() || 'untitled'
  }

  // Essential: Get unique title for display in other parts of the UI, such as
  // the window title.
  //
  // If the editor's buffer is unsaved, its title is "untitled"
  // If the editor's buffer is saved, its unique title is formatted as one
  // of the following,
  // * "<filename>" when it is the only editing buffer with this file name.
  // * "<filename> — <unique-dir-prefix>" when other buffers have this file name.
  //
  // Returns a {String}
  getLongTitle () {
    if (this.getPath()) {
      const fileName = this.getFileName()

      let myPathSegments
      const openEditorPathSegmentsWithSameFilename = []
      for (const textEditor of atom.workspace.getTextEditors()) {
        if (textEditor.getFileName() === fileName) {
          const pathSegments = fs.tildify(textEditor.getDirectoryPath()).split(path.sep)
          openEditorPathSegmentsWithSameFilename.push(pathSegments)
          if (textEditor === this) myPathSegments = pathSegments
        }
      }

      if (!myPathSegments || openEditorPathSegmentsWithSameFilename.length === 1) return fileName

      let commonPathSegmentCount
      for (let i = 0, {length} = myPathSegments; i < length; i++) {
        const myPathSegment = myPathSegments[i]
        if (openEditorPathSegmentsWithSameFilename.some(segments => (segments.length === i + 1) || (segments[i] !== myPathSegment))) {
          commonPathSegmentCount = i
          break
        }
      }

      return `${fileName} \u2014 ${path.join(...myPathSegments.slice(commonPathSegmentCount))}`
    } else {
      return 'untitled'
    }
  }

  // Essential: Returns the {String} path of this editor's text buffer.
  getPath () {
    return this.buffer.getPath()
  }

  getFileName () {
    const fullPath = this.getPath()
    if (fullPath) return path.basename(fullPath)
  }

  getDirectoryPath () {
    const fullPath = this.getPath()
    if (fullPath) return path.dirname(fullPath)
  }

  // Extended: Returns the {String} character set encoding of this editor's text
  // buffer.
  getEncoding () { return this.buffer.getEncoding() }

  // Extended: Set the character set encoding to use in this editor's text
  // buffer.
  //
  // * `encoding` The {String} character set encoding name such as 'utf8'
  setEncoding (encoding) { this.buffer.setEncoding(encoding) }

  // Essential: Returns {Boolean} `true` if this editor has been modified.
  isModified () { return this.buffer.isModified() }

  // Essential: Returns {Boolean} `true` if this editor has no content.
  isEmpty () { return this.buffer.isEmpty() }

  /*
  Section: File Operations
  */

  // Essential: Saves the editor's text buffer.
  //
  // See {TextBuffer::save} for more details.
  save () { return this.buffer.save() }

  // Essential: Saves the editor's text buffer as the given path.
  //
  // See {TextBuffer::saveAs} for more details.
  //
  // * `filePath` A {String} path.
  saveAs (filePath) { return this.buffer.saveAs(filePath) }

  // Determine whether the user should be prompted to save before closing
  // this editor.
  shouldPromptToSave ({windowCloseRequested, projectHasPaths} = {}) {
    if (windowCloseRequested && projectHasPaths && atom.stateStore.isConnected()) {
      return this.buffer.isInConflict()
    } else {
      return this.isModified() && !this.buffer.hasMultipleEditors()
    }
  }

  // Returns an {Object} to configure dialog shown when this editor is saved
  // via {Pane::saveItemAs}.
  getSaveDialogOptions () { return {} }

  /*
  Section: Reading Text
  */

  // Essential: Returns a {String} representing the entire contents of the editor.
  getText () { return this.buffer.getText() }

  // Essential: Get the text in the given {Range} in buffer coordinates.
  //
  // * `range` A {Range} or range-compatible {Array}.
  //
  // Returns a {String}.
  getTextInBufferRange (range) {
    return this.buffer.getTextInRange(range)
  }

  // Essential: Returns a {Number} representing the number of lines in the buffer.
  getLineCount () { return this.buffer.getLineCount() }

  // Essential: Returns a {Number} representing the number of screen lines in the
  // editor. This accounts for folds.
  getScreenLineCount () { return this.displayLayer.getScreenLineCount() }

  getApproximateScreenLineCount () { return this.displayLayer.getApproximateScreenLineCount() }

  // Essential: Returns a {Number} representing the last zero-indexed buffer row
  // number of the editor.
  getLastBufferRow () { return this.buffer.getLastRow() }

  // Essential: Returns a {Number} representing the last zero-indexed screen row
  // number of the editor.
  getLastScreenRow () { return this.getScreenLineCount() - 1 }

  // Essential: Returns a {String} representing the contents of the line at the
  // given buffer row.
  //
  // * `bufferRow` A {Number} representing a zero-indexed buffer row.
  lineTextForBufferRow (bufferRow) { return this.buffer.lineForRow(bufferRow) }

  // Essential: Returns a {String} representing the contents of the line at the
  // given screen row.
  //
  // * `screenRow` A {Number} representing a zero-indexed screen row.
  lineTextForScreenRow (screenRow) {
    const screenLine = this.screenLineForScreenRow(screenRow)
    if (screenLine) return screenLine.lineText
  }

  logScreenLines (start = 0, end = this.getLastScreenRow()) {
    for (let row = start; row <= end; row++) {
      const line = this.lineTextForScreenRow(row)
      console.log(row, this.bufferRowForScreenRow(row), line, line.length)
    }
  }

  tokensForScreenRow (screenRow) {
    const tokens = []
    let lineTextIndex = 0
    const currentTokenScopes = []
    const {lineText, tags} = this.screenLineForScreenRow(screenRow)
    for (const tag of tags) {
      if (this.displayLayer.isOpenTag(tag)) {
        currentTokenScopes.push(this.displayLayer.classNameForTag(tag))
      } else if (this.displayLayer.isCloseTag(tag)) {
        currentTokenScopes.pop()
      } else {
        tokens.push({
          text: lineText.substr(lineTextIndex, tag),
          scopes: currentTokenScopes.slice()
        })
        lineTextIndex += tag
      }
    }
    return tokens
  }

  screenLineForScreenRow (screenRow) {
    return this.displayLayer.getScreenLine(screenRow)
  }

  bufferRowForScreenRow (screenRow) {
    return this.displayLayer.translateScreenPosition(Point(screenRow, 0)).row
  }

  bufferRowsForScreenRows (startScreenRow, endScreenRow) {
    return this.displayLayer.bufferRowsForScreenRows(startScreenRow, endScreenRow + 1)
  }

  screenRowForBufferRow (row) {
    return this.displayLayer.translateBufferPosition(Point(row, 0)).row
  }

  getRightmostScreenPosition () { return this.displayLayer.getRightmostScreenPosition() }

  getApproximateRightmostScreenPosition () { return this.displayLayer.getApproximateRightmostScreenPosition() }

  getMaxScreenLineLength () { return this.getRightmostScreenPosition().column }

  getLongestScreenRow () { return this.getRightmostScreenPosition().row }

  getApproximateLongestScreenRow () { return this.getApproximateRightmostScreenPosition().row }

  lineLengthForScreenRow (screenRow) { return this.displayLayer.lineLengthForScreenRow(screenRow) }

  // Returns the range for the given buffer row.
  //
  // * `row` A row {Number}.
  // * `options` (optional) An options hash with an `includeNewline` key.
  //
  // Returns a {Range}.
  bufferRangeForBufferRow (row, options) {
    return this.buffer.rangeForRow(row, options && options.includeNewline)
  }

  // Get the text in the given {Range}.
  //
  // Returns a {String}.
  getTextInRange (range) { return this.buffer.getTextInRange(range) }

  // {Delegates to: TextBuffer.isRowBlank}
  isBufferRowBlank (bufferRow) { return this.buffer.isRowBlank(bufferRow) }

  // {Delegates to: TextBuffer.nextNonBlankRow}
  nextNonBlankBufferRow (bufferRow) { return this.buffer.nextNonBlankRow(bufferRow) }

  // {Delegates to: TextBuffer.getEndPosition}
  getEofBufferPosition () { return this.buffer.getEndPosition() }

  // Essential: Get the {Range} of the paragraph surrounding the most recently added
  // cursor.
  //
  // Returns a {Range}.
  getCurrentParagraphBufferRange () {
    return this.getLastCursor().getCurrentParagraphBufferRange()
  }

  /*
  Section: Mutating Text
  */

  // Essential: Replaces the entire contents of the buffer with the given {String}.
  //
  // * `text` A {String} to replace with
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor.
  setText (text, options = {}) {
    if (!this.ensureWritable('setText', options)) return
    return this.buffer.setText(text)
  }

  // Essential: Set the text in the given {Range} in buffer coordinates.
  //
  // * `range` A {Range} or range-compatible {Array}.
  // * `text` A {String}
  // * `options` (optional) {Object}
  //   * `normalizeLineEndings` (optional) {Boolean} (default: true)
  //   * `undo` (optional) *Deprecated* {String} 'skip' will skip the undo system. This property is deprecated. Call groupLastChanges() on the {TextBuffer} afterward instead.
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor. (default: false)
  //
  // Returns the {Range} of the newly-inserted text.
  setTextInBufferRange (range, text, options = {}) {
    if (!this.ensureWritable('setTextInBufferRange', options)) return
    return this.getBuffer().setTextInRange(range, text, options)
  }

  // Essential: For each selection, replace the selected text with the given text.
  //
  // * `text` A {String} representing the text to insert.
  // * `options` (optional) See {Selection::insertText}.
  //
  // Returns a {Range} when the text has been inserted. Returns a {Boolean} `false` when the text has not been inserted.
  insertText (text, options = {}) {
    if (!this.ensureWritable('insertText', options)) return
    if (!this.emitWillInsertTextEvent(text)) return false

    let groupLastChanges = false
    if (options.undo === 'skip') {
      options = Object.assign({}, options)
      delete options.undo
      groupLastChanges = true
    }

    const groupingInterval = options.groupUndo ? this.undoGroupingInterval : 0
    if (options.autoIndentNewline == null) options.autoIndentNewline = this.shouldAutoIndent()
    if (options.autoDecreaseIndent == null) options.autoDecreaseIndent = this.shouldAutoIndent()
    const result = this.mutateSelectedText(selection => {
      const range = selection.insertText(text, options)
      const didInsertEvent = {text, range}
      this.emitter.emit('did-insert-text', didInsertEvent)
      return range
    }, groupingInterval)
    if (groupLastChanges) this.buffer.groupLastChanges()
    return result
  }

  // Essential: For each selection, replace the selected text with a newline.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor. (default: false)
  insertNewline (options = {}) {
    return this.insertText('\n', options)
  }

  // Essential: For each selection, if the selection is empty, delete the character
  // following the cursor. Otherwise delete the selected text.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor. (default: false)
  delete (options = {}) {
    if (!this.ensureWritable('delete', options)) return
    return this.mutateSelectedText(selection => selection.delete(options))
  }

  // Essential: For each selection, if the selection is empty, delete the character
  // preceding the cursor. Otherwise delete the selected text.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor. (default: false)
  backspace (options = {}) {
    if (!this.ensureWritable('backspace', options)) return
    return this.mutateSelectedText(selection => selection.backspace(options))
  }

  // Extended: Mutate the text of all the selections in a single transaction.
  //
  // All the changes made inside the given {Function} can be reverted with a
  // single call to {::undo}.
  //
  // * `fn` A {Function} that will be called once for each {Selection}. The first
  //      argument will be a {Selection} and the second argument will be the
  //      {Number} index of that selection.
  mutateSelectedText (fn, groupingInterval = 0) {
    return this.mergeIntersectingSelections(() => {
      return this.transact(groupingInterval, () => {
        return this.getSelectionsOrderedByBufferPosition().map((selection, index) => fn(selection, index))
      })
    })
  }

  // Move lines intersecting the most recent selection or multiple selections
  // up by one row in screen coordinates.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor. (default: false)
  moveLineUp (options = {}) {
    if (!this.ensureWritable('moveLineUp', options)) return

    const selections = this.getSelectedBufferRanges().sort((a, b) => a.compare(b))

    if (selections[0].start.row === 0) return
    if (selections[selections.length - 1].start.row === this.getLastBufferRow() && this.buffer.getLastLine() === '') return

    this.transact(() => {
      const newSelectionRanges = []

      while (selections.length > 0) {
        // Find selections spanning a contiguous set of lines
        const selection = selections.shift()
        const selectionsToMove = [selection]

        while (selection.end.row === (selections[0] != null ? selections[0].start.row : undefined)) {
          selectionsToMove.push(selections[0])
          selection.end.row = selections[0].end.row
          selections.shift()
        }

        // Compute the buffer range spanned by all these selections, expanding it
        // so that it includes any folded region that intersects them.
        let startRow = selection.start.row
        let endRow = selection.end.row
        if (selection.end.row > selection.start.row && selection.end.column === 0) {
          // Don't move the last line of a multi-line selection if the selection ends at column 0
          endRow--
        }

        startRow = this.displayLayer.findBoundaryPrecedingBufferRow(startRow)
        endRow = this.displayLayer.findBoundaryFollowingBufferRow(endRow + 1)
        const linesRange = new Range(Point(startRow, 0), Point(endRow, 0))

        // If selected line range is preceded by a fold, one line above on screen
        // could be multiple lines in the buffer.
        const precedingRow = this.displayLayer.findBoundaryPrecedingBufferRow(startRow - 1)
        const insertDelta = linesRange.start.row - precedingRow

        // Any folds in the text that is moved will need to be re-created.
        // It includes the folds that were intersecting with the selection.
        const rangesToRefold = this.displayLayer
          .destroyFoldsIntersectingBufferRange(linesRange)
          .map(range => range.translate([-insertDelta, 0]))

        // Delete lines spanned by selection and insert them on the preceding buffer row
        let lines = this.buffer.getTextInRange(linesRange)
        if (lines[lines.length - 1] !== '\n') { lines += this.buffer.lineEndingForRow(linesRange.end.row - 2) }
        this.buffer.delete(linesRange)
        this.buffer.insert([precedingRow, 0], lines)

        // Restore folds that existed before the lines were moved
        for (let rangeToRefold of rangesToRefold) {
          this.displayLayer.foldBufferRange(rangeToRefold)
        }

        for (const selectionToMove of selectionsToMove) {
          newSelectionRanges.push(selectionToMove.translate([-insertDelta, 0]))
        }
      }

      this.setSelectedBufferRanges(newSelectionRanges, {autoscroll: false, preserveFolds: true})
      if (this.shouldAutoIndent()) this.autoIndentSelectedRows()
      this.scrollToBufferPosition([newSelectionRanges[0].start.row, 0])
    })
  }

  // Move lines intersecting the most recent selection or multiple selections
  // down by one row in screen coordinates.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor. (default: false)
  moveLineDown (options = {}) {
    if (!this.ensureWritable('moveLineDown', options)) return

    const selections = this.getSelectedBufferRanges()
    selections.sort((a, b) => b.compare(a))

    this.transact(() => {
      this.consolidateSelections()
      const newSelectionRanges = []

      while (selections.length > 0) {
        // Find selections spanning a contiguous set of lines
        const selection = selections.shift()
        const selectionsToMove = [selection]

        // if the current selection start row matches the next selections' end row - make them one selection
        while (selection.start.row === (selections[0] != null ? selections[0].end.row : undefined)) {
          selectionsToMove.push(selections[0])
          selection.start.row = selections[0].start.row
          selections.shift()
        }

        // Compute the buffer range spanned by all these selections, expanding it
        // so that it includes any folded region that intersects them.
        let startRow = selection.start.row
        let endRow = selection.end.row
        if (selection.end.row > selection.start.row && selection.end.column === 0) {
          // Don't move the last line of a multi-line selection if the selection ends at column 0
          endRow--
        }

        startRow = this.displayLayer.findBoundaryPrecedingBufferRow(startRow)
        endRow = this.displayLayer.findBoundaryFollowingBufferRow(endRow + 1)
        const linesRange = new Range(Point(startRow, 0), Point(endRow, 0))

        // If selected line range is followed by a fold, one line below on screen
        // could be multiple lines in the buffer. But at the same time, if the
        // next buffer row is wrapped, one line in the buffer can represent many
        // screen rows.
        const followingRow = Math.min(this.buffer.getLineCount(), this.displayLayer.findBoundaryFollowingBufferRow(endRow + 1))
        const insertDelta = followingRow - linesRange.end.row

        // Any folds in the text that is moved will need to be re-created.
        // It includes the folds that were intersecting with the selection.
        const rangesToRefold = this.displayLayer
          .destroyFoldsIntersectingBufferRange(linesRange)
          .map(range => range.translate([insertDelta, 0]))

        // Delete lines spanned by selection and insert them on the following correct buffer row
        let lines = this.buffer.getTextInRange(linesRange)
        if (followingRow - 1 === this.buffer.getLastRow()) {
          lines = `\n${lines}`
        }

        this.buffer.insert([followingRow, 0], lines)
        this.buffer.delete(linesRange)

