YUI.add('datasource-get', function (Y, NAME) {

/**

 * Provides a DataSource implementation which can be used to retrieve data via the Get Utility.

 *

 * @module datasource

 * @submodule datasource-get

 */

/**

 * Get Utility subclass for the DataSource Utility.

 * @class DataSource.Get

 * @extends DataSource.Local

 * @constructor

 */

var DSGet = function() {

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

};

Y.DataSource.Get = Y.extend(DSGet, Y.DataSource.Local, {

    /**

     * Passes query string to Get Utility. Fires <code>response</code> event when

     * response is received asynchronously.

     *

     * @method _defRequestFn

     * @param e {EventFacade} Event Facade with the following properties:

     * <dl>

     * <dt>tId (Number)</dt> <dd>Unique transaction ID.</dd>

     * <dt>request (Object)</dt> <dd>The request.</dd>

     * <dt>callback (Object)</dt> <dd>The callback object with the following properties:

     *     <dl>

     *         <dt>success (Function)</dt> <dd>Success handler.</dd>

     *         <dt>failure (Function)</dt> <dd>Failure handler.</dd>

     *     </dl>

     * </dd>

     * <dt>cfg (Object)</dt> <dd>Configuration object.</dd>

     * </dl>

     * @protected

     */

    _defRequestFn: function(e) {

        var uri  = this.get("source"),

            get  = this.get("get"),

            guid = Y.guid().replace(/\-/g, '_'),

            generateRequest = this.get( "generateRequestCallback" ),

            payload = e.details[0],

            self = this;

        /**

         * Stores the most recent request id for validation against stale

         * response handling.

         *

         * @property _last

         * @type {String}

         * @protected

         */

        this._last = guid;

        // Dynamically add handler function with a closure to the callback stack

        // for access to guid

        YUI.Env.DataSource.callbacks[guid] = function(response) {

            delete YUI.Env.DataSource.callbacks[guid];

            delete Y.DataSource.Local.transactions[e.tId];

            var process = self.get('asyncMode') !== "ignoreStaleResponses" ||

                          self._last === guid;

            if (process) {

                payload.data = response;

                self.fire("data", payload);

            } else {

                Y.log("DataSource ignored stale response for id " + e.tId + "(" + e.request + ")", "info", "datasource-get");

            }

        };

        // Add the callback param to the request url

        uri += e.request + generateRequest.call( this, guid );

        Y.log("DataSource is querying URL " + uri, "info", "datasource-get");

        Y.DataSource.Local.transactions[e.tId] = get.script(uri, {

            autopurge: true,

            // Works in Firefox only....

            onFailure: function (o) {

                delete YUI.Env.DataSource.callbacks[guid];

                delete Y.DataSource.Local.transactions[e.tId];

                payload.error = new Error(o.msg || "Script node data failure");

                Y.log("Script node data failure", "error", "datasource-get");

                self.fire("data", payload);

            },

            onTimeout: function(o) {

                delete YUI.Env.DataSource.callbacks[guid];

                delete Y.DataSource.Local.transactions[e.tId];

                payload.error = new Error(o.msg || "Script node data timeout");

                Y.log("Script node data timeout", "error", "datasource-get");

                self.fire("data", payload);

            }

        });

        return e.tId;

    },

    /**

     * Default method for adding callback param to url.  See

     * generateRequestCallback attribute.

     *

     * @method _generateRequest

     * @param guid {String} unique identifier for callback function wrapper

     * @protected

     */

     _generateRequest: function (guid) {

        return "&" + this.get("scriptCallbackParam") +

                "=YUI.Env.DataSource.callbacks." + guid;

    }

}, {

    /**

     * Class name.

     *

     * @property NAME

     * @type String

     * @static

     * @final

     * @value "dataSourceGet"

     */

    NAME: "dataSourceGet",

    ////////////////////////////////////////////////////////////////////////////

    //

    // DataSource.Get Attributes

    //

    ////////////////////////////////////////////////////////////////////////////

    ATTRS: {

        /**

         * Pointer to Get Utility.

         *

         * @attribute get

         * @type Y.Get

         * @default Y.Get

         */

        get: {

            value: Y.Get,

            cloneDefaultValue: false

        },

        /**

         * Defines request/response management in the following manner:

         * <dl>

         *     <!--<dt>queueRequests</dt>

         *     <dd>If a request is already in progress, wait until response is

         *     returned before sending the next request.</dd>

         *     <dt>cancelStaleRequests</dt>

         *     <dd>If a request is already in progress, cancel it before

         *     sending the next request.</dd>-->

         *     <dt>ignoreStaleResponses</dt>

         *     <dd>Send all requests, but handle only the response for the most

         *     recently sent request.</dd>

         *     <dt>allowAll</dt>

         *     <dd>Send all requests and handle all responses.</dd>

         * </dl>

         *

         * @attribute asyncMode

         * @type String

         * @default "allowAll"

         */

        asyncMode: {

            value: "allowAll"

        },

        /**

         * Callback string parameter name sent to the remote script. By default,

         * requests are sent to

         * <URI>?<scriptCallbackParam>=callbackFunction

         *

         * @attribute scriptCallbackParam

         * @type String

         * @default "callback"

         */

        scriptCallbackParam : {

            value: "callback"

        },

        /**

         * Accepts the DataSource instance and a callback ID, and returns a callback

         * param/value string that gets appended to the script URI. Implementers

         * can customize this string to match their server's query syntax.

         *

         * @attribute generateRequestCallback

         * @type Function

         */

        generateRequestCallback : {

            value: function () {

                return this._generateRequest.apply(this, arguments);

            }

        }

    }

});

YUI.namespace("Env.DataSource.callbacks");

}, '@VERSION@', {"requires": ["datasource-local", "get"]});