// ==========================================================================
// Project:   SproutCore - JavaScript Application Framework
// Copyright: ©2006-2009 Sprout Systems, Inc. and contributors.
//            Portions ©2008-2009 Apple, Inc. All rights reserved.
// License:   Licened under MIT license (see license.js)
// ==========================================================================

sc_require('models/record');
sc_require('models/record_attribute');

/** @class
  
  ManyAttribute is a subclass of RecordAttribute and handles to-many 
  relationships.
  
  When setting ( .set() ) the value of a toMany attribute, make sure
  to pass in an array of SC.Record objects.
  
  @extends SC.RecordAttribute
  @since SproutCore 1.0
*/
SC.ManyAttribute = SC.RecordAttribute.extend(
  /** @scope SC.ManyAttribute.prototype */ {
  
  // ..........................................................
  // LOW-LEVEL METHODS
  //
  
  /**  @private - adapted for to many relationship */
  toType: function(record, key, value) {
    var transform = this.get('transform'),
        type      = this.get('typeClass'),
        store     = record.get('store');
        
    if (transform && transform.to) {
      return SC.ManyArray.create({ store: store, storeIds: value, recordType: type });
    }
  },
  
  /** @private - adapted for to many relationship */
  fromType: function(record, key, value) {
    var ret = [];
    
    if(!SC.isArray(value)) throw "Expects toMany attribute to be an array";
    
    var len = value.get('length');
    for(var i=0;i<len;i++) {
      ret[i] = value.objectAt(i).get('id');
    }
    
    return ret;
  }
  
});