/*
This file is part of Ext JS 3.4

Copyright (c) 2011-2013 Sencha Inc

Contact:  http://www.sencha.com/contact

GNU General Public License Usage
This file may be used under the terms of the GNU General Public License version 3.0 as
published by the Free Software Foundation and appearing in the file LICENSE included in the
packaging of this file.

Please review the following information to ensure the GNU General Public License version 3.0
requirements will be met: http://www.gnu.org/copyleft/gpl.html.

If you are unsure which license is appropriate for your use, please contact the sales department
at http://www.sencha.com/contact.

Build date: 2013-04-03 15:07:25
*/
/**
 * @class Ext.data.DataWriter
 * <p>Ext.data.DataWriter facilitates create, update, and destroy actions between
 * an Ext.data.Store and a server-side framework. A Writer enabled Store will
 * automatically manage the Ajax requests to perform CRUD actions on a Store.</p>
 * <p>Ext.data.DataWriter is an abstract base class which is intended to be extended
 * and should not be created directly. For existing implementations, see
 * {@link Ext.data.JsonWriter}.</p>
 * <p>Creating a writer is simple:</p>
 * <pre><code>
var writer = new Ext.data.JsonWriter({
    encode: false   // &lt;--- false causes data to be printed to jsonData config-property of Ext.Ajax#reqeust
});
 * </code></pre>
 * * <p>Same old JsonReader as Ext-2.x:</p>
 * <pre><code>
var reader = new Ext.data.JsonReader({idProperty: 'id'}, [{name: 'first'}, {name: 'last'}, {name: 'email'}]);
 * </code></pre>
 *
 * <p>The proxy for a writer enabled store can be configured with a simple <code>url</code>:</p>
 * <pre><code>
// Create a standard HttpProxy instance.
var proxy = new Ext.data.HttpProxy({
    url: 'app.php/users'    // &lt;--- Supports "provides"-type urls, such as '/users.json', '/products.xml' (Hello Rails/Merb)
});
 * </code></pre>
 * <p>For finer grained control, the proxy may also be configured with an <code>API</code>:</p>
 * <pre><code>
// Maximum flexibility with the API-configuration
var proxy = new Ext.data.HttpProxy({
    api: {
        read    : 'app.php/users/read',
        create  : 'app.php/users/create',
        update  : 'app.php/users/update',
        destroy : {  // &lt;--- Supports object-syntax as well
            url: 'app.php/users/destroy',
            method: "DELETE"
        }
    }
});
 * </code></pre>
 * <p>Pulling it all together into a Writer-enabled Store:</p>
 * <pre><code>
var store = new Ext.data.Store({
    proxy: proxy,
    reader: reader,
    writer: writer,
    autoLoad: true,
    autoSave: true  // -- Cell-level updates.
});
 * </code></pre>
 * <p>Initiating write-actions <b>automatically</b>, using the existing Ext2.0 Store/Record API:</p>
 * <pre><code>
var rec = store.getAt(0);
rec.set('email', 'foo@bar.com');  // &lt;--- Immediately initiates an UPDATE action through configured proxy.

store.remove(rec);  // &lt;---- Immediately initiates a DESTROY action through configured proxy.
 * </code></pre>
 * <p>For <b>record/batch</b> updates, use the Store-configuration {@link Ext.data.Store#autoSave autoSave:false}</p>
 * <pre><code>
var store = new Ext.data.Store({
    proxy: proxy,
    reader: reader,
    writer: writer,
    autoLoad: true,
    autoSave: false  // -- disable cell-updates
});

var urec = store.getAt(0);
urec.set('email', 'foo@bar.com');

var drec = store.getAt(1);
store.remove(drec);

// Push the button!
store.save();
 * </code></pre>
 * @constructor Create a new DataWriter
 * @param {Object} meta Metadata configuration options (implementation-specific)
 * @param {Object} recordType Either an Array of field definition objects as specified
 * in {@link Ext.data.Record#create}, or an {@link Ext.data.Record} object created
 * using {@link Ext.data.Record#create}.
 */
Ext.data.DataWriter = function(config){
    Ext.apply(this, config);
};
Ext.data.DataWriter.prototype = {

    /**
     * @cfg {Boolean} writeAllFields
     * <tt>false</tt> by default.  Set <tt>true</tt> to have DataWriter return ALL fields of a modified
     * record -- not just those that changed.
     * <tt>false</tt> to have DataWriter only request modified fields from a record.
     */
    writeAllFields : false,
    /**
     * @cfg {Boolean} listful
     * <tt>false</tt> by default.  Set <tt>true</tt> to have the DataWriter <b>always</b> write HTTP params as a list,
     * even when acting upon a single record.
     */
    listful : false,    // <-- listful is actually not used internally here in DataWriter.  @see Ext.data.Store#execute.

