/**
 * ULS-based display settings panel
 *
 * Copyright (C) 2012 Alolita Sharma, Amir Aharoni, Arun Ganesh, Brandon Harris,
 * Niklas Laxström, Pau Giner, Santhosh Thottingal, Siebrand Mazeland and other
 * contributors. See CREDITS for a list.
 *
 * UniversalLanguageSelector is dual licensed GPLv2 or later and MIT. You don't
 * have to do anything special to choose one license or the other and you don't
 * have to notify anyone which license you are using. You are free to use
 * UniversalLanguageSelector in commercial projects as long as the copyright
 * header is left intact. See files GPL-LICENSE and MIT-LICENSE for details.
 *
 * @file
 * @ingroup Extensions
 * @licence GNU General Public Licence 2.0 or later
 * @licence MIT License
 */

( function( $, mw, undefined ) {
	"use strict";

	var template = '<div class="row"><div class="twelve columns"><h3>Display settings</h3></div></div>'
			+ '<div class="row"><div class="eleven columns"><h4>Language used for menus</h4></div></div>'
			+ '<div class="row"><div class="uls-ui-languages eleven columns">'
			+ '</div></div>'
			+ '<div class="row"><div class="twelve columns"><h4>Font settings</h4></div></div>'
			+ '<div class="row">'
			+ '<div class="eleven columns">'
			+ '<label class="checkbox"><input type="checkbox" id="webfonts-enable-checkbox" />'
			+ '<strong>Download fonts automatically when needed</strong> '
			+ 'Web fonts will be downloaded when text in special scripts is displayed. '
			+ '<a target="_blank" href="//www.mediawiki.org/wiki/Special:MyLanguage/Help:Extension:WebFonts">More information</a>'
			+ '</span></label>'
			+ '</div>'
			+ '</div>'
			+ '<div class="row"><h5 class="twelve columns">Select your preferred fonts</h5></div>'
			+ '<div class="row uls-content-fonts">'
			+ '<div class="six columns"><label class="uls-font-label" id="content-font-selector-label"></label></div>'
			+ '<select id="content-font-selector" class="four columns end uls-font-select"></select>'
			+ '</div>'
			+ '<div class="row uls-ui-fonts">'
			+ '<div class="six columns"><label class="uls-font-label" id="ui-font-selector-label"></label></div>'
			+ '<select id="ui-font-selector" class="four columns end uls-font-select"></select>'
			+ '</div>'
			+ '<div class="row"></div>'
			+ '<div class="row language-settings-buttons">'
			+ '<div class="eleven columns">'
			+ '<button class="button uls-settings-close">Cancel</button>'
			+ '<button id="uls-displaysettings-apply" class="active blue button">Apply changes</button>'
			+ '</div>'
			+ '</div>'; // FIXME i18n and too much hardcoding.

	var DisplaySettings = function ( $parent ) {
		this.name = "Display";
		this.description = "Set language used for menus and fonts";
		this.$template = $( template );
		this.uiLanguage = this.getUILanguage();
		this.contentLanguage = this.getContentLanguage();
		this.$webfonts = null;
		this.$parent = $parent;
		this.webfontPreferences = mw.uls.preferences( 'webfonts' );
	};

	DisplaySettings.prototype = {

		Constructor: DisplaySettings,

		/**
		 * Render the module into a given target
		 */
		render: function () {
			this.$parent.$settingsPanel.empty();
			this.$webfonts = $( 'body' ).data( 'webfonts' );
			this.$parent.$settingsPanel.append( this.$template );
			this.prepareLanguages();
			this.prepareUIFonts();
			this.prepareContentFonts();
			this.prepareWebfontsCheckbox();

			this.listen();
		},

		prepareWebfontsCheckbox: function () {
			$( '#webfonts-enable-checkbox' ).prop( 'checked', this.isWebFontsEnabled() );
		},

		isWebFontsEnabled: function () {
			var enable = this.webfontPreferences.get( 'webfonts-enabled' );

			// If the user didn't use the checkbox, the preference will be undefined.
			// The default for now is to enable webfonts if the user didn't select anything.
			if ( enable === undefined ) {
				enable = true;
			}
			return enable;
		},

