/**
 * Perf optimization: Hook into require() to modify how certain modules load:
 *
 * - `inline-style-prefixer` (used by `material-ui`) takes ~40ms. It is not
 *   actually used because auto-prefixing is disabled with
 *   `darkBaseTheme.userAgent = false`. Return a fake object.
 */
let Module = require('module')
const _require = Module.prototype.require
Module.prototype.require = function (id) {
  if (id === 'inline-style-prefixer') return {}
  return _require.apply(this, arguments)
}

console.time('init')

const crashReporter = require('../crash-reporter')
crashReporter.init()

// Perf optimization: Start asynchronously read on config file before all the
// blocking require() calls below.

const State = require('./lib/state')
State.load(onState)

const createGetter = require('fn-getter')
const dragDrop = require('drag-drop')
const electron = require('electron')
const fs = require('fs')
const React = require('react')
const ReactDOM = require('react-dom')

const config = require('../config')
const telemetry = require('./lib/telemetry')
const sound = require('./lib/sound')
const TorrentPlayer = require('./lib/torrent-player')

// Perf optimization: Needed immediately, so do not lazy load it below
const TorrentListController = require('./controllers/torrent-list-controller')

// Required by Material UI -- adds `onTouchTap` event
require('react-tap-event-plugin')()

const App = require('./pages/app')

// Electron apps have two processes: a main process (node) runs first and starts
// a renderer process (essentially a Chrome window). We're in the renderer process,
// and this IPC channel receives from and sends messages to the main process
const ipcRenderer = electron.ipcRenderer

// Yo-yo pattern: state object lives here and percolates down thru all the views.
// Events come back up from the views via dispatch(...)
require('./lib/dispatcher').setDispatch(dispatch)

// From dispatch(...), events are sent to one of the controllers
let controllers = null

// This dependency is the slowest-loading, so we lazy load it
let Cast = null

// All state lives in state.js. `state.saved` is read from and written to a file.
// All other state is ephemeral. First we load state.saved then initialize the app.
let state

// Root React component
let app

// Called once when the application loads. (Not once per window.)
// Connects to the torrent networks, sets up the UI and OS integrations like
// the dock icon and drag+drop.
function onState (err, _state) {
  if (err) return onError(err)

  // Make available for easier debugging
  state = window.state = _state
  window.dispatch = dispatch

  telemetry.init(state)

  // Log uncaught JS errors
  window.addEventListener(
    'error', (e) => telemetry.logUncaughtError('window', e), true /* capture */
  )

  // Create controllers
  controllers = {
    media: createGetter(() => {
      const MediaController = require('./controllers/media-controller')
      return new MediaController(state)
    }),
    playback: createGetter(() => {
      const PlaybackController = require('./controllers/playback-controller')
      return new PlaybackController(state, config, update)
    }),
    prefs: createGetter(() => {
      const PrefsController = require('./controllers/prefs-controller')
      return new PrefsController(state, config)
    }),
    subtitles: createGetter(() => {
      const SubtitlesController = require('./controllers/subtitles-controller')
      return new SubtitlesController(state)
    }),
    torrent: createGetter(() => {
      const TorrentController = require('./controllers/torrent-controller')
      return new TorrentController(state)
    }),
    torrentList: createGetter(() => {
      return new TorrentListController(state)
    }),
    update: createGetter(() => {
      const UpdateController = require('./controllers/update-controller')
      return new UpdateController(state)
    })
  }

  // Add first page to location history
  state.location.go({
    url: 'home',
    setup: (cb) => {
      state.window.title = config.APP_WINDOW_TITLE
      cb(null)
    }
  })

  // Restart everything we were torrenting last time the app ran
  resumeTorrents()

  // Initialize ReactDOM
  app = ReactDOM.render(<App state={state} />, document.querySelector('#body'))

  // Calling update() updates the UI given the current state
  // Do this at least once a second to give every file in every torrentSummary
  // a progress bar and to keep the cursor in sync when playing a video
  setInterval(update, 1000)

