/*global
    DOCUMENT_POSITION_PRECEDING,
    ELEMENT_NODE,
    TEXT_NODE,
    SHOW_ELEMENT,
    SHOW_TEXT,
    FILTER_ACCEPT,
    FILTER_SKIP,
    win,
    isIOS,
    isMac,
    isGecko,
    isIE8or9or10,
    isIE8,
    isOpera,
    ctrlKey,
    useTextFixer,
    cantFocusEmptyTextNodes,
    losesSelectionOnBlur,
    hasBuggySplit,
    notWS,
    indexOf,

    TreeWalker,

    hasTagAttributes,
    isLeaf,
    isInline,
    isBlock,
    isContainer,
    getPreviousBlock,
    getNextBlock,
    getNearest,
    getPath,
    getLength,
    detach,
    replaceWith,
    empty,
    fixCursor,
    split,
    mergeInlines,
    mergeWithBlock,
    mergeContainers,
    createElement,

    forEachTextNodeInRange,
    getTextContentInRange,
    insertNodeInRange,
    extractContentsOfRange,
    deleteContentsOfRange,
    insertTreeFragmentIntoRange,
    isNodeContainedInRange,
    moveRangeBoundariesDownTree,
    moveRangeBoundariesUpTree,
    getStartBlockOfRange,
    getEndBlockOfRange,
    rangeDoesStartAtBlockBoundary,
    rangeDoesEndAtBlockBoundary,
    expandRangeToBlockBoundaries,

    top,
    console,
    setTimeout
*/
/*jshint strict:false */

function Squire ( doc ) {
    var win = doc.defaultView;
    var body = doc.body;
    this._win = win;
    this._doc = doc;
    this._body = body;

    this._events = {};

    this._sel = win.getSelection();
    this._lastSelection = null;

    // IE loses selection state of iframe on blur, so make sure we
    // cache it just before it loses focus.
    if ( losesSelectionOnBlur ) {
        this.addEventListener( 'beforedeactivate', this.getSelection );
    }

    this._placeholderTextNode = null;
    this._mayRemovePlaceholder = true;
    this._willEnablePlaceholderRemoval = false;

    this._lastAnchorNode = null;
    this._lastFocusNode = null;
    this._path = '';

    this.addEventListener( 'keyup', this._updatePathOnEvent );
    this.addEventListener( 'mouseup', this._updatePathOnEvent );

    win.addEventListener( 'focus', this, false );
    win.addEventListener( 'blur', this, false );

    this._undoIndex = -1;
    this._undoStack = [];
    this._undoStackLength = 0;
    this._isInUndoState = false;

    this.addEventListener( 'keyup', this._docWasChanged );

    // IE sometimes fires the beforepaste event twice; make sure it is not run
    // again before our after paste function is called.
    this._awaitingPaste = false;
    this.addEventListener( isIE8or9or10 ? 'beforecut' : 'cut', this._onCut );
    this.addEventListener( isIE8or9or10 ? 'beforepaste' : 'paste', this._onPaste );

    if ( isIE8 ) {
        this.addEventListener( 'keyup', this._ieSelAllClean );
    }
    // Opera does not fire keydown repeatedly.
    this.addEventListener( isOpera ? 'keypress' : 'keydown', this._onKey );

    // Fix IE8/9's buggy implementation of Text#splitText.
    // If the split is at the end of the node, it doesn't insert the newly split
    // node into the document, and sets its value to undefined rather than ''.
    // And even if the split is not at the end, the original node is removed
    // from the document and replaced by another, rather than just having its
    // data shortened.
    if ( hasBuggySplit ) {
        win.Text.prototype.splitText = function ( offset ) {
            var afterSplit = this.ownerDocument.createTextNode(
                    this.data.slice( offset ) ),
                next = this.nextSibling,
                parent = this.parentNode,
                toDelete = this.length - offset;
            if ( next ) {
                parent.insertBefore( afterSplit, next );
            } else {
                parent.appendChild( afterSplit );
            }
            if ( toDelete ) {
                this.deleteData( offset, toDelete );
            }
            return afterSplit;
        };
    }

    body.setAttribute( 'contenteditable', 'true' );
    this.setHTML( '' );
}

var proto = Squire.prototype;

proto.createElement = function ( tag, props, children ) {
    return createElement( this._doc, tag, props, children );
};

proto.didError = function ( error ) {
    console.log( error );
};

proto.getDocument = function () {
    return this._doc;
};

// --- Events ---

// Subscribing to these events won't automatically add a listener to the
// document node, since these events are fired in a custom manner by the
// editor code.
var customEvents = {
    focus: 1, blur: 1,
    pathChange: 1, select: 1, input: 1, undoStateChange: 1
};

proto.fireEvent = function ( type, event ) {
    var handlers = this._events[ type ],
        i, l, obj;
    if ( handlers ) {
        if ( !event ) {
            event = {};
        }
        if ( event.type !== type ) {
            event.type = type;
        }
        // Clone handlers array, so any handlers added/removed do not affect it.
        handlers = handlers.slice();
        for ( i = 0, l = handlers.length; i < l; i += 1 ) {
            obj = handlers[i];
            try {
                if ( obj.handleEvent ) {
                    obj.handleEvent( event );
                } else {
                    obj.call( this, event );
                }
            } catch ( error ) {
                error.details = 'Squire: fireEvent error. Event type: ' + type;
                this.didError( error );
            }
        }
    }
    return this;
};

proto.handleEvent = function ( event ) {
    this.fireEvent( event.type, event );
};

proto.addEventListener = function ( type, fn ) {
    var handlers = this._events[ type ];
    if ( !fn ) {
        this.didError({
            name: 'Squire: addEventListener with null or undefined fn',
            message: 'Event type: ' + type
        });
        return this;
    }
    if ( !handlers ) {
        handlers = this._events[ type ] = [];
        if ( !customEvents[ type ] ) {
            this._doc.addEventListener( type, this, false );
        }
    }
    handlers.push( fn );
    return this;
};

proto.removeEventListener = function ( type, fn ) {
    var handlers = this._events[ type ],
        l;
    if ( handlers ) {
        l = handlers.length;
        while ( l-- ) {
            if ( handlers[l] === fn ) {
                handlers.splice( l, 1 );
            }
        }
        if ( !handlers.length ) {
            delete this._events[ type ];
            if ( !customEvents[ type ] ) {
                this._doc.removeEventListener( type, this, false );
            }
        }
    }
    return this;
};

// --- Selection and Path ---

proto._createRange =
        function ( range, startOffset, endContainer, endOffset ) {
    if ( range instanceof this._win.Range ) {
        return range.cloneRange();
    }
    var domRange = this._doc.createRange();
    domRange.setStart( range, startOffset );
    if ( endContainer ) {
        domRange.setEnd( endContainer, endOffset );
    } else {
        domRange.setEnd( range, startOffset );
    }
    return domRange;
};

proto.setSelection = function ( range ) {
    if ( range ) {
        // iOS bug: if you don't focus the iframe before setting the
        // selection, you can end up in a state where you type but the input
        // doesn't get directed into the contenteditable area but is instead
        // lost in a black hole. Very strange.
        if ( isIOS ) {
            this._win.focus();
        }
        var sel = this._sel;
        sel.removeAllRanges();
        sel.addRange( range );
    }
    return this;
};

proto.getSelection = function () {
    var sel = this._sel;
    if ( sel.rangeCount ) {
        var lastSelection  = this._lastSelection =
            sel.getRangeAt( 0 ).cloneRange();
        var startContainer = lastSelection.startContainer,
            endContainer = lastSelection.endContainer;
        // FF sometimes throws an error reading the isLeaf property. Let's
        // catch and log it to see if we can find what's going on.
        try {
            // FF can return the selection as being inside an <img>. WTF?
            if ( startContainer && isLeaf( startContainer ) ) {
                lastSelection.setStartBefore( startContainer );
            }
            if ( endContainer && isLeaf( endContainer ) ) {
                lastSelection.setEndBefore( endContainer );
            }
        } catch ( error ) {
            this.didError({
                name: 'Squire#getSelection error',
                message: 'Starts: ' + startContainer.nodeName +
                    '\nEnds: ' + endContainer.nodeName
            });
        }
    }
    return this._lastSelection;
};

proto.getSelectedText = function () {
    return getTextContentInRange( this.getSelection() );
};

proto.getPath = function () {
    return this._path;
};

