Vim-like search functionality (#112)

* feat: basic command system

* feat: implemented forward search, backward search and `:<slide>`-command

* fix: golint

* fix: removed `fmt.Sprintf`

* fix: proper args splitting, added `goto` example

* refactor: less verbose output, removed `goto`-example

* fix: ignore empty commands

* refactor: remove `:`-commands, moved `search` to `navigation` package

* feat: implemented different search-types: header-search, full-text search (case sensitive, insensitive and regex)

* feat: go to next occurrence with `ctrl+n`

* fix: regex search

* docs: added search instructions

* refactor: removed search types, style changes

* docs: update README.md

* docs: update README.md

* refactor: `GetSlides()` -> `Pages()`, `Buffer` -> `Query`

* feat: use `tea.KeyRunes` to allow international characters (such as `ä` or `動`)

* test: added test for search

* test: added ignore-case flag test

README.md

@@ -142,15 +142,26 @@ Go to the previous slide with any of the following key sequences:
 * number + any of the above (go back n slides)
 
 Go to a specific slide with the following key sequence:
+
 * number + <kbd>G</kbd>
 
 Go to the last slide with the following key:
+
 * <kbd>G</kbd>
 
+### Search
+
+To quickly jump to the right slide, you can use the search function.
+
+Press <kbd>/</kbd>, enter your search term and press <kbd>Enter</kbd>  
+(*The search term is interpreted as a regular expression. The `/i` flag causes case-insensitivity.*).
+
+Press <kbd>ctrl+n</kbd> after a search to go to the next search result.
+
 ### Code Execution
 
-If slides finds a code block on the current slides it can execute the code
-block and display the result as virtual text on the screen.
+If slides finds a code block on the current slides it can execute the code block and display the result as virtual text
+on the screen.
 
 Press <kbd>ctrl+e</kbd> on a slide with a code block to execute it and display the result.
 

internal/model/model.go

@@ -38,6 +38,7 @@ type Model struct {
 	// VirtualText is used for additional information that is not part of the
 	// original slides, it will be displayed on a slide and reset on page change
 	VirtualText string
+	search      navigation.Search
 }
 
 type fileWatchMsg struct{}
@@ -103,7 +104,42 @@ func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 	case tea.KeyMsg:
 		keyPress := msg.String()
 
+		// add key presses to action buffer
+		if m.search.Active {
+			switch msg.Type {
+			case tea.KeyRunes:
+				k := string(msg.Runes)
+				// rune key: append to buffer
+				m.search.Write(k)
+
+			case tea.KeyEnter:
+				// execute current buffer
+				if m.search.Query != "" {
+					m.search.Execute(&m)
+				} else {
+					m.search.Done()
+				}
+
+			case tea.KeyBackspace:
+				// delete last char from buffer
+				m.search.Delete()
+
+			case tea.KeyCtrlC, tea.KeyEscape:
+				// quit command mode
+				m.search.Query = ""
+				m.search.Done()
+			}
+			return m, nil
+		}
+
 		switch keyPress {
+		case "/":
+			// Begin search
+			m.search.Begin()
+			return m, nil
+		case "ctrl+n":
+			// Go to next occurrence
+			m.search.Execute(&m)
 		case "ctrl+e":
 			// Run code blocks
 			blocks, err := code.Parse(m.Slides[m.Page])
@@ -122,8 +158,8 @@ func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 			return m, tea.Quit
 		default:
 			newState := navigation.Navigate(navigation.State{
-				Buffer:    m.buffer,
-				Page:     m.Page,
+				Buffer:      m.buffer,
+				Page:        m.Page,
 				TotalSlides: len(m.Slides),
 			}, keyPress)
 			if newState.Page != m.Page {
@@ -156,7 +192,15 @@ func (m Model) View() string {
 	}
 	slide = styles.Slide.Render(slide)
 
-	left := styles.Author.Render(m.Author) + styles.Date.Render(m.Date)
+	var left string
+	if m.search.Active {
+		// render search bar
+		left = styles.ActionStatus.Render(fmt.Sprintf("/%s", m.search.Query))
+	} else {
+		// render author and date
+		left = styles.Author.Render(m.Author) + styles.Date.Render(m.Date)
+	}
+
 	right := styles.Page.Render(m.paging())
 	status := styles.Status.Render(styles.JoinHorizontal(left, right, m.viewport.Width))
 	return styles.JoinVertical(slide, status, m.viewport.Height)
@@ -227,3 +271,15 @@ func readStdin() (string, error) {
 
 	return b.String(), nil
 }
+
+func (m *Model) CurrentPage() int {
+	return m.Page
+}
+
+func (m *Model) SetPage(page int) {
+	m.Page = page
+}
+
+func (m *Model) Pages() []string {
+	return m.Slides
+}

