// getBaselineDiff.js

/*global adventurejs A*/
"use strict";

/**
 * Get the diff between the baseline world state
 * and the current world state
 * to create a minimum data set for writing saved games.
 * @method adventurejs.Game#getBaselineDiff
 * @memberOf adventurejs.Game
 * @param {Object} source_world
 * @returns {String} Returns a stringified diff.
 */
adventurejs.getBaselineDiff = function Adventurejs_getBaselineDiff() {
  var world_diff = {};
  //var starttime = new Date().getTime();

  world_diff = A.diff(this.game.baseline.world, this.game.world);

  // save title for restore verification
  // TODO change to int-fiction global game id
  if ("undefined" === typeof world_diff._titleSerialized) {
    world_diff._titleSerialized = this.game.world._titleSerialized;
  }

  // save timestamp
  if ("undefined" === typeof world_diff._timestamp) {
    world_diff._timestamp = new Date().getTime().toString();
  }

  // save intervals
  if ("undefined" === typeof world_diff._intervals) {
    world_diff._intervals = this.game.world._intervals;
  }

  // save vars
  if ("undefined" === typeof world_diff._vars) {
    world_diff._vars = this.game.world._vars;
  }

  // stringify
  world_diff = JSON.stringify(world_diff);

  //this.game.log( "log", "high", "getBaselineDiff(, 'CopyOperations' ) took "
  //+ (( new Date().getTime() - starttime ) / 1000 )
  //+ " seconds." );

  return world_diff;
};