path: root/content_scripts/vimium_frontend.coffee

#
# This content script takes input from its webpage and executes commands locally on behalf of the background
# page. It must be run prior to domReady so that we perform some operations very early. We tell the
# background page that we're in domReady and ready to accept normal commands by connectiong to a port named
# "domReady".
#

findModeQuery = { rawQuery: "", matchCount: 0 }
findModeQueryHasResults = false
findModeAnchorNode = null
findModeInitialRange = null
isShowingHelpDialog = false
keyPort = null
isEnabledForUrl = true
isIncognitoMode = false
passKeys = null
keyQueue = null
# The user's operating system.
currentCompletionKeys = ""
validFirstKeys = ""

# The types in <input type="..."> that we consider for focusInput command. Right now this is recalculated in
# each content script. Alternatively we could calculate it once in the background page and use a request to
# fetch it each time.
# Should we include the HTML5 date pickers here?

# The corresponding XPath for such elements.
textInputXPath = (->
  textInputTypes = [ "text", "search", "email", "url", "number", "password", "date", "tel" ]
  inputElements = ["input[" +
    "(" + textInputTypes.map((type) -> '@type="' + type + '"').join(" or ") + "or not(@type))" +
    " and not(@disabled or @readonly)]",
    "textarea", "*[@contenteditable='' or translate(@contenteditable, 'TRUE', 'true')='true']"]
  DomUtils.makeXPath(inputElements)
)()

#
# settings provides a browser-global localStorage-backed dict. get() and set() are synchronous, but load()
# must be called beforehand to ensure get() will return up-to-date values.
#
settings =
  port: null
  values: {}
  loadedValues: 0
  valuesToLoad: [ "scrollStepSize", "linkHintCharacters", "linkHintNumbers", "filterLinkHints", "hideHud",
    "previousPatterns", "nextPatterns", "regexFindMode", "userDefinedLinkHintCss",
    "helpDialog_showAdvancedCommands", "smoothScroll", "grabBackFocus" ]
  isLoaded: false
  eventListeners: {}

  init: ->
    @port = chrome.runtime.connect({ name: "settings" })
    @port.onMessage.addListener(@receiveMessage)

    # If the port is closed, the background page has gone away (since we never close it ourselves). Stub the
    # settings object so we don't keep trying to connect to the extension even though it's gone away.
    @port.onDisconnect.addListener =>
      @port = null
      for own property, value of this
        # @get doesn't depend on @port, so we can continue to support it to try and reduce errors.
        @[property] = (->) if "function" == typeof value and property != "get"


  get: (key) -> @values[key]

  set: (key, value) ->
    @init() unless @port

    @values[key] = value
    @port.postMessage({ operation: "set", key: key, value: value })

  load: ->
    @init() unless @port

    for i of @valuesToLoad
      @port.postMessage({ operation: "get", key: @valuesToLoad[i] })

  receiveMessage: (args) ->
    # not using 'this' due to issues with binding on callback
    settings.values[args.key] = args.value
    # since load() can be called more than once, loadedValues can be greater than valuesToLoad, but we test
    # for equality so initializeOnReady only runs once
    if (++settings.loadedValues == settings.valuesToLoad.length)
      settings.isLoaded = true
      listener = null
      while (listener = settings.eventListeners["load"].pop())
        listener()

  addEventListener: (eventName, callback) ->
    if (!(eventName of @eventListeners))
      @eventListeners[eventName] = []
    @eventListeners[eventName].push(callback)

#
# Give this frame a unique id.
#
frameId = Math.floor(Math.random()*999999999)

# If an input grabs the focus before the user has interacted with the page, then grab it back (if the
# grabBackFocus option is set).
class GrabBackFocus extends Mode
  constructor: ->
    super
      name: "grab-back-focus"
      keydown: => @alwaysContinueBubbling => @exit()

    @push
      _name: "grab-back-focus-mousedown"
      mousedown: => @alwaysContinueBubbling => @exit()

    activate = =>
      return @exit() unless settings.get "grabBackFocus"
      @push
        _name: "grab-back-focus-focus"
        focus: (event) => @grabBackFocus event.target
      # An input may already be focused. If so, grab back the focus.
      @grabBackFocus document.activeElement if document.activeElement

    if settings.isLoaded then activate() else settings.addEventListener "load", activate

  grabBackFocus: (element) ->
    return @continueBubbling unless DomUtils.isEditable element
    element.blur()
    @suppressEvent

# Only exported for tests.
window.initializeModes = ->
  class NormalMode extends Mode
    constructor: ->
      super
        name: "normal"
        keydown: (event) => onKeydown.call @, event
        keypress: (event) => onKeypress.call @, event
        keyup: (event) => onKeyup.call @, event

  # Install the permanent modes.  The permanently-installed insert mode tracks focus/blur events, and
  # activates/deactivates itself accordingly.
  new BadgeMode
  new NormalMode
  new PassKeysMode
  new InsertMode permanent: true
  new GrabBackFocus
  Scroller.init settings

#
# Complete initialization work that sould be done prior to DOMReady.
#
initializePreDomReady = ->
  settings.addEventListener("load", LinkHints.init.bind(LinkHints))
  settings.load()

  initializeModes()
  checkIfEnabledForUrl true # true means checkIfEnabledForUrl is being called on start up.
  refreshCompletionKeys()

