x-tools / xtools

( function ( $ ) {

	'use strict';

	var nav, I18N,

		slice = Array.prototype.slice;

	/**

	 * @constructor

	 * @param {Object} options

	 */

	I18N = function ( options ) {

		// Load defaults

		this.options = $.extend( {}, I18N.defaults, options );

		this.parser = this.options.parser;

		this.locale = this.options.locale;

		this.messageStore = this.options.messageStore;

		this.languages = {};

		this.init();

	};

	I18N.prototype = {

		/**

		 * Initialize by loading locales and setting up

		 * String.prototype.toLocaleString and String.locale.

		 */

		init: function () {

			var i18n = this;

			// Set locale of String environment

			String.locale = i18n.locale;

			// Override String.localeString method

			String.prototype.toLocaleString = function () {

				var localeParts, localePartIndex, value, locale, fallbackIndex,

					tryingLocale, message;

				value = this.valueOf();

				locale = i18n.locale;

				fallbackIndex = 0;

				while ( locale ) {

					// Iterate through locales starting at most-specific until

					// localization is found. As in fi-Latn-FI, fi-Latn and fi.

					localeParts = locale.split( '-' );

					localePartIndex = localeParts.length;

					do {

						tryingLocale = localeParts.slice( 0, localePartIndex ).join( '-' );

						message = i18n.messageStore.get( tryingLocale, value );

						if ( message ) {

							return message;

						}

						localePartIndex--;

					} while ( localePartIndex );

					if ( locale === 'en' ) {

						break;

					}

					locale = ( $.i18n.fallbacks[ i18n.locale ] && $.i18n.fallbacks[ i18n.locale ][ fallbackIndex ] ) ||

						i18n.options.fallbackLocale;

					$.i18n.log( 'Trying fallback locale for ' + i18n.locale + ': ' + locale );

					fallbackIndex++;

				}

				// key not found

				return '';

			};

		},

		/*

		 * Destroy the i18n instance.

		 */

		destroy: function () {

			$.removeData( document, 'i18n' );

		},

		/**

		 * General message loading API This can take a URL string for

		 * the json formatted messages. Example:

		 * <code>load('path/to/all_localizations.json');</code>

		 *

		 * To load a localization file for a locale:

		 * <code>

		 * load('path/to/de-messages.json', 'de' );

		 * </code>

		 *

		 * To load a localization file from a directory:

		 * <code>

		 * load('path/to/i18n/directory', 'de' );

		 * </code>

		 * The above method has the advantage of fallback resolution.

		 * ie, it will automatically load the fallback locales for de.

		 * For most usecases, this is the recommended method.

		 * It is optional to have trailing slash at end.

		 *

		 * A data object containing message key- message translation mappings

		 * can also be passed. Example:

		 * <code>

		 * load( { 'hello' : 'Hello' }, optionalLocale );

		 * </code>

		 *

		 * A source map containing key-value pair of languagename and locations

		 * can also be passed. Example:

		 * <code>

		 * load( {

		 * bn: 'i18n/bn.json',

		 * he: 'i18n/he.json',

		 * en: 'i18n/en.json'

		 * } )

		 * </code>

		 *

		 * If the data argument is null/undefined/false,

		 * all cached messages for the i18n instance will get reset.

		 *

		 * @param {string|Object} source

		 * @param {string} locale Language tag

		 * @return {jQuery.Promise}

		 */

		load: function ( source, locale ) {

			var fallbackLocales, locIndex, fallbackLocale, sourceMap = {};

			if ( !source && !locale ) {

				source = 'i18n/' + $.i18n().locale + '.json';

				locale = $.i18n().locale;

			}

			if ( typeof source === 'string' &&

				source.split( '.' ).pop() !== 'json'

			) {

				// Load specified locale then check for fallbacks when directory is specified in load()

				sourceMap[ locale ] = source + '/' + locale + '.json';

				fallbackLocales = ( $.i18n.fallbacks[ locale ] || [] )

					.concat( this.options.fallbackLocale );

				for ( locIndex in fallbackLocales ) {

					fallbackLocale = fallbackLocales[ locIndex ];

					sourceMap[ fallbackLocale ] = source + '/' + fallbackLocale + '.json';

				}

				return this.load( sourceMap );

			} else {

				return this.messageStore.load( source, locale );

			}

		},

		/**

		 * Does parameter and magic word substitution.

