Implement language-selection-method event

Change-Id: If2d207f8a221c8f2a560b1399ad69a3032b2064b

resources/js/ext.uls.displaysettings.js

@@ -295,12 +295,18 @@
 					);
 				},
 				onVisible: function () {
+					var $parent;
+
+					mw.uls.addEventLoggingTriggers();
+
 					if ( !displaySettings.$parent.$window.hasClass( 'callout' ) ) {
 						// callout menus will have position rules. others use
 						// default position
 						return;
 					}
-					var $parent = $( '#language-settings-dialog' );
+
+					$parent = $( '#language-settings-dialog' );
+
 					// Re-position the element according to the window that called it
 					if ( parseInt( $parent.css( 'left' ), 10 ) ) {
 						this.$menu.css( 'left', $parent.css( 'left' ) );

resources/js/ext.uls.eventlogger.js

@@ -146,11 +146,17 @@
 		 * @param {jQuery.Deferred} deferred
 		 */
 		interfaceLanguageChange: function ( language, deferred ) {
-			this.log( {
+			var logParams = {
 				action: 'language-change',
 				context: 'interface',
 				interfaceLanguage: language
-			} ).always( deferred.resolve );
+			};
+
+			if ( mw.uls.languageSelectionMethod !== undefined ) {
+				logParams.languageSelectionMethod = mw.uls.languageSelectionMethod;
+			}
+
+			this.log( logParams ).always( deferred.resolve );
 		},
 
 		/**

resources/js/ext.uls.init.js

@@ -39,6 +39,39 @@
 	mw.uls.previousLanguagesCookie = 'uls-previous-languages';
 	mw.uls.languageSettingsModules = ['ext.uls.inputsettings', 'ext.uls.displaysettings'];
 
+	// What was the last thing that the user did to select the language:
+	// * 'map' - clicked the map
+	// * 'search' - typed in the search box
+	// * 'common' - clicked a link in the "Common languages" section
+	// If the user just clicked in some other section, it remains undefined.
+	// This is useful for logging.
+	mw.uls.languageSelectionMethod = undefined;
+
+	/**
+	 * Add event logging triggers, which are common to different
+	 * ULS instances
+	 */
+	mw.uls.addEventLoggingTriggers = function () {
+		// Remove previous values when reinitializing
+		mw.uls.languageSelectionMethod = undefined;
+
+		$( '#map-block' ).on( 'click', function () {
+			mw.uls.languageSelectionMethod = 'map';
+		} );
+
+		$( '#languagefilter' ).on( 'keydown', function () {
+			// If it's the first letter,
+			// log the usage of the search box
+			if ( $( this ).val() === '' ) {
+				mw.uls.languageSelectionMethod = 'search';
+			}
+		} );
+
+		$( '#uls-lcd-quicklist a' ).on( 'click', function () {
+			mw.uls.languageSelectionMethod = 'common';
+		} );
+	};
+
 	/**
 	 * Change the language of wiki using setlang URL parameter
 	 * @param {string} language Language code.

resources/js/ext.uls.interface.js

@@ -420,6 +420,9 @@
 							},
 							onSelect: function ( language ) {
 								mw.uls.changeLanguage( language );
+							},
+							onVisible: function () {
+								mw.uls.addEventLoggingTriggers();
 							}
 						} ).trigger( 'click', eventParams );