// --- Workaround for browsers that can't focus empty text nodes ---

// WebKit bug: https://bugs.webkit.org/show_bug.cgi?id=15256

proto._enablePlaceholderRemoval = function () {
    this._mayRemovePlaceholder = true;
    this._willEnablePlaceholderRemoval = false;
    this.removeEventListener( 'keydown', this._enablePlaceholderRemoval );
};

proto._removePlaceholderTextNode = function () {
    if ( !this._mayRemovePlaceholder ) { return; }

    var node = this._placeholderTextNode,
        index;

    this._placeholderTextNode = null;

    if ( node.parentNode ) {
        while ( ( index = node.data.indexOf( '\u200B' ) ) > -1 ) {
            node.deleteData( index, 1 );
        }
        if ( !node.data && !node.nextSibling && !node.previousSibling &&
                isInline( node.parentNode ) ) {
            detach( node.parentNode );
        }
    }
};

proto._setPlaceholderTextNode = function ( node ) {
    if ( this._placeholderTextNode ) {
        this._mayRemovePlaceholder = true;
        this._removePlaceholderTextNode();
    }
    if ( !this._willEnablePlaceholderRemoval ) {
        this.addEventListener( 'keydown', this._enablePlaceholderRemoval );
        this._willEnablePlaceholderRemoval = true;
    }
    this._mayRemovePlaceholder = false;
    this._placeholderTextNode = node;
};

// --- Path change events ---

proto._updatePath = function ( range, force ) {
    if ( this._placeholderTextNode && !force ) {
        this._removePlaceholderTextNode( range );
    }
    var anchor = range.startContainer,
        focus = range.endContainer,
        newPath;
    if ( force || anchor !== this._lastAnchorNode ||
            focus !== this._lastFocusNode ) {
        this._lastAnchorNode = anchor;
        this._lastFocusNode = focus;
        newPath = ( anchor && focus ) ? ( anchor === focus ) ?
            getPath( focus ) : '(selection)' : '';
        if ( this._path !== newPath ) {
            this._path = newPath;
            this.fireEvent( 'pathChange', { path: newPath } );
        }
    }
    if ( anchor !== focus ) {
        this.fireEvent( 'select' );
    }
};

proto._updatePathOnEvent = function () {
    this._updatePath( this.getSelection() );
};

// --- Focus ---

proto.focus = function () {
    // FF seems to need the body to be focussed
    // (at least on first load).
    if ( isGecko ) {
        this._body.focus();
    }
    this._win.focus();
    return this;
};

proto.blur = function () {
    // IE will remove the whole browser window from focus if you call
    // win.blur() or body.blur(), so instead we call top.focus() to focus
    // the top frame, thus blurring this frame. This works in everything
    // except FF, so we need to call body.blur() in that as well.
    if ( isGecko ) {
        this._body.blur();
    }
    top.focus();
    return this;
};

// --- Bookmarking ---

var startSelectionId = 'squire-selection-start';
var endSelectionId = 'squire-selection-end';

proto._saveRangeToBookmark = function ( range ) {
    var startNode = this.createElement( 'INPUT', {
            id: startSelectionId,
            type: 'hidden'
        }),
        endNode = this.createElement( 'INPUT', {
            id: endSelectionId,
            type: 'hidden'
        }),
        temp;

    insertNodeInRange( range, startNode );
    range.collapse( false );
    insertNodeInRange( range, endNode );

    // In a collapsed range, the start is sometimes inserted after the end!
    if ( startNode.compareDocumentPosition( endNode ) &
            DOCUMENT_POSITION_PRECEDING ) {
        startNode.id = endSelectionId;
        endNode.id = startSelectionId;
        temp = startNode;
        startNode = endNode;
        endNode = temp;
    }

    range.setStartAfter( startNode );
    range.setEndBefore( endNode );
};

proto._getRangeAndRemoveBookmark = function ( range ) {
    var doc = this._doc,
        start = doc.getElementById( startSelectionId ),
        end = doc.getElementById( endSelectionId );

    if ( start && end ) {
        var startContainer = start.parentNode,
            endContainer = end.parentNode,
            collapsed;

        var _range = {
            startContainer: startContainer,
            endContainer: endContainer,
            startOffset: indexOf.call( startContainer.childNodes, start ),
            endOffset: indexOf.call( endContainer.childNodes, end )
        };

        if ( startContainer === endContainer ) {
            _range.endOffset -= 1;
        }

        detach( start );
        detach( end );

        // Merge any text nodes we split
        mergeInlines( startContainer, _range );
        if ( startContainer !== endContainer ) {
            mergeInlines( endContainer, _range );
        }

        if ( !range ) {
            range = doc.createRange();
        }
        range.setStart( _range.startContainer, _range.startOffset );
        range.setEnd( _range.endContainer, _range.endOffset );
        collapsed = range.collapsed;

        moveRangeBoundariesDownTree( range );
        if ( collapsed ) {
            range.collapse( true );
        }
    }
    return range || null;
};

// --- Undo ---

proto._docWasChanged = function ( event ) {
    var code = event && event.keyCode;
    // Presume document was changed if:
    // 1. A modifier key (other than shift) wasn't held down
    // 2. The key pressed is not in range 16<=x<=20 (control keys)
    // 3. The key pressed is not in range 33<=x<=45 (navigation keys)
    if ( !event || ( !event.ctrlKey && !event.metaKey && !event.altKey &&
            ( code < 16 || code > 20 ) &&
            ( code < 33 || code > 45 ) ) )  {
        if ( this._isInUndoState ) {
            this._isInUndoState = false;
            this.fireEvent( 'undoStateChange', {
                canUndo: true,
                canRedo: false
            });
        }
        this.fireEvent( 'input' );
    }
};

// Leaves bookmark
proto._recordUndoState = function ( range ) {
    // Don't record if we're already in an undo state
    if ( !this._isInUndoState ) {
        // Advance pointer to new position
        var undoIndex = this._undoIndex += 1,
            undoStack = this._undoStack;

        // Truncate stack if longer (i.e. if has been previously undone)
        if ( undoIndex < this._undoStackLength) {
            undoStack.length = this._undoStackLength = undoIndex;
        }

        // Write out data
        if ( range ) {
            this._saveRangeToBookmark( range );
        }
        undoStack[ undoIndex ] = this._getHTML();
        this._undoStackLength += 1;
        this._isInUndoState = true;
    }
};

proto.undo = function () {
    // Sanity check: must not be at beginning of the history stack
    if ( this._undoIndex !== 0 || !this._isInUndoState ) {
        // Make sure any changes since last checkpoint are saved.
        this._recordUndoState( this.getSelection() );

        this._undoIndex -= 1;
        this._setHTML( this._undoStack[ this._undoIndex ] );
        var range = this._getRangeAndRemoveBookmark();
        if ( range ) {
            this.setSelection( range );
        }
        this._isInUndoState = true;
        this.fireEvent( 'undoStateChange', {
            canUndo: this._undoIndex !== 0,
            canRedo: true
        });
        this.fireEvent( 'input' );
    }
    return this;
};

proto.redo = function () {
    // Sanity check: must not be at end of stack and must be in an undo
    // state.
    var undoIndex = this._undoIndex,
        undoStackLength = this._undoStackLength;
    if ( undoIndex + 1 < undoStackLength && this._isInUndoState ) {
        this._undoIndex += 1;
        this._setHTML( this._undoStack[ this._undoIndex ] );
        var range = this._getRangeAndRemoveBookmark();
        if ( range ) {
            this.setSelection( range );
        }
        this.fireEvent( 'undoStateChange', {
            canUndo: true,
            canRedo: undoIndex + 2 < undoStackLength
        });
        this.fireEvent( 'input' );
    }
    return this;
};

// --- Inline formatting ---

// Looks for matching tag and attributes, so won't work
// if <strong> instead of <b> etc.
proto.hasFormat = function ( tag, attributes, range ) {
    // 1. Normalise the arguments and get selection
    tag = tag.toUpperCase();
    if ( !attributes ) { attributes = {}; }
    if ( !range && !( range = this.getSelection() ) ) {
        return false;
    }

    // If the common ancestor is inside the tag we require, we definitely
    // have the format.
    var root = range.commonAncestorContainer,
        walker, node;
    if ( getNearest( root, tag, attributes ) ) {
        return true;
    }

    // If common ancestor is a text node and doesn't have the format, we
    // definitely don't have it.
    if ( root.nodeType === TEXT_NODE ) {
        return false;
    }