        // Restore folds that existed before the lines were moved
        for (let rangeToRefold of rangesToRefold) {
          this.displayLayer.foldBufferRange(rangeToRefold)
        }

        for (const selectionToMove of selectionsToMove) {
          newSelectionRanges.push(selectionToMove.translate([insertDelta, 0]))
        }
      }

      this.setSelectedBufferRanges(newSelectionRanges, {autoscroll: false, preserveFolds: true})
      if (this.shouldAutoIndent()) this.autoIndentSelectedRows()
      this.scrollToBufferPosition([newSelectionRanges[0].start.row - 1, 0])
    })
  }

  // Move any active selections one column to the left.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor. (default: false)
  moveSelectionLeft (options = {}) {
    if (!this.ensureWritable('moveSelectionLeft', options)) return
    const selections = this.getSelectedBufferRanges()
    const noSelectionAtStartOfLine = selections.every(selection => selection.start.column !== 0)

    const translationDelta = [0, -1]
    const translatedRanges = []

    if (noSelectionAtStartOfLine) {
      this.transact(() => {
        for (let selection of selections) {
          const charToLeftOfSelection = new Range(selection.start.translate(translationDelta), selection.start)
          const charTextToLeftOfSelection = this.buffer.getTextInRange(charToLeftOfSelection)

          this.buffer.insert(selection.end, charTextToLeftOfSelection)
          this.buffer.delete(charToLeftOfSelection)
          translatedRanges.push(selection.translate(translationDelta))
        }

        this.setSelectedBufferRanges(translatedRanges)
      })
    }
  }

  // Move any active selections one column to the right.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor. (default: false)
  moveSelectionRight (options = {}) {
    if (!this.ensureWritable('moveSelectionRight', options)) return
    const selections = this.getSelectedBufferRanges()
    const noSelectionAtEndOfLine = selections.every(selection => {
      return selection.end.column !== this.buffer.lineLengthForRow(selection.end.row)
    })

    const translationDelta = [0, 1]
    const translatedRanges = []

    if (noSelectionAtEndOfLine) {
      this.transact(() => {
        for (let selection of selections) {
          const charToRightOfSelection = new Range(selection.end, selection.end.translate(translationDelta))
          const charTextToRightOfSelection = this.buffer.getTextInRange(charToRightOfSelection)

          this.buffer.delete(charToRightOfSelection)
          this.buffer.insert(selection.start, charTextToRightOfSelection)
          translatedRanges.push(selection.translate(translationDelta))
        }

        this.setSelectedBufferRanges(translatedRanges)
      })
    }
  }

  // Duplicate all lines containing active selections.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor. (default: false)
  duplicateLines (options = {}) {
    if (!this.ensureWritable('duplicateLines', options)) return
    this.transact(() => {
      const selections = this.getSelectionsOrderedByBufferPosition()
      const previousSelectionRanges = []

      let i = selections.length - 1
      while (i >= 0) {
        const j = i
        previousSelectionRanges[i] = selections[i].getBufferRange()
        if (selections[i].isEmpty()) {
          const {start} = selections[i].getScreenRange()
          selections[i].setScreenRange([[start.row, 0], [start.row + 1, 0]], {preserveFolds: true})
        }
        let [startRow, endRow] = selections[i].getBufferRowRange()
        endRow++
        while (i > 0) {
          const [previousSelectionStartRow, previousSelectionEndRow] = selections[i - 1].getBufferRowRange()
          if (previousSelectionEndRow === startRow) {
            startRow = previousSelectionStartRow
            previousSelectionRanges[i - 1] = selections[i - 1].getBufferRange()
            i--
          } else {
            break
          }
        }

        const intersectingFolds = this.displayLayer.foldsIntersectingBufferRange([[startRow, 0], [endRow, 0]])
        let textToDuplicate = this.getTextInBufferRange([[startRow, 0], [endRow, 0]])
        if (endRow > this.getLastBufferRow()) textToDuplicate = `\n${textToDuplicate}`
        this.buffer.insert([endRow, 0], textToDuplicate)

        const insertedRowCount = endRow - startRow

        for (let k = i; k <= j; k++) {
          selections[k].setBufferRange(previousSelectionRanges[k].translate([insertedRowCount, 0]))
        }

        for (const fold of intersectingFolds) {
          const foldRange = this.displayLayer.bufferRangeForFold(fold)
          this.displayLayer.foldBufferRange(foldRange.translate([insertedRowCount, 0]))
        }

        i--
      }
    })
  }

  replaceSelectedText (options, fn) {
    this.mutateSelectedText((selection) => {
      selection.getBufferRange()
      if (options && options.selectWordIfEmpty && selection.isEmpty()) {
        selection.selectWord()
      }
      const text = selection.getText()
      selection.deleteSelectedText()
      const range = selection.insertText(fn(text))
      selection.setBufferRange(range)
    })
  }

  // Split multi-line selections into one selection per line.
  //
  // Operates on all selections. This method breaks apart all multi-line
  // selections to create multiple single-line selections that cumulatively cover
  // the same original area.
  splitSelectionsIntoLines () {
    this.mergeIntersectingSelections(() => {
      for (const selection of this.getSelections()) {
        const range = selection.getBufferRange()
        if (range.isSingleLine()) continue

        const {start, end} = range
        this.addSelectionForBufferRange([start, [start.row, Infinity]])
        let {row} = start
        while (++row < end.row) {
          this.addSelectionForBufferRange([[row, 0], [row, Infinity]])
        }
        if (end.column !== 0) this.addSelectionForBufferRange([[end.row, 0], [end.row, end.column]])
        selection.destroy()
      }
    })
  }

  // Extended: For each selection, transpose the selected text.
  //
  // If the selection is empty, the characters preceding and following the cursor
  // are swapped. Otherwise, the selected characters are reversed.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor. (default: false)
  transpose (options = {}) {
    if (!this.ensureWritable('transpose', options)) return
    this.mutateSelectedText(selection => {
      if (selection.isEmpty()) {
        selection.selectRight()
        const text = selection.getText()
        selection.delete()
        selection.cursor.moveLeft()
        selection.insertText(text)
      } else {
        selection.insertText(selection.getText().split('').reverse().join(''))
      }
    })
  }

  // Extended: Convert the selected text to upper case.
  //
  // For each selection, if the selection is empty, converts the containing word
  // to upper case. Otherwise convert the selected text to upper case.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor. (default: false)
  upperCase (options = {}) {
    if (!this.ensureWritable('upperCase', options)) return
    this.replaceSelectedText({selectWordIfEmpty: true}, text => text.toUpperCase(options))
  }

  // Extended: Convert the selected text to lower case.
  //
  // For each selection, if the selection is empty, converts the containing word
  // to upper case. Otherwise convert the selected text to upper case.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor. (default: false)
  lowerCase (options = {}) {
    if (!this.ensureWritable('lowerCase', options)) return
    this.replaceSelectedText({selectWordIfEmpty: true}, text => text.toLowerCase(options))
  }

  // Extended: Toggle line comments for rows intersecting selections.
  //
  // If the current grammar doesn't support comments, does nothing.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor. (default: false)
  toggleLineCommentsInSelection (options = {}) {
    if (!this.ensureWritable('toggleLineCommentsInSelection', options)) return
    this.mutateSelectedText(selection => selection.toggleLineComments(options))
  }

  // Convert multiple lines to a single line.
  //
  // Operates on all selections. If the selection is empty, joins the current
  // line with the next line. Otherwise it joins all lines that intersect the
  // selection.
  //
  // Joining a line means that multiple lines are converted to a single line with
  // the contents of each of the original non-empty lines separated by a space.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor. (default: false)
  joinLines (options = {}) {
    if (!this.ensureWritable('joinLines', options)) return
    this.mutateSelectedText(selection => selection.joinLines())
  }

  // Extended: For each cursor, insert a newline at beginning the following line.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor. (default: false)
  insertNewlineBelow (options = {}) {
    if (!this.ensureWritable('insertNewlineBelow', options)) return
    this.transact(() => {
      this.moveToEndOfLine()
      this.insertNewline(options)
    })
  }

  // Extended: For each cursor, insert a newline at the end of the preceding line.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor. (default: false)
  insertNewlineAbove (options = {}) {
    if (!this.ensureWritable('insertNewlineAbove', options)) return
    this.transact(() => {
      const bufferRow = this.getCursorBufferPosition().row
      const indentLevel = this.indentationForBufferRow(bufferRow)
      const onFirstLine = bufferRow === 0

      this.moveToBeginningOfLine()
      this.moveLeft()
      this.insertNewline(options)

      if (this.shouldAutoIndent() && (this.indentationForBufferRow(bufferRow) < indentLevel)) {
        this.setIndentationForBufferRow(bufferRow, indentLevel)
      }

      if (onFirstLine) {
        this.moveUp()
        this.moveToEndOfLine()
      }
    })
  }

  // Extended: For each selection, if the selection is empty, delete all characters
  // of the containing word that precede the cursor. Otherwise delete the
  // selected text.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor. (default: false)
  deleteToBeginningOfWord (options = {}) {
    if (!this.ensureWritable('deleteToBeginningOfWord', options)) return
    this.mutateSelectedText(selection => selection.deleteToBeginningOfWord(options))
  }

  // Extended: Similar to {::deleteToBeginningOfWord}, but deletes only back to the
  // previous word boundary.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor. (default: false)
  deleteToPreviousWordBoundary (options = {}) {
    if (!this.ensureWritable('deleteToPreviousWordBoundary', options)) return
    this.mutateSelectedText(selection => selection.deleteToPreviousWordBoundary(options))
  }

  // Extended: Similar to {::deleteToEndOfWord}, but deletes only up to the
  // next word boundary.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor. (default: false)
  deleteToNextWordBoundary (options = {}) {
    if (!this.ensureWritable('deleteToNextWordBoundary', options)) return
    this.mutateSelectedText(selection => selection.deleteToNextWordBoundary(options))
  }

  // Extended: For each selection, if the selection is empty, delete all characters
  // of the containing subword following the cursor. Otherwise delete the selected
  // text.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor. (default: false)
  deleteToBeginningOfSubword (options = {}) {
    if (!this.ensureWritable('deleteToBeginningOfSubword', options)) return
    this.mutateSelectedText(selection => selection.deleteToBeginningOfSubword(options))
  }

  // Extended: For each selection, if the selection is empty, delete all characters
  // of the containing subword following the cursor. Otherwise delete the selected
  // text.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor. (default: false)
  deleteToEndOfSubword (options = {}) {
    if (!this.ensureWritable('deleteToEndOfSubword', options)) return
    this.mutateSelectedText(selection => selection.deleteToEndOfSubword(options))
  }

  // Extended: For each selection, if the selection is empty, delete all characters
  // of the containing line that precede the cursor. Otherwise delete the
  // selected text.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor. (default: false)
  deleteToBeginningOfLine (options = {}) {
    if (!this.ensureWritable('deleteToBeginningOfLine', options)) return
    this.mutateSelectedText(selection => selection.deleteToBeginningOfLine(options))
  }

  // Extended: For each selection, if the selection is not empty, deletes the
  // selection; otherwise, deletes all characters of the containing line
  // following the cursor. If the cursor is already at the end of the line,
  // deletes the following newline.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor. (default: false)
  deleteToEndOfLine (options = {}) {
    if (!this.ensureWritable('deleteToEndOfLine', options)) return
    this.mutateSelectedText(selection => selection.deleteToEndOfLine(options))
  }

  // Extended: For each selection, if the selection is empty, delete all characters
  // of the containing word following the cursor. Otherwise delete the selected
  // text.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor. (default: false)
  deleteToEndOfWord (options = {}) {
    if (!this.ensureWritable('deleteToEndOfWord', options)) return
    this.mutateSelectedText(selection => selection.deleteToEndOfWord(options))
  }

  // Extended: Delete all lines intersecting selections.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor. (default: false)
  deleteLine (options = {}) {
    if (!this.ensureWritable('deleteLine', options)) return
    this.mergeSelectionsOnSameRows()
    this.mutateSelectedText(selection => selection.deleteLine(options))
  }

  // Private: Ensure that this editor is not marked read-only before allowing a buffer modification to occur. If
  // the editor is read-only, require an explicit opt-in option to proceed (`bypassReadOnly`) or throw an Error.
  ensureWritable (methodName, opts) {
    if (!opts.bypassReadOnly && this.isReadOnly()) {
      if (atom.inDevMode() || atom.inSpecMode()) {
        const e = new Error('Attempt to mutate a read-only TextEditor')
        e.detail =
          `Your package is attempting to call ${methodName} on an editor that has been marked read-only. ` +
          'Pass {bypassReadOnly: true} to modify it anyway, or test editors with .isReadOnly() before attempting ' +
          'modifications.'
        throw e
      }

      return false
    }

    return true
  }

  /*
  Section: History
  */

  // Essential: Undo the last change.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor. (default: false)
  undo (options = {}) {
    if (!this.ensureWritable('undo', options)) return
    this.avoidMergingSelections(() => this.buffer.undo({selectionsMarkerLayer: this.selectionsMarkerLayer}))
    this.getLastSelection().autoscroll()
  }

  // Essential: Redo the last change.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor. (default: false)
  redo (options = {}) {
    if (!this.ensureWritable('redo', options)) return
    this.avoidMergingSelections(() => this.buffer.redo({selectionsMarkerLayer: this.selectionsMarkerLayer}))
    this.getLastSelection().autoscroll()
  }

  // Extended: Batch multiple operations as a single undo/redo step.
  //
  // Any group of operations that are logically grouped from the perspective of
  // undoing and redoing should be performed in a transaction. If you want to
  // abort the transaction, call {::abortTransaction} to terminate the function's
  // execution and revert any changes performed up to the abortion.
  //
  // * `groupingInterval` (optional) The {Number} of milliseconds for which this
  //   transaction should be considered 'groupable' after it begins. If a transaction
  //   with a positive `groupingInterval` is committed while the previous transaction is
  //   still 'groupable', the two transactions are merged with respect to undo and redo.
  // * `fn` A {Function} to call inside the transaction.
  transact (groupingInterval, fn) {
    const options = {selectionsMarkerLayer: this.selectionsMarkerLayer}
    if (typeof groupingInterval === 'function') {
      fn = groupingInterval
    } else {
      options.groupingInterval = groupingInterval
    }
    return this.buffer.transact(options, fn)
  }

  // Extended: Abort an open transaction, undoing any operations performed so far
  // within the transaction.
  abortTransaction () { return this.buffer.abortTransaction() }

  // Extended: Create a pointer to the current state of the buffer for use
  // with {::revertToCheckpoint} and {::groupChangesSinceCheckpoint}.
  //
  // Returns a checkpoint value.
  createCheckpoint () {
    return this.buffer.createCheckpoint({selectionsMarkerLayer: this.selectionsMarkerLayer})
  }

  // Extended: Revert the buffer to the state it was in when the given
  // checkpoint was created.
  //
  // The redo stack will be empty following this operation, so changes since the
  // checkpoint will be lost. If the given checkpoint is no longer present in the
  // undo history, no changes will be made to the buffer and this method will
  // return `false`.
  //
  // * `checkpoint` The checkpoint to revert to.
  //
  // Returns a {Boolean} indicating whether the operation succeeded.
  revertToCheckpoint (checkpoint) { return this.buffer.revertToCheckpoint(checkpoint) }

  // Extended: Group all changes since the given checkpoint into a single
  // transaction for purposes of undo/redo.
  //
  // If the given checkpoint is no longer present in the undo history, no
  // grouping will be performed and this method will return `false`.
  //
  // * `checkpoint` The checkpoint from which to group changes.
  //
  // Returns a {Boolean} indicating whether the operation succeeded.
  groupChangesSinceCheckpoint (checkpoint) {
    return this.buffer.groupChangesSinceCheckpoint(checkpoint, {selectionsMarkerLayer: this.selectionsMarkerLayer})
  }

