/*******************************************************************************
**
** FileName: APIWrapper.js
**
*******************************************************************************/

/*******************************************************************************
**
** Concurrent Technologies Corporation (CTC) grants you ("Licensee") a non-
** exclusive, royalty free, license to use, modify and redistribute this
** software in source and binary code form, provided that i) this copyright
** notice and license appear on all copies of the software; and ii) Licensee does
** not utilize the software in a manner which is disparaging to CTC.
**
** This software is provided "AS IS," without a warranty of any kind.  ALL
** EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING ANY
** IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NON-
** INFRINGEMENT, ARE HEREBY EXCLUDED.  CTC AND ITS LICENSORS SHALL NOT BE LIABLE
** FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
** DISTRIBUTING THE SOFTWARE OR ITS DERIVATIVES.  IN NO EVENT WILL CTC  OR ITS
** LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT,
** INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER
** CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF
** OR INABILITY TO USE SOFTWARE, EVEN IF CTC  HAS BEEN ADVISED OF THE POSSIBILITY
** OF SUCH DAMAGES.
**
*******************************************************************************/


var _Debug = false;  // set this to false to turn debugging off
// and get rid of those annoying alert boxes.

// Define exception/error codes
var _NoError = 0;
var _GeneralException = 101;
var _InvalidArgumentError = 201;
var _NotInitialized = 301;
var _NotImplementedError = 401;


// local variable definitions
var apiHandle = null;
var hasFinished = false;



function LMSInitialize()
{
   hasFinished = false;
   var api = getAPIHandle();
   if (api == null)
   {
      //alert("Unable to locate the LMS's API Implementation.\nLMSInitialize was not successful.");
      return false;
   }

   // call the LMSInitialize function that should be implemented by the API

   var initResult = api.LMSInitialize("");

   if (initResult.toString() != "true")
   {
      // LMSInitialize did not complete successfully.

      // Note: An assumption is made that if LMSInitialize returns a non-true
      //		 value, then and only then, an error was raised.

      // Note: Each function could define its own error handler, but we'll
      // just implement a generic one in this example.
      var err = ErrorHandler();
   }

   return initResult;

}

function LMSFinish()
{
   var api = getAPIHandle();
   if (api == null)
   {
      //alert("Unable to locate the LMS's API Implementation.\nLMSFinish was not successful.");
   }
   else
   {
      // call the LMSFinish function that should be implemented by the API
      if( hasFinished == false )
      {
      	//var emptyString = new String("");
      	api.LMSFinish("");
      	hasFinished = true;
		}
	
      var err = ErrorHandler();
   }

   return;

}

function LMSGetValue(name)
{
   var api = getAPIHandle();
   if (api == null)
   {
      //alert("Unable to locate the LMS's API Implementation.\nLMSGetValue was not successful.");
      return null;
   }
   else
   {
		if( hasFinished == false )
			{
      var value = api.LMSGetValue(name);
      var err = ErrorHandler();
      // if an error was encountered, then return null,
      // else return the retrieved value
      if (err != _NoError)
      {
         return null;
      }
      else
      {
         return value.toString();
      }
   }
	}
}

function LMSSetValue(name, value)
{
   var api = getAPIHandle();
   if (api == null)
   {
      //alert("Unable to locate the LMS's API Implementation.\nLMSSetValue was not successful.");
   }
   else
   {
	if( hasFinished == false )
	{
      api.LMSSetValue(name, value);
      var err = ErrorHandler();
   }
	}

   return;
}

function LMSCommit()
{
   var api = getAPIHandle();
   if (api == null)
   {
      //alert("Unable to locate the LMS's API Implementation.\nLMSCommit was not successful.");
   }
   else
   {
      // call the LMSCommit function that should be implemented by the API
      var emptyString = new String("");
      api.LMSCommit(emptyString);
      var err = ErrorHandler();
   }

   return;

}

function LMSGetLastError()
{
   var api = getAPIHandle();
   if (api == null)
   {
      //alert("Unable to locate the LMS's API Implementation.\nLMSGetLastError was not successful.");
      //since we can't get the error code from the LMS, return a general error
      return _GeneralError;
   }


   return api.LMSGetLastError().toString();

}

function LMSGetErrorString(errorCode)
{
   var api = getAPIHandle();
   if (api == null)
   {
      //alert("Unable to locate the LMS's API Implementation.\nLMSGetErrorString was not successful.");
   }

   return api.LMSGetErrorString(errorCode).toString();

}

function LMSGetDiagnostic(errorCode)
{
   var api = getAPIHandle();
   if (api == null)
   {
      //alert("Unable to locate the LMS's API Implementation.\nLMSGetDiagnostic was not successful.");
   }

   return api.LMSGetDiagnostic(errorCode).toString();