    // Otherwise, check each text node at least partially contained within
    // the selection and make sure all of them have the format we want.
    walker = new TreeWalker( root, SHOW_TEXT, function ( node ) {
        return isNodeContainedInRange( range, node, true ) ?
            FILTER_ACCEPT : FILTER_SKIP;
    }, false );

    var seenNode = false;
    while ( node = walker.nextNode() ) {
        if ( !getNearest( node, tag, attributes ) ) {
            return false;
        }
        seenNode = true;
    }

    return seenNode;
};

proto._addFormat = function ( tag, attributes, range ) {
    // If the range is collapsed we simply insert the node by wrapping
    // it round the range and focus it.
    var el, walker, startContainer, endContainer, startOffset, endOffset,
        textnode, needsFormat;

    if ( range.collapsed ) {
        el = fixCursor( this.createElement( tag, attributes ) );
        insertNodeInRange( range, el );
        range.setStart( el.firstChild, el.firstChild.length );
        range.collapse( true );
    }
    // Otherwise we find all the textnodes in the range (splitting
    // partially selected nodes) and if they're not already formatted
    // correctly we wrap them in the appropriate tag.
    else {
        // We don't want to apply formatting twice so we check each text
        // node to see if it has an ancestor with the formatting already.
        // Create an iterator to walk over all the text nodes under this
        // ancestor which are in the range and not already formatted
        // correctly.
        walker = new TreeWalker(
            range.commonAncestorContainer,
            SHOW_TEXT,
            function ( node ) {
                return isNodeContainedInRange( range, node, true ) ?
                    FILTER_ACCEPT : FILTER_SKIP;
            },
            false
        );

        // Start at the beginning node of the range and iterate through
        // all the nodes in the range that need formatting.
        startOffset = 0;
        endOffset = 0;
        textnode = walker.currentNode = range.startContainer;

        if ( textnode.nodeType !== TEXT_NODE ) {
            textnode = walker.nextNode();
        }

        do {
            needsFormat = !getNearest( textnode, tag, attributes );
            if ( textnode === range.endContainer ) {
                if ( needsFormat && textnode.length > range.endOffset ) {
                    textnode.splitText( range.endOffset );
                } else {
                    endOffset = range.endOffset;
                }
            }
            if ( textnode === range.startContainer ) {
                if ( needsFormat && range.startOffset ) {
                    textnode = textnode.splitText( range.startOffset );
                } else {
                    startOffset = range.startOffset;
                }
            }
            if ( needsFormat ) {
                el = this.createElement( tag, attributes );
                replaceWith( textnode, el );
                el.appendChild( textnode );
                endOffset = textnode.length;
            }
            endContainer = textnode;
            if ( !startContainer ) { startContainer = endContainer; }
        } while ( textnode = walker.nextNode() );

        // Now set the selection to as it was before
        range = this._createRange(
            startContainer, startOffset, endContainer, endOffset );
    }
    return range;
};

proto._removeFormat = function ( tag, attributes, range, partial ) {
    // Add bookmark
    this._saveRangeToBookmark( range );

    // We need a node in the selection to break the surrounding
    // formatted text.
    var doc = this._doc,
        fixer;
    if ( range.collapsed ) {
        if ( cantFocusEmptyTextNodes ) {
            fixer = doc.createTextNode( '\u200B' );
            this._setPlaceholderTextNode( fixer );
        } else {
            fixer = doc.createTextNode( '' );
        }
        insertNodeInRange( range, fixer );
    }

    // Find block-level ancestor of selection
    var root = range.commonAncestorContainer;
    while ( isInline( root ) ) {
        root = root.parentNode;
    }

    // Find text nodes inside formatTags that are not in selection and
    // add an extra tag with the same formatting.
    var startContainer = range.startContainer,
        startOffset = range.startOffset,
        endContainer = range.endContainer,
        endOffset = range.endOffset,
        toWrap = [],
        examineNode = function ( node, exemplar ) {
            // If the node is completely contained by the range then
            // we're going to remove all formatting so ignore it.
            if ( isNodeContainedInRange( range, node, false ) ) {
                return;
            }

            var isText = ( node.nodeType === TEXT_NODE ),
                child, next;

            // If not at least partially contained, wrap entire contents
            // in a clone of the tag we're removing and we're done.
            if ( !isNodeContainedInRange( range, node, true ) ) {
                // Ignore bookmarks and empty text nodes
                if ( node.nodeName !== 'INPUT' &&
                        ( !isText || node.data ) ) {
                    toWrap.push([ exemplar, node ]);
                }
                return;
            }

            // Split any partially selected text nodes.
            if ( isText ) {
                if ( node === endContainer && endOffset !== node.length ) {
                    toWrap.push([ exemplar, node.splitText( endOffset ) ]);
                }
                if ( node === startContainer && startOffset ) {
                    node.splitText( startOffset );
                    toWrap.push([ exemplar, node ]);
                }
            }
            // If not a text node, recurse onto all children.
            // Beware, the tree may be rewritten with each call
            // to examineNode, hence find the next sibling first.
            else {
                for ( child = node.firstChild; child; child = next ) {
                    next = child.nextSibling;
                    examineNode( child, exemplar );
                }
            }
        },
        formatTags = Array.prototype.filter.call(
            root.getElementsByTagName( tag ), function ( el ) {
                return isNodeContainedInRange( range, el, true ) &&
                    hasTagAttributes( el, tag, attributes );
            }
        );

    if ( !partial ) {
        formatTags.forEach( function ( node ) {
            examineNode( node, node );
        });
    }

    // Now wrap unselected nodes in the tag
    toWrap.forEach( function ( item ) {
        // [ exemplar, node ] tuple
        var el = item[0].cloneNode( false ),
            node = item[1];
        replaceWith( node, el );
        el.appendChild( node );
    });
    // and remove old formatting tags.
    formatTags.forEach( function ( el ) {
        replaceWith( el, empty( el ) );
    });

    // Merge adjacent inlines:
    this._getRangeAndRemoveBookmark( range );
    if ( fixer ) {
        range.collapse( false );
    }
    var _range = {
        startContainer: range.startContainer,
        startOffset: range.startOffset,
        endContainer: range.endContainer,
        endOffset: range.endOffset
    };
    mergeInlines( root, _range );
    range.setStart( _range.startContainer, _range.startOffset );
    range.setEnd( _range.endContainer, _range.endOffset );

    return range;
};

proto.changeFormat = function ( add, remove, range, partial ) {
    // Normalise the arguments and get selection
    if ( !range && !( range = this.getSelection() ) ) {
        return;
    }

    // Save undo checkpoint
    this._recordUndoState( range );
    this._getRangeAndRemoveBookmark( range );

    if ( remove ) {
        range = this._removeFormat( remove.tag.toUpperCase(),
            remove.attributes || {}, range, partial );
    }
    if ( add ) {
        range = this._addFormat( add.tag.toUpperCase(),
            add.attributes || {}, range );
    }

    this.setSelection( range );
    this._updatePath( range, true );

    // We're not still in an undo state
    this._docWasChanged();

    return this;
};

// --- Block formatting ---

var tagAfterSplit = {
    DIV: 'DIV',
    PRE: 'DIV',
    H1:  'DIV',
    H2:  'DIV',
    H3:  'DIV',
    H4:  'DIV',
    H5:  'DIV',
    H6:  'DIV',
    P:   'DIV',
    DT:  'DD',
    DD:  'DT',
    LI:  'LI'
};

var splitBlock = function ( block, node, offset ) {
    var splitTag = tagAfterSplit[ block.nodeName ],
        nodeAfterSplit = split( node, offset, block.parentNode );

    // Make sure the new node is the correct type.
    if ( nodeAfterSplit.nodeName !== splitTag ) {
        block = createElement( nodeAfterSplit.ownerDocument, splitTag );
        block.className = nodeAfterSplit.dir === 'rtl' ? 'dir-rtl' : '';
        block.dir = nodeAfterSplit.dir;
        replaceWith( nodeAfterSplit, block );
        block.appendChild( empty( nodeAfterSplit ) );
        nodeAfterSplit = block;
    }
    return nodeAfterSplit;
};

proto.forEachBlock = function ( fn, mutates, range ) {
    if ( !range && !( range = this.getSelection() ) ) {
        return this;
    }

    // Save undo checkpoint
    if ( mutates ) {
        this._recordUndoState( range );
        this._getRangeAndRemoveBookmark( range );
    }

    var start = getStartBlockOfRange( range ),
        end = getEndBlockOfRange( range );
    if ( start && end ) {
        do {
            if ( fn( start ) || start === end ) { break; }
        } while ( start = getNextBlock( start ) );
    }

    if ( mutates ) {
        this.setSelection( range );

