/**
  A base object we can use to handle models in the Discourse client application.

  @class Model
  @extends Ember.Object
  @uses Discourse.Presence
  @namespace Discourse
  @module Discourse
**/
Discourse.Model = Ember.Object.extend(Discourse.Presence, {

  /**
    Our own AJAX handler that handles erronous responses

    @method ajax
    @param {String} url The url to contact
    @param {Object} args The arguments to pass to $.ajax
  **/
  ajax: function(url, args) {
    var oldError = args.error;
    args.error = function(xhr) {
      return oldError($.parseJSON(xhr.responseText).errors);
    };
    return Discourse.ajax(url, args);
  },

  /**
    Update our object from another object

    @method mergeAttributes
    @param {Object} attrs The attributes we want to merge with
    @param {Object} builders Optional builders to use when merging attributes
  **/
  mergeAttributes: function(attrs, builders) {
    var _this = this;
    return Object.keys(attrs, function(k, v) {
      // If they're in a builder we use that
      var builder, col;
      if (typeof v === 'object' && builders && (builder = builders[k])) {
        if (!_this.get(k)) {
          _this.set(k, Em.A());
        }
        col = _this.get(k);
        return v.each(function(obj) {
          col.pushObject(builder.create(obj));
        });
      } else {
        _this.set(k, v);
      }
    });
  }

});

Discourse.Model.reopenClass({

  /**
   $.get shortcut that uses Discourse.Url and returns a promise
   **/
  getModelAjax: function(url) {
    var modelClass = this;
    return Discourse.ajax({ url: url, cache: false, dataType: 'json' }).then(function (result) {
      return modelClass.create(result);
    });
  },


  /**
    Given an array of values, return them in a hash

    @method extractByKey
    @param {Object} collection The collection of values
    @param {Object} klass Optional The class to instantiate
  **/
  extractByKey: function(collection, klass) {
    var retval = {};
    if (!collection) return retval;
    collection.each(function(c) {
      retval[c.id] = klass.create(c);
    });
    return retval;
  }
});