_ = require 'underscore'
React = require 'react'

{Utils,
 DOMUtils,
 DraftStore} = require 'nylas-exports'

ClipboardService = require './clipboard-service'
FloatingToolbarContainer = require './floating-toolbar-container'

class ContenteditableComponent extends React.Component
  @displayName: "ContenteditableComponent"
  @propTypes:
    html: React.PropTypes.string
    initialSelectionSnapshot: React.PropTypes.object

    filters: React.PropTypes.array
    footerElements: React.PropTypes.node

    # Passes an absolute top coordinate to scroll to.
    onChange: React.PropTypes.func.isRequired
    onFilePaste: React.PropTypes.func
    onScrollTo: React.PropTypes.func
    onScrollToBottom: React.PropTypes.func

  @defaultProps:
    filters: []

  constructor: (@props) ->
    @innerState = {}
    @_setupServices(@props)

  _setupServices: (props) ->
    @clipboardService = new ClipboardService
      onFilePaste: props.onFilePaste

  setInnerState: (innerState={}) ->
    @innerState = _.extend @innerState, innerState
    @refs["toolbarController"]?.componentWillReceiveInnerProps(innerState)

  componentDidMount: =>
    @_editableNode().addEventListener('contextmenu', @_onShowContextualMenu)
    @_setupSelectionListeners()
    @_setupGlobalMouseListener()

    @_disposable = atom.commands.add '.contenteditable-container *', {
      'core:focus-next': (event) =>
        editableNode = @_editableNode()
        range = DOMUtils.getRangeInScope(editableNode)
        for extension in DraftStore.extensions()
          extension.onFocusNext(editableNode, range, event) if extension.onFocusNext

      'core:focus-previous': (event) =>
        editableNode = @_editableNode()
        range = DOMUtils.getRangeInScope(editableNode)
        for extension in DraftStore.extensions()
          extension.onFocusPrevious(editableNode, range, event) if extension.onFocusPrevious
      }

    @_cleanHTML()

    @setInnerState editableNode: @_editableNode()

  shouldComponentUpdate: (nextProps, nextState) ->
    not Utils.isEqualReact(nextProps, @props) or
    not Utils.isEqualReact(nextState, @state)

  componentWillUnmount: =>
    @_editableNode().removeEventListener('contextmenu', @_onShowContextualMenu)
    @_teardownSelectionListeners()
    @_teardownGlobalMouseListener()
    @_disposable.dispose()

  componentWillReceiveProps: (nextProps) =>
    @_setupServices(nextProps)
    if nextProps.initialSelectionSnapshot?
      @_setSelectionSnapshot(nextProps.initialSelectionSnapshot)

  componentDidUpdate: =>
    @_cleanHTML()

    @_restoreSelection()

    editableNode = @_editableNode()
    for extension in DraftStore.extensions()
      extension.onComponentDidUpdate(@_editableNode()) if extension.onComponentDidUpdate

    @setInnerState
      links: editableNode.querySelectorAll("*[href]")
      editableNode: editableNode

  render: =>
    <div className="contenteditable-container">
      <FloatingToolbarContainer
        ref="toolbarController"
        onSaveUrl={@_onSaveUrl}
        onDomMutator={@_onDomMutator} />

      <div id="contenteditable"
           ref="contenteditable"
           contentEditable
           spellCheck={false}
           onBlur={@_onBlur}
           onFocus={@_onFocus}
           onClick={@_onClick}
           onPaste={@clipboardService.onPaste}
           onInput={@_onInput}
           onKeyDown={@_onKeyDown}
           dangerouslySetInnerHTML={@_dangerouslySetInnerHTML()}></div>
      {@props.footerElements}
    </div>

  focus: =>
    @_editableNode().focus()

  selectEnd: =>
    range = document.createRange()
    range.selectNodeContents(@_editableNode())
    range.collapse(false)
    @_editableNode().focus()
    selection = window.getSelection()
    selection.removeAllRanges()
    selection.addRange(range)

  # When some other component (like the `FloatingToolbar` or some
  # `DraftStoreExtension`) wants to mutate the DOM, it declares a
  # `mutator` function. That mutator expects to be passed the latest DOM
  # object (the `_editableNode()`) and will do mutations to it. Once those
  # mutations are done, we need to be sure to notify that changes
  # happened.
  _onDomMutator: (mutator) =>
    @_teardownSelectionListeners()
    mutator(@_editableNode())
    @_setupSelectionListeners()
    @_onInput()