  // Listen for messages from the main process
  setupIpc()

  // Drag and drop files/text to start torrenting or seeding
  dragDrop('body', {
    onDrop: onOpen,
    onDropText: onOpen
  })

  // ...same thing if you paste a torrent
  document.addEventListener('paste', onPaste)

  // ...focus and blur. Needed to show correct dock icon text ('badge') in OSX
  window.addEventListener('focus', onFocus)
  window.addEventListener('blur', onBlur)

  if (electron.remote.getCurrentWindow().isVisible()) {
    sound.play('STARTUP')
  }

  // To keep app startup fast, some code is delayed.
  window.setTimeout(delayedInit, config.DELAYED_INIT)

  // Done! Ideally we want to get here < 500ms after the user clicks the app
  console.timeEnd('init')
}

// Runs a few seconds after the app loads, to avoid slowing down startup time
function delayedInit () {
  telemetry.send(state)

  // Send telemetry data every 12 hours, for users who keep the app running
  // for extended periods of time
  setInterval(() => telemetry.send(state), 12 * 3600 * 1000)

  // Warn if the download dir is gone, eg b/c an external drive is unplugged
  checkDownloadPath()

  // ...window visibility state.
  document.addEventListener('webkitvisibilitychange', onVisibilityChange)
  onVisibilityChange()

  lazyLoadCast()
}

// Lazily loads Chromecast and Airplay support
function lazyLoadCast () {
  if (!Cast) {
    Cast = require('./lib/cast')
    Cast.init(state, update) // Search the local network for Chromecast and Airplays
  }
  return Cast
}

// React loop:
// 1. update() - recompute the virtual DOM, diff, apply to the real DOM
// 2. event - might be a click or other DOM event, or something external
// 3. dispatch - the event handler calls dispatch(), main.js sends it to a controller
// 4. controller - the controller handles the event, changing the state object
function update () {
  controllers.playback().showOrHidePlayerControls()
  app.setState(state)
  updateElectron()
}

// Some state changes can't be reflected in the DOM, instead we have to
// tell the main process to update the window or OS integrations
function updateElectron () {
  if (state.window.title !== state.prev.title) {
    state.prev.title = state.window.title
    ipcRenderer.send('setTitle', state.window.title)
  }
  if (state.dock.progress.toFixed(2) !== state.prev.progress.toFixed(2)) {
    state.prev.progress = state.dock.progress
    ipcRenderer.send('setProgress', state.dock.progress)
  }
  if (state.dock.badge !== state.prev.badge) {
    state.prev.badge = state.dock.badge
    ipcRenderer.send('setBadge', state.dock.badge || 0)
  }
}

const dispatchHandlers = {
  // Torrent list: creating, deleting, selecting torrents
  'openTorrentFile': () => ipcRenderer.send('openTorrentFile'),
  'openFiles': () => ipcRenderer.send('openFiles'), /* shows the open file dialog */
  'openTorrentAddress': () => { state.modal = { id: 'open-torrent-address-modal' } },

  'addTorrent': (torrentId) => controllers.torrentList().addTorrent(torrentId),
  'showCreateTorrent': (paths) => controllers.torrentList().showCreateTorrent(paths),
  'createTorrent': (options) => controllers.torrentList().createTorrent(options),
  'toggleTorrent': (infoHash) => controllers.torrentList().toggleTorrent(infoHash),
  'pauseAllTorrents': () => controllers.torrentList().pauseAllTorrents(),
  'resumeAllTorrents': () => controllers.torrentList().resumeAllTorrents(),
  'toggleTorrentFile': (infoHash, index) =>
    controllers.torrentList().toggleTorrentFile(infoHash, index),
  'confirmDeleteTorrent': (infoHash, deleteData) =>
    controllers.torrentList().confirmDeleteTorrent(infoHash, deleteData),
  'deleteTorrent': (infoHash, deleteData) =>
    controllers.torrentList().deleteTorrent(infoHash, deleteData),
  'toggleSelectTorrent': (infoHash) =>
    controllers.torrentList().toggleSelectTorrent(infoHash),
  'openTorrentContextMenu': (infoHash) =>
    controllers.torrentList().openTorrentContextMenu(infoHash),
  'startTorrentingSummary': (torrentKey) =>
    controllers.torrentList().startTorrentingSummary(torrentKey),
  'saveTorrentFileAs': (torrentKey) =>
    controllers.torrentList().saveTorrentFileAs(torrentKey),