  # Send the key to the key handler in the background page.
  keyPort = chrome.runtime.connect({ name: "keyDown" })
  # If the port is closed, the background page has gone away (since we never close it ourselves). Disable all
  # our event listeners, and stub out chrome.runtime.sendMessage/connect (to prevent errors).
  # TODO(mrmr1993): Do some actual cleanup to free resources, hide UI, etc.
  keyPort.onDisconnect.addListener ->
    isEnabledForUrl = false
    chrome.runtime.sendMessage = ->
    chrome.runtime.connect = ->

  requestHandlers =
    hideUpgradeNotification: -> HUD.hideUpgradeNotification()
    showUpgradeNotification: (request) -> HUD.showUpgradeNotification(request.version)
    showHUDforDuration: (request) -> HUD.showForDuration request.text, request.duration
    toggleHelpDialog: (request) -> toggleHelpDialog(request.dialogHtml, request.frameId)
    focusFrame: (request) -> if (frameId == request.frameId) then focusThisFrame(request.highlight)
    refreshCompletionKeys: refreshCompletionKeys
    getScrollPosition: -> scrollX: window.scrollX, scrollY: window.scrollY
    setScrollPosition: (request) -> setScrollPosition request.scrollX, request.scrollY
    executePageCommand: executePageCommand
    getActiveState: getActiveState
    setState: setState
    currentKeyQueue: (request) ->
      keyQueue = request.keyQueue
      handlerStack.bubbleEvent "registerKeyQueue", { keyQueue: keyQueue }

  chrome.runtime.onMessage.addListener (request, sender, sendResponse) ->
    # In the options page, we will receive requests from both content and background scripts. ignore those
    # from the former.
    return if sender.tab and not sender.tab.url.startsWith 'chrome-extension://'
    return unless isEnabledForUrl or request.name == 'getActiveState' or request.name == 'setState'
    # These requests are delivered to the options page, but there are no handlers there.
    return if request.handler in [ "registerFrame", "frameFocused", "unregisterFrame" ]
    sendResponse requestHandlers[request.name](request, sender)
    # Ensure the sendResponse callback is freed.
    false


# Wrapper to install event listeners.  Syntactic sugar.
installListener = (element, event, callback) ->
  element.addEventListener(event, ->
    if isEnabledForUrl then callback.apply(this, arguments) else true
  , true)

#
# Installing or uninstalling listeners is error prone. Instead we elect to check isEnabledForUrl each time so
# we know whether the listener should run or not.
# Run this as early as possible, so the page can't register any event handlers before us.
#
installedListeners = false
window.initializeWhenEnabled = ->
  unless installedListeners
    # Key event handlers fire on window before they do on document. Prefer window for key events so the page
    # can't set handlers to grab the keys before us.
    for type in [ "keydown", "keypress", "keyup", "click", "focus", "blur", "mousedown" ]
      do (type) -> installListener window, type, (event) -> handlerStack.bubbleEvent type, event
    installListener document, "DOMActivate", (event) -> handlerStack.bubbleEvent 'DOMActivate', event
    installListener window, "focus", registerFocus
    installedListeners = true
    FindModeHistory.init()

setState = (request) ->
  isEnabledForUrl = request.enabled
  passKeys = request.passKeys
  isIncognitoMode = request.incognito
  initializeWhenEnabled() if isEnabledForUrl
  handlerStack.bubbleEvent "registerStateChange",
    enabled: isEnabledForUrl
    passKeys: passKeys

getActiveState = ->
  Mode.updateBadge()
  # getActiveState is called in each frame within the tab.  However, only the response from the first frame is
  # handled on the background page.  Therefore, exclusion rule changes are not propagated to other frames.
  # So, we force a state update for this frame, just in case.
  # FIXME(smblott): This could be avoided if settings were propagated via chrome.storage.
  checkIfEnabledForUrl()
  return enabled: isEnabledForUrl, passKeys: passKeys, url: window.location.toString()

#
# The backend needs to know which frame has focus, and the active URL.
#
registerFocus = ->
  # settings may have changed since the frame last had focus
  settings.load()
  chrome.runtime.sendMessage handler: "frameFocused", frameId: frameId, url: window.location.toString()

#
# Initialization tasks that must wait for the document to be ready.
#
initializeOnDomReady = ->
  # Tell the background page we're in the dom ready state.
  chrome.runtime.connect({ name: "domReady" })
  CursorHider.init()
  Vomnibar.init()

registerFrame = ->
  # Don't register frameset containers; focusing them is no use.
  unless document.body?.tagName.toLowerCase() == "frameset"
    chrome.runtime.sendMessage
      handler: "registerFrame"
      frameId: frameId

# Unregister the frame if we're going to exit.
unregisterFrame = ->
  chrome.runtime.sendMessage
    handler: "unregisterFrame"
    frameId: frameId
    tab_is_closing: window.top == window.self

executePageCommand = (request) ->
  return unless frameId == request.frameId

  if (request.passCountToFunction)
    Utils.invokeCommandString(request.command, [request.count])
  else
    Utils.invokeCommandString(request.command) for i in [0...request.count]

  refreshCompletionKeys(request)

setScrollPosition = (scrollX, scrollY) ->
  if (scrollX > 0 || scrollY > 0)
    DomUtils.documentReady(-> window.scrollTo(scrollX, scrollY))

#
# Called from the backend in order to change frame focus.
#
window.focusThisFrame = (shouldHighlight) ->
  if window.innerWidth < 3 or window.innerHeight < 3
    # This frame is too small to focus. Cancel and tell the background frame to focus the next one instead.
    # This affects sites like Google Inbox, which have many tiny iframes. See #1317.
    # Here we're assuming that there is at least one frame large enough to focus.
    chrome.runtime.sendMessage({ handler: "nextFrame", frameId: frameId })
    return
  window.focus()
  if (document.body && shouldHighlight)
    borderWas = document.body.style.border
    document.body.style.border = '5px solid yellow'
    setTimeout((-> document.body.style.border = borderWas), 200)

extend window,
  scrollToBottom: -> Scroller.scrollTo "y", "max"
  scrollToTop: -> Scroller.scrollTo "y", 0
  scrollToLeft: -> Scroller.scrollTo "x", 0
  scrollToRight: -> Scroller.scrollTo "x", "max"
  scrollUp: -> Scroller.scrollBy "y", -1 * settings.get("scrollStepSize")
  scrollDown: -> Scroller.scrollBy "y", settings.get("scrollStepSize")
  scrollPageUp: -> Scroller.scrollBy "y", "viewSize", -1/2
  scrollPageDown: -> Scroller.scrollBy "y", "viewSize", 1/2
  scrollFullPageUp: -> Scroller.scrollBy "y", "viewSize", -1
  scrollFullPageDown: -> Scroller.scrollBy "y", "viewSize"
  scrollLeft: -> Scroller.scrollBy "x", -1 * settings.get("scrollStepSize")
  scrollRight: -> Scroller.scrollBy "x", settings.get("scrollStepSize")