  _onClick: (event) ->
    # We handle mouseDown, mouseMove, mouseUp, but we want to stop propagation
    # of `click` to make it clear that we've handled the event.
    # Note: Related to composer-view#_onClickComposeBody
    event.stopPropagation()

  _onKeyDown: (event) =>
    if event.key is "Tab"
      @_onTabDown(event)
    if event.key is "Backspace"
      @_onBackspaceDown(event)
    U = 85
    if event.which is U and (event.metaKey or event.ctrlKey)
      event.preventDefault()
      document.execCommand("underline")
    return

  _onInput: (event) =>
    return if @_ignoreInputChanges
    @_ignoreInputChanges = true

    @_resetInnerStateOnInput()

    @_runCoreFilters()

    @_runExtensionFilters(event)

    @_normalize()

    @_saveSelectionState()

    @_saveNewHtml()

    @_ignoreInputChanges = false
    return

  _resetInnerStateOnInput: ->
    @_justCreatedList = false
    @setInnerState dragging: false if @innerState.dragging
    @setInnerState doubleDown: false if @innerState.doubleDown

  _runCoreFilters: ->
    @_createLists()

  _runExtensionFilters: (event) ->
    for extension in DraftStore.extensions()
      extension.onInput(@_editableNode(), event) if extension.onInput

  _saveNewHtml: ->
    html = @_editableNode().innerHTML
    for filter in @props.filters
      html = filter.afterDisplay(html)
    @props.onChange(target: {value: html})

  # Determines if the user wants to add an ordered or unordered list.
  _createLists: ->
    # The `execCommand` will update the DOM and move the cursor. Since
    # this is happening in the middle of an `_onInput` callback, we want
    # the whole operation to look "atomic". As such we'll do any necessary
    # DOM cleanup and fire the `exec` command with the listeners off, then
    # re-enable at the end.
    if @_resetListToText
      @_resetListToText = false
      return

    updateDOM = (command) =>
      @_teardownSelectionListeners()
      document.execCommand(command)
      selection = document.getSelection()
      selection.anchorNode.parentElement.innerHTML = ""
      @_setupSelectionListeners()

    text = @_textContentAtCursor()
    if (/^\d\.\s$/).test text
      @_justCreatedList = text
      updateDOM("insertOrderedList")
    else if (/^[*-]\s$/).test text
      @_justCreatedList = text
      updateDOM("insertUnorderedList")

  _onBackspaceDown: (event) ->
    if document.getSelection()?.isCollapsed
      if @_atStartOfList()
        li = @_closestAtCursor("li")
        list = @_closestAtCursor("ul, ol")
        return unless li and list
        event.preventDefault()
        if list.querySelectorAll('li')?[0] is li # We're in first li
          if @_justCreatedList
            @_resetListToText = true
            @_replaceFirstListItem(li, @_justCreatedList)
          else
            @_replaceFirstListItem(li, "")
        else
          document.execCommand("outdent")

  _closestAtCursor: (selector) ->
    selection = document.getSelection()
    return unless selection?.isCollapsed
    return selection.anchorNode?.closest(selector)

  _replaceFirstListItem: (li, replaceWith) ->
    @_teardownSelectionListeners()
    list = li.closest("ul, ol")

    if replaceWith.length is 0
      replaceWith = replaceWith.replace /\s/g, "&nbsp;"
      text = document.createElement("div")
      text.innerHTML = "<br>"
    else
      replaceWith = replaceWith.replace /\s/g, "&nbsp;"
      text = document.createElement("span")
      text.innerHTML = "#{replaceWith}"

    if list.querySelectorAll('li').length <= 1
      # Delete the whole list and replace with text
      list.parentNode.replaceChild(text, list)
    else
      # Delete the list item and prepend the text before the rest of the
      # list
      li.parentNode.removeChild(li)
      list.parentNode.insertBefore(text, list)

    child = text.childNodes[0] ? text
    index = Math.max(replaceWith.length - 1, 0)
    selection = document.getSelection()
    selection.setBaseAndExtent(child, index, child, index)

    @_setupSelectionListeners()
    @_onInput()

  _onTabDown: (event) ->
    event.preventDefault()
    selection = document.getSelection()
    if selection?.isCollapsed
      # https://developer.mozilla.org/en-US/docs/Web/API/Element/closest
      if selection.anchorNode instanceof HTMLElement
        anchorElement = selection.anchorNode
      else
        anchorElement = selection.anchorNode.parentElement