    /**
     * Compiles a Store recordset into a data-format defined by an extension such as {@link Ext.data.JsonWriter} or {@link Ext.data.XmlWriter} in preparation for a {@link Ext.data.Api#actions server-write action}.  The first two params are similar similar in nature to {@link Ext#apply},
     * Where the first parameter is the <i>receiver</i> of paramaters and the second, baseParams, <i>the source</i>.
     * @param {Object} params The request-params receiver.
     * @param {Object} baseParams as defined by {@link Ext.data.Store#baseParams}.  The baseParms must be encoded by the extending class, eg: {@link Ext.data.JsonWriter}, {@link Ext.data.XmlWriter}.
     * @param {String} action [{@link Ext.data.Api#actions create|update|destroy}]
     * @param {Record/Record[]} rs The recordset to write, the subject(s) of the write action.
     */
    apply : function(params, baseParams, action, rs) {
        var data    = [],
        renderer    = action + 'Record';
        // TODO implement @cfg listful here
        if (Ext.isArray(rs)) {
            Ext.each(rs, function(rec){
                data.push(this[renderer](rec));
            }, this);
        }
        else if (rs instanceof Ext.data.Record) {
            data = this[renderer](rs);
        }
        this.render(params, baseParams, data);
    },

    /**
     * abstract method meant to be overridden by all DataWriter extensions.  It's the extension's job to apply the "data" to the "params".
     * The data-object provided to render is populated with data according to the meta-info defined in the user's DataReader config,
     * @param {String} action [Ext.data.Api.actions.create|read|update|destroy]
     * @param {Record[]} rs Store recordset
     * @param {Object} params Http params to be sent to server.
     * @param {Object} data object populated according to DataReader meta-data.
     */
    render : Ext.emptyFn,

    /**
     * @cfg {Function} updateRecord Abstract method that should be implemented in all subclasses
     * (e.g.: {@link Ext.data.JsonWriter#updateRecord JsonWriter.updateRecord}
     */
    updateRecord : Ext.emptyFn,

    /**
     * @cfg {Function} createRecord Abstract method that should be implemented in all subclasses
     * (e.g.: {@link Ext.data.JsonWriter#createRecord JsonWriter.createRecord})
     */
    createRecord : Ext.emptyFn,

    /**
     * @cfg {Function} destroyRecord Abstract method that should be implemented in all subclasses
     * (e.g.: {@link Ext.data.JsonWriter#destroyRecord JsonWriter.destroyRecord})
     */
    destroyRecord : Ext.emptyFn,

    /**
     * Converts a Record to a hash, taking into account the state of the Ext.data.Record along with configuration properties
     * related to its rendering, such as {@link #writeAllFields}, {@link Ext.data.Record#phantom phantom}, {@link Ext.data.Record#getChanges getChanges} and
     * {@link Ext.data.DataReader#idProperty idProperty}
     * @param {Ext.data.Record} rec The Record from which to create a hash.
     * @param {Object} config <b>NOT YET IMPLEMENTED</b>.  Will implement an exlude/only configuration for fine-control over which fields do/don't get rendered.
     * @return {Object}
     * @protected
     * TODO Implement excludes/only configuration with 2nd param?
     */
    toHash : function(rec, config) {
        var map = rec.fields.map,
            data = {},
            raw = (this.writeAllFields === false && rec.phantom === false) ? rec.getChanges() : rec.data,
            m;
        Ext.iterate(raw, function(prop, value){
            if((m = map[prop])){
                data[m.mapping ? m.mapping : m.name] = value;
            }
        });
        // we don't want to write Ext auto-generated id to hash.  Careful not to remove it on Models not having auto-increment pk though.
        // We can tell its not auto-increment if the user defined a DataReader field for it *and* that field's value is non-empty.
        // we could also do a RegExp here for the Ext.data.Record AUTO_ID prefix.
        if (rec.phantom) {
            if (rec.fields.containsKey(this.meta.idProperty) && Ext.isEmpty(rec.data[this.meta.idProperty])) {
                delete data[this.meta.idProperty];
            }
        } else {
            data[this.meta.idProperty] = rec.id;
        }
        return data;
    },

    /**
     * Converts a {@link Ext.data.DataWriter#toHash Hashed} {@link Ext.data.Record} to fields-array array suitable
     * for encoding to xml via XTemplate, eg:
<code><pre>&lt;tpl for=".">&lt;{name}>{value}&lt;/{name}&lt;/tpl></pre></code>
     * eg, <b>non-phantom</b>:
<code><pre>{id: 1, first: 'foo', last: 'bar'} --> [{name: 'id', value: 1}, {name: 'first', value: 'foo'}, {name: 'last', value: 'bar'}]</pre></code>
     * {@link Ext.data.Record#phantom Phantom} records will have had their idProperty omitted in {@link #toHash} if determined to be auto-generated.
     * Non AUTOINCREMENT pks should have been protected.
     * @param {Hash} data Hashed by Ext.data.DataWriter#toHash
     * @return {Object[]} Array of attribute-objects.
     * @protected
     */
    toArray : function(data) {
        var fields = [];
        Ext.iterate(data, function(k, v) {fields.push({name: k, value: v});},this);
        return fields;
    }
};