  /*
  Section: TextEditor Coordinates
  */

  // Essential: Convert a position in buffer-coordinates to screen-coordinates.
  //
  // The position is clipped via {::clipBufferPosition} prior to the conversion.
  // The position is also clipped via {::clipScreenPosition} following the
  // conversion, which only makes a difference when `options` are supplied.
  //
  // * `bufferPosition` A {Point} or {Array} of [row, column].
  // * `options` (optional) An options hash for {::clipScreenPosition}.
  //
  // Returns a {Point}.
  screenPositionForBufferPosition (bufferPosition, options) {
    if (options && options.clip) {
      Grim.deprecate('The `clip` parameter has been deprecated and will be removed soon. Please, use `clipDirection` instead.')
      if (options.clipDirection) options.clipDirection = options.clip
    }
    if (options && options.wrapAtSoftNewlines != null) {
      Grim.deprecate("The `wrapAtSoftNewlines` parameter has been deprecated and will be removed soon. Please, use `clipDirection: 'forward'` instead.")
      if (options.clipDirection) options.clipDirection = options.wrapAtSoftNewlines ? 'forward' : 'backward'
    }
    if (options && options.wrapBeyondNewlines != null) {
      Grim.deprecate("The `wrapBeyondNewlines` parameter has been deprecated and will be removed soon. Please, use `clipDirection: 'forward'` instead.")
      if (options.clipDirection) options.clipDirection = options.wrapBeyondNewlines ? 'forward' : 'backward'
    }

    return this.displayLayer.translateBufferPosition(bufferPosition, options)
  }

  // Essential: Convert a position in screen-coordinates to buffer-coordinates.
  //
  // The position is clipped via {::clipScreenPosition} prior to the conversion.
  //
  // * `bufferPosition` A {Point} or {Array} of [row, column].
  // * `options` (optional) An options hash for {::clipScreenPosition}.
  //
  // Returns a {Point}.
  bufferPositionForScreenPosition (screenPosition, options) {
    if (options && options.clip) {
      Grim.deprecate('The `clip` parameter has been deprecated and will be removed soon. Please, use `clipDirection` instead.')
      if (options.clipDirection) options.clipDirection = options.clip
    }
    if (options && options.wrapAtSoftNewlines != null) {
      Grim.deprecate("The `wrapAtSoftNewlines` parameter has been deprecated and will be removed soon. Please, use `clipDirection: 'forward'` instead.")
      if (options.clipDirection) options.clipDirection = options.wrapAtSoftNewlines ? 'forward' : 'backward'
    }
    if (options && options.wrapBeyondNewlines != null) {
      Grim.deprecate("The `wrapBeyondNewlines` parameter has been deprecated and will be removed soon. Please, use `clipDirection: 'forward'` instead.")
      if (options.clipDirection) options.clipDirection = options.wrapBeyondNewlines ? 'forward' : 'backward'
    }

    return this.displayLayer.translateScreenPosition(screenPosition, options)
  }

  // Essential: Convert a range in buffer-coordinates to screen-coordinates.
  //
  // * `bufferRange` {Range} in buffer coordinates to translate into screen coordinates.
  //
  // Returns a {Range}.
  screenRangeForBufferRange (bufferRange, options) {
    bufferRange = Range.fromObject(bufferRange)
    const start = this.screenPositionForBufferPosition(bufferRange.start, options)
    const end = this.screenPositionForBufferPosition(bufferRange.end, options)
    return new Range(start, end)
  }

  // Essential: Convert a range in screen-coordinates to buffer-coordinates.
  //
  // * `screenRange` {Range} in screen coordinates to translate into buffer coordinates.
  //
  // Returns a {Range}.
  bufferRangeForScreenRange (screenRange) {
    screenRange = Range.fromObject(screenRange)
    const start = this.bufferPositionForScreenPosition(screenRange.start)
    const end = this.bufferPositionForScreenPosition(screenRange.end)
    return new Range(start, end)
  }

  // Extended: Clip the given {Point} to a valid position in the buffer.
  //
  // If the given {Point} describes a position that is actually reachable by the
  // cursor based on the current contents of the buffer, it is returned
  // unchanged. If the {Point} does not describe a valid position, the closest
  // valid position is returned instead.
  //
  // ## Examples
  //
  // ```js
  // editor.clipBufferPosition([-1, -1]) // -> `[0, 0]`
  //
  // // When the line at buffer row 2 is 10 characters long
  // editor.clipBufferPosition([2, Infinity]) // -> `[2, 10]`
  // ```
  //
  // * `bufferPosition` The {Point} representing the position to clip.
  //
  // Returns a {Point}.
  clipBufferPosition (bufferPosition) { return this.buffer.clipPosition(bufferPosition) }

  // Extended: Clip the start and end of the given range to valid positions in the
  // buffer. See {::clipBufferPosition} for more information.
  //
  // * `range` The {Range} to clip.
  //
  // Returns a {Range}.
  clipBufferRange (range) { return this.buffer.clipRange(range) }

  // Extended: Clip the given {Point} to a valid position on screen.
  //
  // If the given {Point} describes a position that is actually reachable by the
  // cursor based on the current contents of the screen, it is returned
  // unchanged. If the {Point} does not describe a valid position, the closest
  // valid position is returned instead.
  //
  // ## Examples
  //
  // ```js
  // editor.clipScreenPosition([-1, -1]) // -> `[0, 0]`
  //
  // // When the line at screen row 2 is 10 characters long
  // editor.clipScreenPosition([2, Infinity]) // -> `[2, 10]`
  // ```
  //
  // * `screenPosition` The {Point} representing the position to clip.
  // * `options` (optional) {Object}
  //   * `clipDirection` {String} If `'backward'`, returns the first valid
  //     position preceding an invalid position. If `'forward'`, returns the
  //     first valid position following an invalid position. If `'closest'`,
  //     returns the first valid position closest to an invalid position.
  //     Defaults to `'closest'`.
  //
  // Returns a {Point}.
  clipScreenPosition (screenPosition, options) {
    if (options && options.clip) {
      Grim.deprecate('The `clip` parameter has been deprecated and will be removed soon. Please, use `clipDirection` instead.')
      if (options.clipDirection) options.clipDirection = options.clip
    }
    if (options && options.wrapAtSoftNewlines != null) {
      Grim.deprecate("The `wrapAtSoftNewlines` parameter has been deprecated and will be removed soon. Please, use `clipDirection: 'forward'` instead.")
      if (options.clipDirection) options.clipDirection = options.wrapAtSoftNewlines ? 'forward' : 'backward'
    }
    if (options && options.wrapBeyondNewlines != null) {
      Grim.deprecate("The `wrapBeyondNewlines` parameter has been deprecated and will be removed soon. Please, use `clipDirection: 'forward'` instead.")
      if (options.clipDirection) options.clipDirection = options.wrapBeyondNewlines ? 'forward' : 'backward'
    }

    return this.displayLayer.clipScreenPosition(screenPosition, options)
  }

  // Extended: Clip the start and end of the given range to valid positions on screen.
  // See {::clipScreenPosition} for more information.
  //
  // * `range` The {Range} to clip.
  // * `options` (optional) See {::clipScreenPosition} `options`.
  //
  // Returns a {Range}.
  clipScreenRange (screenRange, options) {
    screenRange = Range.fromObject(screenRange)
    const start = this.displayLayer.clipScreenPosition(screenRange.start, options)
    const end = this.displayLayer.clipScreenPosition(screenRange.end, options)
    return Range(start, end)
  }

  /*
  Section: Decorations
  */

  // Essential: Add a decoration that tracks a {DisplayMarker}. When the
  // marker moves, is invalidated, or is destroyed, the decoration will be
  // updated to reflect the marker's state.
  //
  // The following are the supported decorations types:
  //
  // * __line__: Adds your CSS `class` to the line nodes within the range
  //     marked by the marker
  // * __line-number__: Adds your CSS `class` to the line number nodes within the
  //     range marked by the marker
  // * __highlight__: Adds a new highlight div to the editor surrounding the
  //     range marked by the marker. When the user selects text, the selection is
  //     visualized with a highlight decoration internally. The structure of this
  //     highlight will be
  //     ```html
  //     <div class="highlight <your-class>">
  //       <!-- Will be one region for each row in the range. Spans 2 lines? There will be 2 regions. -->
  //       <div class="region"></div>
  //     </div>
  //     ```
  // * __overlay__: Positions the view associated with the given item at the head
  //     or tail of the given `DisplayMarker`.
  // * __gutter__: A decoration that tracks a {DisplayMarker} in a {Gutter}. Gutter
  //     decorations are created by calling {Gutter::decorateMarker} on the
  //     desired `Gutter` instance.
  // * __block__: Positions the view associated with the given item before or
  //     after the row of the given `TextEditorMarker`.
  //
  // ## Arguments
  //
  // * `marker` A {DisplayMarker} you want this decoration to follow.
  // * `decorationParams` An {Object} representing the decoration e.g.
  //   `{type: 'line-number', class: 'linter-error'}`
  //   * `type` There are several supported decoration types. The behavior of the
  //     types are as follows:
  //     * `line` Adds the given `class` to the lines overlapping the rows
  //        spanned by the `DisplayMarker`.
  //     * `line-number` Adds the given `class` to the line numbers overlapping
  //       the rows spanned by the `DisplayMarker`.
  //     * `text` Injects spans into all text overlapping the marked range,
  //       then adds the given `class` or `style` properties to these spans.
  //       Use this to manipulate the foreground color or styling of text in
  //       a given range.
  //     * `highlight` Creates an absolutely-positioned `.highlight` div
  //       containing nested divs to cover the marked region. For example, this
  //       is used to implement selections.
  //     * `overlay` Positions the view associated with the given item at the
  //       head or tail of the given `DisplayMarker`, depending on the `position`
  //       property.
  //     * `gutter` Tracks a {DisplayMarker} in a {Gutter}. Created by calling
  //       {Gutter::decorateMarker} on the desired `Gutter` instance.
  //     * `block` Positions the view associated with the given item before or
  //       after the row of the given `TextEditorMarker`, depending on the `position`
  //       property.
  //     * `cursor` Renders a cursor at the head of the given marker. If multiple
  //       decorations are created for the same marker, their class strings and
  //       style objects are combined into a single cursor. You can use this
  //       decoration type to style existing cursors by passing in their markers
  //       or render artificial cursors that don't actually exist in the model
  //       by passing a marker that isn't actually associated with a cursor.
  //   * `class` This CSS class will be applied to the decorated line number,
  //     line, text spans, highlight regions, cursors, or overlay.
  //   * `style` An {Object} containing CSS style properties to apply to the
  //     relevant DOM node. Currently this only works with a `type` of `cursor`
  //     or `text`.
  //   * `item` (optional) An {HTMLElement} or a model {Object} with a
  //     corresponding view registered. Only applicable to the `gutter`,
  //     `overlay` and `block` decoration types.
  //   * `onlyHead` (optional) If `true`, the decoration will only be applied to
  //     the head of the `DisplayMarker`. Only applicable to the `line` and
  //     `line-number` decoration types.
  //   * `onlyEmpty` (optional) If `true`, the decoration will only be applied if
  //     the associated `DisplayMarker` is empty. Only applicable to the `gutter`,
  //     `line`, and `line-number` decoration types.
  //   * `onlyNonEmpty` (optional) If `true`, the decoration will only be applied
  //     if the associated `DisplayMarker` is non-empty. Only applicable to the
  //     `gutter`, `line`, and `line-number` decoration types.
  //   * `omitEmptyLastRow` (optional) If `false`, the decoration will be applied
  //     to the last row of a non-empty range, even if it ends at column 0.
  //     Defaults to `true`. Only applicable to the `gutter`, `line`, and
  //     `line-number` decoration types.
  //   * `position` (optional) Only applicable to decorations of type `overlay` and `block`.
  //     Controls where the view is positioned relative to the `TextEditorMarker`.
  //     Values can be `'head'` (the default) or `'tail'` for overlay decorations, and
  //     `'before'` (the default) or `'after'` for block decorations.
  //   * `avoidOverflow` (optional) Only applicable to decorations of type
  //      `overlay`. Determines whether the decoration adjusts its horizontal or
  //      vertical position to remain fully visible when it would otherwise
  //      overflow the editor. Defaults to `true`.
  //
  // Returns a {Decoration} object
  decorateMarker (marker, decorationParams) {
    return this.decorationManager.decorateMarker(marker, decorationParams)
  }

  // Essential: Add a decoration to every marker in the given marker layer. Can
  // be used to decorate a large number of markers without having to create and
  // manage many individual decorations.
  //
  // * `markerLayer` A {DisplayMarkerLayer} or {MarkerLayer} to decorate.
  // * `decorationParams` The same parameters that are passed to
  //   {TextEditor::decorateMarker}, except the `type` cannot be `overlay` or `gutter`.
  //
  // Returns a {LayerDecoration}.
  decorateMarkerLayer (markerLayer, decorationParams) {
    return this.decorationManager.decorateMarkerLayer(markerLayer, decorationParams)
  }

  // Deprecated: Get all the decorations within a screen row range on the default
  // layer.
  //
  // * `startScreenRow` the {Number} beginning screen row
  // * `endScreenRow` the {Number} end screen row (inclusive)
  //
  // Returns an {Object} of decorations in the form
  //  `{1: [{id: 10, type: 'line-number', class: 'someclass'}], 2: ...}`
  //   where the keys are {DisplayMarker} IDs, and the values are an array of decoration
  //   params objects attached to the marker.
  // Returns an empty object when no decorations are found
  decorationsForScreenRowRange (startScreenRow, endScreenRow) {
    return this.decorationManager.decorationsForScreenRowRange(startScreenRow, endScreenRow)
  }

  decorationsStateForScreenRowRange (startScreenRow, endScreenRow) {
    return this.decorationManager.decorationsStateForScreenRowRange(startScreenRow, endScreenRow)
  }

  // Extended: Get all decorations.
  //
  // * `propertyFilter` (optional) An {Object} containing key value pairs that
  //   the returned decorations' properties must match.
  //
  // Returns an {Array} of {Decoration}s.
  getDecorations (propertyFilter) {
    return this.decorationManager.getDecorations(propertyFilter)
  }

  // Extended: Get all decorations of type 'line'.
  //
  // * `propertyFilter` (optional) An {Object} containing key value pairs that
  //   the returned decorations' properties must match.
  //
  // Returns an {Array} of {Decoration}s.
  getLineDecorations (propertyFilter) {
    return this.decorationManager.getLineDecorations(propertyFilter)
  }

  // Extended: Get all decorations of type 'line-number'.
  //
  // * `propertyFilter` (optional) An {Object} containing key value pairs that
  //   the returned decorations' properties must match.
  //
  // Returns an {Array} of {Decoration}s.
  getLineNumberDecorations (propertyFilter) {
    return this.decorationManager.getLineNumberDecorations(propertyFilter)
  }

  // Extended: Get all decorations of type 'highlight'.
  //
  // * `propertyFilter` (optional) An {Object} containing key value pairs that
  //   the returned decorations' properties must match.
  //
  // Returns an {Array} of {Decoration}s.
  getHighlightDecorations (propertyFilter) {
    return this.decorationManager.getHighlightDecorations(propertyFilter)
  }

  // Extended: Get all decorations of type 'overlay'.
  //
  // * `propertyFilter` (optional) An {Object} containing key value pairs that
  //   the returned decorations' properties must match.
  //
  // Returns an {Array} of {Decoration}s.
  getOverlayDecorations (propertyFilter) {
    return this.decorationManager.getOverlayDecorations(propertyFilter)
  }

  /*
  Section: Markers
  */

  // Essential: Create a marker on the default marker layer with the given range
  // in buffer coordinates. This marker will maintain its logical location as the
  // buffer is changed, so if you mark a particular word, the marker will remain
  // over that word even if the word's location in the buffer changes.
  //
  // * `range` A {Range} or range-compatible {Array}
  // * `properties` A hash of key-value pairs to associate with the marker. There
  //   are also reserved property names that have marker-specific meaning.
  //   * `maintainHistory` (optional) {Boolean} Whether to store this marker's
  //     range before and after each change in the undo history. This allows the
  //     marker's position to be restored more accurately for certain undo/redo
  //     operations, but uses more time and memory. (default: false)
  //   * `reversed` (optional) {Boolean} Creates the marker in a reversed
  //     orientation. (default: false)
  //   * `invalidate` (optional) {String} Determines the rules by which changes
  //     to the buffer *invalidate* the marker. (default: 'overlap') It can be
  //     any of the following strategies, in order of fragility:
  //     * __never__: The marker is never marked as invalid. This is a good choice for
  //       markers representing selections in an editor.
  //     * __surround__: The marker is invalidated by changes that completely surround it.
  //     * __overlap__: The marker is invalidated by changes that surround the
  //       start or end of the marker. This is the default.
  //     * __inside__: The marker is invalidated by changes that extend into the
  //       inside of the marker. Changes that end at the marker's start or
  //       start at the marker's end do not invalidate the marker.
  //     * __touch__: The marker is invalidated by a change that touches the marked
  //       region in any way, including changes that end at the marker's
  //       start or start at the marker's end. This is the most fragile strategy.
  //
  // Returns a {DisplayMarker}.
  markBufferRange (bufferRange, options) {
    return this.defaultMarkerLayer.markBufferRange(bufferRange, options)
  }

  // Essential: Create a marker on the default marker layer with the given range
  // in screen coordinates. This marker will maintain its logical location as the
  // buffer is changed, so if you mark a particular word, the marker will remain
  // over that word even if the word's location in the buffer changes.
  //
  // * `range` A {Range} or range-compatible {Array}
  // * `properties` A hash of key-value pairs to associate with the marker. There
  //   are also reserved property names that have marker-specific meaning.
  //   * `maintainHistory` (optional) {Boolean} Whether to store this marker's
  //     range before and after each change in the undo history. This allows the
  //     marker's position to be restored more accurately for certain undo/redo
  //     operations, but uses more time and memory. (default: false)
  //   * `reversed` (optional) {Boolean} Creates the marker in a reversed
  //     orientation. (default: false)
  //   * `invalidate` (optional) {String} Determines the rules by which changes
  //     to the buffer *invalidate* the marker. (default: 'overlap') It can be
  //     any of the following strategies, in order of fragility:
  //     * __never__: The marker is never marked as invalid. This is a good choice for
  //       markers representing selections in an editor.
  //     * __surround__: The marker is invalidated by changes that completely surround it.
  //     * __overlap__: The marker is invalidated by changes that surround the
  //       start or end of the marker. This is the default.
  //     * __inside__: The marker is invalidated by changes that extend into the
  //       inside of the marker. Changes that end at the marker's start or
  //       start at the marker's end do not invalidate the marker.
  //     * __touch__: The marker is invalidated by a change that touches the marked
  //       region in any way, including changes that end at the marker's
  //       start or start at the marker's end. This is the most fragile strategy.
  //
  // Returns a {DisplayMarker}.
  markScreenRange (screenRange, options) {
    return this.defaultMarkerLayer.markScreenRange(screenRange, options)
  }