      # Only Elements (not Text nodes) have the `closest` method
      if anchorElement.closest("li")
        if event.shiftKey
          document.execCommand("outdent")
        else
          document.execCommand("indent")
        return
      else if event.shiftKey
        if @_atTabChar()
          @_removeLastCharacter()
        else if @_atBeginning()
          return # Don't stop propagation
      else
        document.execCommand("insertText", false, "\t")
    else
      if event.shiftKey
        document.execCommand("insertText", false, "")
      else
        document.execCommand("insertText", false, "\t")
    event.stopPropagation()

  _selectionInText: (selection) ->
    return false unless selection
    return selection.isCollapsed and selection.anchorNode.nodeType is Node.TEXT_NODE and selection.anchorOffset > 0

  _atTabChar: ->
    selection = document.getSelection()
    if @_selectionInText(selection)
      return selection.anchorNode.textContent[selection.anchorOffset - 1] is "\t"
    else return false

  _atStartOfList: ->
    selection = document.getSelection()
    anchor = selection.anchorNode
    return false if not selection.isCollapsed
    return true if anchor?.nodeName is "LI"
    return false if selection.anchorOffset > 0
    li = anchor.closest("li")
    return unless li
    return DOMUtils.isFirstChild(li, anchor)

  _atBeginning: ->
    selection = document.getSelection()
    return false if not selection.isCollapsed
    return false if selection.anchorOffset > 0
    el = @_editableNode()
    return true if el.childNodes.length is 0
    return true if selection.anchorNode is el
    firstChild = el.childNodes[0]
    return selection.anchorNode is firstChild

  _removeLastCharacter: ->
    selection = document.getSelection()
    if @_selectionInText(selection)
      node = selection.anchorNode
      offset = selection.anchorOffset
      @_teardownSelectionListeners()
      selection.setBaseAndExtent(node, offset - 1, node, offset)
      document.execCommand("delete")
      @_setupSelectionListeners()

  _textContentAtCursor: ->
    selection = document.getSelection()
    if selection.isCollapsed
      return selection.anchorNode?.textContent
    else return null

  # This component works by re-rendering on every change and restoring the
  # selection. This is also how standard React controlled inputs work too.
  #
  # Since the contents of the contenteditable are complex, nested DOM
  # structures, a simple replacement of the DOM is not easy. There are a
  # variety of edge cases that we need to correct for and prepare both the
  # HTML and the selection to be serialized without error.
  _normalize: ->
    @_cleanHTML()
    @_cleanSelection()

  # We need to clean the HTML on input to fix several edge cases that
  # arise when we go to save the selection state and restore it on the
  # next render.
  _cleanHTML: ->
    return unless @_editableNode()

    # One issue is that we need to pre-normalize the HTML so it looks the
    # same after it gets re-inserted. If we key selection markers off of an
    # non normalized DOM, then they won't match up when the HTML gets reset.
    #
    # The Node.normalize() method puts the specified node and all of its
    # sub-tree into a "normalized" form. In a normalized sub-tree, no text
    # nodes in the sub-tree are empty and there are no adjacent text
    # nodes.
    @_editableNode().normalize()

    @_collapseAdjacentLists()

    @_fixLeadingBRCondition()

  # An issue arises from <br/> tags immediately inside of divs. In this
  # case the cursor's anchor node will not be the <br/> tag, but rather
  # the entire enclosing element. Sometimes, that enclosing element is the
  # container wrapping all of the content. The browser has a native
  # built-in feature that will automatically scroll the page to the bottom
  # of the current element that the cursor is in if the cursor is off the
  # screen. In the given case, that element is the whole div. The net
  # effect is that the browser will scroll erroneously to the bottom of
  # the whole content div, which is likely NOT where the cursor is or the
  # user wants. The solution to this is to replace this particular case
  # with <span></span> tags and place the cursor in there.
  _fixLeadingBRCondition: ->
    treeWalker = document.createTreeWalker @_editableNode()
    while treeWalker.nextNode()
      currentNode = treeWalker.currentNode
      if @_hasLeadingBRCondition(currentNode)
        newNode = document.createElement("div")
        newNode.appendChild(document.createElement("br"))
        currentNode.replaceChild(newNode, currentNode.childNodes[0])
    return