		/**
		 * Prepare the UI language selector
		 */
		prepareLanguages: function () {
			var that = this;
			var $languages = this.$template.find( 'div.uls-ui-languages' );
			$languages.empty();
			var previousLanguages = this.frequentLanguageList();
			var languages = [this.uiLanguage];
			for ( var lang in previousLanguages ) {
				if ( previousLanguages[lang] === this.uiLanguage ) {
					continue;
				}
				languages.push( previousLanguages[lang] );
			}

			function buttonHandler ( button ) {
				return function () {
					that.uiLanguage = button.data( "language" ) || that.uiLanguage;
					$( "div.uls-ui-languages button.button" ).removeClass( "down" );
					button.addClass( "down" );
					that.prepareUIFonts();
				};
			}

			for ( var i = 0; i < 3; i++ ) {
				var language = languages[i];
				var $button = $( '<button>' )
					.addClass( 'button uls-language-button' )
					.text( $.uls.data.autonym( language ) );
				if ( language === this.uiLanguage ) {
					$button.addClass( 'down' );
				}
				$button.data( 'language', language );
				$languages.append( $button );
				$button.on( 'click', buttonHandler( $button ) );
			}
			this.prepareMoreLanguages();
		},

		/**
		 * Prepare the more languages button. It is a ULS trigger
		 */
		prepareMoreLanguages: function () {
			var that = this;
			var $languages = this.$template.find( 'div.uls-ui-languages' );
			var $moreLanguagesButton = $( '<button>' )
				.prop( 'id', 'uls-more-languages' )
				.addClass( 'button' ).text( '...' );

			$languages.append( $moreLanguagesButton );
			// Show the long language list to select a language for display settings
			$moreLanguagesButton.uls( {
				left: that.$parent.left,
				top: that.$parent.top,
				onReady: function ( uls ) {
					var $back = $( '<a>' ).prop( 'href', '#' )
						.prop( 'title', 'Back to display settings' )
						.text( '← Back to display settings' ); // FIXME i18n

					$back.click( function () {
						uls.hide();
						that.$parent.show();
					} );

					uls.$menu.find( 'div.uls-title' ).append( $back );
					uls.$menu.find( 'div.uls-title h1' ).text( 'Select display language' );
				},
				onSelect: function ( langCode ) {
					that.uiLanguage = langCode;
					that.$parent.show();
					that.prepareUIFonts();
					that.prepareLanguages();
				},
				quickList: function () {
					return mw.uls.getFrequentLanguageList();
				}
			} );

			$moreLanguagesButton.on( 'click', function () {
				that.$parent.hide();
			} );
		},

		/**
		 * Get previous languages
		 * @returns {Array}
		 */
		frequentLanguageList: function () {
			return mw.uls.getFrequentLanguageList();
		},

		/**
		 * Get the current user interface language.
		 * @returns String Current UI language
		 */
		getUILanguage: function () {
			return mw.config.get( 'wgUserLanguage' );
		},

		/**
		 * Get the current content language.
		 * @returns String Current content language
		 */
		getContentLanguage: function () {
			return mw.config.get( 'wgContentLanguage' );
		},

		/**
		 * Prepare the font selector for UI language.
		 * TODO Can this be merged with prepareContentLanguages?
		 */
		prepareUIFonts: function () {
			if ( this.uiLanguage === this.contentLanguage ) {
				$( 'div.uls-ui-fonts' ).hide();
				return;
			} else {
				$( 'div.uls-ui-fonts' ).show();
			}
			var fonts = this.$webfonts.list( this.uiLanguage );
			var $fontSelector = this.$template.find( 'select#ui-font-selector' );

			$fontSelector.find( 'option' ).remove();
			var savedFont = this.webfontPreferences.get( this.uiLanguage );

			if ( fonts && fonts.length ) {
				$.each( fonts, function ( key, font ) {
					var $fontOption = $( "<option>" ).attr( "value", font ).text( font );
					$fontSelector.append( $fontOption );
					$fontOption.attr( 'selected', savedFont === font );
				} );
			}