extend window,
  reload: -> window.location.reload()
  goBack: (count) -> history.go(-count)
  goForward: (count) -> history.go(count)

  goUp: (count) ->
    url = window.location.href
    if (url[url.length - 1] == "/")
      url = url.substring(0, url.length - 1)

    urlsplit = url.split("/")
    # make sure we haven't hit the base domain yet
    if (urlsplit.length > 3)
      urlsplit = urlsplit.slice(0, Math.max(3, urlsplit.length - count))
      window.location.href = urlsplit.join('/')

  goToRoot: () ->
    window.location.href = window.location.origin

  toggleViewSource: ->
    chrome.runtime.sendMessage { handler: "getCurrentTabUrl" }, (url) ->
      if (url.substr(0, 12) == "view-source:")
        url = url.substr(12, url.length - 12)
      else
        url = "view-source:" + url
      chrome.runtime.sendMessage({ handler: "openUrlInNewTab", url: url, selected: true })

  copyCurrentUrl: ->
    # TODO(ilya): When the following bug is fixed, revisit this approach of sending back to the background
    # page to copy.
    # http://code.google.com/p/chromium/issues/detail?id=55188
    chrome.runtime.sendMessage { handler: "getCurrentTabUrl" }, (url) ->
      chrome.runtime.sendMessage { handler: "copyToClipboard", data: url }
      url = url[0..25] + "...." if 28 < url.length
      HUD.showForDuration("Yanked #{url}", 2000)

  enterInsertMode: ->
    # If a focusable element receives the focus, then we exit and leave the permanently-installed insert-mode
    # instance to take over.
    new InsertMode global: true, exitOnFocus: true

  enterVisualMode: ->
    new VisualMode()

  enterVisualLineMode: ->
    new VisualLineMode

  enterEditMode: ->
    @focusInput 1, EditMode

  focusInput: do ->
    # Track the most recently focused input element.
    recentlyFocusedElement = null
    window.addEventListener "focus",
      (event) -> recentlyFocusedElement = event.target if DomUtils.isEditable event.target
    , true

    (count, mode = InsertMode) ->
      # Focus the first input element on the page, and create overlays to highlight all the input elements, with
      # the currently-focused element highlighted specially. Tabbing will shift focus to the next input element.
      # Pressing any other key will remove the overlays and the special tab behavior.
      # The mode argument is the mode to enter once an input is selected.
      resultSet = DomUtils.evaluateXPath textInputXPath, XPathResult.ORDERED_NODE_SNAPSHOT_TYPE
      visibleInputs =
        for i in [0...resultSet.snapshotLength] by 1
          element = resultSet.snapshotItem i
          rect = DomUtils.getVisibleClientRect element
          continue if rect == null
          { element: element, rect: rect }

      if visibleInputs.length == 0
        HUD.showForDuration("There are no inputs to focus.", 1000)
        return

      selectedInputIndex =
        if count == 1
          # As the starting index, we pick that of the most recently focused input element (or 0).
          elements = visibleInputs.map (visibleInput) -> visibleInput.element
          Math.max 0, elements.indexOf recentlyFocusedElement
        else
          Math.min(count, visibleInputs.length) - 1

      hints = for tuple in visibleInputs
        hint = document.createElement "div"
        hint.className = "vimiumReset internalVimiumInputHint vimiumInputHint"

        # minus 1 for the border
        hint.style.left = (tuple.rect.left - 1) + window.scrollX + "px"
        hint.style.top = (tuple.rect.top - 1) + window.scrollY  + "px"
        hint.style.width = tuple.rect.width + "px"
        hint.style.height = tuple.rect.height + "px"

        hint

      new class FocusSelector extends Mode
        constructor: ->
          super
            name: "focus-selector"
            badge: "?"
            exitOnClick: true
            keydown: (event) =>
              if event.keyCode == KeyboardUtils.keyCodes.tab
                hints[selectedInputIndex].classList.remove 'internalVimiumSelectedInputHint'
                selectedInputIndex += hints.length + (if event.shiftKey then -1 else 1)
                selectedInputIndex %= hints.length
                hints[selectedInputIndex].classList.add 'internalVimiumSelectedInputHint'
                # Deactivate any active modes on this element (PostFindMode, or a suspended edit mode).
                @deactivateSingleton visibleInputs[selectedInputIndex].element
                visibleInputs[selectedInputIndex].element.focus()
                @suppressEvent
              else unless event.keyCode == KeyboardUtils.keyCodes.shiftKey
                @exit()
                # Give the new mode the opportunity to handle the event.
                @restartBubbling

          @hintContainingDiv = DomUtils.addElementList hints,
            id: "vimiumInputMarkerContainer"
            className: "vimiumReset"

          # Deactivate any active modes on this element (PostFindMode, or a suspended edit mode).
          @deactivateSingleton visibleInputs[selectedInputIndex].element
          visibleInputs[selectedInputIndex].element.focus()
          if visibleInputs.length == 1
            @exit()
            return
          else
            hints[selectedInputIndex].classList.add 'internalVimiumSelectedInputHint'

        exit: ->
          super()
          DomUtils.removeElement @hintContainingDiv
          if mode and document.activeElement and DomUtils.isEditable document.activeElement
            new mode
              singleton: document.activeElement
              targetElement: document.activeElement

# Track which keydown events we have handled, so that we can subsequently suppress the corresponding keyup
# event.
KeydownEvents =
  handledEvents: {}

  stringify: (event) ->
    JSON.stringify
      metaKey: event.metaKey
      altKey: event.altKey
      ctrlKey: event.ctrlKey
      keyIdentifier: event.keyIdentifier
      keyCode: event.keyCode

  push: (event) ->
    @handledEvents[@stringify event] = true

  # Yields truthy or falsy depending upon whether a corresponding keydown event is present (and removes that
  # event).
  pop: (event) ->
    detailString = @stringify event
    value = @handledEvents[detailString]
    delete @handledEvents[detailString]
    value

