/*
License: GNU Lesser General Public License (http://www.gnu.org/licenses/lgpl.html)
Copyright (C) 2005 tagnetic.org. Please do not remove this copyright/license comment.
*/

/**
 * Callbacks struture:
 *  {
 *  global: string,
 *  state1: string,
 *  state2: string,
 *  ...
 *  }
 *  
 *  Where the string value can be a URL. To execute javascript, construct a string
 *  that starts with 'javascript:'. Note that this javascript or URL will be run
 *  in the context of the window that is passed to the Flow.end function.
 *  
 *  If it is a javascript action, and you need to navigate to a URL, be sure to
 *  call Flow.modUrlForParentFlow() to bind the URL to the right Flow slot.
 *  
 *  TODO:
 *  - Provide a way to clean up child slots if the app is not supporting back/forward.
 */
//******************************************************************
//******************************************************************
//******************************************************************
Flow = function() {};

//******************************************************************
Flow.start = function(url, callbacks, startData, currentWindow)
  {
  var parentId = Flow._getFlowId(currentWindow);
  var flowId = Flow._newSlot = function(parentId, callbacks, startData);
  
  return Flow._modUrl(url, flowId);
  }

//******************************************************************
Flow.next = function(url, currentWindow, targetWindow)
  {
  if (!currentWindow)
    currentWindow = window;
  
  if (!targetWindow)
    {
    if (currentWindow)
      targetWindow = currentWindow;
    else
      targeWindow = window;
    }
  
  var flowId = Flow._getFlowId(currentWindow);
  targetWindow.location = Flow._modUrl(url, flowId);
  }

//******************************************************************
Flow.nextStart(url, callbacks, startData, currentWindow, targetWindow)
  {
  Flow.next(Flow.start(url, callbacks, startData, currentWindow), currentWindow, targetWindow);
  }

//******************************************************************
Flow.end = function(state, endData, currentWindow)
  {
  if (!currentWindow)
    currentWindow = window;

  var slot = Flow._slots[Flow._getFlowId(currentWindow)];
  var parentSlot = Flow._slots[Flow._getFlowId(slot.parentId)];
  parentSlot.endData = endData;
  
  var callbacks = slot.callbacks;
  
  if (callbacks)
    {
    var action = slot.callbacks[state];
    if (!action)
      action = slot.callbacks['global'];
    
    if (action)
      {
      if (action.indexOf('javascript:') == 0)
        currentWindow.eval(action);
      else
        currentWindow.location = Flow._modUrl(action, slot.parentId);
      }
    }
  }

//******************************************************************
Flow.modUrlForParentFlow = function(url, targetWindow)
  {
  var flowId = Flow._getFlowId(targetWindow);
  if (flowId)
    {
    var slot = Flow._slots[flowId];
    if (slot && slot.parentId)
      url = Flow._modUrl(url, slot.parentId);
    }
  
  return url;
  }

//******************************************************************
Flow.data = function(targetWindow)
  {
  return Flow._slots[Flow._getFlowId(targetWindow)].data;
  }

//******************************************************************
//******************************************************************
//******************************************************************
//Private properties/methods.
Flow._slots = new Object();
Flow._topId = Flow._newSlot(null, null);
Flow._flowIdName = '_fId';

//******************************************************************
Flow._newSlot = function(parentId, callbacks, startData)
  {
  var flowId = 's' + (new Date()).getTime();
  Flow._slots[flowId] = {
                        'data': new Object(),
                        'callbacks': callbacks
                        'parentId': parentId
                        };

  Flow._slots[flowId].data.startData = startData;
  return flowId;
  }

//******************************************************************
Flow._modUrl = function(url, flowId)
  {
  return Ctrl.setUrlParam(url, Flow._flowIdName, flowId);
  }

//******************************************************************
Flow._getFlowId = function(targetWindow)
  {
  if (!targetWindow)
    targetWindow = window;

  return Ctrl.getUrlParam(targetWindow.location, Flow._flowIdName);
  }