( function() {

	var
		trim = $.trim,

		/**
		 * @param {string} sHtml
		 * @return {string}
		 */
		htmlToPlain = function (sHtml)
		{
			var
				sText = '',
				sQuoteChar = '> ',

				convertBlockquote = function () {
					if (arguments && 1 < arguments.length)
					{
						var	sText = trim(arguments[1])
							.replace(/__bq__start__(.|[\s\S\n\r]*)__bq__end__/gm, convertBlockquote)
						;

						sText = '\n' + sQuoteChar + trim(sText).replace(/\n/gm, '\n' + sQuoteChar) + '\n>\n';

						return sText.replace(/\n([> ]+)/gm, function () {
							return (arguments && 1 < arguments.length) ? '\n' + trim(arguments[1].replace(/[\s]/, '')) + ' ' : '';
						});
					}

					return '';
				},

				convertDivs = function () {
					if (arguments && 1 < arguments.length)
					{
						var sText = trim(arguments[1]);
						if (0 < sText.length)
						{
							sText = sText.replace(/<div[^>]*>(.|[\s\S\r\n]*)<\/div>/gmi, convertDivs);
							sText = '\n' + trim(sText) + '\n';
						}
						return sText;
					}
					return '';
				},

				fixAttibuteValue = function () {
					if (arguments && 1 < arguments.length)
					{
						return '' + arguments[1] + arguments[2].replace(/</g, '&lt;').replace(/>/g, '&gt;');
					}

					return '';
				},

				convertLinks = function () {
					return (arguments && 1 < arguments.length) ? trim(arguments[1]) : '';
				}
			;

			sText = sHtml
				.replace(/[\s]+/gm, ' ')
				.replace(/((?:href|data)\s?=\s?)("[^"]+?"|'[^']+?')/gmi, fixAttibuteValue)
				.replace(/<br\s?\/?>/gmi, '\n')
				.replace(/<\/h\d>/gi, '\n')
				.replace(/<\/p>/gi, '\n\n')
				.replace(/<\/li>/gi, '\n')
				.replace(/<\/td>/gi, '\n')
				.replace(/<\/tr>/gi, '\n')
				.replace(/<hr[^>]*>/gmi, '\n_______________________________\n\n')
				.replace(/<img [^>]*>/gmi, '')
				.replace(/<div[^>]*>(.|[\s\S\r\n]*)<\/div>/gmi, convertDivs)
				.replace(/<blockquote[^>]*>/gmi, '\n__bq__start__\n')
				.replace(/<\/blockquote>/gmi, '\n__bq__end__\n')
				.replace(/<a [^>]*>(.|[\s\S\r\n]*)<\/a>/gmi, convertLinks)
				.replace(/&nbsp;/gi, ' ')
				.replace(/<[^>]*>/gm, '')
				.replace(/&gt;/gi, '>')
				.replace(/&lt;/gi, '<')
				.replace(/&amp;/gi, '&')
				.replace(/&\w{2,6};/gi, '')
			;

			return sText
				.replace(/\n[ \t]+/gm, '\n')
				.replace(/[\n]{3,}/gm, '\n\n')
				.replace(/__bq__start__(.|[\s\S\r\n]*)__bq__end__/gm, convertBlockquote)
				.replace(/__bq__start__/gm, '')
				.replace(/__bq__end__/gm, '')
			;
		},

		/**
		 * @param {string} sPlain
		 * @return {string}
		 */
		plainToHtml = function (sPlain)
		{
			return sPlain.toString()
				.replace(/&/g, '&amp;').replace(/>/g, '&gt;').replace(/</g, '&lt;')
				.replace(/\r/g, '').replace(/\n/g, '<br />');
		}
	;