  // Essential: Create a marker on the default marker layer with the given buffer
  // position and no tail. To group multiple markers together in their own
  // private layer, see {::addMarkerLayer}.
  //
  // * `bufferPosition` A {Point} or point-compatible {Array}
  // * `options` (optional) An {Object} with the following keys:
  //   * `invalidate` (optional) {String} Determines the rules by which changes
  //     to the buffer *invalidate* the marker. (default: 'overlap') It can be
  //     any of the following strategies, in order of fragility:
  //     * __never__: The marker is never marked as invalid. This is a good choice for
  //       markers representing selections in an editor.
  //     * __surround__: The marker is invalidated by changes that completely surround it.
  //     * __overlap__: The marker is invalidated by changes that surround the
  //       start or end of the marker. This is the default.
  //     * __inside__: The marker is invalidated by changes that extend into the
  //       inside of the marker. Changes that end at the marker's start or
  //       start at the marker's end do not invalidate the marker.
  //     * __touch__: The marker is invalidated by a change that touches the marked
  //       region in any way, including changes that end at the marker's
  //       start or start at the marker's end. This is the most fragile strategy.
  //
  // Returns a {DisplayMarker}.
  markBufferPosition (bufferPosition, options) {
    return this.defaultMarkerLayer.markBufferPosition(bufferPosition, options)
  }

  // Essential: Create a marker on the default marker layer with the given screen
  // position and no tail. To group multiple markers together in their own
  // private layer, see {::addMarkerLayer}.
  //
  // * `screenPosition` A {Point} or point-compatible {Array}
  // * `options` (optional) An {Object} with the following keys:
  //   * `invalidate` (optional) {String} Determines the rules by which changes
  //     to the buffer *invalidate* the marker. (default: 'overlap') It can be
  //     any of the following strategies, in order of fragility:
  //     * __never__: The marker is never marked as invalid. This is a good choice for
  //       markers representing selections in an editor.
  //     * __surround__: The marker is invalidated by changes that completely surround it.
  //     * __overlap__: The marker is invalidated by changes that surround the
  //       start or end of the marker. This is the default.
  //     * __inside__: The marker is invalidated by changes that extend into the
  //       inside of the marker. Changes that end at the marker's start or
  //       start at the marker's end do not invalidate the marker.
  //     * __touch__: The marker is invalidated by a change that touches the marked
  //       region in any way, including changes that end at the marker's
  //       start or start at the marker's end. This is the most fragile strategy.
  //   * `clipDirection` {String} If `'backward'`, returns the first valid
  //     position preceding an invalid position. If `'forward'`, returns the
  //     first valid position following an invalid position. If `'closest'`,
  //     returns the first valid position closest to an invalid position.
  //     Defaults to `'closest'`.
  //
  // Returns a {DisplayMarker}.
  markScreenPosition (screenPosition, options) {
    return this.defaultMarkerLayer.markScreenPosition(screenPosition, options)
  }

  // Essential: Find all {DisplayMarker}s on the default marker layer that
  // match the given properties.
  //
  // This method finds markers based on the given properties. Markers can be
  // associated with custom properties that will be compared with basic equality.
  // In addition, there are several special properties that will be compared
  // with the range of the markers rather than their properties.
  //
  // * `properties` An {Object} containing properties that each returned marker
  //   must satisfy. Markers can be associated with custom properties, which are
  //   compared with basic equality. In addition, several reserved properties
  //   can be used to filter markers based on their current range:
  //   * `startBufferRow` Only include markers starting at this row in buffer
  //       coordinates.
  //   * `endBufferRow` Only include markers ending at this row in buffer
  //       coordinates.
  //   * `containsBufferRange` Only include markers containing this {Range} or
  //       in range-compatible {Array} in buffer coordinates.
  //   * `containsBufferPosition` Only include markers containing this {Point}
  //       or {Array} of `[row, column]` in buffer coordinates.
  //
  // Returns an {Array} of {DisplayMarker}s
  findMarkers (params) {
    return this.defaultMarkerLayer.findMarkers(params)
  }

  // Extended: Get the {DisplayMarker} on the default layer for the given
  // marker id.
  //
  // * `id` {Number} id of the marker
  getMarker (id) {
    return this.defaultMarkerLayer.getMarker(id)
  }

  // Extended: Get all {DisplayMarker}s on the default marker layer. Consider
  // using {::findMarkers}
  getMarkers () {
    return this.defaultMarkerLayer.getMarkers()
  }

  // Extended: Get the number of markers in the default marker layer.
  //
  // Returns a {Number}.
  getMarkerCount () {
    return this.defaultMarkerLayer.getMarkerCount()
  }

  destroyMarker (id) {
    const marker = this.getMarker(id)
    if (marker) marker.destroy()
  }

  // Essential: Create a marker layer to group related markers.
  //
  // * `options` An {Object} containing the following keys:
  //   * `maintainHistory` A {Boolean} indicating whether marker state should be
  //     restored on undo/redo. Defaults to `false`.
  //   * `persistent` A {Boolean} indicating whether or not this marker layer
  //     should be serialized and deserialized along with the rest of the
  //     buffer. Defaults to `false`. If `true`, the marker layer's id will be
  //     maintained across the serialization boundary, allowing you to retrieve
  //     it via {::getMarkerLayer}.
  //
  // Returns a {DisplayMarkerLayer}.
  addMarkerLayer (options) {
    return this.displayLayer.addMarkerLayer(options)
  }

  // Essential: Get a {DisplayMarkerLayer} by id.
  //
  // * `id` The id of the marker layer to retrieve.
  //
  // Returns a {DisplayMarkerLayer} or `undefined` if no layer exists with the
  // given id.
  getMarkerLayer (id) {
    return this.displayLayer.getMarkerLayer(id)
  }

  // Essential: Get the default {DisplayMarkerLayer}.
  //
  // All marker APIs not tied to an explicit layer interact with this default
  // layer.
  //
  // Returns a {DisplayMarkerLayer}.
  getDefaultMarkerLayer () {
    return this.defaultMarkerLayer
  }

  /*
  Section: Cursors
  */

  // Essential: Get the position of the most recently added cursor in buffer
  // coordinates.
  //
  // Returns a {Point}
  getCursorBufferPosition () {
    return this.getLastCursor().getBufferPosition()
  }

  // Essential: Get the position of all the cursor positions in buffer coordinates.
  //
  // Returns {Array} of {Point}s in the order they were added
  getCursorBufferPositions () {
    return this.getCursors().map((cursor) => cursor.getBufferPosition())
  }

  // Essential: Move the cursor to the given position in buffer coordinates.
  //
  // If there are multiple cursors, they will be consolidated to a single cursor.
  //
  // * `position` A {Point} or {Array} of `[row, column]`
  // * `options` (optional) An {Object} containing the following keys:
  //   * `autoscroll` Determines whether the editor scrolls to the new cursor's
  //     position. Defaults to true.
  setCursorBufferPosition (position, options) {
    return this.moveCursors(cursor => cursor.setBufferPosition(position, options))
  }

  // Essential: Get a {Cursor} at given screen coordinates {Point}
  //
  // * `position` A {Point} or {Array} of `[row, column]`
  //
  // Returns the first matched {Cursor} or undefined
  getCursorAtScreenPosition (position) {
    const selection = this.getSelectionAtScreenPosition(position)
    if (selection && selection.getHeadScreenPosition().isEqual(position)) {
      return selection.cursor
    }
  }

  // Essential: Get the position of the most recently added cursor in screen
  // coordinates.
  //
  // Returns a {Point}.
  getCursorScreenPosition () {
    return this.getLastCursor().getScreenPosition()
  }

  // Essential: Get the position of all the cursor positions in screen coordinates.
  //
  // Returns {Array} of {Point}s in the order the cursors were added
  getCursorScreenPositions () {
    return this.getCursors().map((cursor) => cursor.getScreenPosition())
  }

  // Essential: Move the cursor to the given position in screen coordinates.
  //
  // If there are multiple cursors, they will be consolidated to a single cursor.
  //
  // * `position` A {Point} or {Array} of `[row, column]`
  // * `options` (optional) An {Object} combining options for {::clipScreenPosition} with:
  //   * `autoscroll` Determines whether the editor scrolls to the new cursor's
  //     position. Defaults to true.
  setCursorScreenPosition (position, options) {
    if (options && options.clip) {
      Grim.deprecate('The `clip` parameter has been deprecated and will be removed soon. Please, use `clipDirection` instead.')
      if (options.clipDirection) options.clipDirection = options.clip
    }
    if (options && options.wrapAtSoftNewlines != null) {
      Grim.deprecate("The `wrapAtSoftNewlines` parameter has been deprecated and will be removed soon. Please, use `clipDirection: 'forward'` instead.")
      if (options.clipDirection) options.clipDirection = options.wrapAtSoftNewlines ? 'forward' : 'backward'
    }
    if (options && options.wrapBeyondNewlines != null) {
      Grim.deprecate("The `wrapBeyondNewlines` parameter has been deprecated and will be removed soon. Please, use `clipDirection: 'forward'` instead.")
      if (options.clipDirection) options.clipDirection = options.wrapBeyondNewlines ? 'forward' : 'backward'
    }

    return this.moveCursors(cursor => cursor.setScreenPosition(position, options))
  }

  // Essential: Add a cursor at the given position in buffer coordinates.
  //
  // * `bufferPosition` A {Point} or {Array} of `[row, column]`
  //
  // Returns a {Cursor}.
  addCursorAtBufferPosition (bufferPosition, options) {
    this.selectionsMarkerLayer.markBufferPosition(bufferPosition, {invalidate: 'never'})
    if (!options || options.autoscroll !== false) this.getLastSelection().cursor.autoscroll()
    return this.getLastSelection().cursor
  }

  // Essential: Add a cursor at the position in screen coordinates.
  //
  // * `screenPosition` A {Point} or {Array} of `[row, column]`
  //
  // Returns a {Cursor}.
  addCursorAtScreenPosition (screenPosition, options) {
    this.selectionsMarkerLayer.markScreenPosition(screenPosition, {invalidate: 'never'})
    if (!options || options.autoscroll !== false) this.getLastSelection().cursor.autoscroll()
    return this.getLastSelection().cursor
  }

  // Essential: Returns {Boolean} indicating whether or not there are multiple cursors.
  hasMultipleCursors () {
    return this.getCursors().length > 1
  }

  // Essential: Move every cursor up one row in screen coordinates.
  //
  // * `lineCount` (optional) {Number} number of lines to move
  moveUp (lineCount) {
    return this.moveCursors(cursor => cursor.moveUp(lineCount, {moveToEndOfSelection: true}))
  }

  // Essential: Move every cursor down one row in screen coordinates.
  //
  // * `lineCount` (optional) {Number} number of lines to move
  moveDown (lineCount) {
    return this.moveCursors(cursor => cursor.moveDown(lineCount, {moveToEndOfSelection: true}))
  }

  // Essential: Move every cursor left one column.
  //
  // * `columnCount` (optional) {Number} number of columns to move (default: 1)
  moveLeft (columnCount) {
    return this.moveCursors(cursor => cursor.moveLeft(columnCount, {moveToEndOfSelection: true}))
  }

  // Essential: Move every cursor right one column.
  //
  // * `columnCount` (optional) {Number} number of columns to move (default: 1)
  moveRight (columnCount) {
    return this.moveCursors(cursor => cursor.moveRight(columnCount, {moveToEndOfSelection: true}))
  }

  // Essential: Move every cursor to the beginning of its line in buffer coordinates.
  moveToBeginningOfLine () {
    return this.moveCursors(cursor => cursor.moveToBeginningOfLine())
  }

  // Essential: Move every cursor to the beginning of its line in screen coordinates.
  moveToBeginningOfScreenLine () {
    return this.moveCursors(cursor => cursor.moveToBeginningOfScreenLine())
  }

  // Essential: Move every cursor to the first non-whitespace character of its line.
  moveToFirstCharacterOfLine () {
    return this.moveCursors(cursor => cursor.moveToFirstCharacterOfLine())
  }

  // Essential: Move every cursor to the end of its line in buffer coordinates.
  moveToEndOfLine () {
    return this.moveCursors(cursor => cursor.moveToEndOfLine())
  }

  // Essential: Move every cursor to the end of its line in screen coordinates.
  moveToEndOfScreenLine () {
    return this.moveCursors(cursor => cursor.moveToEndOfScreenLine())
  }

  // Essential: Move every cursor to the beginning of its surrounding word.
  moveToBeginningOfWord () {
    return this.moveCursors(cursor => cursor.moveToBeginningOfWord())
  }

  // Essential: Move every cursor to the end of its surrounding word.
  moveToEndOfWord () {
    return this.moveCursors(cursor => cursor.moveToEndOfWord())
  }

  // Cursor Extended

  // Extended: Move every cursor to the top of the buffer.
  //
  // If there are multiple cursors, they will be merged into a single cursor.
  moveToTop () {
    return this.moveCursors(cursor => cursor.moveToTop())
  }

  // Extended: Move every cursor to the bottom of the buffer.
  //
  // If there are multiple cursors, they will be merged into a single cursor.
  moveToBottom () {
    return this.moveCursors(cursor => cursor.moveToBottom())
  }

  // Extended: Move every cursor to the beginning of the next word.
  moveToBeginningOfNextWord () {
    return this.moveCursors(cursor => cursor.moveToBeginningOfNextWord())
  }

  // Extended: Move every cursor to the previous word boundary.
  moveToPreviousWordBoundary () {
    return this.moveCursors(cursor => cursor.moveToPreviousWordBoundary())
  }

  // Extended: Move every cursor to the next word boundary.
  moveToNextWordBoundary () {
    return this.moveCursors(cursor => cursor.moveToNextWordBoundary())
  }

  // Extended: Move every cursor to the previous subword boundary.
  moveToPreviousSubwordBoundary () {
    return this.moveCursors(cursor => cursor.moveToPreviousSubwordBoundary())
  }

  // Extended: Move every cursor to the next subword boundary.
  moveToNextSubwordBoundary () {
    return this.moveCursors(cursor => cursor.moveToNextSubwordBoundary())
  }

  // Extended: Move every cursor to the beginning of the next paragraph.
  moveToBeginningOfNextParagraph () {
    return this.moveCursors(cursor => cursor.moveToBeginningOfNextParagraph())
  }

  // Extended: Move every cursor to the beginning of the previous paragraph.
  moveToBeginningOfPreviousParagraph () {
    return this.moveCursors(cursor => cursor.moveToBeginningOfPreviousParagraph())
  }

  // Extended: Returns the most recently added {Cursor}
  getLastCursor () {
    this.createLastSelectionIfNeeded()
    return _.last(this.cursors)
  }

  // Extended: Returns the word surrounding the most recently added cursor.
  //
  // * `options` (optional) See {Cursor::getBeginningOfCurrentWordBufferPosition}.
  getWordUnderCursor (options) {
    return this.getTextInBufferRange(this.getLastCursor().getCurrentWordBufferRange(options))
  }

  // Extended: Get an Array of all {Cursor}s.
  getCursors () {
    this.createLastSelectionIfNeeded()
    return this.cursors.slice()
  }

  // Extended: Get all {Cursor}s, ordered by their position in the buffer
  // instead of the order in which they were added.
  //
  // Returns an {Array} of {Selection}s.
  getCursorsOrderedByBufferPosition () {
    return this.getCursors().sort((a, b) => a.compare(b))
  }

  cursorsForScreenRowRange (startScreenRow, endScreenRow) {
    const cursors = []
    for (let marker of this.selectionsMarkerLayer.findMarkers({intersectsScreenRowRange: [startScreenRow, endScreenRow]})) {
      const cursor = this.cursorsByMarkerId.get(marker.id)
      if (cursor) cursors.push(cursor)
    }
    return cursors
  }

  // Add a cursor based on the given {DisplayMarker}.
  addCursor (marker) {
    const cursor = new Cursor({editor: this, marker, showCursorOnSelection: this.showCursorOnSelection})
    this.cursors.push(cursor)
    this.cursorsByMarkerId.set(marker.id, cursor)
    return cursor
  }

  moveCursors (fn) {
    return this.transact(() => {
      this.getCursors().forEach(fn)
      return this.mergeCursors()
    })
  }

  cursorMoved (event) {
    return this.emitter.emit('did-change-cursor-position', event)
  }

  // Merge cursors that have the same screen position
  mergeCursors () {
    const positions = {}
    for (let cursor of this.getCursors()) {
      const position = cursor.getBufferPosition().toString()
      if (positions.hasOwnProperty(position)) {
        cursor.destroy()
      } else {
        positions[position] = true
      }
    }
  }

  /*
  Section: Selections
  */

  // Essential: Get the selected text of the most recently added selection.
  //
  // Returns a {String}.
  getSelectedText () {
    return this.getLastSelection().getText()
  }

