/*

Copyright (c) 2009, Yahoo! Inc. All rights reserved.

Code licensed under the BSD License:

http://developer.yahoo.net/yui/license.txt

version: 3.0.0b1

build: 1163

*/

YUI.add('plugin', function(Y) {

    /**

     * Provides the base Plugin class, which plugin developers should extend, when creating custom plugins

     *

     * @module plugin

     */

    /**

     * The base class for all Plugin instances.

     *

     * @class Plugin.Base 

     * @extends Base

     * @param {Object} config Configuration object with property name/value pairs.

     */

    function Plugin(config) {

        Plugin.superclass.constructor.apply(this, arguments);

    }

    /**

     * Object defining the set of attributes supported by the Plugin.Base class

     * 

     * @property Plugin.Base.ATTRS

     * @type Object

     * @static

     */

    Plugin.ATTRS = {

        /**

         * The plugin's host object.

         *

         * @attribute host

         * @writeonce

         * @type Plugin.Host

         */

        host : {

            writeOnce: true

        }

    };

    /**

     * The string identifying the Plugin.Base class. Plugins extending

     * Plugin.Base should set their own NAME value.

     *

     * @property Plugin.Base.NAME

     * @type String

     * @static

     */

    Plugin.NAME = 'plugin';

    /**

     * The name of the property the the plugin will be attached to

     * when plugged into a Plugin Host. Plugins extending Plugin.Base,

     * should set their own NS value.

     *

     * @property Plugin.NS

     * @type String

     * @static

     */

    Plugin.NS = 'plugin';

    Y.extend(Plugin, Y.Base, {

        /**

         * The list of event handles for event listeners or AOP injected methods

         * applied by the plugin to the host object.

         *

         * @property _handles

         * @private

         * @type Array

         * @value null

         */

        _handles: null,

        /**

         * Initializer lifecycle implementation.

         *

         * @method initializer

         * @param {Object} config Configuration object with property name/value pairs.

         */

        initializer : function(config) {

            this._handles = [];

            if (!this.get("host")) { Y.log('No host defined for plugin ' + this, 'warn', 'Plugin');}

            Y.log('Initializing: ' + this.constructor.NAME, 'info', 'Plugin');

        },

        /**

         * Destructor lifecycle implementation.

         *

         * Removes any event listeners or injected methods applied by the Plugin

         *

         * @method destructor

         */

        destructor: function() {

            // remove all handles

            if (this._handles) {

                for (var i = 0, l = this._handles.length; i < l; i++) {

                   this._handles[i].detach();

                }

            }

        },

        /**

         * Listens for the "on" moment of events fired by the host, 

         * or injects code "before" a given method on the host.

         *

         * @method doBefore

         *

         * @param sFn {String} The event to listen for, or method to inject logic before.

         * @param fn {Function} The handler function. For events, the "on" moment listener. For methods, the function to execute before the given method is executed.

         * @param context {Object} An optional context to call the handler with. The default context is the plugin instance.

         * @return handle {EventHandle} The detach handle for the handler.

         */

        doBefore: function(sFn, fn, context) {

            var host = this.get("host"),

                handle;

            context = context || this;

            if (sFn in host) { // method

                handle = Y.Do.before(fn, host, sFn, context);

            } else if (host.on) { // event

                handle = host.on(sFn, fn, context);

            }

            this._handles.push(handle);

            return handle;

        },

        /**

         * Listens for the "after" moment of events fired by the host, 

         * or injects code "after" a given method on the host.

         *

         * @method doAfter

         *

         * @param sFn {String} The event to listen for, or method to inject logic after.

         * @param fn {Function} The handler function. For events, the "after" moment listener. For methods, the function to execute after the given method is executed.

         * @param context {Object} An optional context to call the handler with. The default context is the plugin instance.

         * @return handle {EventHandle} The detach handle for the handler.

         */

        doAfter: function(sFn, fn, context) {

            var host = this.get("host"),

                handle;

            context = context || this;

            if (sFn in host) { // method

                handle = Y.Do.after(fn, host, sFn, context);

            } else if (host.after) { // event

                handle = host.after(sFn, fn, context);

            }

            this._handles.push(handle);

            return handle;

        },

        toString: function() {

            return this.constructor.NAME + '[' + this.constructor.NS + ']';

        }

    });

    Y.namespace("Plugin").Base = Plugin;

}, '3.0.0b1' ,{requires:['base']});