	CKEDITOR.plugins.add('plain', {
		lang: '',
		icons: 'plain',
		hidpi: false,
		init: function(editor) {
			// Source mode isn't available in inline mode yet.
			if (editor.elementMode === CKEDITOR.ELEMENT_MODE_INLINE)
				return;

			var plain = CKEDITOR.plugins.plain;
			editor.addMode( 'plain', function( callback ) {
				var contentsSpace = editor.ui.space('contents'),
					textarea = contentsSpace.getDocument().createElement('textarea');

				textarea.setStyles(
					CKEDITOR.tools.extend( {
						// IE7 has overflow the <textarea> from wrapping table cell.
						width: CKEDITOR.env.ie7Compat ? '99%' : '100%',
						height: '100%',
						resize: 'none',
						outline: 'none',
						'text-align': 'left'
					},
					CKEDITOR.tools.cssVendorPrefix( 'tab-size', 4 ) ) );

				// Make sure that source code is always displayed LTR,
				// regardless of editor language (#10105).
				textarea.setAttribute( 'dir', 'ltr' );

				textarea.addClass( 'cke_plain' );

				contentsSpace.append( textarea );

				var editable = editor.editable(new plainEditable(editor, textarea));

				// Fill the textarea with the current editor data.
				editable.setData(editor.getData(1));
				editor.__plain = editable;

				// Having to make <textarea> fixed sized to conquer the following bugs:
				// 1. The textarea height/width='100%' doesn't constraint to the 'td' in IE6/7.
				// 2. Unexpected vertical-scrolling behavior happens whenever focus is moving out of editor
				// if text content within it has overflowed. (#4762)
				if (CKEDITOR.env.ie) {
					editable.attachListener(editor, 'resize', onResize, editable);
					editable.attachListener(CKEDITOR.document.getWindow(), 'resize', onResize, editable);
					CKEDITOR.tools.setTimeout(onResize, 0, editable);
				}

				editor.fire('ariaWidget', this);
				callback();
			} );

			editor.addCommand('plain', plain.commands.plain);

			if (editor.ui.addButton) {
				editor.ui.addButton('plain', {
					label: '',
					command: 'plain',
					toolbar: 'spec,10'
				});
			}

			editor.on('mode', function() {
				editor.getCommand('plain').setState(editor.mode === 'plain' ? CKEDITOR.TRISTATE_ON : CKEDITOR.TRISTATE_OFF);
			});

			function onResize() {
				// Holder rectange size is stretched by textarea,
				// so hide it just for a moment.
				this.hide();
				this.setStyle( 'height', this.getParent().$.clientHeight + 'px' );
				this.setStyle( 'width', this.getParent().$.clientWidth + 'px' );
				// When we have proper holder size, show textarea again.
				this.show();
			}
		}
	} );

	var plainEditable = CKEDITOR.tools.createClass({
		base: CKEDITOR.editable,
		proto: {

			setData: function(data) {
				this.setValue(htmlToPlain(data));
				this.editor.fire('dataReady');
			},

			getData: function() {
				return plainToHtml(this.getValue());
			},

			getRawData: function() {
				return this.getValue();
			},

			// Insertions are not supported in source editable.
			insertHtml: function() {},
			insertElement: function() {},
			insertText: function() {},

			// Read-only support for textarea.
			setReadOnly: function( isReadOnly ) {
				this[ ( isReadOnly ? 'set' : 'remove' ) + 'Attribute' ]( 'readOnly', 'readonly' );
			},

			detach: function() {
				plainEditable.baseProto.detach.call( this );
				this.clearCustomData();
				this.remove();
			}
		}
	} );
} )();

CKEDITOR.plugins.plain = {
	commands: {
		plain: {
			modes: { wysiwyg: 1, plain: 1 },
			editorFocus: false,
			readOnly: 1,
			exec: function(editor)
			{
				if (editor.mode === 'wysiwyg')
				{
					editor.fire('saveSnapshot');
				}
				
				editor.getCommand('plain').setState(CKEDITOR.TRISTATE_DISABLED);
				editor.setMode(editor.mode === 'plain' ? 'wysiwyg' : 'plain');
			},
			canUndo: false
		}
	}
};