// ==========================================================================
// Project:   SproutCore - JavaScript Application Framework
// Copyright: ©2006-2011 Strobe Inc. and contributors.
//            Portions ©2008-2011 Apple Inc. All rights reserved.
// License:   Licensed under MIT license (see license.js)
// ==========================================================================

sc_require('controllers/controller');
sc_require('mixins/selection_support');

/**
  @class

  An ArrayController provides a way for you to publish an array of objects
  for CollectionView or other controllers to work with.  To work with an
  ArrayController, set the content property to the array you want the
  controller to manage.  Then work directly with the controller object as if
  it were the array itself.

  When you want to display an array of objects in a CollectionView, bind the
  "arrangedObjects" of the array controller to the CollectionView's "content"
  property.  This will automatically display the array in the collection view.

  @extends SC.Controller
  @extends SC.Array
  @extends SC.SelectionSupport
  @author Charles Jolley
  @since SproutCore 1.0
*/
SC.ArrayController = SC.Controller.extend(SC.Array, SC.SelectionSupport,
/** @scope SC.ArrayController.prototype */ {

  //@if(debug)
  /* BEGIN DEBUG ONLY PROPERTIES AND METHODS */

  /* @private */
  toString: function () {
    var content = this.get('content'),
      ret = sc_super();

    return content ? "%@:\n  ↳ %@".fmt(ret, content) : ret;
  },

  /* END DEBUG ONLY PROPERTIES AND METHODS */
  //@endif

  // ..........................................................
  // PROPERTIES
  //

  /**
    The content array managed by this controller.

    You can set the content of the ArrayController to any object that
    implements SC.Array or SC.Enumerable.  If you set the content to an object
    that implements SC.Enumerable only, you must also set the orderBy property
    so that the ArrayController can order the enumerable for you.

    If you set the content to a non-enumerable and non-array object, then the
    ArrayController will wrap the item in an array in an attempt to normalize
    the result.

    @type SC.Array
  */
  content: null,

  /**
    Makes the array editable or not.  If this is set to NO, then any attempts
    at changing the array content itself will throw an exception.

    @type Boolean
  */
  isEditable: YES,

  /**
    Used to sort the array.

    If you set this property to a key name, array of key names, or a function,
    then then ArrayController will automatically reorder your content array
    to match the sort order.  When using key names, you may specify the
    direction of the sort by appending ASC or DESC to the key name.  By default
    sorting is done in ascending order.

    For example,

        myController.set('orderBy', 'title DESC');
        myController.set('orderBy', ['lastName ASC', 'firstName DESC']);

    Normally, you should only use this property if you set the content of the
    controller to an unordered enumerable such as SC.Set or SC.SelectionSet.
    In this case the orderBy property is required in order for the controller
    to property order the content for display.

    If you set the content to an array, it is usually best to maintain the
    array in the proper order that you want to display things rather than
    using this method to order the array since it requires an extra processing
    step.  You can use this orderBy property, however, for displaying smaller
    arrays of content.

    Note that you can only use addObject() to insert new objects into an
    array that is ordered.  You cannot manually reorder or insert new objects
    into specific locations because the order is managed by this property
    instead.

    If you pass a function, it should be suitable for use in compare().

    @type String|Array|Function
  */
  orderBy: null,

  /**
    Set to YES if you want the controller to wrap non-enumerable content
    in an array and publish it.  Otherwise, it will treat single content like
    null content.

    @type Boolean
  */
  allowsSingleContent: YES,

  /**
    Set to YES if you want objects removed from the array to also be
    deleted.  This is a convenient way to manage lists of items owned
    by a parent record object.

    Note that even if this is set to NO, calling destroyObject() instead of
    removeObject() will still destroy the object in question as well as
    removing it from the parent array.

    @type Boolean
  */
  destroyOnRemoval: NO,

  /**
    Returns an SC.Array object suitable for use in a CollectionView.
    Depending on how you have your ArrayController configured, this property
    may be one of several different values.

    @type SC.Array
  */
  arrangedObjects: function () {
    return this;
  }.property().cacheable(),

  /**
    Computed property indicates whether or not the array controller can
    remove content.  You can delete content only if the content is not single
    content and isEditable is YES.