  // Essential: Get the {Range} of the most recently added selection in buffer
  // coordinates.
  //
  // Returns a {Range}.
  getSelectedBufferRange () {
    return this.getLastSelection().getBufferRange()
  }

  // Essential: Get the {Range}s of all selections in buffer coordinates.
  //
  // The ranges are sorted by when the selections were added. Most recent at the end.
  //
  // Returns an {Array} of {Range}s.
  getSelectedBufferRanges () {
    return this.getSelections().map((selection) => selection.getBufferRange())
  }

  // Essential: Set the selected range in buffer coordinates. If there are multiple
  // selections, they are reduced to a single selection with the given range.
  //
  // * `bufferRange` A {Range} or range-compatible {Array}.
  // * `options` (optional) An options {Object}:
  //   * `reversed` A {Boolean} indicating whether to create the selection in a
  //     reversed orientation.
  //   * `preserveFolds` A {Boolean}, which if `true` preserves the fold settings after the
  //     selection is set.
  setSelectedBufferRange (bufferRange, options) {
    return this.setSelectedBufferRanges([bufferRange], options)
  }

  // Essential: Set the selected ranges in buffer coordinates. If there are multiple
  // selections, they are replaced by new selections with the given ranges.
  //
  // * `bufferRanges` An {Array} of {Range}s or range-compatible {Array}s.
  // * `options` (optional) An options {Object}:
  //   * `reversed` A {Boolean} indicating whether to create the selection in a
  //     reversed orientation.
  //   * `preserveFolds` A {Boolean}, which if `true` preserves the fold settings after the
  //     selection is set.
  setSelectedBufferRanges (bufferRanges, options = {}) {
    if (!bufferRanges.length) throw new Error('Passed an empty array to setSelectedBufferRanges')

    const selections = this.getSelections()
    for (let selection of selections.slice(bufferRanges.length)) {
      selection.destroy()
    }

    this.mergeIntersectingSelections(options, () => {
      for (let i = 0; i < bufferRanges.length; i++) {
        let bufferRange = bufferRanges[i]
        bufferRange = Range.fromObject(bufferRange)
        if (selections[i]) {
          selections[i].setBufferRange(bufferRange, options)
        } else {
          this.addSelectionForBufferRange(bufferRange, options)
        }
      }
    })
  }

  // Essential: Get the {Range} of the most recently added selection in screen
  // coordinates.
  //
  // Returns a {Range}.
  getSelectedScreenRange () {
    return this.getLastSelection().getScreenRange()
  }

  // Essential: Get the {Range}s of all selections in screen coordinates.
  //
  // The ranges are sorted by when the selections were added. Most recent at the end.
  //
  // Returns an {Array} of {Range}s.
  getSelectedScreenRanges () {
    return this.getSelections().map((selection) => selection.getScreenRange())
  }

  // Essential: Set the selected range in screen coordinates. If there are multiple
  // selections, they are reduced to a single selection with the given range.
  //
  // * `screenRange` A {Range} or range-compatible {Array}.
  // * `options` (optional) An options {Object}:
  //   * `reversed` A {Boolean} indicating whether to create the selection in a
  //     reversed orientation.
  setSelectedScreenRange (screenRange, options) {
    return this.setSelectedBufferRange(this.bufferRangeForScreenRange(screenRange, options), options)
  }

  // Essential: Set the selected ranges in screen coordinates. If there are multiple
  // selections, they are replaced by new selections with the given ranges.
  //
  // * `screenRanges` An {Array} of {Range}s or range-compatible {Array}s.
  // * `options` (optional) An options {Object}:
  //   * `reversed` A {Boolean} indicating whether to create the selection in a
  //     reversed orientation.
  setSelectedScreenRanges (screenRanges, options = {}) {
    if (!screenRanges.length) throw new Error('Passed an empty array to setSelectedScreenRanges')

    const selections = this.getSelections()
    for (let selection of selections.slice(screenRanges.length)) {
      selection.destroy()
    }

    this.mergeIntersectingSelections(options, () => {
      for (let i = 0; i < screenRanges.length; i++) {
        let screenRange = screenRanges[i]
        screenRange = Range.fromObject(screenRange)
        if (selections[i]) {
          selections[i].setScreenRange(screenRange, options)
        } else {
          this.addSelectionForScreenRange(screenRange, options)
        }
      }
    })
  }

  // Essential: Add a selection for the given range in buffer coordinates.
  //
  // * `bufferRange` A {Range}
  // * `options` (optional) An options {Object}:
  //   * `reversed` A {Boolean} indicating whether to create the selection in a
  //     reversed orientation.
  //   * `preserveFolds` A {Boolean}, which if `true` preserves the fold settings after the
  //     selection is set.
  //
  // Returns the added {Selection}.
  addSelectionForBufferRange (bufferRange, options = {}) {
    bufferRange = Range.fromObject(bufferRange)
    if (!options.preserveFolds) {
      this.displayLayer.destroyFoldsContainingBufferPositions([bufferRange.start, bufferRange.end], true)
    }
    this.selectionsMarkerLayer.markBufferRange(bufferRange, {invalidate: 'never', reversed: options.reversed != null ? options.reversed : false})
    if (options.autoscroll !== false) this.getLastSelection().autoscroll()
    return this.getLastSelection()
  }

  // Essential: Add a selection for the given range in screen coordinates.
  //
  // * `screenRange` A {Range}
  // * `options` (optional) An options {Object}:
  //   * `reversed` A {Boolean} indicating whether to create the selection in a
  //     reversed orientation.
  //   * `preserveFolds` A {Boolean}, which if `true` preserves the fold settings after the
  //     selection is set.
  // Returns the added {Selection}.
  addSelectionForScreenRange (screenRange, options = {}) {
    return this.addSelectionForBufferRange(this.bufferRangeForScreenRange(screenRange), options)
  }

  // Essential: Select from the current cursor position to the given position in
  // buffer coordinates.
  //
  // This method may merge selections that end up intersecting.
  //
  // * `position` An instance of {Point}, with a given `row` and `column`.
  selectToBufferPosition (position) {
    const lastSelection = this.getLastSelection()
    lastSelection.selectToBufferPosition(position)
    return this.mergeIntersectingSelections({reversed: lastSelection.isReversed()})
  }

  // Essential: Select from the current cursor position to the given position in
  // screen coordinates.
  //
  // This method may merge selections that end up intersecting.
  //
  // * `position` An instance of {Point}, with a given `row` and `column`.
  selectToScreenPosition (position, options) {
    const lastSelection = this.getLastSelection()
    lastSelection.selectToScreenPosition(position, options)
    if (!options || !options.suppressSelectionMerge) {
      return this.mergeIntersectingSelections({reversed: lastSelection.isReversed()})
    }
  }

  // Essential: Move the cursor of each selection one character upward while
  // preserving the selection's tail position.
  //
  // * `rowCount` (optional) {Number} number of rows to select (default: 1)
  //
  // This method may merge selections that end up intersecting.
  selectUp (rowCount) {
    return this.expandSelectionsBackward(selection => selection.selectUp(rowCount))
  }

  // Essential: Move the cursor of each selection one character downward while
  // preserving the selection's tail position.
  //
  // * `rowCount` (optional) {Number} number of rows to select (default: 1)
  //
  // This method may merge selections that end up intersecting.
  selectDown (rowCount) {
    return this.expandSelectionsForward(selection => selection.selectDown(rowCount))
  }

  // Essential: Move the cursor of each selection one character leftward while
  // preserving the selection's tail position.
  //
  // * `columnCount` (optional) {Number} number of columns to select (default: 1)
  //
  // This method may merge selections that end up intersecting.
  selectLeft (columnCount) {
    return this.expandSelectionsBackward(selection => selection.selectLeft(columnCount))
  }

  // Essential: Move the cursor of each selection one character rightward while
  // preserving the selection's tail position.
  //
  // * `columnCount` (optional) {Number} number of columns to select (default: 1)
  //
  // This method may merge selections that end up intersecting.
  selectRight (columnCount) {
    return this.expandSelectionsForward(selection => selection.selectRight(columnCount))
  }

  // Essential: Select from the top of the buffer to the end of the last selection
  // in the buffer.
  //
  // This method merges multiple selections into a single selection.
  selectToTop () {
    return this.expandSelectionsBackward(selection => selection.selectToTop())
  }

  // Essential: Selects from the top of the first selection in the buffer to the end
  // of the buffer.
  //
  // This method merges multiple selections into a single selection.
  selectToBottom () {
    return this.expandSelectionsForward(selection => selection.selectToBottom())
  }

  // Essential: Select all text in the buffer.
  //
  // This method merges multiple selections into a single selection.
  selectAll () {
    return this.expandSelectionsForward(selection => selection.selectAll())
  }

  // Essential: Move the cursor of each selection to the beginning of its line
  // while preserving the selection's tail position.
  //
  // This method may merge selections that end up intersecting.
  selectToBeginningOfLine () {
    return this.expandSelectionsBackward(selection => selection.selectToBeginningOfLine())
  }

  // Essential: Move the cursor of each selection to the first non-whitespace
  // character of its line while preserving the selection's tail position. If the
  // cursor is already on the first character of the line, move it to the
  // beginning of the line.
  //
  // This method may merge selections that end up intersecting.
  selectToFirstCharacterOfLine () {
    return this.expandSelectionsBackward(selection => selection.selectToFirstCharacterOfLine())
  }

  // Essential: Move the cursor of each selection to the end of its line while
  // preserving the selection's tail position.
  //
  // This method may merge selections that end up intersecting.
  selectToEndOfLine () {
    return this.expandSelectionsForward(selection => selection.selectToEndOfLine())
  }

  // Essential: Expand selections to the beginning of their containing word.
  //
  // Operates on all selections. Moves the cursor to the beginning of the
  // containing word while preserving the selection's tail position.
  selectToBeginningOfWord () {
    return this.expandSelectionsBackward(selection => selection.selectToBeginningOfWord())
  }

  // Essential: Expand selections to the end of their containing word.
  //
  // Operates on all selections. Moves the cursor to the end of the containing
  // word while preserving the selection's tail position.
  selectToEndOfWord () {
    return this.expandSelectionsForward(selection => selection.selectToEndOfWord())
  }

  // Extended: For each selection, move its cursor to the preceding subword
  // boundary while maintaining the selection's tail position.
  //
  // This method may merge selections that end up intersecting.
  selectToPreviousSubwordBoundary () {
    return this.expandSelectionsBackward(selection => selection.selectToPreviousSubwordBoundary())
  }

  // Extended: For each selection, move its cursor to the next subword boundary
  // while maintaining the selection's tail position.
  //
  // This method may merge selections that end up intersecting.
  selectToNextSubwordBoundary () {
    return this.expandSelectionsForward(selection => selection.selectToNextSubwordBoundary())
  }

  // Essential: For each cursor, select the containing line.
  //
  // This method merges selections on successive lines.
  selectLinesContainingCursors () {
    return this.expandSelectionsForward(selection => selection.selectLine())
  }

  // Essential: Select the word surrounding each cursor.
  selectWordsContainingCursors () {
    return this.expandSelectionsForward(selection => selection.selectWord())
  }

  // Selection Extended

  // Extended: For each selection, move its cursor to the preceding word boundary
  // while maintaining the selection's tail position.
  //
  // This method may merge selections that end up intersecting.
  selectToPreviousWordBoundary () {
    return this.expandSelectionsBackward(selection => selection.selectToPreviousWordBoundary())
  }

  // Extended: For each selection, move its cursor to the next word boundary while
  // maintaining the selection's tail position.
  //
  // This method may merge selections that end up intersecting.
  selectToNextWordBoundary () {
    return this.expandSelectionsForward(selection => selection.selectToNextWordBoundary())
  }

  // Extended: Expand selections to the beginning of the next word.
  //
  // Operates on all selections. Moves the cursor to the beginning of the next
  // word while preserving the selection's tail position.
  selectToBeginningOfNextWord () {
    return this.expandSelectionsForward(selection => selection.selectToBeginningOfNextWord())
  }

  // Extended: Expand selections to the beginning of the next paragraph.
  //
  // Operates on all selections. Moves the cursor to the beginning of the next
  // paragraph while preserving the selection's tail position.
  selectToBeginningOfNextParagraph () {
    return this.expandSelectionsForward(selection => selection.selectToBeginningOfNextParagraph())
  }

  // Extended: Expand selections to the beginning of the next paragraph.
  //
  // Operates on all selections. Moves the cursor to the beginning of the next
  // paragraph while preserving the selection's tail position.
  selectToBeginningOfPreviousParagraph () {
    return this.expandSelectionsBackward(selection => selection.selectToBeginningOfPreviousParagraph())
  }

  // Extended: For each selection, select the syntax node that contains
  // that selection.
  selectLargerSyntaxNode () {
    const languageMode = this.buffer.getLanguageMode()
    if (!languageMode.getRangeForSyntaxNodeContainingRange) return

    this.expandSelectionsForward(selection => {
      const currentRange = selection.getBufferRange()
      const newRange = languageMode.getRangeForSyntaxNodeContainingRange(currentRange)
      if (newRange) {
        if (!selection._rangeStack) selection._rangeStack = []
        selection._rangeStack.push(currentRange)
        selection.setBufferRange(newRange)
      }
    })
  }

  // Extended: Undo the effect a preceding call to {::selectLargerSyntaxNode}.
  selectSmallerSyntaxNode () {
    this.expandSelectionsForward(selection => {
      if (selection._rangeStack) {
        const lastRange = selection._rangeStack[selection._rangeStack.length - 1]
        if (lastRange && selection.getBufferRange().containsRange(lastRange)) {
          selection._rangeStack.length--
          selection.setBufferRange(lastRange)
        }
      }
    })
  }

  // Extended: Select the range of the given marker if it is valid.
  //
  // * `marker` A {DisplayMarker}
  //
  // Returns the selected {Range} or `undefined` if the marker is invalid.
  selectMarker (marker) {
    if (marker.isValid()) {
      const range = marker.getBufferRange()
      this.setSelectedBufferRange(range)
      return range
    }
  }

  // Extended: Get the most recently added {Selection}.
  //
  // Returns a {Selection}.
  getLastSelection () {
    this.createLastSelectionIfNeeded()
    return _.last(this.selections)
  }

  getSelectionAtScreenPosition (position) {
    const markers = this.selectionsMarkerLayer.findMarkers({containsScreenPosition: position})
    if (markers.length > 0) return this.cursorsByMarkerId.get(markers[0].id).selection
  }

  // Extended: Get current {Selection}s.
  //
  // Returns: An {Array} of {Selection}s.
  getSelections () {
    this.createLastSelectionIfNeeded()
    return this.selections.slice()
  }

  // Extended: Get all {Selection}s, ordered by their position in the buffer
  // instead of the order in which they were added.
  //
  // Returns an {Array} of {Selection}s.
  getSelectionsOrderedByBufferPosition () {
    return this.getSelections().sort((a, b) => a.compare(b))
  }

  // Extended: Determine if a given range in buffer coordinates intersects a
  // selection.
  //
  // * `bufferRange` A {Range} or range-compatible {Array}.
  //
  // Returns a {Boolean}.
  selectionIntersectsBufferRange (bufferRange) {
    return this.getSelections().some(selection => selection.intersectsBufferRange(bufferRange))
  }

  // Selections Private

  // Add a similarly-shaped selection to the next eligible line below
  // each selection.
  //
  // Operates on all selections. If the selection is empty, adds an empty
  // selection to the next following non-empty line as close to the current
  // selection's column as possible. If the selection is non-empty, adds a
  // selection to the next line that is long enough for a non-empty selection
  // starting at the same column as the current selection to be added to it.
  addSelectionBelow () {
    return this.expandSelectionsForward(selection => selection.addSelectionBelow())
  }

  // Add a similarly-shaped selection to the next eligible line above
  // each selection.
  //
  // Operates on all selections. If the selection is empty, adds an empty
  // selection to the next preceding non-empty line as close to the current
  // selection's column as possible. If the selection is non-empty, adds a
  // selection to the next line that is long enough for a non-empty selection
  // starting at the same column as the current selection to be added to it.
  addSelectionAbove () {
    return this.expandSelectionsBackward(selection => selection.addSelectionAbove())
  }

  // Calls the given function with each selection, then merges selections
  expandSelectionsForward (fn) {
    this.mergeIntersectingSelections(() => this.getSelections().forEach(fn))
  }

  // Calls the given function with each selection, then merges selections in the
  // reversed orientation
  expandSelectionsBackward (fn) {
    this.mergeIntersectingSelections({reversed: true}, () => this.getSelections().forEach(fn))
  }

  finalizeSelections () {
    for (let selection of this.getSelections()) { selection.finalize() }
  }

  selectionsForScreenRows (startRow, endRow) {
    return this.getSelections().filter(selection => selection.intersectsScreenRowRange(startRow, endRow))
  }