#
# Sends everything except i & ESC to the handler in background_page. i & ESC are special because they control
# insert mode which is local state to the page. The key will be are either a single ascii letter or a
# key-modifier pair, e.g. <c-a> for control a.
#
# Note that some keys will only register keydown events and not keystroke events, e.g. ESC.
#
# @/this, here, is the the normal-mode Mode object.
onKeypress = (event) ->
  keyChar = ""

  # Ignore modifier keys by themselves.
  if (event.keyCode > 31)
    keyChar = String.fromCharCode(event.charCode)

    if (keyChar)
      if currentCompletionKeys.indexOf(keyChar) != -1 or isValidFirstKey(keyChar)
        DomUtils.suppressEvent(event)
        keyPort.postMessage({ keyChar:keyChar, frameId:frameId })
        return @stopBubblingAndTrue

      keyPort.postMessage({ keyChar:keyChar, frameId:frameId })

  return @continueBubbling

# @/this, here, is the the normal-mode Mode object.
onKeydown = (event) ->
  keyChar = ""

  # handle special keys, and normal input keys with modifiers being pressed. don't handle shiftKey alone (to
  # avoid / being interpreted as ?
  if (((event.metaKey || event.ctrlKey || event.altKey) && event.keyCode > 31) || (
      # TODO(philc): some events don't have a keyidentifier. How is that possible?
      event.keyIdentifier && event.keyIdentifier.slice(0, 2) != "U+"))
    keyChar = KeyboardUtils.getKeyChar(event)
    # Again, ignore just modifiers. Maybe this should replace the keyCode>31 condition.
    if (keyChar != "")
      modifiers = []

      if (event.shiftKey)
        keyChar = keyChar.toUpperCase()
      if (event.metaKey)
        modifiers.push("m")
      if (event.ctrlKey)
        modifiers.push("c")
      if (event.altKey)
        modifiers.push("a")

      for i of modifiers
        keyChar = modifiers[i] + "-" + keyChar

      if (modifiers.length > 0 || keyChar.length > 1)
        keyChar = "<" + keyChar + ">"

  if (isShowingHelpDialog && KeyboardUtils.isEscape(event))
    hideHelpDialog()
    DomUtils.suppressEvent event
    KeydownEvents.push event
    return @stopBubblingAndTrue

  else
    if (keyChar)
      if (currentCompletionKeys.indexOf(keyChar) != -1 or isValidFirstKey(keyChar))
        DomUtils.suppressEvent event
        KeydownEvents.push event
        keyPort.postMessage({ keyChar:keyChar, frameId:frameId })
        return @stopBubblingAndTrue

      keyPort.postMessage({ keyChar:keyChar, frameId:frameId })

    else if (KeyboardUtils.isEscape(event))
      keyPort.postMessage({ keyChar:"<ESC>", frameId:frameId })

  # Added to prevent propagating this event to other listeners if it's one that'll trigger a Vimium command.
  # The goal is to avoid the scenario where Google Instant Search uses every keydown event to dump us
  # back into the search box. As a side effect, this should also prevent overriding by other sites.
  #
  # Subject to internationalization issues since we're using keyIdentifier instead of charCode (in keypress).
  #
  # TOOD(ilya): Revisit this. Not sure it's the absolute best approach.
  if keyChar == "" &&
     (currentCompletionKeys.indexOf(KeyboardUtils.getKeyChar(event)) != -1 ||
      isValidFirstKey(KeyboardUtils.getKeyChar(event)))
    DomUtils.suppressPropagation(event)
    KeydownEvents.push event
    return @stopBubblingAndTrue

  return @continueBubbling

# @/this, here, is the the normal-mode Mode object.
onKeyup = (event) ->
  return @continueBubbling unless KeydownEvents.pop event
  DomUtils.suppressPropagation(event)
  @stopBubblingAndTrue

checkIfEnabledForUrl = (onStartUp = false) ->
  url = window.location.toString()

  chrome.runtime.sendMessage { handler: "isEnabledForUrl", url: url }, (response) ->
    isEnabledForUrl = response.isEnabledForUrl
    passKeys = response.passKeys
    isIncognitoMode = response.incognito
    if isEnabledForUrl
      initializeWhenEnabled()
    else if onStartUp and HUD.isReady()
      # Quickly hide any HUD we might already be showing, e.g. if we entered insert mode on page load.
      HUD.hide()
    handlerStack.bubbleEvent "registerStateChange",
      enabled: isEnabledForUrl
      passKeys: passKeys

# Exported to window, but only for DOM tests.
window.refreshCompletionKeys = (response) ->
  if (response)
    currentCompletionKeys = response.completionKeys

    if (response.validFirstKeys)
      validFirstKeys = response.validFirstKeys
  else
    chrome.runtime.sendMessage({ handler: "getCompletionKeys" }, refreshCompletionKeys)

isValidFirstKey = (keyChar) ->
  validFirstKeys[keyChar] || /^[1-9]/.test(keyChar)

# This implements find-mode query history (using the "findModeRawQueryList" setting) as a list of raw queries,
# most recent first.
FindModeHistory =
  storage: chrome.storage.local
  key: "findModeRawQueryList"
  max: 50
  rawQueryList: null

  init: ->
    unless @rawQueryList
      @rawQueryList = [] # Prevent repeated initialization.
      @key = "findModeRawQueryListIncognito" if isIncognitoMode
      @storage.get @key, (items) =>
        unless chrome.runtime.lastError
          @rawQueryList = items[@key] if items[@key]
          if isIncognitoMode and not items[@key]
            # This is the first incognito tab, so we need to initialize the incognito-mode query history.
            @storage.get "findModeRawQueryList", (items) =>
              unless chrome.runtime.lastError
                @rawQueryList = items.findModeRawQueryList
                @storage.set findModeRawQueryListIncognito: @rawQueryList

    chrome.storage.onChanged.addListener (changes, area) =>
      @rawQueryList = changes[@key].newValue if changes[@key]

  getQuery: (index = 0) ->
    @rawQueryList[index] or ""

  saveQuery: (query) ->
    if 0 < query.length
      @rawQueryList = @refreshRawQueryList query, @rawQueryList
      newSetting = {}; newSetting[@key] = @rawQueryList
      @storage.set newSetting
      # If there are any active incognito-mode tabs, then propagte this query to those tabs too.
      unless isIncognitoMode
        @storage.get "findModeRawQueryListIncognito", (items) =>
          if not chrome.runtime.lastError and items.findModeRawQueryListIncognito
            @storage.set
              findModeRawQueryListIncognito: @refreshRawQueryList query, items.findModeRawQueryListIncognito

  refreshRawQueryList: (query, rawQueryList) ->
    ([ query ].concat rawQueryList.filter (q) => q != query)[0..@max]