			$fontSelector.prop( "disabled", !this.isWebFontsEnabled() );

			var $systemFont = $( "<option>" ).val( 'system' ).text( 'System font' );
			$fontSelector.append( $systemFont );
			$systemFont.attr( 'selected', savedFont === 'system' || !savedFont );
			var $fontLabel = this.$template.find( 'label#ui-font-selector-label' );
			$fontLabel.html( "<strong>Select font for " + $.uls.data.autonym( this.uiLanguage )
					+ "</strong><div>Used for menus</div>" );
		},

		/**
		 * Prepare the font selector for UI language.
		 */
		prepareContentFonts: function () {
			var fonts = this.$webfonts.list( this.contentLanguage );
			var $fontSelector = this.$template.find( '#content-font-selector' );

			$fontSelector.find( 'option' ).remove();
			var savedFont = this.webfontPreferences.get( this.contentLanguage );

			if ( fonts && fonts.length ) {
				$.each( fonts, function ( key, font ) {
					var $fontOption = $( "<option>" ).attr( "value", font ).text( font );
					$fontSelector.append( $fontOption );
					$fontOption.attr( 'selected', savedFont === font );
				} );
			}

			$fontSelector.prop( "disabled", !this.isWebFontsEnabled() );

			var $systemFont = $( "<option>" ).val( 'system' ).text( 'System font' );
			$fontSelector.append( $systemFont );
			$systemFont.attr( 'selected', savedFont === 'system' || !savedFont );
			var $fontLabel = this.$template.find( '#content-font-selector-label' );
			$fontLabel.html( "<strong>Select font for " + $.uls.data.autonym( this.contentLanguage )
					+ "</strong><div>Used for content</div>" );
		},

		/**
		 * Register general event listeners
		 */
		listen: function () {
			var that = this;
			var $contentFontSelector = this.$template
				.find( "#content-font-selector" );
			var $uiFontSelector = this.$template
				.find( "select#ui-font-selector" );
			// TODO all these repeated selectors can be placed in object constructor.

			this.$template.find( '#uls-displaysettings-apply' ).on( 'click', function () {
				that.apply();
			} );

			this.$template.find( 'button.uls-settings-close' ).on( 'click', function () {
				that.close();
			} );

			this.$template.find( '#webfonts-enable-checkbox' ).on( 'click', function () {
				if ( this.checked ) {
					that.webfontPreferences.set( 'webfonts-enabled', true );
					$contentFontSelector.prop( "disabled", false );
					$uiFontSelector.prop( "disabled", false );
					that.$webfonts.apply( $uiFontSelector.find( 'option:selected' ) );
				} else {
					that.webfontPreferences.set( 'webfonts-enabled', false );
					$contentFontSelector.prop( "disabled", true );
					$uiFontSelector.prop( "disabled", true );
					that.$webfonts.reset();
				}
			} );

			$uiFontSelector.on( "change", function () {
				var font = $( this ).find( 'option:selected' ).val();
				that.webfontPreferences.set( that.uiLanguage, font );
				that.$webfonts.refresh();
			} );

			$contentFontSelector.on( "change", function () {
				var font = $( this ).find( 'option:selected' ).val();
				that.webfontPreferences.set( that.contentLanguage, font );
				that.$webfonts.refresh();
			} );

		},

		/**
		 * Hide this window.
		 * Used while navigating to language selector and need coming back
		 */
		hide: function () {
			this.$parent.hide();
		},

		/**
		 * Close the language settings window.
		 * Depending on the context, actions vary.
		 */
		close:  function () {
			this.$parent.close();
		},

		/**
		 * Callback for save preferences
		 */
		onSave: function ( success ) {
			if ( success ) {
				// Live font update
				this.$webfonts.refresh();
				this.$parent.hide();
				// we delay change UI language to here, because it causes a page refresh
				if ( this.uiLanguage !== this.getUILanguage() ) {
					mw.uls.changeLanguage( this.uiLanguage );
				}
			} else {
				// FIXME failure. what to do?!
			}
		},

		/**
		 * Handle the apply button press
		 */
		apply: function () {
			var that = this;

			// Save the preferences
			this.webfontPreferences.save( function ( result ) {
				// closure for not losing the scope
				that.onSave( result );
			} );
		}
	};

	// Register this module to language settings modules
	$.fn.languagesettings.modules = $.extend( $.fn.languagesettings.modules, {
		display: DisplaySettings
	} );
} ) ( jQuery, mediaWiki );