window.wp = window.wp || {};

(function ($) {

	// Check for the utility settings.

	var settings = typeof _wpUtilSettings === 'undefined' ? {} : _wpUtilSettings;

	/**

	 * wp.template( id )

	 *

	 * Fetches a template by id.

	 *

	 * @param  {string} id   A string that corresponds to a DOM element with an id prefixed with "tmpl-".

	 *                       For example, "attachment" maps to "tmpl-attachment".

	 * @return {function}    A function that lazily-compiles the template requested.

	 */

	wp.template = _.memoize(function ( id ) {

		var compiled,

			options = {

				evaluate:    /<#([\s\S]+?)#>/g,

				interpolate: /\{\{\{([\s\S]+?)\}\}\}/g,

				escape:      /\{\{([^\}]+?)\}\}(?!\})/g,

				variable:    'data'

			};

		return function ( data ) {

			compiled = compiled || _.template( $( '#tmpl-' + id ).html(), null, options );

			return compiled( data );

		};

	});

	// wp.ajax

	// ------

	//

	// Tools for sending ajax requests with JSON responses and built in error handling.

	// Mirrors and wraps jQuery's ajax APIs.

	wp.ajax = {

		settings: settings.ajax || {},

		/**

		 * wp.ajax.post( [action], [data] )

		 *

		 * Sends a POST request to WordPress.

		 *

		 * @param  {string} action The slug of the action to fire in WordPress.

		 * @param  {object} data   The data to populate $_POST with.

		 * @return {$.promise}     A jQuery promise that represents the request.

		 */

		post: function( action, data ) {

			return wp.ajax.send({

				data: _.isObject( action ) ? action : _.extend( data || {}, { action: action })

			});

		},

		/**

		 * wp.ajax.send( [action], [options] )

		 *

		 * Sends a POST request to WordPress.

		 *

		 * @param  {string} action  The slug of the action to fire in WordPress.

		 * @param  {object} options The options passed to jQuery.ajax.

		 * @return {$.promise}      A jQuery promise that represents the request.

		 */

		send: function( action, options ) {

			if ( _.isObject( action ) ) {

				options = action;

			} else {

				options = options || {};

				options.data = _.extend( options.data || {}, { action: action });

			}

			options = _.defaults( options || {}, {

				type:    'POST',

				url:     wp.ajax.settings.url,

				context: this

			});

			return $.Deferred( function( deferred ) {

				// Transfer success/error callbacks.

				if ( options.success )

					deferred.done( options.success );

				if ( options.error )

					deferred.fail( options.error );

				delete options.success;

				delete options.error;

				// Use with PHP's wp_send_json_success() and wp_send_json_error()

				$.ajax( options ).done( function( response ) {

					// Treat a response of `1` as successful for backwards

					// compatibility with existing handlers.

					if ( response === '1' || response === 1 )

						response = { success: true };

					if ( _.isObject( response ) && ! _.isUndefined( response.success ) )

						deferred[ response.success ? 'resolveWith' : 'rejectWith' ]( this, [response.data] );

					else

						deferred.rejectWith( this, [response] );

				}).fail( function() {

					deferred.rejectWith( this, arguments );

				});

			}).promise();

		}

	};

}(jQuery));