  _hasLeadingBRCondition: (node) ->
    childNodes = node.childNodes
    return childNodes.length >= 2 and childNodes[0].nodeName is "BR"

  # If users ended up with two <ul> lists adjacent to each other, we
  # collapse them into one. We leave adjacent <ol> lists intact in case
  # the user wanted to restart the numbering sequence
  _collapseAdjacentLists: ->
    els = @_editableNode().querySelectorAll('ul')

    # This mutates the DOM in place.
    DOMUtils.collapseAdjacentElements(els)

  # After an input, the selection can sometimes get itself into a state
  # that either can't be restored properly, or will cause undersirable
  # native behavior. This method, in combination with `_cleanHTML`, fixes
  # each of those scenarios before we save and later restore the
  # selection.
  _cleanSelection: ->
    selection = document.getSelection()
    return unless selection.anchorNode? and selection.focusNode?

    # The _unselectableNode case only is valid when it's at the very top
    # (offset 0) of the node. If the offsets are > 0 that means we're
    # trying to select somewhere within some sort of containing element.
    # This is okay to do. The odd case only arises at the top of
    # unselectable elements.
    return if selection.anchorOffset > 0 or selection.focusOffset > 0

    if selection.isCollapsed and @_unselectableNode(selection.focusNode)
      @_teardownSelectionListeners()
      treeWalker = document.createTreeWalker(selection.focusNode)
      while treeWalker.nextNode()
        currentNode = treeWalker.currentNode
        if @_unselectableNode(currentNode)
          selection.setBaseAndExtent(currentNode, 0, currentNode, 0)
          break
      @_setupSelectionListeners()
    return

  _unselectableNode: (node) ->
    return true if not node
    if node.nodeType is Node.TEXT_NODE and DOMUtils.isBlankTextNode(node)
      return true
    else if node.nodeType is Node.ELEMENT_NODE
      child = node.firstChild
      return true if not child
      hasText = (child.nodeType is Node.TEXT_NODE and not DOMUtils.isBlankTextNode(node))
      hasBr = (child.nodeType is Node.ELEMENT_NODE and node.nodeName is "BR")
      return not hasText and not hasBr

    else return false

  _onBlur: (event) =>
    @setInnerState dragging: false
    # The delay here is necessary to see if the blur was caused by us
    # navigating to the toolbar and focusing on the set-url input.
    return if @_editableNode().parentElement.contains event.relatedTarget
    @setInnerState editableFocused: false

  _onFocus: (event) =>
    @setInnerState editableFocused: true
    @props.onFocus?(event)

  _editableNode: =>
    React.findDOMNode(@refs.contenteditable)

  _dangerouslySetInnerHTML: =>
    html = @props.html
    for filter in @props.filters
      html = filter.beforeDisplay(html)
    return __html: html

  ######### SELECTION MANAGEMENT ##########
  #
  # Saving and restoring a selection is difficult with React.
  #
  # React only handles Input and Textarea elements:
  # https://github.com/facebook/react/blob/master/src/browser/ui/ReactInputSelection.js
  # This is because they expose a very convenient `selectionStart` and
  # `selectionEnd` integer.
  #
  # Contenteditable regions are trickier. They require the more
  # sophisticated `Range` and `Selection` APIs.
  #
  # Range docs:
  # http://www.w3.org/TR/DOM-Level-2-Traversal-Range/ranges.html
  #
  # Selection API docs:
  # http://www.w3.org/TR/selection-api/#dfn-range
  #
  # A Contenteditable region can have arbitrary html inside of it. This
  # means that a selection start point can be some node (the `anchorNode`)
  # and its end point can be a completely different node (the `focusNode`)
  #
  # When React re-renders, all of the DOM nodes may change. They may
  # look exactly the same, but have different object references.
  #
  # This means that your old references to `anchorNode` and `focusNode`
  # may be bad and no longer in scope or painted.
  #
  # In order to restore the selection properly we need to re-find the
  # equivalent `anchorNode` and `focusNode`. Luckily we can use the
  # `isEqualNode` method to get a shallow comparison of the nodes.
  #
  # Unfortunately it's possible for `isEqualNode` to match more than one
  # node since two nodes may look very similar.
  #
  # To fix this we need to keep track of the original indices to determine
  # which node is most likely the matching one.