        // Path may have changed
        this._updatePath( range, true );

        // We're not still in an undo state
        this._docWasChanged();
    }
    return this;
};

proto.modifyBlocks = function ( modify, range ) {
    if ( !range && !( range = this.getSelection() ) ) {
        return this;
    }
    // 1. Stop firefox adding an extra <BR> to <BODY>
    // if we remove everything. Don't want to do this in Opera
    // as it can cause focus problems.
    var body = this._body;
    if ( !isOpera ) {
        body.setAttribute( 'contenteditable', 'false' );
    }

    // 2. Save undo checkpoint and bookmark selection
    if ( this._isInUndoState ) {
        this._saveRangeToBookmark( range );
    } else {
        this._recordUndoState( range );
    }

    // 3. Expand range to block boundaries
    expandRangeToBlockBoundaries( range );

    // 4. Remove range.
    moveRangeBoundariesUpTree( range, body );
    var frag = extractContentsOfRange( range, body );

    // 5. Modify tree of fragment and reinsert.
    insertNodeInRange( range, modify.call( this, frag ) );

    // 6. Merge containers at edges
    if ( range.endOffset < range.endContainer.childNodes.length ) {
        mergeContainers( range.endContainer.childNodes[ range.endOffset ] );
    }
    mergeContainers( range.startContainer.childNodes[ range.startOffset ] );

    // 7. Make it editable again
    if ( !isOpera ) {
        body.setAttribute( 'contenteditable', 'true' );
    }

    // 8. Restore selection
    this._getRangeAndRemoveBookmark( range );
    this.setSelection( range );
    this._updatePath( range, true );

    // 9. We're not still in an undo state
    this._docWasChanged();

    return this;
};

var increaseBlockQuoteLevel = function ( frag ) {
    return this.createElement( 'BLOCKQUOTE', [
        frag
    ]);
};

var decreaseBlockQuoteLevel = function ( frag ) {
    var blockquotes = frag.querySelectorAll( 'blockquote' );
    Array.prototype.filter.call( blockquotes, function ( el ) {
        return !getNearest( el.parentNode, 'BLOCKQUOTE' );
    }).forEach( function ( el ) {
        replaceWith( el, empty( el ) );
    });
    return frag;
};

var removeBlockQuote = function ( frag ) {
    var blockquotes = frag.querySelectorAll( 'blockquote' ),
        l = blockquotes.length,
        bq;
    while ( l-- ) {
        bq = blockquotes[l];
        replaceWith( bq, empty( bq ) );
    }
    return frag;
};

var makeList = function ( self, nodes, type ) {
    var i, l, node, tag, prev, replacement;
    for ( i = 0, l = nodes.length; i < l; i += 1 ) {
        node = nodes[i];
        tag = node.nodeName;
        if ( isBlock( node ) ) {
            if ( tag !== 'LI' ) {
                replacement = self.createElement( 'LI', {
                    'class': node.dir === 'rtl' ? 'dir-rtl' : '',
                    dir: node.dir
                }, [
                    empty( node )
                ]);
                if ( node.parentNode.nodeName === type ) {
                    replaceWith( node, replacement );
                }
                else if ( ( prev = node.previousSibling ) &&
                        prev.nodeName === type ) {
                    prev.appendChild( replacement );
                    detach( node );
                    i -= 1;
                    l -= 1;
                }
                else {
                    replaceWith(
                        node,
                        self.createElement( type, [
                            replacement
                        ])
                    );
                }
            }
        } else if ( isContainer( node ) ) {
            if ( tag !== type && ( /^[DOU]L$/.test( tag ) ) ) {
                replaceWith( node,
                    self.createElement( type, [ empty( node ) ] )
                );
            } else {
                makeList( self, node.childNodes, type );
            }
        }
    }
};

var makeUnorderedList = function ( frag ) {
    makeList( this, frag.childNodes, 'UL' );
    return frag;
};

var makeOrderedList = function ( frag ) {
    makeList( this, frag.childNodes, 'OL' );
    return frag;
};

var decreaseListLevel = function ( frag ) {
    var lists = frag.querySelectorAll( 'UL, OL' );
    Array.prototype.filter.call( lists, function ( el ) {
        return !getNearest( el.parentNode, 'UL' ) &&
            !getNearest( el.parentNode, 'OL' );
    }).forEach( function ( el ) {
        var frag = empty( el ),
            children = frag.childNodes,
            l = children.length,
            child;
        while ( l-- ) {
            child = children[l];
            if ( child.nodeName === 'LI' ) {
                frag.replaceChild( this.createElement( 'DIV', {
                    'class': child.dir === 'rtl' ? 'dir-rtl' : '',
                    dir: child.dir
                }, [
                    empty( child )
                ]), child );
            }
        }
        replaceWith( el, frag );
    }, this );
    return frag;
};

// --- Clean ---

var linkRegExp = /\b((?:(?:ht|f)tps?:\/\/|www\d{0,3}[.]|[a-z0-9.\-]+[.][a-z]{2,4}\/)(?:[^\s()<>]+|\([^\s()<>]+\))+(?:\((?:[^\s()<>]+|(?:\([^\s()<>]+\)))*\)|[^\s`!()\[\]{};:'".,<>?«»“”‘’])|(?:[\w\-.%+]+@(?:[\w\-]+\.)+[A-Z]{2,4}))/i;

var addLinks = function ( frag ) {
    var doc = frag.ownerDocument,
        walker = new TreeWalker( frag, SHOW_TEXT,
                function ( node ) {
            return getNearest( node, 'A' ) ? FILTER_SKIP : FILTER_ACCEPT;
        }, false ),
        node, parts, i, l, text, parent, next;
    while ( node = walker.nextNode() ) {
        parts = node.data.split( linkRegExp );
        l = parts.length;
        if ( l > 1 ) {
            parent = node.parentNode;
            next = node.nextSibling;
            for ( i = 0; i < l; i += 1 ) {
                text = parts[i];
                if ( i ) {
                    if ( i % 2 ) {
                        node = doc.createElement( 'A' );
                        node.textContent = text;
                        node.href = /@/.test( text ) ? 'mailto:' + text :
                            /^(?:ht|f)tps?:/.test( text ) ?
                            text : 'http://' + text;
                    } else {
                        node = doc.createTextNode( text );
                    }
                    if ( next ) {
                        parent.insertBefore( node, next );
                    } else {
                        parent.appendChild( node );
                    }
                } else {
                    node.data = text;
                }
            }
            walker.currentNode = node;
        }
    }
};

var allowedBlock = /^(?:A(?:DDRESS|RTICLE|SIDE)|BLOCKQUOTE|CAPTION|D(?:[DLT]|IV)|F(?:IGURE|OOTER)|H[1-6]|HEADER|L(?:ABEL|EGEND|I)|O(?:L|UTPUT)|P(?:RE)?|SECTION|T(?:ABLE|BODY|D|FOOT|H|HEAD|R)|UL)$/;

var fontSizes = {
    1: 10,
    2: 13,
    3: 16,
    4: 18,
    5: 24,
    6: 32,
    7: 48
};

var spanToSemantic = {
    backgroundColor: {
        regexp: notWS,
        replace: function ( doc, colour ) {
            return createElement( doc, 'SPAN', {
                'class': 'highlight',
                style: 'background-color: ' + colour
            });
        }
    },
    color: {
        regexp: notWS,
        replace: function ( doc, colour ) {
            return createElement( doc, 'SPAN', {
                'class': 'colour',
                style: 'color:' + colour
            });
        }
    },
    fontWeight: {
        regexp: /^bold/i,
        replace: function ( doc ) {
            return createElement( doc, 'B' );
        }
    },
    fontStyle: {
        regexp: /^italic/i,
        replace: function ( doc ) {
            return createElement( doc, 'I' );
        }
    },
    fontFamily: {
        regexp: notWS,
        replace: function ( doc, family ) {
            return createElement( doc, 'SPAN', {
                'class': 'font',
                style: 'font-family:' + family
            });
        }
    },
    fontSize: {
        regexp: notWS,
        replace: function ( doc, size ) {
            return createElement( doc, 'SPAN', {
                'class': 'size',
                style: 'font-size:' + size
            });
        }
    }
};