  // Merges intersecting selections. If passed a function, it executes
  // the function with merging suppressed, then merges intersecting selections
  // afterward.
  mergeIntersectingSelections (...args) {
    return this.mergeSelections(...args, (previousSelection, currentSelection) => {
      const exclusive = !currentSelection.isEmpty() && !previousSelection.isEmpty()
      return previousSelection.intersectsWith(currentSelection, exclusive)
    })
  }

  mergeSelectionsOnSameRows (...args) {
    return this.mergeSelections(...args, (previousSelection, currentSelection) => {
      const screenRange = currentSelection.getScreenRange()
      return previousSelection.intersectsScreenRowRange(screenRange.start.row, screenRange.end.row)
    })
  }

  avoidMergingSelections (...args) {
    return this.mergeSelections(...args, () => false)
  }

  mergeSelections (...args) {
    const mergePredicate = args.pop()
    let fn = args.pop()
    let options = args.pop()
    if (typeof fn !== 'function') {
      options = fn
      fn = () => {}
    }

    if (this.suppressSelectionMerging) return fn()

    this.suppressSelectionMerging = true
    const result = fn()
    this.suppressSelectionMerging = false

    const selections = this.getSelectionsOrderedByBufferPosition()
    let lastSelection = selections.shift()
    for (const selection of selections) {
      if (mergePredicate(lastSelection, selection)) {
        lastSelection.merge(selection, options)
      } else {
        lastSelection = selection
      }
    }

    return result
  }

  // Add a {Selection} based on the given {DisplayMarker}.
  //
  // * `marker` The {DisplayMarker} to highlight
  // * `options` (optional) An {Object} that pertains to the {Selection} constructor.
  //
  // Returns the new {Selection}.
  addSelection (marker, options = {}) {
    const cursor = this.addCursor(marker)
    let selection = new Selection(Object.assign({editor: this, marker, cursor}, options))
    this.selections.push(selection)
    const selectionBufferRange = selection.getBufferRange()
    this.mergeIntersectingSelections({preserveFolds: options.preserveFolds})

    if (selection.destroyed) {
      for (selection of this.getSelections()) {
        if (selection.intersectsBufferRange(selectionBufferRange)) return selection
      }
    } else {
      this.emitter.emit('did-add-cursor', cursor)
      this.emitter.emit('did-add-selection', selection)
      return selection
    }
  }

  // Remove the given selection.
  removeSelection (selection) {
    _.remove(this.cursors, selection.cursor)
    _.remove(this.selections, selection)
    this.cursorsByMarkerId.delete(selection.cursor.marker.id)
    this.emitter.emit('did-remove-cursor', selection.cursor)
    return this.emitter.emit('did-remove-selection', selection)
  }

  // Reduce one or more selections to a single empty selection based on the most
  // recently added cursor.
  clearSelections (options) {
    this.consolidateSelections()
    this.getLastSelection().clear(options)
  }

  // Reduce multiple selections to the least recently added selection.
  consolidateSelections () {
    const selections = this.getSelections()
    if (selections.length > 1) {
      for (let selection of selections.slice(1, (selections.length))) { selection.destroy() }
      selections[0].autoscroll({center: true})
      return true
    } else {
      return false
    }
  }

  // Called by the selection
  selectionRangeChanged (event) {
    if (this.component) this.component.didChangeSelectionRange()
    this.emitter.emit('did-change-selection-range', event)
  }

  createLastSelectionIfNeeded () {
    if (this.selections.length === 0) {
      this.addSelectionForBufferRange([[0, 0], [0, 0]], {autoscroll: false, preserveFolds: true})
    }
  }

  /*
  Section: Searching and Replacing
  */

  // Essential: Scan regular expression matches in the entire buffer, calling the
  // given iterator function on each match.
  //
  // `::scan` functions as the replace method as well via the `replace`
  //
  // If you're programmatically modifying the results, you may want to try
  // {::backwardsScanInBufferRange} to avoid tripping over your own changes.
  //
  // * `regex` A {RegExp} to search for.
  // * `options` (optional) {Object}
  //   * `leadingContextLineCount` {Number} default `0`; The number of lines
  //      before the matched line to include in the results object.
  //   * `trailingContextLineCount` {Number} default `0`; The number of lines
  //      after the matched line to include in the results object.
  // * `iterator` A {Function} that's called on each match
  //   * `object` {Object}
  //     * `match` The current regular expression match.
  //     * `matchText` A {String} with the text of the match.
  //     * `range` The {Range} of the match.
  //     * `stop` Call this {Function} to terminate the scan.
  //     * `replace` Call this {Function} with a {String} to replace the match.
  scan (regex, options = {}, iterator) {
    if (_.isFunction(options)) {
      iterator = options
      options = {}
    }

    return this.buffer.scan(regex, options, iterator)
  }

  // Essential: Scan regular expression matches in a given range, calling the given
  // iterator function on each match.
  //
  // * `regex` A {RegExp} to search for.
  // * `range` A {Range} in which to search.
  // * `iterator` A {Function} that's called on each match with an {Object}
  //   containing the following keys:
  //   * `match` The current regular expression match.
  //   * `matchText` A {String} with the text of the match.
  //   * `range` The {Range} of the match.
  //   * `stop` Call this {Function} to terminate the scan.
  //   * `replace` Call this {Function} with a {String} to replace the match.
  scanInBufferRange (regex, range, iterator) { return this.buffer.scanInRange(regex, range, iterator) }

  // Essential: Scan regular expression matches in a given range in reverse order,
  // calling the given iterator function on each match.
  //
  // * `regex` A {RegExp} to search for.
  // * `range` A {Range} in which to search.
  // * `iterator` A {Function} that's called on each match with an {Object}
  //   containing the following keys:
  //   * `match` The current regular expression match.
  //   * `matchText` A {String} with the text of the match.
  //   * `range` The {Range} of the match.
  //   * `stop` Call this {Function} to terminate the scan.
  //   * `replace` Call this {Function} with a {String} to replace the match.
  backwardsScanInBufferRange (regex, range, iterator) { return this.buffer.backwardsScanInRange(regex, range, iterator) }

  /*
  Section: Tab Behavior
  */

  // Essential: Returns a {Boolean} indicating whether softTabs are enabled for this
  // editor.
  getSoftTabs () { return this.softTabs }

  // Essential: Enable or disable soft tabs for this editor.
  //
  // * `softTabs` A {Boolean}
  setSoftTabs (softTabs) {
    this.softTabs = softTabs
    this.update({softTabs: this.softTabs})
  }

  // Returns a {Boolean} indicating whether atomic soft tabs are enabled for this editor.
  hasAtomicSoftTabs () { return this.displayLayer.atomicSoftTabs }

  // Essential: Toggle soft tabs for this editor
  toggleSoftTabs () { this.setSoftTabs(!this.getSoftTabs()) }

  // Essential: Get the on-screen length of tab characters.
  //
  // Returns a {Number}.
  getTabLength () { return this.displayLayer.tabLength }

  // Essential: Set the on-screen length of tab characters. Setting this to a
  // {Number} This will override the `editor.tabLength` setting.
  //
  // * `tabLength` {Number} length of a single tab. Setting to `null` will
  //   fallback to using the `editor.tabLength` config setting
  setTabLength (tabLength) { this.update({tabLength}) }

  // Returns an {Object} representing the current invisible character
  // substitutions for this editor. See {::setInvisibles}.
  getInvisibles () {
    if (!this.mini && this.showInvisibles && (this.invisibles != null)) {
      return this.invisibles
    } else {
      return {}
    }
  }

  doesShowIndentGuide () { return this.showIndentGuide && !this.mini }

  getSoftWrapHangingIndentLength () { return this.displayLayer.softWrapHangingIndent }

  // Extended: Determine if the buffer uses hard or soft tabs.
  //
  // Returns `true` if the first non-comment line with leading whitespace starts
  // with a space character. Returns `false` if it starts with a hard tab (`\t`).
  //
  // Returns a {Boolean} or undefined if no non-comment lines had leading
  // whitespace.
  usesSoftTabs () {
    const languageMode = this.buffer.getLanguageMode()
    const hasIsRowCommented = languageMode.isRowCommented
    for (let bufferRow = 0, end = Math.min(1000, this.buffer.getLastRow()); bufferRow <= end; bufferRow++) {
      if (hasIsRowCommented && languageMode.isRowCommented(bufferRow)) continue
      const line = this.buffer.lineForRow(bufferRow)
      if (line[0] === ' ') return true
      if (line[0] === '\t') return false
    }
  }

  // Extended: Get the text representing a single level of indent.
  //
  // If soft tabs are enabled, the text is composed of N spaces, where N is the
  // tab length. Otherwise the text is a tab character (`\t`).
  //
  // Returns a {String}.
  getTabText () { return this.buildIndentString(1) }

  // If soft tabs are enabled, convert all hard tabs to soft tabs in the given
  // {Range}.
  normalizeTabsInBufferRange (bufferRange) {
    if (!this.getSoftTabs()) { return }
    return this.scanInBufferRange(/\t/g, bufferRange, ({replace}) => replace(this.getTabText()))
  }

  /*
  Section: Soft Wrap Behavior
  */

  // Essential: Determine whether lines in this editor are soft-wrapped.
  //
  // Returns a {Boolean}.
  isSoftWrapped () { return this.softWrapped }

  // Essential: Enable or disable soft wrapping for this editor.
  //
  // * `softWrapped` A {Boolean}
  //
  // Returns a {Boolean}.
  setSoftWrapped (softWrapped) {
    this.update({softWrapped})
    return this.isSoftWrapped()
  }

  getPreferredLineLength () { return this.preferredLineLength }

  // Essential: Toggle soft wrapping for this editor
  //
  // Returns a {Boolean}.
  toggleSoftWrapped () { return this.setSoftWrapped(!this.isSoftWrapped()) }

  // Essential: Gets the column at which column will soft wrap
  getSoftWrapColumn () {
    if (this.isSoftWrapped() && !this.mini) {
      if (this.softWrapAtPreferredLineLength) {
        return Math.min(this.getEditorWidthInChars(), this.preferredLineLength)
      } else {
        return this.getEditorWidthInChars()
      }
    } else {
      return this.maxScreenLineLength
    }
  }

  /*
  Section: Indentation
  */

  // Essential: Get the indentation level of the given buffer row.
  //
  // Determines how deeply the given row is indented based on the soft tabs and
  // tab length settings of this editor. Note that if soft tabs are enabled and
  // the tab length is 2, a row with 4 leading spaces would have an indentation
  // level of 2.
  //
  // * `bufferRow` A {Number} indicating the buffer row.
  //
  // Returns a {Number}.
  indentationForBufferRow (bufferRow) {
    return this.indentLevelForLine(this.lineTextForBufferRow(bufferRow))
  }

  // Essential: Set the indentation level for the given buffer row.
  //
  // Inserts or removes hard tabs or spaces based on the soft tabs and tab length
  // settings of this editor in order to bring it to the given indentation level.
  // Note that if soft tabs are enabled and the tab length is 2, a row with 4
  // leading spaces would have an indentation level of 2.
  //
  // * `bufferRow` A {Number} indicating the buffer row.
  // * `newLevel` A {Number} indicating the new indentation level.
  // * `options` (optional) An {Object} with the following keys:
  //   * `preserveLeadingWhitespace` `true` to preserve any whitespace already at
  //      the beginning of the line (default: false).
  setIndentationForBufferRow (bufferRow, newLevel, {preserveLeadingWhitespace} = {}) {
    let endColumn
    if (preserveLeadingWhitespace) {
      endColumn = 0
    } else {
      endColumn = this.lineTextForBufferRow(bufferRow).match(/^\s*/)[0].length
    }
    const newIndentString = this.buildIndentString(newLevel)
    return this.buffer.setTextInRange([[bufferRow, 0], [bufferRow, endColumn]], newIndentString)
  }

  // Extended: Indent rows intersecting selections by one level.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor.
  indentSelectedRows (options = {}) {
    if (!this.ensureWritable('indentSelectedRows', options)) return
    return this.mutateSelectedText(selection => selection.indentSelectedRows(options))
  }

  // Extended: Outdent rows intersecting selections by one level.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor.
  outdentSelectedRows (options = {}) {
    if (!this.ensureWritable('outdentSelectedRows', options)) return
    return this.mutateSelectedText(selection => selection.outdentSelectedRows(options))
  }

  // Extended: Get the indentation level of the given line of text.
  //
  // Determines how deeply the given line is indented based on the soft tabs and
  // tab length settings of this editor. Note that if soft tabs are enabled and
  // the tab length is 2, a row with 4 leading spaces would have an indentation
  // level of 2.
  //
  // * `line` A {String} representing a line of text.
  //
  // Returns a {Number}.
  indentLevelForLine (line) {
    const tabLength = this.getTabLength()
    let indentLength = 0
    for (let i = 0, {length} = line; i < length; i++) {
      const char = line[i]
      if (char === '\t') {
        indentLength += tabLength - (indentLength % tabLength)
      } else if (char === ' ') {
        indentLength++
      } else {
        break
      }
    }
    return indentLength / tabLength
  }

  // Extended: Indent rows intersecting selections based on the grammar's suggested
  // indent level.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor.
  autoIndentSelectedRows (options = {}) {
    if (!this.ensureWritable('autoIndentSelectedRows', options)) return
    return this.mutateSelectedText(selection => selection.autoIndentSelectedRows(options))
  }

  // Indent all lines intersecting selections. See {Selection::indent} for more
  // information.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor.
  indent (options = {}) {
    if (!this.ensureWritable('indent', options)) return
    if (options.autoIndent == null) options.autoIndent = this.shouldAutoIndent()
    this.mutateSelectedText(selection => selection.indent(options))
  }

  // Constructs the string used for indents.
  buildIndentString (level, column = 0) {
    if (this.getSoftTabs()) {
      const tabStopViolation = column % this.getTabLength()
      return _.multiplyString(' ', Math.floor(level * this.getTabLength()) - tabStopViolation)
    } else {
      const excessWhitespace = _.multiplyString(' ', Math.round((level - Math.floor(level)) * this.getTabLength()))
      return _.multiplyString('\t', Math.floor(level)) + excessWhitespace
    }
  }

  /*
  Section: Grammars
  */

  // Essential: Get the current {Grammar} of this editor.
  getGrammar () {
    const languageMode = this.buffer.getLanguageMode()
    return languageMode.getGrammar && languageMode.getGrammar() || NullGrammar
  }

  // Deprecated: Set the current {Grammar} of this editor.
  //
  // Assigning a grammar will cause the editor to re-tokenize based on the new
  // grammar.
  //
  // * `grammar` {Grammar}
  setGrammar (grammar) {
    const buffer = this.getBuffer()
    buffer.setLanguageMode(atom.grammars.languageModeForGrammarAndBuffer(grammar, buffer))
  }

  // Experimental: Get a notification when async tokenization is completed.
  onDidTokenize (callback) {
    return this.emitter.on('did-tokenize', callback)
  }

  /*
  Section: Managing Syntax Scopes
  */

  // Essential: Returns a {ScopeDescriptor} that includes this editor's language.
  // e.g. `['.source.ruby']`, or `['.source.coffee']`. You can use this with
  // {Config::get} to get language specific config values.
  getRootScopeDescriptor () {
    return this.buffer.getLanguageMode().rootScopeDescriptor
  }

  // Essential: Get the syntactic {ScopeDescriptor} for the given position in buffer
  // coordinates. Useful with {Config::get}.
  //
  // For example, if called with a position inside the parameter list of an
  // anonymous CoffeeScript function, this method returns a {ScopeDescriptor} with
  // the following scopes array:
  // `["source.coffee", "meta.function.inline.coffee", "meta.parameters.coffee", "variable.parameter.function.coffee"]`
  //
  // * `bufferPosition` A {Point} or {Array} of `[row, column]`.
  //
  // Returns a {ScopeDescriptor}.
  scopeDescriptorForBufferPosition (bufferPosition) {
    const languageMode = this.buffer.getLanguageMode()
    return languageMode.scopeDescriptorForPosition
      ? languageMode.scopeDescriptorForPosition(bufferPosition)
      : new ScopeDescriptor({scopes: ['text']})
  }

  // Extended: Get the range in buffer coordinates of all tokens surrounding the
  // cursor that match the given scope selector.
  //
  // For example, if you wanted to find the string surrounding the cursor, you
  // could call `editor.bufferRangeForScopeAtCursor(".string.quoted")`.
  //
  // * `scopeSelector` {String} selector. e.g. `'.source.ruby'`
  //
  // Returns a {Range}.
  bufferRangeForScopeAtCursor (scopeSelector) {
    return this.bufferRangeForScopeAtPosition(scopeSelector, this.getCursorBufferPosition())
  }

  bufferRangeForScopeAtPosition (scopeSelector, position) {
    return this.buffer.getLanguageMode().bufferRangeForScopeAtPosition(scopeSelector, position)
  }

  // Extended: Determine if the given row is entirely a comment
  isBufferRowCommented (bufferRow) {
    const match = this.lineTextForBufferRow(bufferRow).match(/\S/)
    if (match) {
      if (!this.commentScopeSelector) this.commentScopeSelector = new TextMateScopeSelector('comment.*')
      return this.commentScopeSelector.matches(this.scopeDescriptorForBufferPosition([bufferRow, match.index]).scopes)
    }
  }