# should be called whenever rawQuery is modified.
updateFindModeQuery = ->
  # the query can be treated differently (e.g. as a plain string versus regex depending on the presence of
  # escape sequences. '\' is the escape character and needs to be escaped itself to be used as a normal
  # character. here we grep for the relevant escape sequences.
  findModeQuery.isRegex = settings.get 'regexFindMode'
  hasNoIgnoreCaseFlag = false
  findModeQuery.parsedQuery = findModeQuery.rawQuery.replace /\\./g, (match) ->
    switch (match)
      when "\\r"
        findModeQuery.isRegex = true
        return ""
      when "\\R"
        findModeQuery.isRegex = false
        return ""
      when "\\I"
        hasNoIgnoreCaseFlag = true
        return ""
      when "\\\\"
        return "\\"
      else
        return match

  # default to 'smartcase' mode, unless noIgnoreCase is explicitly specified
  findModeQuery.ignoreCase = !hasNoIgnoreCaseFlag && !Utils.hasUpperCase(findModeQuery.parsedQuery)

  # Don't count matches in the HUD.
  HUD.hide(true)

  # if we are dealing with a regex, grep for all matches in the text, and then call window.find() on them
  # sequentially so the browser handles the scrolling / text selection.
  if findModeQuery.isRegex
    try
      pattern = new RegExp(findModeQuery.parsedQuery, "g" + (if findModeQuery.ignoreCase then "i" else ""))
    catch error
      # if we catch a SyntaxError, assume the user is not done typing yet and return quietly
      return
    # innerText will not return the text of hidden elements, and strip out tags while preserving newlines
    text = document.body.innerText
    findModeQuery.regexMatches = text.match(pattern)
    findModeQuery.activeRegexIndex = 0
    findModeQuery.matchCount = findModeQuery.regexMatches?.length
  # if we are doing a basic plain string match, we still want to grep for matches of the string, so we can
  # show a the number of results. We can grep on document.body.innerText, as it should be indistinguishable
  # from the internal representation used by window.find.
  else
    # escape all special characters, so RegExp just parses the string 'as is'.
    # Taken from http://stackoverflow.com/questions/3446170/escape-string-for-use-in-javascript-regex
    escapeRegExp = /[\-\[\]\/\{\}\(\)\*\+\?\.\\\^\$\|]/g
    parsedNonRegexQuery = findModeQuery.parsedQuery.replace(escapeRegExp, (char) -> "\\" + char)
    pattern = new RegExp(parsedNonRegexQuery, "g" + (if findModeQuery.ignoreCase then "i" else ""))
    text = document.body.innerText
    findModeQuery.matchCount = text.match(pattern)?.length

updateQueryForFindMode = (rawQuery) ->
  findModeQuery.rawQuery = rawQuery
  updateFindModeQuery()
  performFindInPlace()
  showFindModeHUDForQuery()

handleKeyCharForFindMode = (keyChar) ->
  updateQueryForFindMode findModeQuery.rawQuery + keyChar

handleEscapeForFindMode = ->
  exitFindMode()
  document.body.classList.remove("vimiumFindMode")
  # removing the class does not re-color existing selections. we recreate the current selection so it reverts
  # back to the default color.
  selection = window.getSelection()
  unless selection.isCollapsed
    range = window.getSelection().getRangeAt(0)
    window.getSelection().removeAllRanges()
    window.getSelection().addRange(range)
  focusFoundLink() || selectFoundInputElement()

# Return true if character deleted, false otherwise.
handleDeleteForFindMode = ->
  if findModeQuery.rawQuery.length == 0
    exitFindMode()
    performFindInPlace()
    false
  else
    updateQueryForFindMode findModeQuery.rawQuery.substring(0, findModeQuery.rawQuery.length - 1)
    true

# <esc> sends us into insert mode if possible, but <cr> does not.
# <esc> corresponds approximately to 'nevermind, I have found it already' while <cr> means 'I want to save
# this query and do more searches with it'
handleEnterForFindMode = ->
  exitFindMode()
  focusFoundLink()
  document.body.classList.add("vimiumFindMode")
  FindModeHistory.saveQuery findModeQuery.rawQuery

class FindMode extends Mode
  constructor: ->
    @historyIndex = -1
    @partialQuery = ""
    super
      name: "find"
      badge: "/"
      exitOnEscape: true
      exitOnClick: true

      keydown: (event) =>
        if event.keyCode == keyCodes.backspace || event.keyCode == keyCodes.deleteKey
          @exit() unless handleDeleteForFindMode()
          @suppressEvent
        else if event.keyCode == keyCodes.enter
          handleEnterForFindMode()
          @exit()
          @suppressEvent
        else if event.keyCode == keyCodes.upArrow
          if rawQuery = FindModeHistory.getQuery @historyIndex + 1
            @historyIndex += 1
            @partialQuery = findModeQuery.rawQuery if @historyIndex == 0
            updateQueryForFindMode rawQuery
          @suppressEvent
        else if event.keyCode == keyCodes.downArrow
          @historyIndex = Math.max -1, @historyIndex - 1
          rawQuery = if 0 <= @historyIndex then FindModeHistory.getQuery @historyIndex else @partialQuery
          updateQueryForFindMode rawQuery
          @suppressEvent
        else
          DomUtils.suppressPropagation(event)
          handlerStack.stopBubblingAndFalse