    @type Boolean
  */
  canRemoveContent: function () {
    var content = this.get('content'), ret;
    ret = !!content && this.get('isEditable') && this.get('hasContent');
    if (ret) {
      return !content.isEnumerable ||
             (SC.typeOf(content.removeObject) === SC.T_FUNCTION);
    } else return NO;
  }.property('content', 'isEditable', 'hasContent'),

  /**
    Computed property indicates whether you can reorder content.  You can
    reorder content as long a the controller isEditable and the content is a
    real SC.Array-like object.  You cannot reorder content when orderBy is
    non-null.

    @type Boolean
  */
  canReorderContent: function () {
    var content = this.get('content'), ret;
    ret = !!content && this.get('isEditable') && !this.get('orderBy');
    return ret && !!content.isSCArray;
  }.property('content', 'isEditable', 'orderBy'),

  /**
    Computed property insides whether you can add content.  You can add
    content as long as the controller isEditable and the content is not a
    single object.

    Note that the only way to simply add object to an ArrayController is to
    use the addObject() or pushObject() methods.  All other methods imply
    reordering and will fail.

    @type Boolean
  */
  canAddContent: function () {
    var content = this.get('content'), ret;
    ret = content && this.get('isEditable') && content.isEnumerable;
    if (ret) {
      return (SC.typeOf(content.addObject) === SC.T_FUNCTION) ||
             (SC.typeOf(content.pushObject) === SC.T_FUNCTION);
    } else return NO;
  }.property('content', 'isEditable'),

  /**
    Set to YES if the controller has valid content that can be displayed,
    even an empty array.  Returns NO if the content is null or not enumerable
    and allowsSingleContent is NO.

    @type Boolean
  */
  hasContent: function () {
    var content = this.get('content');
    return !!content &&
           (!!content.isEnumerable || !!this.get('allowsSingleContent'));
  }.property('content', 'allowSingleContent'),

  /**
    Returns the current status property for the content.  If the content does
    not have a status property, returns SC.Record.READY.

    @type Number
  */
  status: function () {
    var content = this.get('content'),
        ret = content ? content.get('status') : null;
    return ret ? ret : SC.Record.READY;
  }.property().cacheable(),

  // ..........................................................
  // METHODS
  //

  /**
    Adds an object to the array.  If the content is ordered, this will add the
    object to the end of the content array.  The content is not ordered, the
    location depends on the implementation of the content.

    If the source content does not support adding an object, then this method
    will throw an exception.

    @param {Object} object The object to add to the array.
    @returns {SC.ArrayController} The receiver.
  */
  addObject: function (object) {
    if (!this.get('canAddContent')) { throw new Error("%@ cannot add content".fmt(this)); }

    var content = this.get('content');
    if (content.isSCArray) { content.pushObject(object); }
    else if (content.addObject) { content.addObject(object); }
    else { throw new Error("%@.content does not support addObject".fmt(this)); }

    return this;
  },

  /**
    Removes the passed object from the array.  If the underlying content
    is a single object, then this simply sets the content to null.  Otherwise
    it will call removeObject() on the content.

    Also, if destroyOnRemoval is YES, this will actually destroy the object.

    @param {Object} object the object to remove
    @returns {SC.ArrayController} receiver
  */
  removeObject: function (object) {
    if (!this.get('canRemoveContent')) {
      throw new Error("%@ cannot remove content".fmt(this));
    }

    var content = this.get('content');
    if (content.isEnumerable) {
      content.removeObject(object);
    } else {
      this.set('content', null);
    }

    if (this.get('destroyOnRemoval') && object.destroy) { object.destroy(); }
    return this;
  },

  // ..........................................................
  // SC.ARRAY SUPPORT
  //

  /**
    Compute the length of the array based on the observable content

    @type Number
  */
  length: function () {
    var content = this._scac_observableContent();
    return content ? content.get('length') : 0;
  }.property().cacheable(),

  /** @private
    Returns the object at the specified index based on the observable content
  */
  objectAt: function (idx) {
    var content = this._scac_observableContent();
    return content ? content.objectAt(idx) : undefined;
  },