  // Playback
  'playFile': (infoHash, index) => controllers.playback().playFile(infoHash, index),
  'playPause': () => controllers.playback().playPause(),
  'nextTrack': () => controllers.playback().nextTrack(),
  'previousTrack': () => controllers.playback().previousTrack(),
  'skip': (time) => controllers.playback().skip(time),
  'skipTo': (time) => controllers.playback().skipTo(time),
  'changePlaybackRate': (dir) => controllers.playback().changePlaybackRate(dir),
  'changeVolume': (delta) => controllers.playback().changeVolume(delta),
  'setVolume': (vol) => controllers.playback().setVolume(vol),
  'openItem': (infoHash, index) => controllers.playback().openItem(infoHash, index),

  // Subtitles
  'openSubtitles': () => controllers.subtitles().openSubtitles(),
  'selectSubtitle': (index) => controllers.subtitles().selectSubtitle(index),
  'toggleSubtitlesMenu': () => controllers.subtitles().toggleSubtitlesMenu(),
  'checkForSubtitles': () => controllers.subtitles().checkForSubtitles(),
  'addSubtitles': (files, autoSelect) => controllers.subtitles().addSubtitles(files, autoSelect),

  // Local media: <video>, <audio>, external players
  'mediaStalled': () => controllers.media().mediaStalled(),
  'mediaError': (err) => controllers.media().mediaError(err),
  'mediaSuccess': () => controllers.media().mediaSuccess(),
  'mediaTimeUpdate': () => controllers.media().mediaTimeUpdate(),
  'mediaMouseMoved': () => controllers.media().mediaMouseMoved(),
  'mediaControlsMouseEnter': () => controllers.media().controlsMouseEnter(),
  'mediaControlsMouseLeave': () => controllers.media().controlsMouseLeave(),
  'openExternalPlayer': () => controllers.media().openExternalPlayer(),
  'externalPlayerNotFound': () => controllers.media().externalPlayerNotFound(),

  // Remote casting: Chromecast, Airplay, etc
  'toggleCastMenu': (deviceType) => lazyLoadCast().toggleMenu(deviceType),
  'selectCastDevice': (index) => lazyLoadCast().selectDevice(index),
  'stopCasting': () => lazyLoadCast().stop(),

  // Preferences screen
  'preferences': () => controllers.prefs().show(),
  'updatePreferences': (key, value) => controllers.prefs().update(key, value),
  'checkDownloadPath': checkDownloadPath,

  // Update (check for new versions on Linux, where there's no auto updater)
  'updateAvailable': (version) => controllers.update().updateAvailable(version),
  'skipVersion': (version) => controllers.update().skipVersion(version),

  // Navigation between screens (back, forward, ESC, etc)
  'exitModal': () => { state.modal = null },
  'backToList': backToList,
  'escapeBack': escapeBack,
  'back': () => state.location.back(),
  'forward': () => state.location.forward(),
  'cancel': () => state.location.cancel(),

  // Controlling the window
  'setDimensions': setDimensions,
  'toggleFullScreen': (setTo) => ipcRenderer.send('toggleFullScreen', setTo),
  'setTitle': (title) => { state.window.title = title },
  'resetTitle': () => { state.window.title = config.APP_WINDOW_TITLE },