      keypress: (event) ->
        handlerStack.neverContinueBubbling ->
          if event.keyCode > 31
            keyChar = String.fromCharCode event.charCode
            handleKeyCharForFindMode keyChar if keyChar

      keyup: (event) => @suppressEvent

  exit: (event) ->
    super()
    handleEscapeForFindMode() if event?.type == "keydown" and KeyboardUtils.isEscape event
    handleEscapeForFindMode() if event?.type == "click"
    if findModeQueryHasResults and event?.type != "click"
      new PostFindMode

performFindInPlace = ->
  # Restore the selection.  That way, we're always searching forward from the same place, so we find the right
  # match as the user adds matching characters, or removes previously-matched characters. See #1434.
  findModeRestoreSelection()
  query = if findModeQuery.isRegex then getNextQueryFromRegexMatches(0) else findModeQuery.parsedQuery
  findModeQueryHasResults = executeFind(query, { caseSensitive: !findModeQuery.ignoreCase })

# :options is an optional dict. valid parameters are 'caseSensitive' and 'backwards'.
executeFind = (query, options) ->
  result = null
  options = options || {}

  document.body.classList.add("vimiumFindMode")

  # prevent find from matching its own search query in the HUD
  HUD.hide(true)
  # ignore the selectionchange event generated by find()
  document.removeEventListener("selectionchange",restoreDefaultSelectionHighlight, true)
  result = window.find(query, options.caseSensitive, options.backwards, true, false, true, false)
  setTimeout(
    -> document.addEventListener("selectionchange", restoreDefaultSelectionHighlight, true)
    0)

  # We are either in normal mode ("n"), or find mode ("/").  We are not in insert mode.  Nevertheless, if a
  # previous find landed in an editable element, then that element may still be activated.  In this case, we
  # don't want to leave it behind (see #1412).
  if document.activeElement and DomUtils.isEditable document.activeElement
    document.activeElement.blur() unless DomUtils.isSelected document.activeElement

  # we need to save the anchor node here because <esc> seems to nullify it, regardless of whether we do
  # preventDefault()
  findModeAnchorNode = document.getSelection().anchorNode
  result

restoreDefaultSelectionHighlight = -> document.body.classList.remove("vimiumFindMode")

focusFoundLink = ->
  if (findModeQueryHasResults)
    link = getLinkFromSelection()
    link.focus() if link

selectFoundInputElement = ->
  # if the found text is in an input element, getSelection().anchorNode will be null, so we use activeElement
  # instead. however, since the last focused element might not be the one currently pointed to by find (e.g.
  # the current one might be disabled and therefore unable to receive focus), we use the approximate
  # heuristic of checking that the last anchor node is an ancestor of our element.
  if (findModeQueryHasResults && document.activeElement &&
      DomUtils.isSelectable(document.activeElement) &&
      DomUtils.isDOMDescendant(findModeAnchorNode, document.activeElement))
    DomUtils.simulateSelect(document.activeElement)

getNextQueryFromRegexMatches = (stepSize) ->
  # find()ing an empty query always returns false
  return "" unless findModeQuery.regexMatches

  totalMatches = findModeQuery.regexMatches.length
  findModeQuery.activeRegexIndex += stepSize + totalMatches
  findModeQuery.activeRegexIndex %= totalMatches

  findModeQuery.regexMatches[findModeQuery.activeRegexIndex]

window.getFindModeQuery = (backwards) ->
  # check if the query has been changed by a script in another frame
  mostRecentQuery = FindModeHistory.getQuery()
  if (mostRecentQuery != findModeQuery.rawQuery)
    findModeQuery.rawQuery = mostRecentQuery
    updateFindModeQuery()

  if findModeQuery.isRegex
    getNextQueryFromRegexMatches(if backwards then -1 else 1)
  else
    findModeQuery.parsedQuery

findAndFocus = (backwards) ->
  query = getFindModeQuery backwards

  findModeQueryHasResults =
    executeFind(query, { backwards: backwards, caseSensitive: !findModeQuery.ignoreCase })

  if findModeQueryHasResults
    focusFoundLink()
    new PostFindMode() if findModeQueryHasResults
  else
    HUD.showForDuration("No matches for '" + findModeQuery.rawQuery + "'", 1000)

window.performFind = -> findAndFocus()

window.performBackwardsFind = -> findAndFocus(true)

getLinkFromSelection = ->
  node = window.getSelection().anchorNode
  while (node && node != document.body)
    return node if (node.nodeName.toLowerCase() == "a")
    node = node.parentNode
  null

# used by the findAndFollow* functions.
followLink = (linkElement) ->
  if (linkElement.nodeName.toLowerCase() == "link")
    window.location.href = linkElement.href
  else
    # if we can click on it, don't simply set location.href: some next/prev links are meant to trigger AJAX
    # calls, like the 'more' button on GitHub's newsfeed.
    linkElement.scrollIntoView()
    linkElement.focus()
    DomUtils.simulateClick(linkElement)

#
# Find and follow a link which matches any one of a list of strings. If there are multiple such links, they
# are prioritized for shortness, by their position in :linkStrings, how far down the page they are located,
# and finally by whether the match is exact. Practically speaking, this means we favor 'next page' over 'the
# next big thing', and 'more' over 'nextcompany', even if 'next' occurs before 'more' in :linkStrings.
#
findAndFollowLink = (linkStrings) ->
  linksXPath = DomUtils.makeXPath(["a", "*[@onclick or @role='link' or contains(@class, 'button')]"])
  links = DomUtils.evaluateXPath(linksXPath, XPathResult.ORDERED_NODE_SNAPSHOT_TYPE)
  candidateLinks = []

  # at the end of this loop, candidateLinks will contain all visible links that match our patterns
  # links lower in the page are more likely to be the ones we want, so we loop through the snapshot backwards
  for i in [(links.snapshotLength - 1)..0] by -1
    link = links.snapshotItem(i)