  // Get the scope descriptor at the cursor.
  getCursorScope () {
    return this.getLastCursor().getScopeDescriptor()
  }

  tokenForBufferPosition (bufferPosition) {
    return this.buffer.getLanguageMode().tokenForPosition(bufferPosition)
  }

  /*
  Section: Clipboard Operations
  */

  // Essential: For each selection, copy the selected text.
  copySelectedText () {
    let maintainClipboard = false
    for (let selection of this.getSelectionsOrderedByBufferPosition()) {
      if (selection.isEmpty()) {
        const previousRange = selection.getBufferRange()
        selection.selectLine()
        selection.copy(maintainClipboard, true)
        selection.setBufferRange(previousRange)
      } else {
        selection.copy(maintainClipboard, false)
      }
      maintainClipboard = true
    }
  }

  // Private: For each selection, only copy highlighted text.
  copyOnlySelectedText () {
    let maintainClipboard = false
    for (let selection of this.getSelectionsOrderedByBufferPosition()) {
      if (!selection.isEmpty()) {
        selection.copy(maintainClipboard, false)
        maintainClipboard = true
      }
    }
  }

  // Essential: For each selection, cut the selected text.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor.
  cutSelectedText (options = {}) {
    if (!this.ensureWritable('cutSelectedText', options)) return
    let maintainClipboard = false
    this.mutateSelectedText(selection => {
      if (selection.isEmpty()) {
        selection.selectLine()
        selection.cut(maintainClipboard, true, options.bypassReadOnly)
      } else {
        selection.cut(maintainClipboard, false, options.bypassReadOnly)
      }
      maintainClipboard = true
    })
  }

  // Essential: For each selection, replace the selected text with the contents of
  // the clipboard.
  //
  // If the clipboard contains the same number of selections as the current
  // editor, each selection will be replaced with the content of the
  // corresponding clipboard selection text.
  //
  // * `options` (optional) See {Selection::insertText}.
  pasteText (options = {}) {
    if (!this.ensureWritable('parseText', options)) return
    options = Object.assign({}, options)
    let {text: clipboardText, metadata} = this.constructor.clipboard.readWithMetadata()
    if (!this.emitWillInsertTextEvent(clipboardText)) return false

    if (!metadata) metadata = {}
    if (options.autoIndent == null) options.autoIndent = this.shouldAutoIndentOnPaste()

    this.mutateSelectedText((selection, index) => {
      let fullLine, indentBasis, text
      if (metadata.selections && metadata.selections.length === this.getSelections().length) {
        ({text, indentBasis, fullLine} = metadata.selections[index])
      } else {
        ({indentBasis, fullLine} = metadata)
        text = clipboardText
      }

      if (indentBasis != null && (text.includes('\n') || !selection.cursor.hasPrecedingCharactersOnLine())) {
        options.indentBasis = indentBasis
      } else {
        options.indentBasis = null
      }

      let range
      if (fullLine && selection.isEmpty()) {
        const oldPosition = selection.getBufferRange().start
        selection.setBufferRange([[oldPosition.row, 0], [oldPosition.row, 0]])
        range = selection.insertText(text, options)
        const newPosition = oldPosition.translate([1, 0])
        selection.setBufferRange([newPosition, newPosition])
      } else {
        range = selection.insertText(text, options)
      }

      this.emitter.emit('did-insert-text', {text, range})
    })
  }

  // Essential: For each selection, if the selection is empty, cut all characters
  // of the containing screen line following the cursor. Otherwise cut the selected
  // text.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor.
  cutToEndOfLine (options = {}) {
    if (!this.ensureWritable('cutToEndOfLine', options)) return
    let maintainClipboard = false
    this.mutateSelectedText(selection => {
      selection.cutToEndOfLine(maintainClipboard, options)
      maintainClipboard = true
    })
  }

  // Essential: For each selection, if the selection is empty, cut all characters
  // of the containing buffer line following the cursor. Otherwise cut the
  // selected text.
  //
  // * `options` (optional) {Object}
  //   * `bypassReadOnly` (optional) {Boolean} Must be `true` to modify a read-only editor.
  cutToEndOfBufferLine (options = {}) {
    if (!this.ensureWritable('cutToEndOfBufferLine', options)) return
    let maintainClipboard = false
    this.mutateSelectedText(selection => {
      selection.cutToEndOfBufferLine(maintainClipboard, options)
      maintainClipboard = true
    })
  }

  /*
  Section: Folds
  */

  // Essential: Fold the most recent cursor's row based on its indentation level.
  //
  // The fold will extend from the nearest preceding line with a lower
  // indentation level up to the nearest following row with a lower indentation
  // level.
  foldCurrentRow () {
    const {row} = this.getCursorBufferPosition()
    const languageMode = this.buffer.getLanguageMode()
    const range = (
      languageMode.getFoldableRangeContainingPoint &&
      languageMode.getFoldableRangeContainingPoint(Point(row, Infinity), this.getTabLength())
    )
    if (range) return this.displayLayer.foldBufferRange(range)
  }

  // Essential: Unfold the most recent cursor's row by one level.
  unfoldCurrentRow () {
    const {row} = this.getCursorBufferPosition()
    return this.displayLayer.destroyFoldsContainingBufferPositions([Point(row, Infinity)], false)
  }

  // Essential: Fold the given row in buffer coordinates based on its indentation
  // level.
  //
  // If the given row is foldable, the fold will begin there. Otherwise, it will
  // begin at the first foldable row preceding the given row.
  //
  // * `bufferRow` A {Number}.
  foldBufferRow (bufferRow) {
    let position = Point(bufferRow, Infinity)
    const languageMode = this.buffer.getLanguageMode()
    while (true) {
      const foldableRange = (
        languageMode.getFoldableRangeContainingPoint &&
        languageMode.getFoldableRangeContainingPoint(position, this.getTabLength())
      )
      if (foldableRange) {
        const existingFolds = this.displayLayer.foldsIntersectingBufferRange(Range(foldableRange.start, foldableRange.start))
        if (existingFolds.length === 0) {
          this.displayLayer.foldBufferRange(foldableRange)
        } else {
          const firstExistingFoldRange = this.displayLayer.bufferRangeForFold(existingFolds[0])
          if (firstExistingFoldRange.start.isLessThan(position)) {
            position = Point(firstExistingFoldRange.start.row, 0)
            continue
          }
        }
      }
      break
    }
  }

  // Essential: Unfold all folds containing the given row in buffer coordinates.
  //
  // * `bufferRow` A {Number}
  unfoldBufferRow (bufferRow) {
    const position = Point(bufferRow, Infinity)
    return this.displayLayer.destroyFoldsContainingBufferPositions([position])
  }

  // Extended: For each selection, fold the rows it intersects.
  foldSelectedLines () {
    for (let selection of this.selections) {
      selection.fold()
    }
  }

  // Extended: Fold all foldable lines.
  foldAll () {
    const languageMode = this.buffer.getLanguageMode()
    const foldableRanges = (
      languageMode.getFoldableRanges &&
      languageMode.getFoldableRanges(this.getTabLength())
    )
    this.displayLayer.destroyAllFolds()
    for (let range of foldableRanges || []) {
      this.displayLayer.foldBufferRange(range)
    }
  }

  // Extended: Unfold all existing folds.
  unfoldAll () {
    const result = this.displayLayer.destroyAllFolds()
    this.scrollToCursorPosition()
    return result
  }

  // Extended: Fold all foldable lines at the given indent level.
  //
  // * `level` A {Number} starting at 0.
  foldAllAtIndentLevel (level) {
    const languageMode = this.buffer.getLanguageMode()
    const foldableRanges = (
      languageMode.getFoldableRangesAtIndentLevel &&
      languageMode.getFoldableRangesAtIndentLevel(level, this.getTabLength())
    )
    this.displayLayer.destroyAllFolds()
    for (let range of foldableRanges || []) {
      this.displayLayer.foldBufferRange(range)
    }
  }

  // Extended: Determine whether the given row in buffer coordinates is foldable.
  //
  // A *foldable* row is a row that *starts* a row range that can be folded.
  //
  // * `bufferRow` A {Number}
  //
  // Returns a {Boolean}.
  isFoldableAtBufferRow (bufferRow) {
    const languageMode = this.buffer.getLanguageMode()
    return languageMode.isFoldableAtRow && languageMode.isFoldableAtRow(bufferRow)
  }

  // Extended: Determine whether the given row in screen coordinates is foldable.
  //
  // A *foldable* row is a row that *starts* a row range that can be folded.
  //
  // * `bufferRow` A {Number}
  //
  // Returns a {Boolean}.
  isFoldableAtScreenRow (screenRow) {
    return this.isFoldableAtBufferRow(this.bufferRowForScreenRow(screenRow))
  }

  // Extended: Fold the given buffer row if it isn't currently folded, and unfold
  // it otherwise.
  toggleFoldAtBufferRow (bufferRow) {
    if (this.isFoldedAtBufferRow(bufferRow)) {
      return this.unfoldBufferRow(bufferRow)
    } else {
      return this.foldBufferRow(bufferRow)
    }
  }

  // Extended: Determine whether the most recently added cursor's row is folded.
  //
  // Returns a {Boolean}.
  isFoldedAtCursorRow () {
    return this.isFoldedAtBufferRow(this.getCursorBufferPosition().row)
  }

  // Extended: Determine whether the given row in buffer coordinates is folded.
  //
  // * `bufferRow` A {Number}
  //
  // Returns a {Boolean}.
  isFoldedAtBufferRow (bufferRow) {
    const range = Range(
      Point(bufferRow, 0),
      Point(bufferRow, this.buffer.lineLengthForRow(bufferRow))
    )
    return this.displayLayer.foldsIntersectingBufferRange(range).length > 0
  }

  // Extended: Determine whether the given row in screen coordinates is folded.
  //
  // * `screenRow` A {Number}
  //
  // Returns a {Boolean}.
  isFoldedAtScreenRow (screenRow) {
    return this.isFoldedAtBufferRow(this.bufferRowForScreenRow(screenRow))
  }

  // Creates a new fold between two row numbers.
  //
  // startRow - The row {Number} to start folding at
  // endRow - The row {Number} to end the fold
  //
  // Returns the new {Fold}.
  foldBufferRowRange (startRow, endRow) {
    return this.foldBufferRange(Range(Point(startRow, Infinity), Point(endRow, Infinity)))
  }

  foldBufferRange (range) {
    return this.displayLayer.foldBufferRange(range)
  }

  // Remove any {Fold}s found that intersect the given buffer range.
  destroyFoldsIntersectingBufferRange (bufferRange) {
    return this.displayLayer.destroyFoldsIntersectingBufferRange(bufferRange)
  }

  // Remove any {Fold}s found that contain the given array of buffer positions.
  destroyFoldsContainingBufferPositions (bufferPositions, excludeEndpoints) {
    return this.displayLayer.destroyFoldsContainingBufferPositions(bufferPositions, excludeEndpoints)
  }

  /*
  Section: Gutters
  */

  // Essential: Add a custom {Gutter}.
  //
  // * `options` An {Object} with the following fields:
  //   * `name` (required) A unique {String} to identify this gutter.
  //   * `priority` (optional) A {Number} that determines stacking order between
  //       gutters. Lower priority items are forced closer to the edges of the
  //       window. (default: -100)
  //   * `visible` (optional) {Boolean} specifying whether the gutter is visible
  //       initially after being created. (default: true)
  //
  // Returns the newly-created {Gutter}.
  addGutter (options) {
    return this.gutterContainer.addGutter(options)
  }

  // Essential: Get this editor's gutters.
  //
  // Returns an {Array} of {Gutter}s.
  getGutters () {
    return this.gutterContainer.getGutters()
  }

  getLineNumberGutter () {
    return this.lineNumberGutter
  }

  // Essential: Get the gutter with the given name.
  //
  // Returns a {Gutter}, or `null` if no gutter exists for the given name.
  gutterWithName (name) {
    return this.gutterContainer.gutterWithName(name)
  }

  /*
  Section: Scrolling the TextEditor
  */

  // Essential: Scroll the editor to reveal the most recently added cursor if it is
  // off-screen.
  //
  // * `options` (optional) {Object}
  //   * `center` Center the editor around the cursor if possible. (default: true)
  scrollToCursorPosition (options) {
    this.getLastCursor().autoscroll({center: options && options.center !== false})
  }

  // Essential: Scrolls the editor to the given buffer position.
  //
  // * `bufferPosition` An object that represents a buffer position. It can be either
  //   an {Object} (`{row, column}`), {Array} (`[row, column]`), or {Point}
  // * `options` (optional) {Object}
  //   * `center` Center the editor around the position if possible. (default: false)
  scrollToBufferPosition (bufferPosition, options) {
    return this.scrollToScreenPosition(this.screenPositionForBufferPosition(bufferPosition), options)
  }

  // Essential: Scrolls the editor to the given screen position.
  //
  // * `screenPosition` An object that represents a screen position. It can be either
  //    an {Object} (`{row, column}`), {Array} (`[row, column]`), or {Point}
  // * `options` (optional) {Object}
  //   * `center` Center the editor around the position if possible. (default: false)
  scrollToScreenPosition (screenPosition, options) {
    this.scrollToScreenRange(new Range(screenPosition, screenPosition), options)
  }

  scrollToTop () {
    Grim.deprecate('This is now a view method. Call TextEditorElement::scrollToTop instead.')
    this.getElement().scrollToTop()
  }

  scrollToBottom () {
    Grim.deprecate('This is now a view method. Call TextEditorElement::scrollToTop instead.')
    this.getElement().scrollToBottom()
  }

  scrollToScreenRange (screenRange, options = {}) {
    if (options.clip !== false) screenRange = this.clipScreenRange(screenRange)
    const scrollEvent = {screenRange, options}
    if (this.component) this.component.didRequestAutoscroll(scrollEvent)
    this.emitter.emit('did-request-autoscroll', scrollEvent)
  }

  getHorizontalScrollbarHeight () {
    Grim.deprecate('This is now a view method. Call TextEditorElement::getHorizontalScrollbarHeight instead.')
    return this.getElement().getHorizontalScrollbarHeight()
  }

  getVerticalScrollbarWidth () {
    Grim.deprecate('This is now a view method. Call TextEditorElement::getVerticalScrollbarWidth instead.')
    return this.getElement().getVerticalScrollbarWidth()
  }

  pageUp () {
    this.moveUp(this.getRowsPerPage())
  }

  pageDown () {
    this.moveDown(this.getRowsPerPage())
  }

  selectPageUp () {
    this.selectUp(this.getRowsPerPage())
  }

  selectPageDown () {
    this.selectDown(this.getRowsPerPage())
  }

  // Returns the number of rows per page
  getRowsPerPage () {
    if (this.component) {
      const clientHeight = this.component.getScrollContainerClientHeight()
      const lineHeight = this.component.getLineHeight()
      return Math.max(1, Math.ceil(clientHeight / lineHeight))
    } else {
      return 1
    }
  }

  /*
  Section: Config
  */

  // Experimental: Is auto-indentation enabled for this editor?
  //
  // Returns a {Boolean}.
  shouldAutoIndent () { return this.autoIndent }

  // Experimental: Is auto-indentation on paste enabled for this editor?
  //
  // Returns a {Boolean}.
  shouldAutoIndentOnPaste () { return this.autoIndentOnPaste }

  // Experimental: Does this editor allow scrolling past the last line?
  //
  // Returns a {Boolean}.
  getScrollPastEnd () {
    if (this.getAutoHeight()) {
      return false
    } else {
      return this.scrollPastEnd
    }
  }

  // Experimental: How fast does the editor scroll in response to mouse wheel
  // movements?
  //
  // Returns a positive {Number}.
  getScrollSensitivity () { return this.scrollSensitivity }

  // Experimental: Does this editor show cursors while there is a selection?
  //
  // Returns a positive {Boolean}.
  getShowCursorOnSelection () { return this.showCursorOnSelection }

  // Experimental: Are line numbers enabled for this editor?
  //
  // Returns a {Boolean}
  doesShowLineNumbers () { return this.showLineNumbers }

  // Experimental: Get the time interval within which text editing operations
  // are grouped together in the editor's undo history.
  //
  // Returns the time interval {Number} in milliseconds.
  getUndoGroupingInterval () { return this.undoGroupingInterval }

  // Experimental: Get the characters that are *not* considered part of words,
  // for the purpose of word-based cursor movements.
  //
  // Returns a {String} containing the non-word characters.
  getNonWordCharacters (position) {
    const languageMode = this.buffer.getLanguageMode()
    return (
      languageMode.getNonWordCharacters &&
      languageMode.getNonWordCharacters(position || Point(0, 0))
    ) || DEFAULT_NON_WORD_CHARACTERS
  }

  /*
  Section: Event Handlers
  */

  handleLanguageModeChange () {
    this.unfoldAll()
    if (this.languageModeSubscription) {
      this.languageModeSubscription.dispose()
      this.disposables.remove(this.languageModeSubscription)
    }
    const languageMode = this.buffer.getLanguageMode()

    if (this.component && this.component.visible && languageMode.startTokenizing) {
      languageMode.startTokenizing()
    }
    this.languageModeSubscription = languageMode.onDidTokenize && languageMode.onDidTokenize(() => {
      this.emitter.emit('did-tokenize')
    })
    if (this.languageModeSubscription) this.disposables.add(this.languageModeSubscription)
    this.emitter.emit('did-change-grammar', languageMode.grammar)
  }

