/*
Copyright (c) 2003-2010, CKSource - Frederico Knabben. All rights reserved.
For licensing, see LICENSE.html or http://ckeditor.com/license
*/

/**
 * A lightweight representation of an HTML DOM structure.
 * @constructor
 * @example
 */
CKEDITOR.htmlParser.fragment = function()
{
	/**
	 * The nodes contained in the root of this fragment.
	 * @type Array
	 * @example
	 * var fragment = CKEDITOR.htmlParser.fragment.fromHtml( '<b>Sample</b> Text' );
	 * alert( fragment.children.length );  "2"
	 */
	this.children = [];

	/**
	 * Get the fragment parent. Should always be null.
	 * @type Object
	 * @default null
	 * @example
	 */
	this.parent = null;

	/** @private */
	this._ =
	{
		isBlockLike : true,
		hasInlineStarted : false
	};
};

(function()
{
	// Elements which the end tag is marked as optional in the HTML 4.01 DTD
	// (expect empty elements).
	var optionalClose = {colgroup:1,dd:1,dt:1,li:1,option:1,p:1,td:1,tfoot:1,th:1,thead:1,tr:1};

	// Block-level elements whose internal structure should be respected during
	// parser fixing.
	var nonBreakingBlocks = CKEDITOR.tools.extend(
			{table:1,ul:1,ol:1,dl:1},
			CKEDITOR.dtd.table, CKEDITOR.dtd.ul, CKEDITOR.dtd.ol, CKEDITOR.dtd.dl ),
		listBlocks = CKEDITOR.dtd.$list, listItems = CKEDITOR.dtd.$listItem;

	/**
	 * Creates a {@link CKEDITOR.htmlParser.fragment} from an HTML string.
	 * @param {String} fragmentHtml The HTML to be parsed, filling the fragment.
	 * @param {Number} [fixForBody=false] Wrap body with specified element if needed.
	 * @returns CKEDITOR.htmlParser.fragment The fragment created.
	 * @example
	 * var fragment = CKEDITOR.htmlParser.fragment.fromHtml( '<b>Sample</b> Text' );
	 * alert( fragment.children[0].name );  "b"
	 * alert( fragment.children[1].value );  " Text"
	 */
	CKEDITOR.htmlParser.fragment.fromHtml = function( fragmentHtml, fixForBody )
	{
		var parser = new CKEDITOR.htmlParser(),
			html = [],
			fragment = new CKEDITOR.htmlParser.fragment(),
			pendingInline = [],
			pendingBRs = [],
			currentNode = fragment,
		    // Indicate we're inside a <pre> element, spaces should be touched differently.
			inPre = false,
			returnPoint;

		function checkPending( newTagName )
		{
			var pendingBRsSent;

			if ( pendingInline.length > 0 )
			{
				for ( var i = 0 ; i < pendingInline.length ; i++ )
				{
					var pendingElement = pendingInline[ i ],
						pendingName = pendingElement.name,
						pendingDtd = CKEDITOR.dtd[ pendingName ],
						currentDtd = currentNode.name && CKEDITOR.dtd[ currentNode.name ];

					if ( ( !currentDtd || currentDtd[ pendingName ] ) && ( !newTagName || !pendingDtd || pendingDtd[ newTagName ] || !CKEDITOR.dtd[ newTagName ] ) )
					{
						if ( !pendingBRsSent )
						{
							sendPendingBRs();
							pendingBRsSent = 1;
						}

						// Get a clone for the pending element.
						pendingElement = pendingElement.clone();

						// Add it to the current node and make it the current,
						// so the new element will be added inside of it.
						pendingElement.parent = currentNode;
						currentNode = pendingElement;

						// Remove the pending element (back the index by one
						// to properly process the next entry).
						pendingInline.splice( i, 1 );
						i--;
					}
				}
			}
		}

		function sendPendingBRs()
		{
			while ( pendingBRs.length )
				currentNode.add( pendingBRs.shift() );
		}

		function addElement( element, target, enforceCurrent )
		{
			target = target || currentNode || fragment;

			// If the target is the fragment and this element can't go inside
			// body (if fixForBody).
			if ( fixForBody && !target.type )
			{
				var elementName, realElementName;
				if ( element.attributes
					 && ( realElementName =
						  element.attributes[ '_cke_real_element_type' ] ) )
					elementName = realElementName;
				else
					elementName =  element.name;
				if ( elementName
						&& !( elementName in CKEDITOR.dtd.$body )
						&& !( elementName in CKEDITOR.dtd.$nonBodyContent )  )
				{
					var savedCurrent = currentNode;

					// Create a <p> in the fragment.
					currentNode = target;
					parser.onTagOpen( fixForBody, {} );