var replaceWithTag = function ( tag ) {
    return function ( node, parent ) {
        var el = createElement( node.ownerDocument, tag );
        parent.replaceChild( el, node );
        el.appendChild( empty( node ) );
        return el;
    };
};

var stylesRewriters = {
    SPAN: function ( span, parent ) {
        var style = span.style,
            doc = span.ownerDocument,
            attr, converter, css, newTreeBottom, newTreeTop, el;

        for ( attr in spanToSemantic ) {
            converter = spanToSemantic[ attr ];
            css = style[ attr ];
            if ( css && converter.regexp.test( css ) ) {
                el = converter.replace( doc, css );
                if ( newTreeBottom ) {
                    newTreeBottom.appendChild( el );
                }
                newTreeBottom = el;
                if ( !newTreeTop ) {
                    newTreeTop = el;
                }
            }
        }

        if ( newTreeTop ) {
            newTreeBottom.appendChild( empty( span ) );
            parent.replaceChild( newTreeTop, span );
        }

        return newTreeBottom || span;
    },
    STRONG: replaceWithTag( 'B' ),
    EM: replaceWithTag( 'I' ),
    STRIKE: replaceWithTag( 'S' ),
    FONT: function ( node, parent ) {
        var face = node.face,
            size = node.size,
            colour = node.color,
            doc = node.ownerDocument,
            fontSpan, sizeSpan, colourSpan,
            newTreeBottom, newTreeTop;
        if ( face ) {
            fontSpan = createElement( doc, 'SPAN', {
                'class': 'font',
                style: 'font-family:' + face
            });
            newTreeTop = fontSpan;
            newTreeBottom = fontSpan;
        }
        if ( size ) {
            sizeSpan = createElement( doc, 'SPAN', {
                'class': 'size',
                style: 'font-size:' + fontSizes[ size ] + 'px'
            });
            if ( !newTreeTop ) {
                newTreeTop = sizeSpan;
            }
            if ( newTreeBottom ) {
                newTreeBottom.appendChild( sizeSpan );
            }
            newTreeBottom = sizeSpan;
        }
        if ( colour && /^#?([\dA-F]{3}){1,2}$/i.test( colour ) ) {
            if ( colour.charAt( 0 ) !== '#' ) {
                colour = '#' + colour;
            }
            colourSpan = createElement( doc, 'SPAN', {
                'class': 'colour',
                style: 'color:' + colour
            });
            if ( !newTreeTop ) {
                newTreeTop = colourSpan;
            }
            if ( newTreeBottom ) {
                newTreeBottom.appendChild( colourSpan );
            }
            newTreeBottom = colourSpan;
        }
        if ( !newTreeTop ) {
            newTreeTop = newTreeBottom = createElement( doc, 'SPAN' );
        }
        parent.replaceChild( newTreeTop, node );
        newTreeBottom.appendChild( empty( node ) );
        return newTreeBottom;
    },
    TT: function ( node, parent ) {
        var el = createElement( node.ownerDocument, 'SPAN', {
            'class': 'font',
            style: 'font-family:menlo,consolas,"courier new",monospace'
        });
        parent.replaceChild( el, node );
        el.appendChild( empty( node ) );
        return el;
    }
};

var removeEmptyInlines = function ( root ) {
    var children = root.childNodes,
        l = children.length,
        child;
    while ( l-- ) {
        child = children[l];
        if ( child.nodeType === ELEMENT_NODE && child.nodeName !== 'IMG' ) {
            removeEmptyInlines( child );
            if ( isInline( child ) && !child.firstChild ) {
                root.removeChild( child );
            }
        }
    }
};

/*
    Two purposes:

    1. Remove nodes we don't want, such as weird <o:p> tags, comment nodes
       and whitespace nodes.
    2. Convert inline tags into our preferred format.
*/
var cleanTree = function ( node, allowStyles ) {
    var children = node.childNodes,
        i, l, child, nodeName, nodeType, rewriter, childLength;
    for ( i = 0, l = children.length; i < l; i += 1 ) {
        child = children[i];
        nodeName = child.nodeName;
        nodeType = child.nodeType;
        rewriter = stylesRewriters[ nodeName ];
        if ( nodeType === ELEMENT_NODE ) {
            childLength = child.childNodes.length;
            if ( rewriter ) {
                child = rewriter( child, node );
            } else if ( !allowedBlock.test( nodeName ) &&
                    !isInline( child ) ) {
                i -= 1;
                l += childLength - 1;
                node.replaceChild( empty( child ), child );
                continue;
            } else if ( !allowStyles && child.style.cssText ) {
                child.removeAttribute( 'style' );
            }
            if ( childLength ) {
                cleanTree( child, allowStyles );
            }
        } else if ( nodeType !== TEXT_NODE || (
                !( notWS.test( child.data ) ) &&
                !( i > 0 && isInline( children[ i - 1 ] ) ) &&
                !( i + 1 < l && isInline( children[ i + 1 ] ) )
                ) ) {
            node.removeChild( child );
            i -= 1;
            l -= 1;
        }
    }
    return node;
};

var wrapTopLevelInline = function ( root, tag ) {
    var children = root.childNodes,
        doc = root.ownerDocument,
        wrapper = null,
        i, l, child, isBR;
    for ( i = 0, l = children.length; i < l; i += 1 ) {
        child = children[i];
        isBR = child.nodeName === 'BR';
        if ( !isBR && isInline( child ) ) {
            if ( !wrapper ) { wrapper = createElement( doc, tag ); }
            wrapper.appendChild( child );
            i -= 1;
            l -= 1;
        } else if ( isBR || wrapper ) {
            if ( !wrapper ) { wrapper = createElement( doc, tag ); }
            fixCursor( wrapper );
            if ( isBR ) {
                root.replaceChild( wrapper, child );
            } else {
                root.insertBefore( wrapper, child );
                i += 1;
                l += 1;
            }
            wrapper = null;
        }
    }
    if ( wrapper ) {
        root.appendChild( fixCursor( wrapper ) );
    }
    return root;
};

var notWSTextNode = function ( node ) {
    return ( node.nodeType === ELEMENT_NODE ?
        node.nodeName === 'BR' :
        notWS.test( node.data ) ) ?
        FILTER_ACCEPT : FILTER_SKIP;
};
var isLineBreak = function ( br ) {
    var block = br.parentNode,
        walker;
    while ( isInline( block ) ) {
        block = block.parentNode;
    }
    walker = new TreeWalker(
        block, SHOW_ELEMENT|SHOW_TEXT, notWSTextNode );
    walker.currentNode = br;
    return !!walker.nextNode();
};

// <br> elements are treated specially, and differently depending on the
// browser, when in rich text editor mode. When adding HTML from external
// sources, we must remove them, replacing the ones that actually affect
// line breaks with a split of the block element containing it (and wrapping
// any not inside a block). Browsers that want <br> elements at the end of
// each block will then have them added back in a later fixCursor method
// call.
var cleanupBRs = function ( root ) {
    var brs = root.querySelectorAll( 'BR' ),
        brBreaksLine = [],
        l = brs.length,
        i, br, block;

    // Must calculate whether the <br> breaks a line first, because if we
    // have two <br>s next to each other, after the first one is converted
    // to a block split, the second will be at the end of a block and
    // therefore seem to not be a line break. But in its original context it
    // was, so we should also convert it to a block split.
    for ( i = 0; i < l; i += 1 ) {
        brBreaksLine[i] = isLineBreak( brs[i] );
    }
    while ( l-- ) {
        br = brs[l];
        // Cleanup may have removed it
        block = br.parentNode;
        if ( !block ) { continue; }
        while ( isInline( block ) ) {
            block = block.parentNode;
        }
        // If this is not inside a block, replace it by wrapping
        // inlines in DIV.
        if ( !isBlock( block ) || !tagAfterSplit[ block.nodeName ] ) {
            wrapTopLevelInline( block, 'DIV' );
        }
        // If in a block we can split, split it instead, but only if there
        // is actual text content in the block. Otherwise, the <br> is a
        // placeholder to stop the block from collapsing, so we must leave
        // it.
        else {
            if ( brBreaksLine[l] ) {
                splitBlock( block, br.parentNode, br );
            }
            detach( br );
        }
    }
};