  /*
  Section: TextEditor Rendering
  */

  // Get the Element for the editor.
  getElement () {
    if (!this.component) {
      if (!TextEditorComponent) TextEditorComponent = require('./text-editor-component')
      if (!TextEditorElement) TextEditorElement = require('./text-editor-element')
      this.component = new TextEditorComponent({
        model: this,
        updatedSynchronously: TextEditorElement.prototype.updatedSynchronously,
        initialScrollTopRow: this.initialScrollTopRow,
        initialScrollLeftColumn: this.initialScrollLeftColumn
      })
    }
    return this.component.element
  }

  getAllowedLocations () {
    return ['center']
  }

  // Essential: Retrieves the greyed out placeholder of a mini editor.
  //
  // Returns a {String}.
  getPlaceholderText () { return this.placeholderText }

  // Essential: Set the greyed out placeholder of a mini editor. Placeholder text
  // will be displayed when the editor has no content.
  //
  // * `placeholderText` {String} text that is displayed when the editor has no content.
  setPlaceholderText (placeholderText) { this.update({placeholderText}) }

  pixelPositionForBufferPosition (bufferPosition) {
    Grim.deprecate('This method is deprecated on the model layer. Use `TextEditorElement::pixelPositionForBufferPosition` instead')
    return this.getElement().pixelPositionForBufferPosition(bufferPosition)
  }

  pixelPositionForScreenPosition (screenPosition) {
    Grim.deprecate('This method is deprecated on the model layer. Use `TextEditorElement::pixelPositionForScreenPosition` instead')
    return this.getElement().pixelPositionForScreenPosition(screenPosition)
  }

  getVerticalScrollMargin () {
    const maxScrollMargin = Math.floor(((this.height / this.getLineHeightInPixels()) - 1) / 2)
    return Math.min(this.verticalScrollMargin, maxScrollMargin)
  }

  setVerticalScrollMargin (verticalScrollMargin) {
    this.verticalScrollMargin = verticalScrollMargin
    return this.verticalScrollMargin
  }

  getHorizontalScrollMargin () {
    return Math.min(this.horizontalScrollMargin, Math.floor(((this.width / this.getDefaultCharWidth()) - 1) / 2))
  }
  setHorizontalScrollMargin (horizontalScrollMargin) {
    this.horizontalScrollMargin = horizontalScrollMargin
    return this.horizontalScrollMargin
  }

  getLineHeightInPixels () { return this.lineHeightInPixels }
  setLineHeightInPixels (lineHeightInPixels) {
    this.lineHeightInPixels = lineHeightInPixels
    return this.lineHeightInPixels
  }

  getKoreanCharWidth () { return this.koreanCharWidth }
  getHalfWidthCharWidth () { return this.halfWidthCharWidth }
  getDoubleWidthCharWidth () { return this.doubleWidthCharWidth }
  getDefaultCharWidth () { return this.defaultCharWidth }

  ratioForCharacter (character) {
    if (isKoreanCharacter(character)) {
      return this.getKoreanCharWidth() / this.getDefaultCharWidth()
    } else if (isHalfWidthCharacter(character)) {
      return this.getHalfWidthCharWidth() / this.getDefaultCharWidth()
    } else if (isDoubleWidthCharacter(character)) {
      return this.getDoubleWidthCharWidth() / this.getDefaultCharWidth()
    } else {
      return 1
    }
  }

  setDefaultCharWidth (defaultCharWidth, doubleWidthCharWidth, halfWidthCharWidth, koreanCharWidth) {
    if (doubleWidthCharWidth == null) { doubleWidthCharWidth = defaultCharWidth }
    if (halfWidthCharWidth == null) { halfWidthCharWidth = defaultCharWidth }
    if (koreanCharWidth == null) { koreanCharWidth = defaultCharWidth }
    if (defaultCharWidth !== this.defaultCharWidth ||
        (doubleWidthCharWidth !== this.doubleWidthCharWidth &&
         halfWidthCharWidth !== this.halfWidthCharWidth &&
         koreanCharWidth !== this.koreanCharWidth)) {
      this.defaultCharWidth = defaultCharWidth
      this.doubleWidthCharWidth = doubleWidthCharWidth
      this.halfWidthCharWidth = halfWidthCharWidth
      this.koreanCharWidth = koreanCharWidth
      if (this.isSoftWrapped()) {
        this.displayLayer.reset({
          softWrapColumn: this.getSoftWrapColumn()
        })
      }
    }
    return defaultCharWidth
  }

  setHeight (height) {
    Grim.deprecate('This is now a view method. Call TextEditorElement::setHeight instead.')
    this.getElement().setHeight(height)
  }

  getHeight () {
    Grim.deprecate('This is now a view method. Call TextEditorElement::getHeight instead.')
    return this.getElement().getHeight()
  }

  getAutoHeight () { return this.autoHeight != null ? this.autoHeight : true }

  getAutoWidth () { return this.autoWidth != null ? this.autoWidth : false }

  setWidth (width) {
    Grim.deprecate('This is now a view method. Call TextEditorElement::setWidth instead.')
    this.getElement().setWidth(width)
  }

  getWidth () {
    Grim.deprecate('This is now a view method. Call TextEditorElement::getWidth instead.')
    return this.getElement().getWidth()
  }

  // Use setScrollTopRow instead of this method
  setFirstVisibleScreenRow (screenRow) {
    this.setScrollTopRow(screenRow)
  }

  getFirstVisibleScreenRow () {
    return this.getElement().component.getFirstVisibleRow()
  }

  getLastVisibleScreenRow () {
    return this.getElement().component.getLastVisibleRow()
  }

  getVisibleRowRange () {
    return [this.getFirstVisibleScreenRow(), this.getLastVisibleScreenRow()]
  }

  // Use setScrollLeftColumn instead of this method
  setFirstVisibleScreenColumn (column) {
    return this.setScrollLeftColumn(column)
  }

  getFirstVisibleScreenColumn () {
    return this.getElement().component.getFirstVisibleColumn()
  }

  getScrollTop () {
    Grim.deprecate('This is now a view method. Call TextEditorElement::getScrollTop instead.')
    return this.getElement().getScrollTop()
  }

  setScrollTop (scrollTop) {
    Grim.deprecate('This is now a view method. Call TextEditorElement::setScrollTop instead.')
    this.getElement().setScrollTop(scrollTop)
  }

  getScrollBottom () {
    Grim.deprecate('This is now a view method. Call TextEditorElement::getScrollBottom instead.')
    return this.getElement().getScrollBottom()
  }

  setScrollBottom (scrollBottom) {
    Grim.deprecate('This is now a view method. Call TextEditorElement::setScrollBottom instead.')
    this.getElement().setScrollBottom(scrollBottom)
  }

  getScrollLeft () {
    Grim.deprecate('This is now a view method. Call TextEditorElement::getScrollLeft instead.')
    return this.getElement().getScrollLeft()
  }

  setScrollLeft (scrollLeft) {
    Grim.deprecate('This is now a view method. Call TextEditorElement::setScrollLeft instead.')
    this.getElement().setScrollLeft(scrollLeft)
  }

  getScrollRight () {
    Grim.deprecate('This is now a view method. Call TextEditorElement::getScrollRight instead.')
    return this.getElement().getScrollRight()
  }

  setScrollRight (scrollRight) {
    Grim.deprecate('This is now a view method. Call TextEditorElement::setScrollRight instead.')
    this.getElement().setScrollRight(scrollRight)
  }

  getScrollHeight () {
    Grim.deprecate('This is now a view method. Call TextEditorElement::getScrollHeight instead.')
    return this.getElement().getScrollHeight()
  }

  getScrollWidth () {
    Grim.deprecate('This is now a view method. Call TextEditorElement::getScrollWidth instead.')
    return this.getElement().getScrollWidth()
  }

  getMaxScrollTop () {
    Grim.deprecate('This is now a view method. Call TextEditorElement::getMaxScrollTop instead.')
    return this.getElement().getMaxScrollTop()
  }

  getScrollTopRow () {
    return this.getElement().component.getScrollTopRow()
  }

  setScrollTopRow (scrollTopRow) {
    this.getElement().component.setScrollTopRow(scrollTopRow)
  }

  getScrollLeftColumn () {
    return this.getElement().component.getScrollLeftColumn()
  }

  setScrollLeftColumn (scrollLeftColumn) {
    this.getElement().component.setScrollLeftColumn(scrollLeftColumn)
  }

  intersectsVisibleRowRange (startRow, endRow) {
    Grim.deprecate('This is now a view method. Call TextEditorElement::intersectsVisibleRowRange instead.')
    return this.getElement().intersectsVisibleRowRange(startRow, endRow)
  }

  selectionIntersectsVisibleRowRange (selection) {
    Grim.deprecate('This is now a view method. Call TextEditorElement::selectionIntersectsVisibleRowRange instead.')
    return this.getElement().selectionIntersectsVisibleRowRange(selection)
  }

  screenPositionForPixelPosition (pixelPosition) {
    Grim.deprecate('This is now a view method. Call TextEditorElement::screenPositionForPixelPosition instead.')
    return this.getElement().screenPositionForPixelPosition(pixelPosition)
  }

  pixelRectForScreenRange (screenRange) {
    Grim.deprecate('This is now a view method. Call TextEditorElement::pixelRectForScreenRange instead.')
    return this.getElement().pixelRectForScreenRange(screenRange)
  }

  /*
  Section: Utility
  */

  inspect () {
    return `<TextEditor ${this.id}>`
  }

  emitWillInsertTextEvent (text) {
    let result = true
    const cancel = () => { result = false }
    this.emitter.emit('will-insert-text', {cancel, text})
    return result
  }

  /*
  Section: Language Mode Delegated Methods
  */

  suggestedIndentForBufferRow (bufferRow, options) {
    const languageMode = this.buffer.getLanguageMode()
    return (
      languageMode.suggestedIndentForBufferRow &&
      languageMode.suggestedIndentForBufferRow(bufferRow, this.getTabLength(), options)
    )
  }

  // Given a buffer row, indent it.
  //
  // * bufferRow - The row {Number}.
  // * options - An options {Object} to pass through to {TextEditor::setIndentationForBufferRow}.
  autoIndentBufferRow (bufferRow, options) {
    const indentLevel = this.suggestedIndentForBufferRow(bufferRow, options)
    return this.setIndentationForBufferRow(bufferRow, indentLevel, options)
  }

  // Indents all the rows between two buffer row numbers.
  //
  // * startRow - The row {Number} to start at
  // * endRow - The row {Number} to end at
  autoIndentBufferRows (startRow, endRow) {
    let row = startRow
    while (row <= endRow) {
      this.autoIndentBufferRow(row)
      row++
    }
  }

  autoDecreaseIndentForBufferRow (bufferRow) {
    const languageMode = this.buffer.getLanguageMode()
    const indentLevel = (
      languageMode.suggestedIndentForEditedBufferRow &&
      languageMode.suggestedIndentForEditedBufferRow(bufferRow, this.getTabLength())
    )
    if (indentLevel != null) this.setIndentationForBufferRow(bufferRow, indentLevel)
  }

  toggleLineCommentForBufferRow (row) { this.toggleLineCommentsForBufferRows(row, row) }

  toggleLineCommentsForBufferRows (start, end) {
    const languageMode = this.buffer.getLanguageMode()
    let {commentStartString, commentEndString} =
      languageMode.commentStringsForPosition &&
      languageMode.commentStringsForPosition(Point(start, 0)) || {}
    if (!commentStartString) return
    commentStartString = commentStartString.trim()

    if (commentEndString) {
      commentEndString = commentEndString.trim()
      const startDelimiterColumnRange = columnRangeForStartDelimiter(
        this.buffer.lineForRow(start),
        commentStartString
      )
      if (startDelimiterColumnRange) {
        const endDelimiterColumnRange = columnRangeForEndDelimiter(
          this.buffer.lineForRow(end),
          commentEndString
        )
        if (endDelimiterColumnRange) {
          this.buffer.transact(() => {
            this.buffer.delete([[end, endDelimiterColumnRange[0]], [end, endDelimiterColumnRange[1]]])
            this.buffer.delete([[start, startDelimiterColumnRange[0]], [start, startDelimiterColumnRange[1]]])
          })
        }
      } else {
        this.buffer.transact(() => {
          const indentLength = this.buffer.lineForRow(start).match(/^\s*/)[0].length
          this.buffer.insert([start, indentLength], commentStartString + ' ')
          this.buffer.insert([end, this.buffer.lineLengthForRow(end)], ' ' + commentEndString)
        })
      }
    } else {
      let hasCommentedLines = false
      let hasUncommentedLines = false
      for (let row = start; row <= end; row++) {
        const line = this.buffer.lineForRow(row)
        if (NON_WHITESPACE_REGEXP.test(line)) {
          if (columnRangeForStartDelimiter(line, commentStartString)) {
            hasCommentedLines = true
          } else {
            hasUncommentedLines = true
          }
        }
      }

      const shouldUncomment = hasCommentedLines && !hasUncommentedLines

      if (shouldUncomment) {
        for (let row = start; row <= end; row++) {
          const columnRange = columnRangeForStartDelimiter(
            this.buffer.lineForRow(row),
            commentStartString
          )
          if (columnRange) this.buffer.delete([[row, columnRange[0]], [row, columnRange[1]]])
        }
      } else {
        let minIndentLevel = Infinity
        let minBlankIndentLevel = Infinity
        for (let row = start; row <= end; row++) {
          const line = this.buffer.lineForRow(row)
          const indentLevel = this.indentLevelForLine(line)
          if (NON_WHITESPACE_REGEXP.test(line)) {
            if (indentLevel < minIndentLevel) minIndentLevel = indentLevel
          } else {
            if (indentLevel < minBlankIndentLevel) minBlankIndentLevel = indentLevel
          }
        }
        minIndentLevel = Number.isFinite(minIndentLevel)
          ? minIndentLevel
          : Number.isFinite(minBlankIndentLevel)
              ? minBlankIndentLevel
              : 0

        const indentString = this.buildIndentString(minIndentLevel)
        for (let row = start; row <= end; row++) {
          const line = this.buffer.lineForRow(row)
          if (NON_WHITESPACE_REGEXP.test(line)) {
            const indentColumn = columnForIndentLevel(line, minIndentLevel, this.getTabLength())
            this.buffer.insert(Point(row, indentColumn), commentStartString + ' ')
          } else {
            this.buffer.setTextInRange(
              new Range(new Point(row, 0), new Point(row, Infinity)),
              indentString + commentStartString + ' '
            )
          }
        }
      }
    }
  }

  rowRangeForParagraphAtBufferRow (bufferRow) {
    if (!NON_WHITESPACE_REGEXP.test(this.lineTextForBufferRow(bufferRow))) return

    const languageMode = this.buffer.getLanguageMode()
    const isCommented = languageMode.isRowCommented(bufferRow)

    let startRow = bufferRow
    while (startRow > 0) {
      if (!NON_WHITESPACE_REGEXP.test(this.lineTextForBufferRow(startRow - 1))) break
      if (languageMode.isRowCommented(startRow - 1) !== isCommented) break
      startRow--
    }

    let endRow = bufferRow
    const rowCount = this.getLineCount()
    while (endRow < rowCount) {
      if (!NON_WHITESPACE_REGEXP.test(this.lineTextForBufferRow(endRow + 1))) break
      if (languageMode.isRowCommented(endRow + 1) !== isCommented) break
      endRow++
    }

    return new Range(new Point(startRow, 0), new Point(endRow, this.buffer.lineLengthForRow(endRow)))
  }
}

function columnForIndentLevel (line, indentLevel, tabLength) {
  let column = 0
  let indentLength = 0
  const goalIndentLength = indentLevel * tabLength
  while (indentLength < goalIndentLength) {
    const char = line[column]
    if (char === '\t') {
      indentLength += tabLength - (indentLength % tabLength)
    } else if (char === ' ') {
      indentLength++
    } else {
      break
    }
    column++
  }
  return column
}

function columnRangeForStartDelimiter (line, delimiter) {
  const startColumn = line.search(NON_WHITESPACE_REGEXP)
  if (startColumn === -1) return null
  if (!line.startsWith(delimiter, startColumn)) return null

  let endColumn = startColumn + delimiter.length
  if (line[endColumn] === ' ') endColumn++
  return [startColumn, endColumn]
}

function columnRangeForEndDelimiter (line, delimiter) {
  let startColumn = line.lastIndexOf(delimiter)
  if (startColumn === -1) return null

  const endColumn = startColumn + delimiter.length
  if (NON_WHITESPACE_REGEXP.test(line.slice(endColumn))) return null
  if (line[startColumn - 1] === ' ') startColumn--
  return [startColumn, endColumn]
}

class ChangeEvent {
  constructor ({oldRange, newRange}) {
    this.oldRange = oldRange
    this.newRange = newRange
  }

  get start () {
    return this.newRange.start
  }

  get oldExtent () {
    return this.oldRange.getExtent()
  }

  get newExtent () {
    return this.newRange.getExtent()
  }
}