/**

 * @output wp-includes/js/wp-util.js

 */

/* global _wpUtilSettings */

/** @namespace wp */

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

(function ($) {

	// Check for the utility settings.

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

	/**

	 * wp.template( id )

	 *

	 * Fetch a JavaScript template for an id, and return a templating function for it.

	 *

	 * @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,

			/*

			 * Underscore's default ERB-style templates are incompatible with PHP

			 * when asp_tags is enabled, so WordPress uses Mustache-inspired templating syntax.

			 *

			 * @see trac ticket #22344.

			 */

			options = {

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

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

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

				variable:    'data'

			};

		return function ( data ) {

			if ( ! document.getElementById( 'tmpl-' + id ) ) {

				throw new Error( 'Template not found: ' + '#tmpl-' + id );

			}

			compiled = compiled || _.template( $( '#tmpl-' + id ).html(),  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|Object)} action The slug of the action to fire in WordPress or options passed

		 *                                 to jQuery.ajax.

		 * @param {Object=}         data   Optional. The data to populate $_POST with.

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

		 *                     decorated with an abort() method.

		 */

		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|Object)} action  The slug of the action to fire in WordPress or options passed

		 *                                  to jQuery.ajax.

		 * @param {Object=}         options Optional. The options passed to jQuery.ajax.

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

		 *                     decorated with an abort() method.

		 */

		send: function( action, options ) {

			var promise, deferred;

			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

			});

			deferred = $.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().

				deferred.jqXHR = $.ajax( options ).done( function( response ) {

					// Treat a response of 1 as successful for backward compatibility with existing handlers.

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

						response = { success: true };

					}

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

						// When handling a media attachments request, get the total attachments from response headers.

						var context = this;

						deferred.done( function() {

							if (

								action &&

								action.data &&

								'query-attachments' === action.data.action &&

								deferred.jqXHR.hasOwnProperty( 'getResponseHeader' ) &&

								deferred.jqXHR.getResponseHeader( 'X-WP-Total' )

							) {

								context.totalAttachments = parseInt( deferred.jqXHR.getResponseHeader( 'X-WP-Total' ), 10 );

							} else {

								context.totalAttachments = 0;

							}

						} );

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

					} else {

						deferred.rejectWith( this, [response] );

					}

				}).fail( function() {

					deferred.rejectWith( this, arguments );

				});

			});

			promise = deferred.promise();

			promise.abort = function() {

				deferred.jqXHR.abort();

				return this;

			};

			return promise;

		}

	};

}(jQuery));