    # ensure link is visible (we don't mind if it is scrolled offscreen)
    boundingClientRect = link.getBoundingClientRect()
    if (boundingClientRect.width == 0 || boundingClientRect.height == 0)
      continue
    computedStyle = window.getComputedStyle(link, null)
    if (computedStyle.getPropertyValue("visibility") != "visible" ||
        computedStyle.getPropertyValue("display") == "none")
      continue

    linkMatches = false
    for linkString in linkStrings
      if (link.innerText.toLowerCase().indexOf(linkString) != -1)
        linkMatches = true
        break
    continue unless linkMatches

    candidateLinks.push(link)

  return if (candidateLinks.length == 0)

  for link in candidateLinks
    link.wordCount = link.innerText.trim().split(/\s+/).length

  # We can use this trick to ensure that Array.sort is stable. We need this property to retain the reverse
  # in-page order of the links.

  candidateLinks.forEach((a,i) -> a.originalIndex = i)

  # favor shorter links, and ignore those that are more than one word longer than the shortest link
  candidateLinks =
    candidateLinks
      .sort((a, b) ->
        if (a.wordCount == b.wordCount) then a.originalIndex - b.originalIndex else a.wordCount - b.wordCount
      )
      .filter((a) -> a.wordCount <= candidateLinks[0].wordCount + 1)

  for linkString in linkStrings
    exactWordRegex =
      if /\b/.test(linkString[0]) or /\b/.test(linkString[linkString.length - 1])
        new RegExp "\\b" + linkString + "\\b", "i"
      else
        new RegExp linkString, "i"
    for candidateLink in candidateLinks
      if (exactWordRegex.test(candidateLink.innerText))
        followLink(candidateLink)
        return true
  false

findAndFollowRel = (value) ->
  relTags = ["link", "a", "area"]
  for tag in relTags
    elements = document.getElementsByTagName(tag)
    for element in elements
      if (element.hasAttribute("rel") && element.rel.toLowerCase() == value)
        followLink(element)
        return true

window.goPrevious = ->
  previousPatterns = settings.get("previousPatterns") || ""
  previousStrings = previousPatterns.split(",").filter( (s) -> s.trim().length )
  findAndFollowRel("prev") || findAndFollowLink(previousStrings)

window.goNext = ->
  nextPatterns = settings.get("nextPatterns") || ""
  nextStrings = nextPatterns.split(",").filter( (s) -> s.trim().length )
  findAndFollowRel("next") || findAndFollowLink(nextStrings)

showFindModeHUDForQuery = ->
  if findModeQuery.rawQuery and (findModeQueryHasResults || findModeQuery.parsedQuery.length == 0)
    plural = if findModeQuery.matchCount == 1 then "" else "es"
    HUD.show("/" + findModeQuery.rawQuery + " (" + findModeQuery.matchCount + " Match#{plural})")
  else if findModeQuery.rawQuery
    HUD.show("/" + findModeQuery.rawQuery + " (No Matches)")
  else
    HUD.show("/")

getCurrentRange = ->
  selection = getSelection()
  if selection.type == "None"
    range = document.createRange()
    range.setStart document.body, 0
    range.setEnd document.body, 0
    range
  else
    selection.collapseToStart() if selection.type == "Range"
    selection.getRangeAt 0

findModeSaveSelection = ->
  findModeInitialRange = getCurrentRange()

findModeRestoreSelection = (range = findModeInitialRange) ->
  selection = getSelection()
  selection.removeAllRanges()
  selection.addRange range

# Enters find mode.  Returns the new find-mode instance.
window.enterFindMode = ->
  # Save the selection, so performFindInPlace can restore it.
  findModeSaveSelection()
  findModeQuery = { rawQuery: "" }
  HUD.show("/")
  new FindMode()

exitFindMode = ->
  HUD.hide()

window.showHelpDialog = (html, fid) ->
  return if (isShowingHelpDialog || !document.body || fid != frameId)
  isShowingHelpDialog = true
  container = document.createElement("div")
  container.id = "vimiumHelpDialogContainer"
  container.className = "vimiumReset"

  document.body.appendChild(container)

  container.innerHTML = html
  container.getElementsByClassName("closeButton")[0].addEventListener("click", hideHelpDialog, false)

  VimiumHelpDialog =
    # This setting is pulled out of local storage. It's false by default.
    getShowAdvancedCommands: -> settings.get("helpDialog_showAdvancedCommands")

    init: () ->
      this.dialogElement = document.getElementById("vimiumHelpDialog")
      this.dialogElement.getElementsByClassName("toggleAdvancedCommands")[0].addEventListener("click",
        VimiumHelpDialog.toggleAdvancedCommands, false)
      this.dialogElement.style.maxHeight = window.innerHeight - 80
      this.showAdvancedCommands(this.getShowAdvancedCommands())

    #
    # Advanced commands are hidden by default so they don't overwhelm new and casual users.
    #
    toggleAdvancedCommands: (event) ->
      event.preventDefault()
      showAdvanced = VimiumHelpDialog.getShowAdvancedCommands()
      VimiumHelpDialog.showAdvancedCommands(!showAdvanced)
      settings.set("helpDialog_showAdvancedCommands", !showAdvanced)

    showAdvancedCommands: (visible) ->
      VimiumHelpDialog.dialogElement.getElementsByClassName("toggleAdvancedCommands")[0].innerHTML =
        if visible then "Hide advanced commands" else "Show advanced commands"
      advancedEls = VimiumHelpDialog.dialogElement.getElementsByClassName("advanced")
      for el in advancedEls
        el.style.display = if visible then "table-row" else "none"

  VimiumHelpDialog.init()

  container.getElementsByClassName("optionsPage")[0].addEventListener("click", (clickEvent) ->
      clickEvent.preventDefault()
      chrome.runtime.sendMessage({handler: "openOptionsPageInNewTab"})
    false)


hideHelpDialog = (clickEvent) ->
  isShowingHelpDialog = false
  helpDialog = document.getElementById("vimiumHelpDialogContainer")
  if (helpDialog)
    helpDialog.parentNode.removeChild(helpDialog)
  if (clickEvent)
    clickEvent.preventDefault()

toggleHelpDialog = (html, fid) ->
  if (isShowingHelpDialog)
    hideHelpDialog()
  else
    showHelpDialog(html, fid)