}


function LMSIsInitialized()
{
   // there is no direct method for determining if the LMS API is initialized
   // for example an LMSIsInitialized function defined on the API so we'll try
   // a simple LMSGetValue and trap for the LMS Not Initialized Error

   var api = getAPIHandle();
   if (api == null)
   {
      //alert("Unable to locate the LMS's API Implementation.\nLMSIsInitialized() failed.");
      // no choice but to return false.
      return false;
   }
   else
   {
      var value = api.LMSGetValue("cmi.core.student_name");
      var errCode = api.LMSGetLastError().toString();
      if (errCode == _NotInitialized)
      {
         return false;
      }
      else
      {
         return true;
      }
   }
}


function ErrorHandler()
{
   var api = getAPIHandle();
   if (api == null)
   {
      //alert("Unable to locate the LMS's API Implementation.\nCannot determine LMS error code.");
      return;
   }

   // check for errors caused by or from the LMS
   var errCode = api.LMSGetLastError().toString();
   if (errCode != _NoError)
   {
      // an error was encountered so display the error description
      var errDescription = api.LMSGetErrorString(errCode);

      if (_Debug == true)
      {
         errDescription += "\n";
         errDescription += api.LMSGetDiagnostic(null);
         // by passing null to LMSGetDiagnostic, we get any available diagnostics
         // on the previous error.
      }

      //alert(errDescription);
   }

   return errCode;
}

function getAPIHandle()
{
   if (apiHandle == null)
   {
      apiHandle = getAPI();
   }

   return apiHandle;
}


/******************************************************************************************
**
** Function findAPI(win)
** Inputs:  win - a Window Object
** Return:  If an API object is found, it is returned, otherwise null is returned.
**
** Description:
** This function looks for an object named API in the supported window hierarchy,
**
******************************************************************************************/
function findAPI(win)
{

   // Search the window hierarchy for an object named "API"
   // Look in the current window (win) and recursively look in any child frames
	if (_Debug) 
	{
		alert("win is: "+win.location.href);
	}

	if (win.API != null) 
	{
		if (_Debug) 
		{
			alert("found api in this window");
		}
		return win.API;
	}

	// does the window have frames?
	if (win.length > 0) 
	{
		if (_Debug) 
		{
			alert("looking for api in windows frames");
		}
		for (var i=0;i<win.length;i++) 
		{
			if (_Debug) 
			{
				alert("looking for api in frames["+i+"]");
			}
			var theAPI = findAPI(win.frames[i]);
			if (theAPI != null) {
				return theAPI;
			}
		}
	}

	if (_Debug) 
	{
		alert("didn't find api in this window (or its children)");
	}
	return null;
	
}


function findProxyAPI(win) {
	// Search the window hierarchy for an object named "proxyAPI"
	// Look in the current window (win) and recursively look in any child frames
	if (_Debug) {
		alert("win is: "+win.location.href);
	}

	if (win.proxyAPI != null) {
		if (_Debug) {
			alert("found proxy api in this window");
		}
		return win.proxyAPI;
	}

	// does the window have frames?
	if (win.length > 0) {
		if (_Debug) {
			alert("looking for proxy api in windows frames");
		}
		for (var i=0;i<win.length;i++) {
			if (_Debug) {
				alert("looking for proxy api in frames["+i+"]");
			}
			var theAPI = findProxyAPI(win.frames[i]);
			if (theAPI != null) {
				return theAPI;
			}
		}
	}

	if (_Debug) {
		alert("didn't find proxy api in this window (or its children)");
	}
	return null;
}

/******************************************************************************************
**
** Function getAPI()
** Inputs:  none
** Return:  If an API object is found, it is returned, otherwise null is returned.
**
** Description:
** This function looks for an object named API, first in the current window's hierarchy,
**  and then, if necessary, in the current window's opener window hierarchy (if there is
**  an opener window).
******************************************************************************************/

function getAPI()
{
	// first attempt to find proxy API
	var theAPI = findProxyAPI(this.top);

	if (theAPI != null) return theAPI;

	if (_Debug) {
		alert("checking to see if this winodow has an opener");
		alert("window.opener typeof is> " + typeof(window.opener));
	}
	if (typeof(top.opener) != "undefined") {
		if (_Debug) {
			alert("checking this window's opener");
		}
		if (top.opener != null) {
			if (_Debug) {
				alert("this window's opener is NOT null - looking there");
			}
			theAPI = findProxyAPI(top.opener.top);
		} else {
			if (_Debug) {
				alert("this window's opener is null");
			}
		}
	}

	if (theAPI != null) return theAPI;

   // no proxy API, check for 'real' API
   // start at the topmost window - findAPI will recurse down through
   // all of the child frames
   theAPI = findAPI(this.top);

   if (theAPI != null) return theAPI;

	// the API wasn't found in the current window's hierarchy.  If the
	// current window has an opener (was launched by another window),
	// check the opener's window hierarchy.
	if (_Debug) {
		alert("checking to see if this window has an opener");
		alert("window.opener typeof is> "+typeof(window.opener));
	}
	if (typeof(top.opener) != "undefined") {
		if (_Debug) {
			alert("checking this windows opener");
		}
		if (top.opener != null) {
			if (_Debug) {
				alert("this windows opener is NOT null - looking there");
			}
			theAPI = findAPI(top.opener.top);
		} else {
			if (_Debug) {
				alert("this windows opener is null");
			}
		}
	}

	return theAPI;
}