// --- Cut and Paste ---

proto._onCut = function () {
    // Save undo checkpoint
    var range = this.getSelection();
    var self = this;
    this._recordUndoState( range );
    this._getRangeAndRemoveBookmark( range );
    this.setSelection( range );
    setTimeout( function () {
        try {
            // If all content removed, ensure div at start of body.
            fixCursor( self._body );
        } catch ( error ) {
            self.didError( error );
        }
    }, 0 );
};

proto._onPaste = function ( event ) {
    if ( this._awaitingPaste ) { return; }

    // Treat image paste as a drop of an image file.
    var clipboardData = event.clipboardData,
        items = clipboardData && clipboardData.items,
        fireDrop = false,
        hasImage = false,
        l, type;
    if ( items ) {
        l = items.length;
        while ( l-- ) {
            type = items[l].type;
            if ( type === 'text/html' ) {
                hasImage = false;
                break;
            }
            if ( /^image\/.*/.test( type ) ) {
                hasImage = true;
            }
        }
        if ( hasImage ) {
            event.preventDefault();
                this.fireEvent( 'dragover', {
                dataTransfer: clipboardData,
                /*jshint loopfunc: true */
                preventDefault: function () {
                    fireDrop = true;
                }
                /*jshint loopfunc: false */
            });
            if ( fireDrop ) {
                this.fireEvent( 'drop', {
                    dataTransfer: clipboardData
                });
            }
            return;
        }
    }

    this._awaitingPaste = true;

    var self = this,
        body = this._body,
        range = this.getSelection(),
        startContainer = range.startContainer,
        startOffset = range.startOffset,
        endContainer = range.endContainer,
        endOffset = range.endOffset;

    var pasteArea = this.createElement( 'DIV', {
        style: 'position: absolute; overflow: hidden; top:' +
            (body.scrollTop + 30) + 'px; left: 0; width: 1px; height: 1px;'
    });
    body.appendChild( pasteArea );
    range.selectNodeContents( pasteArea );
    this.setSelection( range );

    // A setTimeout of 0 means this is added to the back of the
    // single javascript thread, so it will be executed after the
    // paste event.
    setTimeout( function () {
        try {
            // Get the pasted content and clean
            var frag = empty( detach( pasteArea ) ),
                first = frag.firstChild,
                range = self._createRange(
                    startContainer, startOffset, endContainer, endOffset );

            // Was anything actually pasted?
            if ( first ) {
                // Safari and IE like putting extra divs around things.
                if ( first === frag.lastChild &&
                        first.nodeName === 'DIV' ) {
                    frag.replaceChild( empty( first ), first );
                }

                frag.normalize();
                addLinks( frag );
                cleanTree( frag, false );
                cleanupBRs( frag );
                removeEmptyInlines( frag );

                var node = frag,
                    doPaste = true;
                while ( node = getNextBlock( node ) ) {
                    fixCursor( node );
                }

                self.fireEvent( 'willPaste', {
                    fragment: frag,
                    preventDefault: function () {
                        doPaste = false;
                    }
                });

                // Insert pasted data
                if ( doPaste ) {
                    insertTreeFragmentIntoRange( range, frag );
                    self._docWasChanged();

                    range.collapse( false );
                }
            }

            self.setSelection( range );
            self._updatePath( range, true );

            self._awaitingPaste = false;
        } catch ( error ) {
            self.didError( error );
        }
    }, 0 );
};

// --- Keyboard interaction ---

var keys = {
    8: 'backspace',
    9: 'tab',
    13: 'enter',
    32: 'space',
    37: 'left',
    39: 'right',
    46: 'delete'
};

var mapKeyTo = function ( method ) {
    return function ( self, event ) {
        event.preventDefault();
        self[ method ]();
    };
};

var mapKeyToFormat = function ( tag, remove ) {
    remove = remove || null;
    return function ( self, event ) {
        event.preventDefault();
        var range = self.getSelection();
        if ( self.hasFormat( tag, null, range ) ) {
            self.changeFormat( null, { tag: tag }, range );
        } else {
            self.changeFormat( { tag: tag }, remove, range );
        }
    };
};

// If you delete the content inside a span with a font styling, Webkit will
// replace it with a <font> tag (!). If you delete all the text inside a
// link in Opera, it won't delete the link. Let's make things consistent. If
// you delete all text inside an inline tag, remove the inline tag.
var afterDelete = function ( self ) {
    try {
        var range = self.getSelection(),
            node = range.startContainer,
            parent;
        if ( node.nodeType === TEXT_NODE ) {
            node = node.parentNode;
        }
        // If focussed in empty inline element
        if ( isInline( node ) && !node.textContent ) {
            do {
                parent = node.parentNode;
            } while ( isInline( parent ) &&
                !parent.textContent && ( node = parent ) );
            range.setStart( parent,
                indexOf.call( parent.childNodes, node ) );
            range.collapse( true );
            parent.removeChild( node );
            if ( !isBlock( parent ) ) {
                parent = getPreviousBlock( parent );
            }
            fixCursor( parent );
            moveRangeBoundariesDownTree( range );
            self.setSelection( range );
            self._updatePath( range );
        }
    } catch ( error ) {
        self.didError( error );
    }
};

// If you select all in IE8 then type, it makes a P; replace it with
// a DIV.
if ( isIE8 ) {
    proto._ieSelAllClean = function () {
        var firstChild = this._body.firstChild;
        if ( firstChild.nodeName === 'P' ) {
            this._saveRangeToBookmark( this.getSelection() );
            replaceWith( firstChild, this.createElement( 'DIV', [
                empty( firstChild )
            ]) );
            this.setSelection( this._getRangeAndRemoveBookmark() );
        }
    };
}

var keyHandlers = {
    enter: function ( self, event ) {
        // We handle this ourselves
        event.preventDefault();

        // Must have some form of selection
        var range = self.getSelection();
        if ( !range ) { return; }

        // Save undo checkpoint and add any links in the preceding section.
        self._recordUndoState( range );
        addLinks( range.startContainer );
        self._getRangeAndRemoveBookmark( range );

        // Selected text is overwritten, therefore delete the contents
        // to collapse selection.
        if ( !range.collapsed ) {
            deleteContentsOfRange( range );
        }

        var block = getStartBlockOfRange( range ),
            tag = block ? block.nodeName : 'DIV',
            splitTag = tagAfterSplit[ tag ],
            nodeAfterSplit;

        // If this is a malformed bit of document, just play it safe
        // and insert a <br>.
        if ( !block ) {
            insertNodeInRange( range, self.createElement( 'BR' ) );
            range.collapse( false );
            self.setSelection( range );
            self._updatePath( range, true );
            self._docWasChanged();
            return;
        }

        // We need to wrap the contents in divs.
        var splitNode = range.startContainer,
            splitOffset = range.startOffset,
            replacement;
        if ( !splitTag ) {
            // If the selection point is inside the block, we're going to
            // rewrite it so our saved referece points won't be valid.
            // Pick a node at a deeper point in the tree to avoid this.
            if ( splitNode === block ) {
                splitNode = splitOffset ?
                    splitNode.childNodes[ splitOffset - 1 ] : null;
                splitOffset = 0;
                if ( splitNode ) {
                    if ( splitNode.nodeName === 'BR' ) {
                        splitNode = splitNode.nextSibling;
                    } else {
                        splitOffset = getLength( splitNode );
                    }
                    if ( !splitNode || splitNode.nodeName === 'BR' ) {
                        replacement = fixCursor( self.createElement( 'DIV' ) );
                        if ( splitNode ) {
                            block.replaceChild( replacement, splitNode );
                        } else {
                            block.appendChild( replacement );
                        }
                        splitNode = replacement;
                    }
                }
            }
            wrapTopLevelInline( block, 'DIV' );
            splitTag = 'DIV';
            if ( !splitNode ) {
                splitNode = block.firstChild;
            }
            range.setStart( splitNode, splitOffset );
            range.setEnd( splitNode, splitOffset );
            block = getStartBlockOfRange( range );
        }

        if ( !block.textContent ) {
            // Break list
            if ( getNearest( block, 'UL' ) || getNearest( block, 'OL' ) ) {
                return self.modifyBlocks( decreaseListLevel, range );
            }
            // Break blockquote
            else if ( getNearest( block, 'BLOCKQUOTE' ) ) {
                return self.modifyBlocks( removeBlockQuote, range );
            }
        }

        // Otherwise, split at cursor point.
        nodeAfterSplit = splitBlock( block, splitNode, splitOffset );

        // Focus cursor
        // If there's a <b>/<i> etc. at the beginning of the split
        // make sure we focus inside it.
        while ( nodeAfterSplit.nodeType === ELEMENT_NODE ) {
            var child = nodeAfterSplit.firstChild,
                next;