		 *

		 * @param {string} key Message key

		 * @param {Array} parameters Message parameters

		 * @return {string}

		 */

		parse: function ( key, parameters ) {

			var message = key.toLocaleString();

			// FIXME: This changes the state of the I18N object,

			// should probably not change the 'this.parser' but just

			// pass it to the parser.

			this.parser.language = $.i18n.languages[ $.i18n().locale ] || $.i18n.languages[ 'default' ];

			if ( message === '' ) {

				message = key;

			}

			return this.parser.parse( message, parameters );

		}

	};

	/**

	 * Process a message from the $.I18N instance

	 * for the current document, stored in jQuery.data(document).

	 *

	 * @param {string} key Key of the message.

	 * @param {string} param1 [param...] Variadic list of parameters for {key}.

	 * @return {string|$.I18N} Parsed message, or if no key was given

	 * the instance of $.I18N is returned.

	 */

	$.i18n = function ( key, param1 ) {

		var parameters,

			i18n = $.data( document, 'i18n' ),

			options = typeof key === 'object' && key;

		// If the locale option for this call is different then the setup so far,

		// update it automatically. This doesn't just change the context for this

		// call but for all future call as well.

		// If there is no i18n setup yet, don't do this. It will be taken care of

		// by the `new I18N` construction below.

		// NOTE: It should only change language for this one call.

		// Then cache instances of I18N somewhere.

		if ( options && options.locale && i18n && i18n.locale !== options.locale ) {

			String.locale = i18n.locale = options.locale;

		}

		if ( !i18n ) {

			i18n = new I18N( options );

			$.data( document, 'i18n', i18n );

		}

		if ( typeof key === 'string' ) {

			if ( param1 !== undefined ) {

				parameters = slice.call( arguments, 1 );

			} else {

				parameters = [];

			}

			return i18n.parse( key, parameters );

		} else {

			// FIXME: remove this feature/bug.

			return i18n;

		}

	};

	$.fn.i18n = function () {

		var i18n = $.data( document, 'i18n' );

		if ( !i18n ) {

			i18n = new I18N();

			$.data( document, 'i18n', i18n );

		}

		String.locale = i18n.locale;

		return this.each( function () {

			var $this = $( this ),

				messageKey = $this.data( 'i18n' ),

				lBracket, rBracket, type, key;

			if ( messageKey ) {

				lBracket = messageKey.indexOf( '[' );

				rBracket = messageKey.indexOf( ']' );

				if ( lBracket !== -1 && rBracket !== -1 && lBracket < rBracket ) {

					type = messageKey.slice( lBracket + 1, rBracket );

					key = messageKey.slice( rBracket + 1 );

					if ( type === 'html' ) {

						$this.html( i18n.parse( key ) );

					} else {

						$this.attr( type, i18n.parse( key ) );

					}

				} else {

					$this.text( i18n.parse( messageKey ) );

				}

			} else {

				$this.find( '[data-i18n]' ).i18n();

			}

		} );

	};

	String.locale = String.locale || $( 'html' ).attr( 'lang' );

	if ( !String.locale ) {

		if ( typeof window.navigator !== undefined ) {

			nav = window.navigator;

			String.locale = nav.language || nav.userLanguage || '';

		} else {

			String.locale = '';

		}

	}

	$.i18n.languages = {};

	$.i18n.messageStore = $.i18n.messageStore || {};

	$.i18n.parser = {

		// The default parser only handles variable substitution

		parse: function ( message, parameters ) {

			return message.replace( /\$(\d+)/g, function ( str, match ) {

				var index = parseInt( match, 10 ) - 1;

				return parameters[ index ] !== undefined ? parameters[ index ] : '$' + match;

			} );

		},

		emitter: {}

	};

	$.i18n.fallbacks = {};

	$.i18n.debug = false;

	$.i18n.log = function ( /* arguments */ ) {

		if ( window.console && $.i18n.debug ) {

			window.console.log.apply( window.console, arguments );

		}

	};

	/* Static members */

	I18N.defaults = {

		locale: String.locale,

		fallbackLocale: 'en',

		parser: $.i18n.parser,

		messageStore: $.i18n.messageStore

	};

	// Expose constructor

	$.i18n.constructor = I18N;

}( jQuery ) );