					// The new target now is the <p>.
					target = currentNode;

					if ( enforceCurrent )
						currentNode = savedCurrent;
				}
			}

			// Rtrim empty spaces on block end boundary. (#3585)
			if ( element._.isBlockLike
				 && element.name != 'pre' )
			{

				var length = element.children.length,
					lastChild = element.children[ length - 1 ],
					text;
				if ( lastChild && lastChild.type == CKEDITOR.NODE_TEXT )
				{
					if ( !( text = CKEDITOR.tools.rtrim( lastChild.value ) ) )
						element.children.length = length -1;
					else
						lastChild.value = text;
				}
			}

			target.add( element );

			if ( element.returnPoint )
			{
				currentNode = element.returnPoint;
				delete element.returnPoint;
			}
		}

		parser.onTagOpen = function( tagName, attributes, selfClosing )
		{
			var element = new CKEDITOR.htmlParser.element( tagName, attributes );

			// "isEmpty" will be always "false" for unknown elements, so we
			// must force it if the parser has identified it as a selfClosing tag.
			if ( element.isUnknown && selfClosing )
				element.isEmpty = true;

			// This is a tag to be removed if empty, so do not add it immediately.
			if ( CKEDITOR.dtd.$removeEmpty[ tagName ] )
			{
				pendingInline.push( element );
				return;
			}
			else if ( tagName == 'pre' )
				inPre = true;
			else if ( tagName == 'br' && inPre )
			{
				currentNode.add( new CKEDITOR.htmlParser.text( '\n' ) );
				return;
			}

			if ( tagName == 'br' )
			{
				pendingBRs.push( element );
				return;
			}

			var currentName = currentNode.name;

			var currentDtd = currentName
				&& ( CKEDITOR.dtd[ currentName ]
					|| ( currentNode._.isBlockLike ? CKEDITOR.dtd.div : CKEDITOR.dtd.span ) );

			// If the element cannot be child of the current element.
			if ( currentDtd   // Fragment could receive any elements.
				 && !element.isUnknown && !currentNode.isUnknown && !currentDtd[ tagName ] )
			{

				var reApply = false,
					addPoint;   // New position to start adding nodes.

				// Fixing malformed nested lists by moving it into a previous list item. (#3828)
				if ( tagName in listBlocks
					&& currentName in listBlocks )
				{
					var children = currentNode.children,
						lastChild = children[ children.length - 1 ];

					// Establish the list item if it's not existed.
					if ( !( lastChild && lastChild.name in listItems ) )
						addElement( ( lastChild = new CKEDITOR.htmlParser.element( 'li' ) ), currentNode );

					returnPoint = currentNode, addPoint = lastChild;
				}
				// If the element name is the same as the current element name,
				// then just close the current one and append the new one to the
				// parent. This situation usually happens with <p>, <li>, <dt> and
				// <dd>, specially in IE. Do not enter in this if block in this case.
				else if ( tagName == currentName )
				{
					addElement( currentNode, currentNode.parent );
				}
				else
				{
					if ( nonBreakingBlocks[ currentName ] )
					{
						if ( !returnPoint )
							returnPoint = currentNode;
					}
					else
					{
						addElement( currentNode, currentNode.parent, true );

						if ( !optionalClose[ currentName ] )
						{
							// The current element is an inline element, which
							// cannot hold the new one. Put it in the pending list,
							// and try adding the new one after it.
							pendingInline.unshift( currentNode );
						}
					}

					reApply = true;
				}

				if ( addPoint )
					currentNode = addPoint;
				// Try adding it to the return point, or the parent element.
				else
					currentNode = currentNode.returnPoint || currentNode.parent;

				if ( reApply )
				{
					parser.onTagOpen.apply( this, arguments );
					return;
				}
			}

			checkPending( tagName );

			element.parent = currentNode;
			element.returnPoint = returnPoint;
			returnPoint = 0;

			if ( element.isEmpty )
				addElement( element );
			else
				currentNode = element;
		};

		parser.onTagClose = function( tagName )
		{
			// Check if there is any pending tag to be closed.
			for ( var i = pendingInline.length - 1 ; i >= 0 ; i-- )
			{
				// If found, just remove it from the list.
				if ( tagName == pendingInline[ i ].name )
				{
					pendingInline.splice( i, 1 );
					return;
				}
			}

			var pendingAdd = [],
				newPendingInline = [],
				candidate = currentNode;

			while ( candidate.type && candidate.name != tagName )
			{
				// If this is an inline element, add it to the pending list, if we're
				// really closing one of the parents element later, they will continue
				// after it.
				if ( !candidate._.isBlockLike )
					newPendingInline.unshift( candidate );

				// This node should be added to it's parent at this point. But,
				// it should happen only if the closing tag is really closing
				// one of the nodes. So, for now, we just cache it.
				pendingAdd.push( candidate );

				candidate = candidate.parent;
			}

			if ( candidate.type )
			{
				// Add all elements that have been found in the above loop.
				for ( i = 0 ; i < pendingAdd.length ; i++ )
				{
					var node = pendingAdd[ i ];
					addElement( node, node.parent );
				}

				currentNode = candidate;

				if ( currentNode.name == 'pre' )
					inPre = false;

				if ( candidate._.isBlockLike )
					sendPendingBRs();

				addElement( candidate, candidate.parent );