  /** @private
    Forwards a replace on to the content, but only if reordering is allowed.
  */
  replace: function (start, amt, objects) {
    // check for various conditions before a replace is allowed
    if (!objects || objects.get('length') === 0) {
      if (!this.get('canRemoveContent')) {
        throw new Error("%@ cannot remove objects from the current content".fmt(this));
      }
    } else if (!this.get('canReorderContent')) {
      throw new Error("%@ cannot add or reorder the current content".fmt(this));
    }

    // if we can do this, then just forward the change.  This should fire
    // updates back up the stack, updating rangeObservers, etc.
    var content = this.get('content'); // note: use content, not observable
    var objsToDestroy = [], i, objsLen;

    if (this.get('destroyOnRemoval')) {
      for (i = 0; i < amt; i++) {
        objsToDestroy.push(content.objectAt(i + start));
      }
    }

    if (content) { content.replace(start, amt, objects); }

    for (i = 0, objsLen = objsToDestroy.length; i < objsLen; i++) {

      objsToDestroy[i].destroy();
    }
    objsToDestroy = null;

    return this;
  },

  indexOf: function (object, startAt) {
    var content = this._scac_observableContent();
    return content ? content.indexOf(object, startAt) : -1;
  },

  // ..........................................................
  // INTERNAL SUPPORT
  //

  /** @private */
  init: function () {
    sc_super();
    this._scac_contentDidChange();
  },

  /** @private
    Cached observable content property.  Set to NO to indicate cache is
    invalid.
  */
  _scac_cached: NO,

  /**
    @private

    Returns the current array this controller is actually managing.  Usually
    this should be the same as the content property, but sometimes we need to
    generate something different because the content is not a regular array.

    @returns {SC.Array} observable or null
  */
  _scac_observableContent: function () {
    var ret = this._scac_cached;
    if (ret) { return ret; }

    var content = this.get('content'), func, order;

    // empty content
    if (SC.none(content)) { return (this._scac_cached = []); }

    // wrap non-enumerables
    if (!content.isEnumerable) {
      ret = this.get('allowsSingleContent') ? [content] : [];
      return (this._scac_cached = ret);
    }

    // no-wrap
    var orderBy = this.get('orderBy');
    if (!orderBy) {
      if (content.isSCArray) { return (this._scac_cached = content); }
      else { throw new Error("%@.orderBy is required for unordered content".fmt(this)); }
    }

    // all remaining enumerables must be sorted.

    // build array - then sort it
    var type = SC.typeOf(orderBy);

    if (type === SC.T_STRING) {
      orderBy = [orderBy];
    } else if (type === SC.T_FUNCTION) {
      func = orderBy;
    } else if (type !== SC.T_ARRAY) {
      throw new Error("%@.orderBy must be Array, String, or Function".fmt(this));
    }

    // generate comparison function if needed - use orderBy
    func = func || function (a, b) {
      var status, key, match, valueA, valueB;

      for (var i = 0, l = orderBy.get('length'); i < l && !status; i++) {
        key = orderBy.objectAt(i);

        if (key.search(/(ASC|DESC)/) === 0) {
          //@if(debug)
          SC.warn("Developer Warning: SC.ArrayController's orderBy direction syntax has been changed to match that of SC.Query and MySQL.  Please change your String to 'key DESC' or 'key ASC'.  Having 'ASC' or 'DESC' precede the key has been deprecated.");
          //@endif
          match = key.match(/^(ASC )?(DESC )?(.*)$/);
          key = match[3];
        } else {
          match = key.match(/^(\S*)\s*(DESC)?(?:ASC)?$/);
          key = match[1];
        }
        order = match[2] ? -1 : 1;

        if (a) { valueA = a.isObservable ? a.get(key) : a[key]; }
        if (b) { valueB = b.isObservable ? b.get(key) : b[key]; }

        status = SC.compare(valueA, valueB) * order;
      }

      return status;
    };

    return (this._scac_cached = content.toArray().sort(func));
  },

  propertyWillChange: function (key) {
    if (key === 'content') {
      this.arrayContentWillChange(0, this.get('length'), 0);
    } else {
      return sc_super();
    }
  },

  _scac_arrayContentWillChange: function (start, removed, added) {
    // Repoint arguments if orderBy is present. (If orderBy is present, we can't be sure how any content change
    // translates into an arrangedObject change without calculating the order, which is a complex, potentially
    // expensive operation, so we simply invalidate everything.)
    if (this.get('orderBy')) {
      var len = this.get('length');
      start = 0;
      added = len + added - removed;
      removed = len;
    }