  # http://www.w3.org/TR/selection-api/#selectstart-event
  _setupSelectionListeners: =>
    @_ignoreInputChanges = false
    document.addEventListener("selectionchange", @_saveSelectionState)

  _teardownSelectionListeners: =>
    document.removeEventListener("selectionchange", @_saveSelectionState)
    @_ignoreInputChanges = true

  getCurrentSelection: => _.clone(@_selection ? {})
  getPreviousSelection: => _.clone(@_previousSelection ? {})

  # Every time the cursor changes we need to preserve its location and
  # state.
  #
  # We can't use React's `state` variable because cursor position is not
  # naturally supported in the virtual DOM.
  #
  # We also need to make sure that node references are cloned so they
  # don't change out from underneath us.
  #
  # We also need to keep references to the previous selection state in
  # order for undo/redo to work properly.
  #
  # We need to be sure to deeply `cloneNode`. This is because sometimes
  # our anchorNodes are divs with nested <br> tags. If we don't do a deep
  # clone then when `isEqualNode` is run it will erroneously return false
  # and our selection restoration will fail.
  #
  # The Selection API has the concept of an `anchorNode` and a
  # `focusNode`. The `anchorNode` is where the selection started from and
  # does not move. The `focusNode` is where the end of the selection
  # currently is and may move. A "caret" is simply a selection whose
  # anchorNode == focusNode and anchorOffset == focusOffset.
  #
  # An `anchorNode` is also known as a `startNode`, or `baseNode`. We use
  # the alias `startNode` since I think it makes more intuitive sense.
  #
  # A `focusNode` is also known as an `endNode` or `focusNode`. I use the
  # `endNode` alias since it makes more inuitive sense.
  #
  # When we restore the selection later, we need to find a node that looks
  # the same as the one we saved (since they're different object
  # references). Unfortunately there many be many nodes that "look" the
  # same (match the `isEqualNode`) test. For example, say I have a bunch
  # of lines with the TEXT_NODE "Foo". All of those will match
  # `isEqualNode`. To fix this we assume there will be multiple matches
  # and keep track of the index of the match. e.g. all "Foo" TEXT_NODEs
  # may look alike, but I know I want the Nth "Foo" TEXT_NODE. We store
  # this information in the `startNodeIndex` and `endNodeIndex` fields via
  # the `DOMUtils.getNodeIndex` method.
  _saveSelectionState: =>
    selection = document.getSelection()
    context = @_editableNode()
    return if DOMUtils.isSameSelection(selection, @_selection, context)
    return unless selection.anchorNode? and selection.focusNode?
    return unless DOMUtils.selectionInScope(selection, context)

    @_previousSelection = @_selection

    @_selection =
      startNode: selection.anchorNode.cloneNode(true)
      startOffset: selection.anchorOffset
      startNodeIndex: DOMUtils.getNodeIndex(context, selection.anchorNode)
      endNode: selection.focusNode.cloneNode(true)
      endOffset: selection.focusOffset
      endNodeIndex: DOMUtils.getNodeIndex(context, selection.focusNode)
      isCollapsed: selection.isCollapsed

    @_ensureSelectionVisible(selection)

    @setInnerState
      selection: @_selection
      editableFocused: true

    return @_selection

  _setSelectionSnapshot: (selection) =>
    @_previousSelection = @_selection
    @_selection = selection
    @setInnerState
      selection: @_selection
      editableFocused: true

  # When the selectionState gets set by a parent (e.g. undo-ing and
  # redo-ing) we need to make sure it's visible to the user.
  #
  # Unfortunately, we can't use the native `scrollIntoView` because it
  # naively scrolls the whole window and doesn't know not to scroll if
  # it's already in view. There's a new native method called
  # `scrollIntoViewIfNeeded`, but this only works when the scroll
  # container is a direct parent of the requested element. In this case
  # the scroll container may be many levels up.
  _ensureSelectionVisible: (selection) ->
    # If our parent supports scroll to bottom, check for that
    if @props.onScrollToBottom and DOMUtils.atEndOfContent(selection, @_editableNode())
      @props.onScrollToBottom()

    # Don't bother computing client rects if no scroll method has been provided
    else if @props.onScrollTo
      rangeInScope = DOMUtils.getRangeInScope(@_editableNode())
      return unless rangeInScope

      rect = rangeInScope.getBoundingClientRect()
      if DOMUtils.isEmptyBoudingRect(rect)
        rect = @_getSelectionRectFromDOM(selection)

      if rect
        @props.onScrollTo({rect})