				// The parent should start receiving new nodes now, except if
				// addElement changed the currentNode.
				if ( candidate == currentNode )
					currentNode = currentNode.parent;

				pendingInline = pendingInline.concat( newPendingInline );
			}

			if ( tagName == 'body' )
				fixForBody = false;
		};

		parser.onText = function( text )
		{
			// Trim empty spaces at beginning of element contents except <pre>.
			if ( !currentNode._.hasInlineStarted && !inPre )
			{
				text = CKEDITOR.tools.ltrim( text );

				if ( text.length === 0 )
					return;
			}

			sendPendingBRs();
			checkPending();

			if ( fixForBody
				 && ( !currentNode.type || currentNode.name == 'body' )
				 && CKEDITOR.tools.trim( text ) )
			{
				this.onTagOpen( fixForBody, {} );
			}

			// Shrinking consequential spaces into one single for all elements
			// text contents.
			if ( !inPre )
				text = text.replace( /[\t\r\n ]{2,}|[\t\r\n]/g, ' ' );

			currentNode.add( new CKEDITOR.htmlParser.text( text ) );
		};

		parser.onCDATA = function( cdata )
		{
			currentNode.add( new CKEDITOR.htmlParser.cdata( cdata ) );
		};

		parser.onComment = function( comment )
		{
			currentNode.add( new CKEDITOR.htmlParser.comment( comment ) );
		};

		// Parse it.
		parser.parse( fragmentHtml );

		sendPendingBRs();

		// Close all pending nodes.
		while ( currentNode.type )
		{
			var parent = currentNode.parent,
				node = currentNode;

			if ( fixForBody
				 && ( !parent.type || parent.name == 'body' )
				 && !CKEDITOR.dtd.$body[ node.name ] )
			{
				currentNode = parent;
				parser.onTagOpen( fixForBody, {} );
				parent = currentNode;
			}

			parent.add( node );
			currentNode = parent;
		}

		return fragment;
	};

	CKEDITOR.htmlParser.fragment.prototype =
	{
		/**
		 * Adds a node to this fragment.
		 * @param {Object} node The node to be added. It can be any of of the
		 *		following types: {@link CKEDITOR.htmlParser.element},
		 *		{@link CKEDITOR.htmlParser.text} and
		 *		{@link CKEDITOR.htmlParser.comment}.
		 * @example
		 */
		add : function( node )
		{
			var len = this.children.length,
				previous = len > 0 && this.children[ len - 1 ] || null;

			if ( previous )
			{
				// If the block to be appended is following text, trim spaces at
				// the right of it.
				if ( node._.isBlockLike && previous.type == CKEDITOR.NODE_TEXT )
				{
					previous.value = CKEDITOR.tools.rtrim( previous.value );

					// If we have completely cleared the previous node.
					if ( previous.value.length === 0 )
					{
						// Remove it from the list and add the node again.
						this.children.pop();
						this.add( node );
						return;
					}
				}

				previous.next = node;
			}

			node.previous = previous;
			node.parent = this;

			this.children.push( node );

			this._.hasInlineStarted = node.type == CKEDITOR.NODE_TEXT || ( node.type == CKEDITOR.NODE_ELEMENT && !node._.isBlockLike );
		},

		/**
		 * Writes the fragment HTML to a CKEDITOR.htmlWriter.
		 * @param {CKEDITOR.htmlWriter} writer The writer to which write the HTML.
		 * @example
		 * var writer = new CKEDITOR.htmlWriter();
		 * var fragment = CKEDITOR.htmlParser.fragment.fromHtml( '&lt;P&gt;&lt;B&gt;Example' );
		 * fragment.writeHtml( writer )
		 * alert( writer.getHtml() );  "&lt;p&gt;&lt;b&gt;Example&lt;/b&gt;&lt;/p&gt;"
		 */
		writeHtml : function( writer, filter )
		{
			var isChildrenFiltered;
			this.filterChildren = function()
			{
				var writer = new CKEDITOR.htmlParser.basicWriter();
				this.writeChildrenHtml.call( this, writer, filter, true );
				var html = writer.getHtml();
				this.children = new CKEDITOR.htmlParser.fragment.fromHtml( html ).children;
				isChildrenFiltered = 1;
			};

			// Filtering the root fragment before anything else.
			!this.name && filter && filter.onFragment( this );

			this.writeChildrenHtml( writer, isChildrenFiltered ? null : filter );
		},

		writeChildrenHtml : function( writer, filter )
		{
			for ( var i = 0 ; i < this.children.length ; i++ )
				this.children[i].writeHtml( writer, filter );
		}
	};
})();