  // Everything else
  'onOpen': onOpen,
  'error': onError,
  'uncaughtError': (proc, err) => telemetry.logUncaughtError(proc, err),
  'stateSave': () => State.save(state),
  'stateSaveImmediate': () => State.saveImmediate(state),
  'update': () => {} // No-op, just trigger an update
}

// Events from the UI never modify state directly. Instead they call dispatch()
function dispatch (action, ...args) {
  // Log dispatch calls, for debugging, but don't spam
  if (!['mediaMouseMoved', 'mediaTimeUpdate', 'update'].includes(action)) {
    console.log('dispatch: %s %o', action, args)
  }

  const handler = dispatchHandlers[action]
  if (handler) handler(...args)
  else console.error('Missing dispatch handler: ' + action)

  // Update the virtual DOM, unless it's just a mouse move event
  if (action !== 'mediaMouseMoved' ||
      controllers.playback().showOrHidePlayerControls()) {
    update()
  }
}

// Listen to events from the main and webtorrent processes
function setupIpc () {
  ipcRenderer.on('log', (e, ...args) => console.log(...args))
  ipcRenderer.on('error', (e, ...args) => console.error(...args))

  ipcRenderer.on('dispatch', (e, ...args) => dispatch(...args))

  ipcRenderer.on('fullscreenChanged', onFullscreenChanged)
  ipcRenderer.on('windowBoundsChanged', onWindowBoundsChanged)

  const tc = controllers.torrent()
  ipcRenderer.on('wt-infohash', (e, ...args) => tc.torrentInfoHash(...args))
  ipcRenderer.on('wt-metadata', (e, ...args) => tc.torrentMetadata(...args))
  ipcRenderer.on('wt-done', (e, ...args) => tc.torrentDone(...args))
  ipcRenderer.on('wt-warning', (e, ...args) => tc.torrentWarning(...args))
  ipcRenderer.on('wt-error', (e, ...args) => tc.torrentError(...args))

  ipcRenderer.on('wt-progress', (e, ...args) => tc.torrentProgress(...args))
  ipcRenderer.on('wt-file-modtimes', (e, ...args) => tc.torrentFileModtimes(...args))
  ipcRenderer.on('wt-file-saved', (e, ...args) => tc.torrentFileSaved(...args))
  ipcRenderer.on('wt-poster', (e, ...args) => tc.torrentPosterSaved(...args))
  ipcRenderer.on('wt-audio-metadata', (e, ...args) => tc.torrentAudioMetadata(...args))
  ipcRenderer.on('wt-server-running', (e, ...args) => tc.torrentServerRunning(...args))

  ipcRenderer.on('wt-uncaught-error', (e, err) => telemetry.logUncaughtError('webtorrent', err))

  ipcRenderer.send('ipcReady')

  State.on('stateSaved', () => ipcRenderer.send('stateSaved'))
}

// Quits any modal popovers and returns to the torrent list screen
function backToList () {
  // Exit any modals and screens with a back button
  state.modal = null
  state.location.backToFirst(function () {
    // If we were already on the torrent list, scroll to the top
    const contentTag = document.querySelector('.content')
    if (contentTag) contentTag.scrollTop = 0
  })
}

// Quits modals, full screen, or goes back. Happens when the user hits ESC
function escapeBack () {
  if (state.modal) {
    dispatch('exitModal')
  } else if (state.window.isFullScreen) {
    dispatch('toggleFullScreen')
  } else {
    dispatch('back')
  }
}

// Starts all torrents that aren't paused on program startup
function resumeTorrents () {
  state.saved.torrents
    .map((torrentSummary) => {
      // Torrent keys are ephemeral, reassigned each time the app runs.
      // On startup, give all torrents a key, even the ones that are paused.
      torrentSummary.torrentKey = state.nextTorrentKey++
      return torrentSummary
    })
    .filter((s) => s.status !== 'paused')
    .forEach((s) => controllers.torrentList().startTorrentingSummary(s.torrentKey))
}