    # The bounding client rect has changed
    @setInnerState editableNode: @_editableNode()

  _getSelectionRectFromDOM: (selection) ->
    node = selection.anchorNode
    if node.nodeType is Node.TEXT_NODE
      r = document.createRange()
      r.selectNodeContents(node)
      return r.getBoundingClientRect()
    else if node.nodeType is Node.ELEMENT_NODE
      return node.getBoundingClientRect()
    else
      return null

  # We use global listeners to determine whether or not dragging is
  # happening. This is because dragging may stop outside the scope of
  # this element. Note that the `dragstart` and `dragend` events don't
  # detect text selection. They are for drag & drop.
  _setupGlobalMouseListener: =>
    @__onMouseDown = _.bind(@_onMouseDown, @)
    @__onMouseMove = _.bind(@_onMouseMove, @)
    @__onMouseUp = _.bind(@_onMouseUp, @)
    window.addEventListener("mousedown", @__onMouseDown)
    window.addEventListener("mouseup", @__onMouseUp)

  _teardownGlobalMouseListener: =>
    window.removeEventListener("mousedown", @__onMouseDown)
    window.removeEventListener("mouseup", @__onMouseUp)

  _onShowContextualMenu: (event) =>
    @refs["toolbarController"]?.forceClose()
    event.preventDefault()

    selection = document.getSelection()
    range = selection.getRangeAt(0)

    # On Windows, right-clicking a word does not select it at the OS-level.
    # We need to implement this behavior locally for the rest of the logic here.
    if range.collapsed
      DOMUtils.selectWordContainingRange(range)
      range = selection.getRangeAt(0)

    text = range.toString()

    remote = require('remote')
    clipboard = require('clipboard')
    Menu = remote.require('menu')
    MenuItem = remote.require('menu-item')
    spellchecker = require('spellchecker')

    apply = (newtext) =>
      range.deleteContents()
      node = document.createTextNode(newtext)
      range.insertNode(node)
      range.selectNode(node)
      selection.removeAllRanges()
      selection.addRange(range)
      for extension in DraftStore.extensions()
        if extension.onSubstitutionPerformed
          extension.onSubstitutionPerformed(@_editableNode())

    learnSpelling = =>
      spellchecker.add(text)
      for extension in DraftStore.extensions()
        if extension.onLearnSpelling
          extension.onLearnSpelling(@_editableNode(), text)

    cut = =>
      clipboard.writeText(text)
      apply('')

    copy = =>
      clipboard.writeText(text)

    paste = =>
      apply(clipboard.readText())

    menu = new Menu()

    if spellchecker.isMisspelled(text)
      corrections = spellchecker.getCorrectionsForMisspelling(text)
      if corrections.length > 0
        corrections.forEach (correction) ->
          menu.append(new MenuItem({ label: correction, click:( -> apply(correction))}))
      else
        menu.append(new MenuItem({ label: 'No Guesses Found', enabled: false}))

      menu.append(new MenuItem({ type: 'separator' }))
      menu.append(new MenuItem({ label: 'Learn Spelling', click: learnSpelling}))
      menu.append(new MenuItem({ type: 'separator' }))

    menu.append(new MenuItem({ label: 'Cut', click:cut}))
    menu.append(new MenuItem({ label: 'Copy', click:copy}))
    menu.append(new MenuItem({ label: 'Paste', click:paste}))
    menu.popup(remote.getCurrentWindow())

  _onMouseDown: (event) =>
    @_mouseDownEvent = event
    @_mouseHasMoved = false
    window.addEventListener("mousemove", @__onMouseMove)

    # We can't use the native double click event because that only fires
    # on the second up-stroke
    if Date.now() - (@_lastMouseDown ? 0) < 250
      @_onDoubleDown(event)
      @_lastMouseDown = 0 # to prevent triple down
    else
      @_lastMouseDown = Date.now()

  _onDoubleDown: (event) =>
    editable = @_editableNode()
    return unless editable?
    if editable is event.target or editable.contains(event.target)
      @setInnerState doubleDown: true

  _onMouseMove: (event) =>
    if not @_mouseHasMoved
      @_onDragStart(@_mouseDownEvent)
      @_mouseHasMoved = true

