/*
Copyright (c) 2003-2009, CKSource - Frederico Knabben. All rights reserved.
For licensing, see LICENSE.html or http://ckeditor.com/license
*/

(function()
{
	CKEDITOR.plugins.add( 'enterkey',
	{
		requires : [ 'keystrokes', 'indent' ],

		init : function( editor )
		{
			var specialKeys = editor.specialKeys;
			specialKeys[ 13 ] = enter;
			specialKeys[ CKEDITOR.SHIFT + 13 ] = shiftEnter;
		}
	});

	var forceMode,
		headerTagRegex = /^h[1-6]$/;

	function shiftEnter( editor )
	{
		// On SHIFT+ENTER we want to enforce the mode to be respected, instead
		// of cloning the current block. (#77)
		forceMode = 1;

		return enter( editor, editor.config.shiftEnterMode );
	}

	function enter( editor, mode )
	{
		// Only effective within document.
		if ( editor.mode != 'wysiwyg' )
			return false;

		if ( !mode )
			mode = editor.config.enterMode;

		// Use setTimout so the keys get cancelled immediatelly.
		setTimeout( function()
			{
				editor.fire( 'saveSnapshot' );	// Save undo step.
				if ( mode == CKEDITOR.ENTER_BR || editor.getSelection().getStartElement().hasAscendant( 'pre', true ) )
					enterBr( editor, mode );
				else
					enterBlock( editor, mode );

				forceMode = 0;
			}, 0 );

		return true;
	}

	function enterBlock( editor, mode, range )
	{
		// Get the range for the current selection.
		range = range || getRange( editor );

		var doc = range.document;

		// Determine the block element to be used.
		var blockTag = ( mode == CKEDITOR.ENTER_DIV ? 'div' : 'p' );

		// Split the range.
		var splitInfo = range.splitBlock( blockTag );

		if ( !splitInfo )
			return;

		// Get the current blocks.
		var previousBlock	= splitInfo.previousBlock,
			nextBlock		= splitInfo.nextBlock;

		var isStartOfBlock	= splitInfo.wasStartOfBlock,
			isEndOfBlock	= splitInfo.wasEndOfBlock;

		var node;

		// If this is a block under a list item, split it as well. (#1647)
		if ( nextBlock )
		{
			node = nextBlock.getParent();
			if ( node.is( 'li' ) )
			{
				nextBlock.breakParent( node );
				nextBlock.move( nextBlock.getNext(), true );
			}
		}
		else if ( previousBlock && ( node = previousBlock.getParent() ) && node.is( 'li' ) )
		{
			previousBlock.breakParent( node );
			range.moveToElementEditStart( previousBlock.getNext() );
			previousBlock.move( previousBlock.getPrevious() );
		}

		// If we have both the previous and next blocks, it means that the
		// boundaries were on separated blocks, or none of them where on the
		// block limits (start/end).
		if ( !isStartOfBlock && !isEndOfBlock )
		{
			// If the next block is an <li> with another list tree as the first
			// child, we'll need to append a filler (<br>/NBSP) or the list item
			// wouldn't be editable. (#1420)
			if ( nextBlock.is( 'li' )
				 && ( node = nextBlock.getFirst( CKEDITOR.dom.walker.invisible( true ) ) )
				 && node.is && node.is( 'ul', 'ol' ) )
				( CKEDITOR.env.ie ? doc.createText( '\xa0' ) : doc.createElement( 'br' ) ).insertBefore( node );

			// Move the selection to the end block.
			if ( nextBlock )
				range.moveToElementEditStart( nextBlock );
		}
		else
		{

			if ( isStartOfBlock && isEndOfBlock && previousBlock.is( 'li' ) )
			{
				editor.execCommand( 'outdent' );
				return;
			}

			var newBlock;

			if ( previousBlock )
			{
				// Do not enter this block if it's a header tag, or we are in
				// a Shift+Enter (#77). Create a new block element instead
				// (later in the code).
				if ( !forceMode && !headerTagRegex.test( previousBlock.getName() ) )
				{
					// Otherwise, duplicate the previous block.
					newBlock = previousBlock.clone();
				}
			}
			else if ( nextBlock )
				newBlock = nextBlock.clone();

			if ( !newBlock )
				newBlock = doc.createElement( blockTag );

			// Recreate the inline elements tree, which was available
			// before hitting enter, so the same styles will be available in
			// the new block.
			var elementPath = splitInfo.elementPath;
			if ( elementPath )
			{
				for ( var i = 0, len = elementPath.elements.length ; i < len ; i++ )
				{
					var element = elementPath.elements[ i ];

					if ( element.equals( elementPath.block ) || element.equals( elementPath.blockLimit ) )
						break;

					if ( CKEDITOR.dtd.$removeEmpty[ element.getName() ] )
					{
						element = element.clone();
						newBlock.moveChildren( element );
						newBlock.append( element );
					}
				}
			}

			if ( !CKEDITOR.env.ie )
				newBlock.appendBogus();

			range.insertNode( newBlock );