// Set window dimensions to match video dimensions or fill the screen
function setDimensions (dimensions) {
  // Don't modify the window size if it's already maximized
  if (electron.remote.getCurrentWindow().isMaximized()) {
    state.window.bounds = null
    return
  }

  // Save the bounds of the window for later. See restoreBounds()
  state.window.bounds = {
    x: window.screenX,
    y: window.screenY,
    width: window.outerWidth,
    height: window.outerHeight
  }
  state.window.wasMaximized = electron.remote.getCurrentWindow().isMaximized

  // Limit window size to screen size
  const screenWidth = window.screen.width
  const screenHeight = window.screen.height
  const aspectRatio = dimensions.width / dimensions.height
  const scaleFactor = Math.min(
    Math.min(screenWidth / dimensions.width, 1),
    Math.min(screenHeight / dimensions.height, 1)
  )
  const width = Math.max(
    Math.floor(dimensions.width * scaleFactor),
    config.WINDOW_MIN_WIDTH
  )
  const height = Math.max(
    Math.floor(dimensions.height * scaleFactor),
    config.WINDOW_MIN_HEIGHT
  )

  ipcRenderer.send('setAspectRatio', aspectRatio)
  ipcRenderer.send('setBounds', {contentBounds: true, x: null, y: null, width, height})
  state.playing.aspectRatio = aspectRatio
}

// Called when the user adds files (.torrent, files to seed, subtitles) to the app
// via any method (drag-drop, drag to app icon, command line)
function onOpen (files) {
  if (!Array.isArray(files)) files = [ files ]

  const url = state.location.url()
  const allTorrents = files.every(TorrentPlayer.isTorrent)
  const allSubtitles = files.every(controllers.subtitles().isSubtitle)

  if (allTorrents) {
    // Drop torrents onto the app: go to home screen, add torrents, no matter what
    dispatch('backToList')
    // All .torrent files? Add them.
    files.forEach((file) => controllers.torrentList().addTorrent(file))
  } else if (url === 'player' && allSubtitles) {
    // Drop subtitles onto a playing video: add subtitles
    controllers.subtitles().addSubtitles(files, true)
  } else if (url === 'home') {
    // Drop files onto home screen: show Create Torrent
    state.modal = null
    controllers.torrentList().showCreateTorrent(files)
  } else {
    // Drop files onto any other screen: show error
    return onError('Please go back to the torrent list before creating a new torrent.')
  }

  update()
}

function onError (err) {
  console.error(err.stack || err)
  sound.play('ERROR')
  state.errors.push({
    time: new Date().getTime(),
    message: err.message || err
  })

  update()
}

const editableHtmlTags = new Set(['input', 'textarea'])

function onPaste (e) {
  if (editableHtmlTags.has(e.target.tagName.toLowerCase())) return
  controllers.torrentList().addTorrent(electron.clipboard.readText())

  update()
}

function onFocus (e) {
  state.window.isFocused = true
  state.dock.badge = 0
  update()
}

function onBlur () {
  state.window.isFocused = false
  update()
}

function onVisibilityChange () {
  state.window.isVisible = !document.webkitHidden
}

function onFullscreenChanged (e, isFullScreen) {
  state.window.isFullScreen = isFullScreen
  if (!isFullScreen) {
    // Aspect ratio gets reset in fullscreen mode, so restore it (Mac)
    ipcRenderer.send('setAspectRatio', state.playing.aspectRatio)
  }

  update()
}

function onWindowBoundsChanged (e, newBounds) {
  if (state.location.url() !== 'player') {
    state.saved.bounds = newBounds
    dispatch('stateSave')
  }
}

function checkDownloadPath () {
  fs.stat(state.saved.prefs.downloadPath, function (err, stat) {
    if (err) {
      state.downloadPathStatus = 'missing'
      return console.error(err)
    }
    if (stat.isDirectory()) state.downloadPathStatus = 'ok'
    else state.downloadPathStatus = 'missing'
  })
}