#!/usr/bin/env node

var fs = require('fs')
var exec = require('child_process').exec
var async = require('../build/node_modules/async')

var branchName, leadingBranchName

async.series([
  parseArguments,
  checkCleanWorkingTree,
  checkoutBranch,
  pullUpstreamChanges,
  mergeLeadingBranch,
  fetchUpstreamTags,
  updateVersionNumber,
  pushLocalChanges,
  pushLocalTags,
], finish)

function parseArguments(next) {
  branchName = process.argv[2]
  switch (branchName) {
    case 'beta':
      leadingBranchName = 'master'
      break
    case 'stable':
      leadingBranchName = 'beta'
      break
    default:
      return next(new Error('Usage: script/railcar <beta|stable>'))
  }
  next()
}

function checkCleanWorkingTree(next) {
  console.log('Checking for a clean working tree');
  exec('git status --porcelain', function(error, output) {
    var modifiedEntries = output.split('\n').filter(function(line) {
      return !/^\?\?/.test(line) && line.length > 0
    });

    next(
      modifiedEntries.length === 0 ?
      null  :
      new Error('Cannot run the railcars with a dirty working tree')
    )
  })
}

function checkoutBranch(next) {
  console.log('Checking out ' + branchName);
  exec('git checkout ' + branchName, next)
}

function pullUpstreamChanges(next) {
  console.log('Pulling upstream changes on ' + branchName);
  exec('git pull --ff-only origin ' + branchName, next)
}

function mergeLeadingBranch(next) {
  console.log('Merging new changes from ' + leadingBranchName);
  exec('git pull --ff-only origin ' + leadingBranchName, next)
}

function fetchUpstreamTags(next) {
  console.log('Fetching upstream tags');
  exec('git fetch --tags', next)
}

function updateVersionNumber(next) {
  var newVersion
  if (branchName === 'beta') {
    newVersion = require('../package.json')
      .version
      .replace(/-\w+$/, '-beta-0')
  } else {
    newVersion = 'patch'
  }

  console.log('Updating version to ' + newVersion);
  exec('npm version ' + newVersion, next)
}

function pushLocalChanges(next) {
  console.log('Pushing local changes');
  exec('git push origin ' + branchName, next)
}

function pushLocalTags(next) {
  console.log('Pushing local tags');
  exec('git push --tags origin', next)
}

function finish(error) {
  if (error) {
    console.log('Error: ' + error.message)
    process.exit(1)
  }

  console.log('Success! Now just wait for all CI builds to pass on ' + branchName)
}