define(function(require, exports, module) {
'use strict';

var Abstract = require('./abstract');
var Calc = require('common/calc');
var binsearch = require('common/binsearch');
var core = require('core');
var compare = require('common/compare');
var denodeifyAll = require('common/promise').denodeifyAll;

/**
 * Objects saved in the busytime store:
 *
 *    {
 *      _id: (uuid),
 *      start: Calendar.Calc.dateToTransport(x),
 *      end: Calendar.Calc.dateToTransport(x),
 *      eventId: eventId,
 *      calendarId: calendarId
 *    }
 *
 */
function Busytime() {
  Abstract.apply(this, arguments);
  this._setupCache();

  denodeifyAll(this, [
    'removeEvent',
    'loadSpan'
  ]);
}
module.exports = Busytime;

Busytime.prototype = {
  __proto__: Abstract.prototype,

  _store: 'busytimes',

  _dependentStores: ['alarms', 'busytimes'],

  _setupCache: function() {
    this._byEventId = Object.create(null);
  },

  _createModel: function(input, id) {
    return this.initRecord(input, id);
  },

  initRecord: function(input, id) {
    var _super = Abstract.prototype._createModel;
    var model = _super.apply(this, arguments);
    model.startDate = Calc.dateFromTransport(model.start);
    model.endDate = Calc.dateFromTransport(model.end);
    return model;
  },

  _removeDependents: function(id, trans) {
    core.storeFactory.get('Alarm').removeByIndex('busytimeId', id, trans);
  },

  removeEvent: function(id, trans, callback) {
    if (typeof(trans) === 'function') {
      callback = trans;
      trans = undefined;
    }

    if (typeof(trans) === 'undefined') {
      trans = core.db.transaction(
        this._dependentStores,
        'readwrite'
      );
    }

    // build the request using the inherited method
    var req = this.removeByIndex('eventId', id, trans);

    // get the original method which handles the generic bit
    var success = req.onsuccess;

    // override the default .onsuccess to get the ids
    // so we can emit remove events.
    var self = this;
    req.onsuccess = function(e) {
      var cursor = e.target.result;

      if (cursor) {
        var id = cursor.primaryKey;
        self.emit('remove', id);
      }

      success(e);
    };

    this._transactionCallback(trans, callback);
  },

  _startCompare: function(aObj, bObj) {
    var a = aObj.start.utc;
    var b = bObj.start.utc;
    return compare(a, b);
  },

  /**
   * Loads all busytimes in given timespan.
   *
   * @param {Calendar.Timespan} span timespan.
   * @param {Function} callback node style callback
   *                            where first argument is
   *                            an error (or null)
   *                            and the second argument
   *                            is a list of all loaded
   *                            busytimes in the timespan.
   */
  loadSpan: function(span, callback) {
    var trans = core.db.transaction(this._store);
    var store = trans.objectStore(this._store);

    var startPoint = Calc.dateToTransport(new Date(span.start));
    var endPoint = Calc.dateToTransport(new Date(span.end));

    // XXX: we need to implement busytime chunking
    // to make this efficient.
    var keyRange = IDBKeyRange.lowerBound(startPoint.utc);

    var index = store.index('end');
    var self = this;

    index.mozGetAll(keyRange).onsuccess = function(e) {
      var data = e.target.result;

      // sort data
      data = data.sort(self._startCompare);

      // attempt to find a start time that occurs
      // after the end time of the span
      var idx = binsearch.insert(
        data,
        { start: { utc: endPoint.utc + 1 } },
        self._startCompare
      );

      // remove unrelated timespan...
      data = data.slice(0, idx);

      // fire callback
      if (callback) {
        callback(null, data.map(function(item) {
          return self.initRecord(item);
        }));
      }

    };
  },

  /* we don't use id based caching for busytimes */

  _addToCache: function() {},
  _removeFromCache: function() {}

};

});