  _onMouseUp: (event) =>
    window.removeEventListener("mousemove", @__onMouseMove)

    if @innerState.doubleDown
      @setInnerState doubleDown: false

    if @_mouseHasMoved
      @_mouseHasMoved = false
      @_onDragEnd(event)

    editableNode = @_editableNode()
    selection = document.getSelection()
    return event unless DOMUtils.selectionInScope(selection, editableNode)

    range = DOMUtils.getRangeInScope(editableNode)
    if range
      try
        for extension in DraftStore.extensions()
          extension.onMouseUp(editableNode, range, event) if extension.onMouseUp
      catch e
        console.log('DraftStore extension raised an error: '+e.toString())

    event

  _onDragStart: (event) =>
    editable = @_editableNode()
    return unless editable?
    if editable is event.target or editable.contains(event.target)
      @setInnerState dragging: true

  _onDragEnd: (event) =>
    if @innerState.dragging
      @setInnerState dragging: false
    return event

  # We restore the Selection via the `setBaseAndExtent` property of the
  # `Selection` API
  #
  # See http://w3c.github.io/selection-api/#widl-Selection-setBaseAndExtent-void-Node-anchorNode-unsigned-long-anchorOffset-Node-focusNode-unsigned-long-focusOffset
  #
  # Since the last time we saved the `@_selection`, the DOM may have
  # completely changed due to a re-render. To the user it may look
  # identical, but the newly rendered region may be comprised of
  # completely new DOM nodes. Our old node references may not exist
  # anymore. As such, we have the task of re-finding the nodes again and
  # creating a new selection that matches as accurately as possible.
  #
  # There are multiple ways of setting a new selection with the Selection
  # API. One very common one is to create a new Range object and then call
  # `addRange` on a selection instance. This does NOT work for us because
  # `Range` objects are direction-less. A Selection's start node (aka
  # anchor node aka base node) can be "after" a selection's end node (aka
  # focus node aka extent node).
  #
  # force - when set to true it will not care whether or not the selection
  #         is already in the box. Normally we only restore when the
  #         contenteditable is in focus
  # collapse - Can either be "end" or "start". When we reset the
  #            selection, we'll collapse the range into a single caret
  #            position
  _restoreSelection: ({force, collapse}={}) =>
    return if @innerState.dragging
    return if not @_selection?
    return if document.activeElement isnt @_editableNode() and not force
    return if not @_selection.startNode? or not @_selection.endNode?

    editable = @_editableNode()
    newStartNode = DOMUtils.findSimilarNodes(editable, @_selection.startNode)[@_selection.startNodeIndex]
    newEndNode = DOMUtils.findSimilarNodes(editable, @_selection.endNode)[@_selection.endNodeIndex]
    return if not newStartNode? or not newEndNode?

    @_teardownSelectionListeners()
    selection = document.getSelection()
    selection.setBaseAndExtent(newStartNode,
                               @_selection.startOffset,
                               newEndNode,
                               @_selection.endOffset)

    @_ensureSelectionVisible(selection)
    @_setupSelectionListeners()

  _getNodeIndex: (nodeToFind) =>
    DOMUtils.findSimilarNodes(@_editableNode(), nodeToFind).indexOf nodeToFind

  # This needs to be in the contenteditable area because we need to first
  # restore the selection before calling the `execCommand`
  #
  # If the url is empty, that means we want to remove the url.
  _onSaveUrl: (url, linkToModify) =>
    if linkToModify?
      linkToModify = DOMUtils.findSimilarNodes(@_editableNode(), linkToModify)?[0]?.childNodes[0]

      return unless linkToModify?
      return if linkToModify.getAttribute?('href').trim() is url.trim()

      range =
        anchorNode: linkToModify
        anchorOffset: 0
        focusNode: linkToModify
        focusOffset: linkToModify.length

      if url.trim().length is 0
        @_execCommand ["unlink", false], range
      else @_execCommand ["createLink", false, url], range

    else
      @_restoreSelection(force: true)
      if not document.getSelection().isCollapsed
        if url.trim().length is 0
          @_execCommand ["unlink", false]
        else @_execCommand ["createLink", false, url]
        @_restoreSelection(force: true, collapse: "end")

  _execCommand: (commandArgs=[], selectionRange={}) =>
    {anchorNode, anchorOffset, focusNode, focusOffset} = selectionRange
    @_teardownSelectionListeners()
    if anchorNode and focusNode
      selection = document.getSelection()
      selection.setBaseAndExtent(anchorNode, anchorOffset, focusNode, focusOffset)
    document.execCommand.apply(document, commandArgs)
    @_setupSelectionListeners()
    @_onInput()

module.exports = ContenteditableComponent