#
# A heads-up-display (HUD) for showing Vimium page operations.
# Note: you cannot interact with the HUD until document.body is available.
#
HUD =
  _tweenId: -1
  _displayElement: null
  _upgradeNotificationElement: null

  # This HUD is styled to precisely mimick the chrome HUD on Mac. Use the "has_popup_and_link_hud.html"
  # test harness to tweak these styles to match Chrome's. One limitation of our HUD display is that
  # it doesn't sit on top of horizontal scrollbars like Chrome's HUD does.

  showForDuration: (text, duration) ->
    HUD.show(text)
    HUD._showForDurationTimerId = setTimeout((-> HUD.hide()), duration)

  show: (text) ->
    return unless HUD.enabled()
    clearTimeout(HUD._showForDurationTimerId)
    HUD.displayElement().innerText = text
    clearInterval(HUD._tweenId)
    HUD._tweenId = Tween.fade(HUD.displayElement(), 1.0, 150)
    HUD.displayElement().style.display = ""

  showUpgradeNotification: (version) ->
    HUD.upgradeNotificationElement().innerHTML = "Vimium has been upgraded to #{version}. See
      <a class='vimiumReset' target='_blank'
      href='https://github.com/philc/vimium#release-notes'>
      what's new</a>.<a class='vimiumReset close-button' href='#'>&times;</a>"
    links = HUD.upgradeNotificationElement().getElementsByTagName("a")
    links[0].addEventListener("click", HUD.onUpdateLinkClicked, false)
    links[1].addEventListener "click", (event) ->
      event.preventDefault()
      HUD.onUpdateLinkClicked()
    Tween.fade(HUD.upgradeNotificationElement(), 1.0, 150)

  onUpdateLinkClicked: (event) ->
    HUD.hideUpgradeNotification()
    chrome.runtime.sendMessage({ handler: "upgradeNotificationClosed" })

  hideUpgradeNotification: (clickEvent) ->
    Tween.fade(HUD.upgradeNotificationElement(), 0, 150,
      -> HUD.upgradeNotificationElement().style.display = "none")

  #
  # Retrieves the HUD HTML element.
  #
  displayElement: ->
    if (!HUD._displayElement)
      HUD._displayElement = HUD.createHudElement()
      # Keep this far enough to the right so that it doesn't collide with the "popups blocked" chrome HUD.
      HUD._displayElement.style.right = "150px"
    HUD._displayElement

  upgradeNotificationElement: ->
    if (!HUD._upgradeNotificationElement)
      HUD._upgradeNotificationElement = HUD.createHudElement()
      # Position this just to the left of our normal HUD.
      HUD._upgradeNotificationElement.style.right = "315px"
    HUD._upgradeNotificationElement

  createHudElement: ->
    element = document.createElement("div")
    element.className = "vimiumReset vimiumHUD"
    document.body.appendChild(element)
    element

  hide: (immediate) ->
    clearInterval(HUD._tweenId)
    if (immediate)
      HUD.displayElement().style.display = "none"
    else
      HUD._tweenId = Tween.fade(HUD.displayElement(), 0, 150,
        -> HUD.displayElement().style.display = "none")

  isReady: -> document.body != null

  # A preference which can be toggled in the Options page. */
  enabled: -> !settings.get("hideHud")

Tween =
  #
  # Fades an element's alpha. Returns a timer ID which can be used to stop the tween via clearInterval.
  #
  fade: (element, toAlpha, duration, onComplete) ->
    state = {}
    state.duration = duration
    state.startTime = (new Date()).getTime()
    state.from = parseInt(element.style.opacity) || 0
    state.to = toAlpha
    state.onUpdate = (value) ->
      element.style.opacity = value
      if (value == state.to && onComplete)
        onComplete()
    state.timerId = setInterval((-> Tween.performTweenStep(state)), 50)
    state.timerId

  performTweenStep: (state) ->
    elapsed = (new Date()).getTime() - state.startTime
    if (elapsed >= state.duration)
      clearInterval(state.timerId)
      state.onUpdate(state.to)
    else
      value = (elapsed / state.duration)  * (state.to - state.from) + state.from
      state.onUpdate(value)

CursorHider =
  #
  # Hide the cursor when the browser scrolls, and prevent mouse from hovering while invisible.
  #
  cursorHideStyle: null
  isScrolling: false

  onScroll: (event) ->
    CursorHider.isScrolling = true
    unless CursorHider.cursorHideStyle.parentElement
      document.head.appendChild CursorHider.cursorHideStyle

  onMouseMove: (event) ->
    if CursorHider.cursorHideStyle.parentElement and not CursorHider.isScrolling
      CursorHider.cursorHideStyle.remove()
    CursorHider.isScrolling = false

  init: ->
    # Temporarily disabled pending consideration of #1359 (in particular, whether cursor hiding is too fragile
    # as to provide a consistent UX).
    return

    # Disable cursor hiding for Chrome versions less than 39.0.2171.71 due to a suspected browser error.
    # See #1345 and #1348.
    return unless Utils.haveChromeVersion "39.0.2171.71"

    @cursorHideStyle = document.createElement("style")
    @cursorHideStyle.innerHTML = """
      body * {pointer-events: none !important; cursor: none !important;}
      body, html {cursor: none !important;}
    """
    window.addEventListener "mousemove", @onMouseMove
    window.addEventListener "scroll", @onScroll

initializePreDomReady()
DomUtils.documentReady initializeOnDomReady
DomUtils.documentReady registerFrame
window.addEventListener "unload", unregisterFrame

window.onbeforeunload = ->
  chrome.runtime.sendMessage(
    handler: "updateScrollPosition"
    scrollX: window.scrollX
    scrollY: window.scrollY)

root = exports ? window
root.settings = settings
root.HUD = HUD
root.handlerStack = handlerStack
root.frameId = frameId