/**
 * @class Ext.form.action.Load
 * @extends Ext.form.action.Action
 * 
A class which handles loading of data from a server into the Fields of an {@link Ext.form.Basic}.
 * 
Instances of this class are only created by a {@link Ext.form.Basic Form} when
 * {@link Ext.form.Basic#load load}ing.
 * 
Response Packet Criteria
 * 
A response packet must contain:
 * 

 * 
success property : Boolean
 * 
data property : Object
 * 
The data property contains the values of Fields to load.
 * The individual value object for each Field is passed to the Field's
 * {@link Ext.form.Field#setValue setValue} method.
 * 
 * 
JSON Packets
 * 
By default, response packets are assumed to be JSON, so for the following form load call:

var myFormPanel = new Ext.form.FormPanel({
    title: 'Client and routing info',
    items: [{
        fieldLabel: 'Client',
        name: 'clientName'
    }, {
        fieldLabel: 'Port of loading',
        name: 'portOfLoading'
    }, {
        fieldLabel: 'Port of discharge',
        name: 'portOfDischarge'
    }]
});
myFormPanel.{@link Ext.form.FormPanel#getForm getForm}().{@link Ext.form.Basic#load load}({
    url: '/getRoutingInfo.php',
    params: {
        consignmentRef: myConsignmentRef
    },
    failure: function(form, action) {
        Ext.Msg.alert("Load failed", action.result.errorMessage);
    }
});

 * a success response packet may look like this:

{
    success: true,
    data: {
        clientName: "Fred. Olsen Lines",
        portOfLoading: "FXT",
        portOfDischarge: "OSL"
    }
}
 * while a failure response packet may look like this:

{
    success: false,
    errorMessage: "Consignment reference not found"
}
 * 
Other data may be placed into the response for processing the {@link Ext.form.Basic Form}'s
 * callback or event handler methods. The object decoded from this JSON is available in the
 * {@link Ext.form.action.Action#result result} property.
 */
Ext.define('Ext.form.action.Load', {
    extend:'Ext.form.action.Action',
    requires: ['Ext.data.Connection'],
    alternateClassName: 'Ext.form.Action.Load',
    alias: 'formaction.load',

    type: 'load',

    /**
     * @private
     */
    run: function() {
        Ext.Ajax.request(Ext.apply(
            this.createCallback(),
            {
                method: this.getMethod(),
                url: this.getUrl(),
                headers: this.headers,
                params: this.getParams()
            }
        ));
    },

    /**
     * @private
     */
    onSuccess: function(response){
        var result = this.processResponse(response),
            form = this.form;
        if (result === true || !result.success || !result.data) {
            this.failureType = Ext.form.action.Action.LOAD_FAILURE;
            form.afterAction(this, false);
            return;
        }
        form.clearInvalid();
        form.setValues(result.data);
        form.afterAction(this, true);
    },

    /**
     * @private
     */
    handleResponse: function(response) {
        var reader = this.form.reader,
            rs, data;
        if (reader) {
            rs = reader.read(response);
            data = rs.records && rs.records[0] ? rs.records[0].data : null;
            return {
                success : rs.success,
                data : data
            };
        }
        return Ext.decode(response.responseText);
    }
});