/**
 * @license Copyright (c) 2003-2021, CKSource - Frederico Knabben. All rights reserved.
 * For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-oss-license
 */

CKEDITOR.dialog.add( 'a11yHelp', function( editor ) {
	var lang = editor.lang.a11yhelp,
		coreLang = editor.lang.common.keyboard,
		id = CKEDITOR.tools.getNextId(),
		variablesPattern = /\$\{(.*?)\}/g,
		// Sort in desc.
		modifiers = [ CKEDITOR.ALT, CKEDITOR.SHIFT, CKEDITOR.CTRL ],
		// CharCode <-> KeyChar.
		keyMap = {
			8: coreLang[ 8 ],
			9: lang.tab,
			13: coreLang[ 13 ],
			16: coreLang[ 16 ],
			17: coreLang[ 17 ],
			18: coreLang[ 18 ],
			19: lang.pause,
			20: lang.capslock,
			27: lang.escape,
			33: lang.pageUp,
			34: lang.pageDown,
			35: coreLang[ 35 ],
			36: coreLang[ 36 ],
			37: lang.leftArrow,
			38: lang.upArrow,
			39: lang.rightArrow,
			40: lang.downArrow,
			45: lang.insert,
			46: coreLang[ 46 ],
			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 ] = coreLang[ 18 ];
	keyMap[ CKEDITOR.SHIFT ] = coreLang[ 16 ];
	keyMap[ CKEDITOR.CTRL ] = CKEDITOR.env.mac ? coreLang[ 224 ] : coreLang[ 17 ];

	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( '+' );
	}

	function replaceVariables( match, name ) {
		var keystrokeCodes = editor.getCommandKeystroke( name, true );

		// Display multiple command keystrokes (#2519).
		if ( keystrokeCodes.length ) {
			return CKEDITOR.tools.array.map( keystrokeCodes, representKeyStroke ).join( ' / ' );
		}

		// Leave match untouched if there's no keystroke for such command.
		return 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 ],
					// (https://dev.ckeditor.com/ticket/16980) There should be a different hotkey shown in Commands on Edge browser.
					itemLegend = CKEDITOR.env.edge && item.legendEdge ? item.legendEdge : item.legend;

				itemLegend = itemLegend.replace( variablesPattern, replaceVariables );

				// (https://dev.ckeditor.com/ticket/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" (https://dev.ckeditor.com/ticket/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 ]
	};
} );