internal/navigation/search.go

@@ -0,0 +1,84 @@
+package navigation
+
+import (
+	"regexp"
+	"strings"
+)
+
+// Model is an interface for models.model, so that cycle imports are avoided
+type Model interface {
+	CurrentPage() int
+	SetPage(page int)
+	Pages() []string
+}
+
+// Search represents the current search
+type Search struct {
+	// Active - Show search bar instead of author and date?
+	// Store keystrokes in Query?
+	Active bool
+	// Query stores the current "search term"
+	Query string
+}
+
+// Mark Search as
+// Done - Do not delete search buffer
+// This is useful if, for example, you want to jump to the next result
+// and you therefore still need the buffer
+func (s *Search) Done() {
+	s.Active = false
+}
+
+// Begin a new search (deletes old buffer)
+func (s *Search) Begin() {
+	s.Active = true
+	s.Query = ""
+}
+
+// Write a keystroke to the buffer
+func (s *Search) Write(key string) {
+	s.Query += key
+}
+
+// Delete the last keystroke from the buffer
+func (s *Search) Delete() {
+	if len(s.Query) > 0 {
+		s.Query = s.Query[0 : len(s.Query)-1]
+	}
+}
+
+// Execute search
+func (s *Search) Execute(m Model) {
+	defer s.Done()
+	if s.Query == "" {
+		return
+	}
+	expr := s.Query
+	if strings.HasSuffix(expr, "/i") {
+		expr = "(?i)" + expr[:len(expr)-2]
+	}
+	pattern, err := regexp.Compile(expr)
+	if err != nil {
+		return
+	}
+	check := func(i int) bool {
+		content := m.Pages()[i]
+		if len(pattern.FindAllStringSubmatch(content, 1)) != 0 {
+			m.SetPage(i)
+			return true
+		}
+		return false
+	}
+	// search from next slide to end
+	for i := m.CurrentPage() + 1; i < len(m.Pages()); i++ {
+		if check(i) {
+			return
+		}
+	}
+	// search from first slide to previous
+	for i := 0; i < m.CurrentPage(); i++ {
+		if check(i) {
+			return
+		}
+	}
+}

internal/navigation/search_test.go

@@ -0,0 +1,71 @@
+package navigation
+
+import (
+	"testing"
+)
+
+type mockModel struct {
+	slides []string
+	page   int
+}
+
+func (m *mockModel) CurrentPage() int {
+	return m.page
+}
+
+func (m *mockModel) SetPage(page int) {
+	m.page = page
+}
+
+func (m *mockModel) Pages() []string {
+	return m.slides
+}
+
+func TestSearch(t *testing.T) {
+	data := []string{
+		"hi",
+		"first",
+		"second",
+		"third",
+		"AbCdEfG",
+		"abcdefg",
+		"seconds",
+	}
+
+	type query struct {
+		desc     string
+		query    string
+		expected int
+	}
+
+	// query -> expected page
+	queries := []query{
+		{"basic 'first'", "first", 1},
+		{"basic 'abc'", "abc", 5},
+		{"basic 'abc' next occurrence", "abc", 5},
+		{"'abc' ignore case", "abc/i", 4},
+		{"'abc' ignore case", "abc/i", 5},
+		{"'abc' ignore case", "abc/i", 4},
+		{"next occurrence 1/2", "sec", 6},
+		{"next occurrence 2/2", "sec", 2},
+		{"regex", "a.c", 5},
+		{"regex next occurrence", "a.c", 5},
+		{"regex ignore case", "a.c/i", 4},
+		{"regex ignore case next occurrence", "a.c/i", 5},
+	}
+
+	m := &mockModel{
+		slides: data,
+		page:   0,
+	}
+
+	s := &Search{}
+	for _, query := range queries {
+		s.Query = query.query
+		s.Execute(m)
+		if m.CurrentPage() != query.expected {
+			t.Errorf("[%s] expected page %d, got %d", query.desc, query.expected, m.CurrentPage())
+		}
+	}
+
+}

styles/styles.go

@@ -18,11 +18,15 @@ const (
 )
 
 var (
-	Author = lipgloss.NewStyle().Foreground(salmon).Align(lipgloss.Left).MarginLeft(2)
-	Date   = lipgloss.NewStyle().Faint(true).Align(lipgloss.Left).Margin(0, 1)
-	Page   = lipgloss.NewStyle().Foreground(salmon).Align(lipgloss.Right).MarginRight(3)
-	Slide  = lipgloss.NewStyle().Padding(1)
-	Status = lipgloss.NewStyle().Padding(1)
+	Author       = lipgloss.NewStyle().Foreground(salmon).Align(lipgloss.Left).MarginLeft(2)
+	Date         = lipgloss.NewStyle().Faint(true).Align(lipgloss.Left).Margin(0, 1)
+	Page         = lipgloss.NewStyle().Foreground(salmon).Align(lipgloss.Right).MarginRight(3)
+	Slide        = lipgloss.NewStyle().Padding(1)
+	Status       = lipgloss.NewStyle().Padding(1)
+	ActionStatus = lipgloss.NewStyle().
+			Foreground(salmon).
+			Align(lipgloss.Left).
+			MarginLeft(3)
 )
 
 var (