			// This is tricky, but to make the new block visible correctly
			// we must select it.
			// The previousBlock check has been included because it may be
			// empty if we have fixed a block-less space (like ENTER into an
			// empty table cell).
			if ( CKEDITOR.env.ie && isStartOfBlock && ( !isEndOfBlock || !previousBlock.getChildCount() ) )
			{
				// Move the selection to the new block.
				range.moveToElementEditStart( isEndOfBlock ? previousBlock : newBlock );
				range.select();
			}

			// Move the selection to the new block.
			range.moveToElementEditStart( isStartOfBlock && !isEndOfBlock ? nextBlock : newBlock );
		}

		if ( !CKEDITOR.env.ie )
		{
			if ( nextBlock )
			{
				// If we have split the block, adds a temporary span at the
				// range position and scroll relatively to it.
				var tmpNode = doc.createElement( 'span' );

				// We need some content for Safari.
				tmpNode.setHtml( '&nbsp;' );

				range.insertNode( tmpNode );
				tmpNode.scrollIntoView();
				range.deleteContents();
			}
			else
			{
				// We may use the above scroll logic for the new block case
				// too, but it gives some weird result with Opera.
				newBlock.scrollIntoView();
			}
		}

		range.select();
	}

	function enterBr( editor, mode )
	{
		// Get the range for the current selection.
		var range = getRange( editor ),
			doc = range.document;

		// Determine the block element to be used.
		var blockTag = ( mode == CKEDITOR.ENTER_DIV ? 'div' : 'p' );

		var isEndOfBlock = range.checkEndOfBlock();

		var elementPath = new CKEDITOR.dom.elementPath( editor.getSelection().getStartElement() );

		var startBlock = elementPath.block,
			startBlockTag = startBlock && elementPath.block.getName();

		var isPre = false;

		if ( !forceMode && startBlockTag == 'li' )
		{
			enterBlock( editor, mode, range );
			return;
		}

		// If we are at the end of a header block.
		if ( !forceMode && isEndOfBlock && headerTagRegex.test( startBlockTag ) )
		{
			// Insert a <br> after the current paragraph.
			doc.createElement( 'br' ).insertAfter( startBlock );

			// A text node is required by Gecko only to make the cursor blink.
			if ( CKEDITOR.env.gecko )
				doc.createText( '' ).insertAfter( startBlock );

			// IE has different behaviors regarding position.
			range.setStartAt( startBlock.getNext(), CKEDITOR.env.ie ? CKEDITOR.POSITION_BEFORE_START : CKEDITOR.POSITION_AFTER_START );
		}
		else
		{
			var lineBreak;

			isPre = ( startBlockTag == 'pre' );

			if ( isPre )
				lineBreak = doc.createText( CKEDITOR.env.ie ? '\r' : '\n' );
			else
				lineBreak = doc.createElement( 'br' );

			range.deleteContents();
			range.insertNode( lineBreak );

			// A text node is required by Gecko only to make the cursor blink.
			// We need some text inside of it, so the bogus <br> is properly
			// created.
			if ( !CKEDITOR.env.ie )
				doc.createText( '\ufeff' ).insertAfter( lineBreak );

			// If we are at the end of a block, we must be sure the bogus node is available in that block.
			if ( isEndOfBlock && !CKEDITOR.env.ie )
				lineBreak.getParent().appendBogus();

			// Now we can remove the text node contents, so the caret doesn't
			// stop on it.
			if ( !CKEDITOR.env.ie )
				lineBreak.getNext().$.nodeValue = '';
			// IE has different behavior regarding position.
			if ( CKEDITOR.env.ie )
				range.setStartAt( lineBreak, CKEDITOR.POSITION_AFTER_END );
			else
				range.setStartAt( lineBreak.getNext(), CKEDITOR.POSITION_AFTER_START );

			// Scroll into view, for non IE.
			if ( !CKEDITOR.env.ie )
			{
				var dummy = null;

				// BR is not positioned in Opera and Webkit.
				if ( !CKEDITOR.env.gecko )
				{
					dummy = doc.createElement( 'span' );
					// We need have some contents for Webkit to position it
					// under parent node. ( #3681)
					dummy.setHtml('&nbsp;');
				}
				else
					dummy = doc.createElement( 'br' );

				dummy.insertBefore( lineBreak.getNext() );
				dummy.scrollIntoView();
				dummy.remove();
			}
		}

		// This collapse guarantees the cursor will be blinking.
		range.collapse( true );

		range.select( isPre );
	}

	function getRange( editor )
	{
		// Get the selection ranges.
		var ranges = editor.getSelection().getRanges();

		// Delete the contents of all ranges except the first one.
		for ( var i = ranges.length - 1 ; i > 0 ; i-- )
		{
			ranges[ i ].deleteContents();
		}

		// Return the first range.
		return ranges[ 0 ];
	}
})();