    // Continue.
    this.arrayContentWillChange(start, removed, added);
    if (this._kvo_enumerable_property_chains) {
      var removedObjects = this.slice(start, start + removed);
      this.teardownEnumerablePropertyChains(removedObjects);
    }
  },

  _scac_arrayContentDidChange: function (start, removed, added) {
    this._scac_cached = NO;

    // Repoint arguments if orderBy is present. (If orderBy is present, we can't be sure how any content change
    // translates into an arrangedObject change without calculating the order, which is a complex, potentially
    // expensive operation, so we simply invalidate everything.)
    if (this.get('orderBy')) {
      var len = this.get('length');
      start = 0;
      added = len + added - removed;
      removed = len;
    }

    // Notify range, firstObject, lastObject and '[]' observers.
    this.arrayContentDidChange(start, removed, added);

    if (this._kvo_enumerable_property_chains) {
      var addedObjects = this.slice(start, start + added);
      this.setupEnumerablePropertyChains(addedObjects);
    }
    this.updateSelectionAfterContentChange();
  },

  /** @private
    Whenever content changes, setup and teardown observers on the content
    as needed.
  */
  _scac_contentDidChange: function () {
    this._scac_cached = NO; // invalidate observable content
    var content     = this.get('content'),
        lastContent = this._scac_content,
        didChange   = this._scac_arrayContentDidChange,
        willChange  = this._scac_arrayContentWillChange,
        sfunc       = this._scac_contentStatusDidChange,
        efunc       = this._scac_enumerableDidChange,
        newlen;

    if (content === lastContent) { return this; } // nothing to do

    // teardown old observer
    if (lastContent) {
      if (lastContent.isSCArray) {
        lastContent.removeArrayObservers({
          target: this,
          didChange: didChange,
          willChange: willChange
        });
      } else if (lastContent.isEnumerable) {
        lastContent.removeObserver('[]', this, efunc);
      }

      lastContent.removeObserver('status', this, sfunc);

      this.teardownEnumerablePropertyChains(lastContent);
    }

    // save new cached values
    this._scac_cached = NO;
    this._scac_content = content;

    // setup new observer
    // also, calculate new length.  do it manually instead of using
    // get(length) because we want to avoid computed an ordered array.
    if (content) {
      // Content is an enumerable, so listen for changes to its
      // content, and get its length.
      if (content.isSCArray) {
        content.addArrayObservers({
          target: this,
          didChange: didChange,
          willChange: willChange
        });

        newlen = content.get('length');
      } else if (content.isEnumerable) {
        content.addObserver('[]', this, efunc);
        newlen = content.get('length');
      } else {
        // Assume that someone has set a non-enumerable as the content, and
        // treat it as the sole member of an array.
        newlen = 1;
      }

      // Observer for changes to the status property, in case this is an
      // SC.Record or SC.RecordArray.
      content.addObserver('status', this, sfunc);

      this.setupEnumerablePropertyChains(content);
    } else {
      newlen = SC.none(content) ? 0 : 1;
    }

    // finally, notify enumerable content has changed.
    this._scac_length = newlen;
    this._scac_contentStatusDidChange();

    this.arrayContentDidChange(0, 0, newlen);
    this.updateSelectionAfterContentChange();
  }.observes('content'),

  /** @private
    Whenever enumerable content changes, need to regenerate the
    observableContent and notify that the range has changed.

    This is called whenever the content enumerable changes or whenever orderBy
    changes.
  */
  _scac_enumerableDidChange: function () {
    var content = this.get('content'), // use content directly
        newlen  = content ? content.get('length') : 0,
        oldlen  = this._scac_length;

    this._scac_length = newlen;
    this._scac_cached = NO; // invalidate
    // If this is an unordered enumerable, we have no way
    // of knowing which indices changed. Instead, we just
    // invalidate the whole array.
    this.arrayContentWillChange(0, oldlen, newlen);
    this.arrayContentDidChange(0, oldlen, newlen);
    this.updateSelectionAfterContentChange();
  }.observes('orderBy'),

  /** @private
    Whenever the content "status" property changes, relay out.
  */
  _scac_contentStatusDidChange: function () {
    this.notifyPropertyChange('status');
  }

});