/**
 * @license Copyright (c) 2003-2016, CKSource - Frederico Knabben. All rights reserved.
 * For licensing, see LICENSE.md or http://ckeditor.com/license
 */

CKEDITOR.dialog.add( 'a11yHelp', function( editor ) {
	var lang = editor.lang.a11yhelp,
		id = CKEDITOR.tools.getNextId();

	// CharCode <-> KeyChar.
	var keyMap = {
		8: lang.backspace,
		9: lang.tab,
		13: lang.enter,
		16: lang.shift,
		17: lang.ctrl,
		18: lang.alt,
		19: lang.pause,
		20: lang.capslock,
		27: lang.escape,
		33: lang.pageUp,
		34: lang.pageDown,
		35: lang.end,
		36: lang.home,
		37: lang.leftArrow,
		38: lang.upArrow,
		39: lang.rightArrow,
		40: lang.downArrow,
		45: lang.insert,
		46: lang[ 'delete' ],
		91: lang.leftWindowKey,
		92: lang.rightWindowKey,
		93: lang.selectKey,
		96: lang.numpad0,
		97: lang.numpad1,
		98: lang.numpad2,
		99: lang.numpad3,
		100: lang.numpad4,
		101: lang.numpad5,
		102: lang.numpad6,
		103: lang.numpad7,
		104: lang.numpad8,
		105: lang.numpad9,
		106: lang.multiply,
		107: lang.add,
		109: lang.subtract,
		110: lang.decimalPoint,
		111: lang.divide,
		112: lang.f1,
		113: lang.f2,
		114: lang.f3,
		115: lang.f4,
		116: lang.f5,
		117: lang.f6,
		118: lang.f7,
		119: lang.f8,
		120: lang.f9,
		121: lang.f10,
		122: lang.f11,
		123: lang.f12,
		144: lang.numLock,
		145: lang.scrollLock,
		186: lang.semiColon,
		187: lang.equalSign,
		188: lang.comma,
		189: lang.dash,
		190: lang.period,
		191: lang.forwardSlash,
		192: lang.graveAccent,
		219: lang.openBracket,
		220: lang.backSlash,
		221: lang.closeBracket,
		222: lang.singleQuote
	};

	// Modifier keys override.
	keyMap[ CKEDITOR.ALT ] = lang.alt;
	keyMap[ CKEDITOR.SHIFT ] = lang.shift;
	keyMap[ CKEDITOR.CTRL ] = lang.ctrl;

	// Sort in desc.
	var modifiers = [ CKEDITOR.ALT, CKEDITOR.SHIFT, CKEDITOR.CTRL ];

	function representKeyStroke( keystroke ) {
		var quotient, modifier,
			presentation = [];

		for ( var i = 0; i < modifiers.length; i++ ) {
			modifier = modifiers[ i ];
			quotient = keystroke / modifiers[ i ];
			if ( quotient > 1 && quotient <= 2 ) {
				keystroke -= modifier;
				presentation.push( keyMap[ modifier ] );
			}
		}

		presentation.push( keyMap[ keystroke ] || String.fromCharCode( keystroke ) );

		return presentation.join( '+' );
	}

	var variablesPattern = /\$\{(.*?)\}/g;

	var replaceVariables = ( function() {
		// Swaps keystrokes with their commands in object literal.
		// This makes searching keystrokes by command much easier.
		var keystrokesByCode = editor.keystrokeHandler.keystrokes,
			keystrokesByName = {};

		for ( var i in keystrokesByCode )
			keystrokesByName[ keystrokesByCode[ i ] ] = i;

		return function( match, name ) {
			// Return the keystroke representation or leave match untouched
			// if there's no keystroke for such command.
			return keystrokesByName[ name ] ? representKeyStroke( keystrokesByName[ name ] ) : match;
		};
	} )();

	// Create the help list directly from lang file entries.
	function buildHelpContents() {
		var pageTpl = '<div class="cke_accessibility_legend" role="document" aria-labelledby="' + id + '_arialbl" tabIndex="-1">%1</div>' +
				'<span id="' + id + '_arialbl" class="cke_voice_label">' + lang.contents + ' </span>',
			sectionTpl = '<h1>%1</h1><dl>%2</dl>',
			itemTpl = '<dt>%1</dt><dd>%2</dd>';

		var pageHtml = [],
			sections = lang.legend,
			sectionLength = sections.length;

		for ( var i = 0; i < sectionLength; i++ ) {
			var section = sections[ i ],
				sectionHtml = [],
				items = section.items,
				itemsLength = items.length;

			for ( var j = 0; j < itemsLength; j++ ) {
				var item = items[ j ],
					itemLegend = item.legend.replace( variablesPattern, replaceVariables );

				// (#9765) If some commands haven't been replaced in the legend,
				// most likely their keystrokes are unavailable and we shouldn't include
				// them in our help list.
				if ( itemLegend.match( variablesPattern ) )
					continue;

				sectionHtml.push( itemTpl.replace( '%1', item.name ).replace( '%2', itemLegend ) );
			}

			pageHtml.push( sectionTpl.replace( '%1', section.name ).replace( '%2', sectionHtml.join( '' ) ) );
		}

		return pageTpl.replace( '%1', pageHtml.join( '' ) );
	}

	return {
		title: lang.title,
		minWidth: 600,
		minHeight: 400,
		contents: [ {
			id: 'info',
			label: editor.lang.common.generalTab,
			expand: true,
			elements: [
				{
					type: 'html',
					id: 'legends',
					style: 'white-space:normal;',
					focus: function() {
						this.getElement().focus();
					},
					html: buildHelpContents() + '<style type="text/css">' +
						'.cke_accessibility_legend' +
						'{' +
							'width:600px;' +
							'height:400px;' +
							'padding-right:5px;' +
							'overflow-y:auto;' +
							'overflow-x:hidden;' +
						'}' +
						// Some adjustments are to be done for Quirks to work "properly" (#5757)
						'.cke_browser_quirks .cke_accessibility_legend,' +
						'{' +
							'height:390px' +
						'}' +
						// Override non-wrapping white-space rule in reset css.
						'.cke_accessibility_legend *' +
						'{' +
							'white-space:normal;' +
						'}' +
						'.cke_accessibility_legend h1' +
						'{' +
							'font-size: 20px;' +
							'border-bottom: 1px solid #AAA;' +
							'margin: 5px 0px 15px;' +
						'}' +
						'.cke_accessibility_legend dl' +
						'{' +
							'margin-left: 5px;' +
						'}' +
						'.cke_accessibility_legend dt' +
						'{' +
							'font-size: 13px;' +
							'font-weight: bold;' +
						'}' +
						'.cke_accessibility_legend dd' +
						'{' +
							'margin:10px' +
						'}' +
						'</style>'
				}
			]
		} ],
		buttons: [ CKEDITOR.dialog.cancelButton ]
	};
} );