            // Don't continue links over a block break; unlikely to be the
            // desired outcome.
            if ( nodeAfterSplit.nodeName === 'A' ) {
                replaceWith( nodeAfterSplit, empty( nodeAfterSplit ) );
                nodeAfterSplit = child;
                continue;
            }

            while ( child && child.nodeType === TEXT_NODE && !child.data ) {
                next = child.nextSibling;
                if ( !next || next.nodeName === 'BR' ) {
                    break;
                }
                detach( child );
                child = next;
            }

            // 'BR's essentially don't count; they're a browser hack.
            // If you try to select the contents of a 'BR', FF will not let
            // you type anything!
            if ( !child || child.nodeName === 'BR' ||
                    ( child.nodeType === TEXT_NODE && !isOpera ) ) {
                break;
            }
            nodeAfterSplit = child;
        }
        range = self._createRange( nodeAfterSplit, 0 );
        self.setSelection( range );
        self._updatePath( range, true );

        // Scroll into view
        if ( nodeAfterSplit.nodeType === TEXT_NODE ) {
            nodeAfterSplit = nodeAfterSplit.parentNode;
        }
        var doc = self._doc,
            body = self._body;
        if ( nodeAfterSplit.offsetTop + nodeAfterSplit.offsetHeight >
                ( doc.documentElement.scrollTop || body.scrollTop ) +
                body.offsetHeight ) {
            nodeAfterSplit.scrollIntoView( false );
        }

        // We're not still in an undo state
        self._docWasChanged();
    },
    backspace: function ( self, event ) {
        var range = self.getSelection();
        // If not collapsed, delete contents
        if ( !range.collapsed ) {
            self._recordUndoState( range );
            self._getRangeAndRemoveBookmark( range );
            event.preventDefault();
            deleteContentsOfRange( range );
            self.setSelection( range );
            self._updatePath( range, true );
        }
        // If at beginning of block, merge with previous
        else if ( rangeDoesStartAtBlockBoundary( range ) ) {
            self._recordUndoState( range );
            self._getRangeAndRemoveBookmark( range );
            event.preventDefault();
            var current = getStartBlockOfRange( range ),
                previous = current && getPreviousBlock( current );
            // Must not be at the very beginning of the text area.
            if ( previous ) {
                // If not editable, just delete whole block.
                if ( !previous.isContentEditable ) {
                    detach( previous );
                    return;
                }
                // Otherwise merge.
                mergeWithBlock( previous, current, range );
                // If deleted line between containers, merge newly adjacent
                // containers.
                current = previous.parentNode;
                while ( current && !current.nextSibling ) {
                    current = current.parentNode;
                }
                if ( current && ( current = current.nextSibling ) ) {
                    mergeContainers( current );
                }
                self.setSelection( range );
            }
            // If at very beginning of text area, allow backspace
            // to break lists/blockquote.
            else if ( current ) {
                // Break list
                if ( getNearest( current, 'UL' ) ||
                        getNearest( current, 'OL' ) ) {
                    return self.modifyBlocks( decreaseListLevel, range );
                }
                // Break blockquote
                else if ( getNearest( current, 'BLOCKQUOTE' ) ) {
                    return self.modifyBlocks( decreaseBlockQuoteLevel, range );
                }
                self.setSelection( range );
                self._updatePath( range, true );
            }
        }
        // Otherwise, leave to browser but check afterwards whether it has
        // left behind an empty inline tag.
        else {
            var text = range.startContainer.data || '';
            if ( !notWS.test( text.charAt( range.startOffset - 1 ) ) ) {
                self._recordUndoState( range );
                self._getRangeAndRemoveBookmark( range );
                self.setSelection( range );
            }
            setTimeout( function () { afterDelete( self ); }, 0 );
        }
    },
    'delete': function ( self, event ) {
        var range = self.getSelection();
        // If not collapsed, delete contents
        if ( !range.collapsed ) {
            self._recordUndoState( range );
            self._getRangeAndRemoveBookmark( range );
            event.preventDefault();
            deleteContentsOfRange( range );
            self.setSelection( range );
            self._updatePath( range, true );
        }
        // If at end of block, merge next into this block
        else if ( rangeDoesEndAtBlockBoundary( range ) ) {
            self._recordUndoState( range );
            self._getRangeAndRemoveBookmark( range );
            event.preventDefault();
            var current = getStartBlockOfRange( range ),
                next = current && getNextBlock( current );
            // Must not be at the very end of the text area.
            if ( next ) {
                // If not editable, just delete whole block.
                if ( !next.isContentEditable ) {
                    detach( next );
                    return;
                }
                // Otherwise merge.
                mergeWithBlock( current, next, range );
                // If deleted line between containers, merge newly adjacent
                // containers.
                next = current.parentNode;
                while ( next && !next.nextSibling ) {
                    next = next.parentNode;
                }
                if ( next && ( next = next.nextSibling ) ) {
                    mergeContainers( next );
                }
                self.setSelection( range );
                self._updatePath( range, true );
            }
        }
        // Otherwise, leave to browser but check afterwards whether it has
        // left behind an empty inline tag.
        else {
            // Record undo point if deleting whitespace
            var text = range.startContainer.data || '';
            if ( !notWS.test( text.charAt( range.startOffset ) ) ) {
                self._recordUndoState( range );
                self._getRangeAndRemoveBookmark( range );
                self.setSelection( range );
            }
            setTimeout( function () { afterDelete( self ); }, 0 );
        }
    },
    space: function ( self ) {
        var range = self.getSelection();
        self._recordUndoState( range );
        addLinks( range.startContainer );
        self._getRangeAndRemoveBookmark( range );
        self.setSelection( range );
    }
};
// Firefox incorrectly handles Cmd-left/Cmd-right on Mac:
// it goes back/forward in history! Override to do the right
// thing.
// https://bugzilla.mozilla.org/show_bug.cgi?id=289384
if ( isMac && isGecko && win.getSelection().modify ) {
    keyHandlers[ 'meta-left' ] = function ( self, event ) {
        event.preventDefault();
        self._sel.modify( 'move', 'backward', 'lineboundary' );
    };
    keyHandlers[ 'meta-right' ] = function ( self, event ) {
        event.preventDefault();
        self._sel.modify( 'move', 'forward', 'lineboundary' );
    };
}

keyHandlers[ ctrlKey + 'b' ] = mapKeyToFormat( 'B' );
keyHandlers[ ctrlKey + 'i' ] = mapKeyToFormat( 'I' );
keyHandlers[ ctrlKey + 'u' ] = mapKeyToFormat( 'U' );
keyHandlers[ ctrlKey + 'shift-7' ] = mapKeyToFormat( 'S' );
keyHandlers[ ctrlKey + 'shift-5' ] = mapKeyToFormat( 'SUB', { tag: 'SUP' } );
keyHandlers[ ctrlKey + 'shift-6' ] = mapKeyToFormat( 'SUP', { tag: 'SUB' } );
keyHandlers[ ctrlKey + 'y' ] = mapKeyTo( 'redo' );
keyHandlers[ ctrlKey + 'z' ] = mapKeyTo( 'undo' );
keyHandlers[ ctrlKey + 'shift-z' ] = mapKeyTo( 'redo' );

// Ref: http://unixpapa.com/js/key.html
proto._onKey = function ( event ) {
    var code = event.keyCode,
        key = keys[ code ] || String.fromCharCode( code ).toLowerCase(),
        modifiers = '';

    // On keypress, delete and '.' both have event.keyCode 46
    // Must check event.which to differentiate.
    if ( isOpera && event.which === 46 ) {
        key = '.';
    }

    // Function keys
    if ( 111 < code && code < 124 ) {
        key = 'f' + ( code - 111 );
    }

    if ( event.altKey ) { modifiers += 'alt-'; }
    if ( event.ctrlKey ) { modifiers += 'ctrl-'; }
    if ( event.metaKey ) { modifiers += 'meta-'; }
    if ( event.shiftKey ) { modifiers += 'shift-'; }

    key = modifiers + key;

    if ( keyHandlers[ key ] ) {
        keyHandlers[ key ]( this, event );
    }
};

