var $ = jQuery,

	Attachment, Attachments, l10n, media;

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

/**

 * Create and return a media frame.

 *

 * Handles the default media experience.

 *

 * @param  {object} attributes The properties passed to the main media controller.

 * @return {wp.media.view.MediaFrame} A media workflow.

 */

media = wp.media = function( attributes ) {

	var MediaFrame = media.view.MediaFrame,

		frame;

	if ( ! MediaFrame ) {

		return;

	}

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

		frame: 'select'

	});

	if ( 'select' === attributes.frame && MediaFrame.Select ) {

		frame = new MediaFrame.Select( attributes );

	} else if ( 'post' === attributes.frame && MediaFrame.Post ) {

		frame = new MediaFrame.Post( attributes );

	} else if ( 'manage' === attributes.frame && MediaFrame.Manage ) {

		frame = new MediaFrame.Manage( attributes );

	} else if ( 'image' === attributes.frame && MediaFrame.ImageDetails ) {

		frame = new MediaFrame.ImageDetails( attributes );

	} else if ( 'audio' === attributes.frame && MediaFrame.AudioDetails ) {

		frame = new MediaFrame.AudioDetails( attributes );

	} else if ( 'video' === attributes.frame && MediaFrame.VideoDetails ) {

		frame = new MediaFrame.VideoDetails( attributes );

	} else if ( 'edit-attachments' === attributes.frame && MediaFrame.EditAttachments ) {

		frame = new MediaFrame.EditAttachments( attributes );

	}

	delete attributes.frame;

	media.frame = frame;

	return frame;

};

_.extend( media, { model: {}, view: {}, controller: {}, frames: {} });

// Link any localized strings.

l10n = media.model.l10n = window._wpMediaModelsL10n || {};

// Link any settings.

media.model.settings = l10n.settings || {};

delete l10n.settings;

/**

 * ========================================================================

 * UTILITIES

 * ========================================================================

 */

/**

 * A basic equality comparator for Backbone models.

 *

 * Used to order models within a collection - @see wp.media.model.Attachments.comparator().

 *

 * @param  {mixed}  a  The primary parameter to compare.

 * @param  {mixed}  b  The primary parameter to compare.

 * @param  {string} ac The fallback parameter to compare, a's cid.

 * @param  {string} bc The fallback parameter to compare, b's cid.

 * @return {number}    -1: a should come before b.

 *                      0: a and b are of the same rank.

 *                      1: b should come before a.

 */

media.compare = function( a, b, ac, bc ) {

	if ( _.isEqual( a, b ) ) {

		return ac === bc ? 0 : (ac > bc ? -1 : 1);

	} else {

		return a > b ? -1 : 1;

	}

};

	/**

	 * media.template( id )

	 *

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

	 *

	 * See wp.template() in `wp-includes/js/wp-util.js`.

	 *

	 * @borrows wp.template as template

	 */

	template: wp.template,

	/**

	 * media.post( [action], [data] )

	 *

	 * Sends a POST request to WordPress.

	 * See wp.ajax.post() in `wp-includes/js/wp-util.js`.

	 *

	 * @borrows wp.ajax.post as post

	 */

	post: wp.ajax.post,

	/**

	 * media.ajax( [action], [options] )

	 *

	 * Sends an XHR request to WordPress.

	 * See wp.ajax.send() in `wp-includes/js/wp-util.js`.

	 *

	 * @borrows wp.ajax.send as ajax

	 */

	ajax: wp.ajax.send,

	/**

	 * Scales a set of dimensions to fit within bounding dimensions.

	 *

	 * @param {Object} dimensions

	 * @returns {Object}

	 */

	fit: function( dimensions ) {

		var width     = dimensions.width,

			height    = dimensions.height,

			maxWidth  = dimensions.maxWidth,

			maxHeight = dimensions.maxHeight,

			constraint;

		// Compare ratios between the two values to determine which

		// max to constrain by. If a max value doesn't exist, then the

		// opposite side is the constraint.

		if ( ! _.isUndefined( maxWidth ) && ! _.isUndefined( maxHeight ) ) {

			constraint = ( width / height > maxWidth / maxHeight ) ? 'width' : 'height';

		} else if ( _.isUndefined( maxHeight ) ) {

			constraint = 'width';

		} else if (  _.isUndefined( maxWidth ) && height > maxHeight ) {

			constraint = 'height';

		}

		// If the value of the constrained side is larger than the max,

		// then scale the values. Otherwise return the originals; they fit.

		if ( 'width' === constraint && width > maxWidth ) {

			return {

				width : maxWidth,

				height: Math.round( maxWidth * height / width )

			};

		} else if ( 'height' === constraint && height > maxHeight ) {

			return {

				width : Math.round( maxHeight * width / height ),

				height: maxHeight

			};

		} else {

			return {

				width : width,

				height: height

			};

		}

	},

	/**

	 * Truncates a string by injecting an ellipsis into the middle.

	 * Useful for filenames.

	 *

	 * @param {String} string

	 * @param {Number} [length=30]

	 * @param {String} [replacement=…]

	 * @returns {String} The string, unless length is greater than string.length.

	 */

	truncate: function( string, length, replacement ) {

		length = length || 30;

		replacement = replacement || '…';

		if ( string.length <= length ) {

			return string;

		}

		return string.substr( 0, length / 2 ) + replacement + string.substr( -1 * length / 2 );

	}

});

/**

 * ========================================================================

 * MODELS

 * ========================================================================

 */

/**

 * wp.media.attachment

 *

 * @static

 * @param {String} id A string used to identify a model.

 * @returns {wp.media.model.Attachment}

 */

media.attachment = function( id ) {

	return Attachment.get( id );

};

/**

 * A collection of all attachments that have been fetched from the server.

 *

 * @static

 * @member {wp.media.model.Attachments}

 */

Attachments.all = new Attachments();

/**

 * wp.media.query

 *

 * Shorthand for creating a new Attachments Query.

 *

 * @param {object} [props]

 * @returns {wp.media.model.Attachments}

 */

media.query = function( props ) {

	return new Attachments( null, {

		props: _.extend( _.defaults( props || {}, { orderby: 'date' } ), { query: true } )

	});

};

// Clean up. Prevents mobile browsers caching

$(window).on('unload', function(){

	window.wp = null;

});

/**

 * wp.media.model.Attachment

 *

 * @class

 * @augments Backbone.Model

 */

	/**

	 * Triggered when attachment details change

	 * Overrides Backbone.Model.sync

	 *

	 * @param {string} method

	 * @param {wp.media.model.Attachment} model

	 * @param {Object} [options={}]

	 *

	 * @returns {Promise}

	 */

	sync: function( method, model, options ) {

		// If the attachment does not yet have an `id`, return an instantly

		// rejected promise. Otherwise, all of our requests will fail.

		if ( _.isUndefined( this.id ) ) {

			return $.Deferred().rejectWith( this ).promise();

		}

		// Overload the `read` request so Attachment.fetch() functions correctly.

		if ( 'read' === method ) {

			options = options || {};

			options.context = this;

			options.data = _.extend( options.data || {}, {

				action: 'get-attachment',

				id: this.id

			});

			return wp.media.ajax( options );

		// Overload the `update` request so properties can be saved.

		} else if ( 'update' === method ) {

			// If we do not have the necessary nonce, fail immeditately.

			if ( ! this.get('nonces') || ! this.get('nonces').update ) {

				return $.Deferred().rejectWith( this ).promise();

			}