// --- Get/Set data ---

proto._getHTML = function () {
    return this._body.innerHTML;
};

proto._setHTML = function ( html ) {
    var node = this._body;
    node.innerHTML = html;
    do {
        fixCursor( node );
    } while ( node = getNextBlock( node ) );
};

proto.getHTML = function ( withBookMark ) {
    var brs = [],
        node, fixer, html, l, range;
    if ( withBookMark && ( range = this.getSelection() ) ) {
        this._saveRangeToBookmark( range );
    }
    if ( useTextFixer ) {
        node = this._body;
        while ( node = getNextBlock( node ) ) {
            if ( !node.textContent && !node.querySelector( 'BR' ) ) {
                fixer = this.createElement( 'BR' );
                node.appendChild( fixer );
                brs.push( fixer );
            }
        }
    }
    html = this._getHTML();
    if ( useTextFixer ) {
        l = brs.length;
        while ( l-- ) {
            detach( brs[l] );
        }
    }
    if ( range ) {
        this._getRangeAndRemoveBookmark( range );
    }
    return html;
};

proto.setHTML = function ( html ) {
    var frag = this._doc.createDocumentFragment(),
        div = this.createElement( 'DIV' ),
        child;

    // Parse HTML into DOM tree
    div.innerHTML = html;
    frag.appendChild( empty( div ) );

    cleanTree( frag, true );
    cleanupBRs( frag );

    wrapTopLevelInline( frag, 'DIV' );

    // Fix cursor
    var node = frag;
    while ( node = getNextBlock( node ) ) {
        fixCursor( node );
    }

    // Remove existing body children
    var body = this._body;
    while ( child = body.lastChild ) {
        body.removeChild( child );
    }

    // And insert new content
    body.appendChild( frag );
    fixCursor( body );

    // Reset the undo stack
    this._undoIndex = -1;
    this._undoStack.length = 0;
    this._undoStackLength = 0;
    this._isInUndoState = false;

    // Record undo state
    var range = this._getRangeAndRemoveBookmark() ||
        this._createRange( body.firstChild, 0 );
    this._recordUndoState( range );
    this._getRangeAndRemoveBookmark( range );
    // IE will also set focus when selecting text so don't use
    // setSelection. Instead, just store it in lastSelection, so if
    // anything calls getSelection before first focus, we have a range
    // to return.
    if ( losesSelectionOnBlur ) {
        this._lastSelection = range;
    } else {
        this.setSelection( range );
    }
    this._updatePath( range, true );

    return this;
};

proto.insertElement = function ( el, range ) {
    if ( !range ) { range = this.getSelection(); }
    range.collapse( true );
    if ( isInline( el ) ) {
        insertNodeInRange( range, el );
        range.setStartAfter( el );
    } else {
        // Get containing block node.
        var body = this._body,
            splitNode = getStartBlockOfRange( range ) || body,
            parent, nodeAfterSplit;
        // While at end of container node, move up DOM tree.
        while ( splitNode !== body && !splitNode.nextSibling ) {
            splitNode = splitNode.parentNode;
        }
        // If in the middle of a container node, split up to body.
        if ( splitNode !== body ) {
            parent = splitNode.parentNode;
            nodeAfterSplit = split( parent, splitNode.nextSibling, body );
        }
        if ( nodeAfterSplit ) {
            body.insertBefore( el, nodeAfterSplit );
            range.setStart( nodeAfterSplit, 0 );
            range.setStart( nodeAfterSplit, 0 );
            moveRangeBoundariesDownTree( range );
        } else {
            body.appendChild( el );
            // Insert blank line below block.
            body.appendChild( fixCursor( this.createElement( 'div' ) ) );
            range.setStart( el, 0 );
            range.setEnd( el, 0 );
        }
        this.focus();
        this.setSelection( range );
        this._updatePath( range );
    }
    return this;
};

proto.insertImage = function ( src ) {
    var img = this.createElement( 'IMG', {
        src: src
    });
    this.insertElement( img );
    return img;
};

// --- Formatting ---

var command = function ( method, arg, arg2 ) {
    return function () {
        this[ method ]( arg, arg2 );
        return this.focus();
    };
};

proto.addStyles = function ( styles ) {
    if ( styles ) {
        var head = this._doc.documentElement.firstChild,
            style = this.createElement( 'STYLE', {
                type: 'text/css'
            });
        if ( style.styleSheet ) {
            // IE8: must append to document BEFORE adding styles
            // or you get the IE7 CSS parser!
            head.appendChild( style );
            style.styleSheet.cssText = styles;
        } else {
            // Everyone else
            style.appendChild( this._doc.createTextNode( styles ) );
            head.appendChild( style );
        }
    }
    return this;
};

proto.bold = command( 'changeFormat', { tag: 'B' } );
proto.italic = command( 'changeFormat', { tag: 'I' } );
proto.underline = command( 'changeFormat', { tag: 'U' } );
proto.strikethrough = command( 'changeFormat', { tag: 'S' } );
proto.subscript = command( 'changeFormat', { tag: 'SUB' }, { tag: 'SUP' } );
proto.superscript = command( 'changeFormat', { tag: 'SUP' }, { tag: 'SUB' } );

proto.removeBold = command( 'changeFormat', null, { tag: 'B' } );
proto.removeItalic = command( 'changeFormat', null, { tag: 'I' } );
proto.removeUnderline = command( 'changeFormat', null, { tag: 'U' } );
proto.removeStrikethrough = command( 'changeFormat', null, { tag: 'S' } );
proto.removeSubscript = command( 'changeFormat', null, { tag: 'SUB' } );
proto.removeSuperscript = command( 'changeFormat', null, { tag: 'SUP' } );

proto.makeLink = function ( url ) {
    url = encodeURI( url );
    var range = this.getSelection();
    if ( range.collapsed ) {
        var protocolEnd = url.indexOf( ':' ) + 1;
        if ( protocolEnd ) {
            while ( url[ protocolEnd ] === '/' ) { protocolEnd += 1; }
        }
        insertNodeInRange(
            range,
            this._doc.createTextNode( url.slice( protocolEnd ) )
        );
    }
    this.changeFormat({
        tag: 'A',
        attributes: {
            href: url
        }
    }, {
        tag: 'A'
    }, range );
    return this.focus();
};
proto.removeLink = function () {
    this.changeFormat( null, {
        tag: 'A'
    }, this.getSelection(), true );
    return this.focus();
};

proto.setFontFace = function ( name ) {
    this.changeFormat({
        tag: 'SPAN',
        attributes: {
            'class': 'font',
            style: 'font-family: ' + name + ', sans-serif;'
        }
    }, {
        tag: 'SPAN',
        attributes: { 'class': 'font' }
    });
    return this.focus();
};
proto.setFontSize = function ( size ) {
    this.changeFormat({
        tag: 'SPAN',
        attributes: {
            'class': 'size',
            style: 'font-size: ' +
                ( typeof size === 'number' ? size + 'px' : size )
        }
    }, {
        tag: 'SPAN',
        attributes: { 'class': 'size' }
    });
    return this.focus();
};

proto.setTextColour = function ( colour ) {
    this.changeFormat({
        tag: 'SPAN',
        attributes: {
            'class': 'colour',
            style: 'color: ' + colour
        }
    }, {
        tag: 'SPAN',
        attributes: { 'class': 'colour' }
    });
    return this.focus();
};

proto.setHighlightColour = function ( colour ) {
    this.changeFormat({
        tag: 'SPAN',
        attributes: {
            'class': 'highlight',
            style: 'background-color: ' + colour
        }
    }, {
        tag: 'SPAN',
        attributes: { 'class': 'highlight' }
    });
    return this.focus();
};

proto.setTextAlignment = function ( alignment ) {
    this.forEachBlock( function ( block ) {
        block.className = ( block.className
            .split( /\s+/ )
            .filter( function ( klass ) {
                return !( /align/.test( klass ) );
            })
            .join( ' ' ) +
            ' align-' + alignment ).trim();
        block.style.textAlign = alignment;
    }, true );
    return this.focus();
};

proto.setTextDirection = function ( direction ) {
    this.forEachBlock( function ( block ) {
        block.className = ( block.className
            .split( /\s+/ )
            .filter( function ( klass ) {
                return !( /dir/.test( klass ) );
            })
            .join( ' ' ) +
            ' dir-' + direction ).trim();
        block.dir = direction;
    }, true );
    return this.focus();
};

proto.increaseQuoteLevel = command( 'modifyBlocks', increaseBlockQuoteLevel );
proto.decreaseQuoteLevel = command( 'modifyBlocks', decreaseBlockQuoteLevel );

proto.makeUnorderedList = command( 'modifyBlocks', makeUnorderedList );
proto.makeOrderedList = command( 'modifyBlocks', makeOrderedList );
proto.removeList = command( 'modifyBlocks', decreaseListLevel );