///////////////////////////////////////////////////////////////////////////////////////////////////
//
//	Copyright © 2000, Microsoft Corp.  All rights reserved.
//
//	@doc INTERNAL
//
//  @module LMS_API.inc |
//		Contains the AICC LMS API Implementation for rich clients (IE5+).
//	
//	@end
//	Creator:		a-mbatem		
//	Created:		11/29/99
//	Current Owner:	tmarsh
//
///////////////////////////////////////////////////////////////////////////////////////////////////

///////////////////////////////////////////////////////////////////////////////////////////////////
//
//	Client-Side script
//
///////////////////////////////////////////////////////////////////////////////////////////////////

///////////////////////////////////////////////////////////////////////////////////////////////////
//
//	Global variables
//
///////////////////////////////////////////////////////////////////////////////////////////////////
// Localizable strings
var L_Success_Message		= "Success";

var Trace					= NoTrace;
var gc_strUserDataPrefix	= "lrnpers&";
var gc_strPersDBShortName	= "lrnpers";
var gc_strMainXMLAttribute	= "mainXML";
var gc_strPropertyPropName	= "property";
var gc_strValuePropName		= "property_value";
var gc_strXMLValuePropName	= "property__value";
var gc_strScopePropName         = "scope";
var gc_strScopeProperty         = "lrn.startlocation";
var gc_strLRNPrefix		= "lrn.";

// Error details types
var gc_strParseError		= "XML_Parse_Error";
var gc_strJScriptError		= "JScript_Error";
var gc_strMultiStatusError	= "Multi-Status_Error";
var gc_strString			= "String";
var gc_strNoDetails			= "Null";


///////////////////////////////////////////////////////////////////////////////////////////////////
//
//	Error handling and other utility functions
//
///////////////////////////////////////////////////////////////////////////////////////////////////

////////////////////////////////////////////////////////////////////////////////////////////////////
//
//	@doc INTERNAL
//
//	@jsfunc NoTrace | Default trace function -- don't do anything with trace output.
//
//	@parm  String	| strMessage		| The message to trace.  Not used.
//
//	@rdesc  None.
//
////////////////////////////////////////////////////////////////////////////////////////////////////
function NoTrace
(
strMessage
)
{
	return;
}

////////////////////////////////////////////////////////////////////////////////////////////////////
//
//	@doc INTERNAL
//
//	@jsfunc ErrorStringFromID | Searches error XML for the description of an error.
//
//	@parm  Integer	| iNumber			| The numeric identifier of the error for which to search.
//
//	@rdesc  If the errors XML has not yet finished loading, returns null.  If the ID cannot be found
//			in the errors XML, an empty string is returned.  If the ID is found, the error
//			description is returned.
//
////////////////////////////////////////////////////////////////////////////////////////////////////
function ErrorStringFromID
(
iNumber
)
{
	if("complete" != oLMSErrorsXML.readyState)
	{
		// Return null for now.  When a client requests the description again, we will make another
		// attempt to load the string.
		return null;
	}
	else
	{
		// Search for the string corresponding to the current number
		var oError = oLMSErrorsXML.XMLDocument.selectSingleNode("/root/PersError[@ID=" + iNumber + "]");
		if(null == oError)
		{
			return "";
		}
		else
		{
			return oError.text;
		}
	}
}

////////////////////////////////////////////////////////////////////////////////////////////////////
//
//	@doc INTERNAL
//
//	@jsfunc PersError | Constructor function for personalization error objects.
//
//	@parm  Integer	| iNumber			| The numeric identifier of this error.  The description
//											string will be loaded from the XML.
//	@parm  String	| strDetailsType	| A string description of the type of information in
//											oErrorDetails.  Several constants have been defined
//											above as types we understand.  This parameter is
//											required if oErrorDetails is not null, but is ignored
//											if oErrorDetails is null.
//	@parm  Object	| oErrorDetails		| Additional information about the error that occurred.
//											The type of this object is indicated by the
//											strDetailsType parameter.  This parameter is optional.
//
//	@rdesc  Javascript personalization error object.
//
////////////////////////////////////////////////////////////////////////////////////////////////////
function PersError
(
iNumber,
strDetailsType,
oErrorDetails
)
{
	if("string" != typeof(strDetailsType))
	{
		strDetailsType = gc_strNoDetails;
	}
	
	// Validate the inputs.
	if("number" != typeof(iNumber))
	{
		// $ TODO: M2: Assert here.
		return null;
	}

	// Store the error number, details type, and details
	this.number = iNumber;
	if("undefined" != typeof(oErrorDetails) && null != oErrorDetails)
	{
		this.strDetailsType	= strDetailsType;
		this.oErrorDetails	= oErrorDetails;
	}
	else
	{
		this.strDetailsType = gc_strNoDetails;
		this.oErrorDetails	= null;
	}

	// Fetch and store the string.
	this.description = ErrorStringFromID(iNumber);

	return this;
}


///////////////////////////////////////////////////////////////////////////////////////////////////
//
//	Implementation of the private methods of the LMSAPI object
//
///////////////////////////////////////////////////////////////////////////////////////////////////

///////////////////////////////////////////////////////////////////////////////////////////////////
//
//  @doc Internal
//
//	@jsfunc		LMSAPI_Instance	| Constructor for an LMSAPI object.  One LMSAPI object should be
//									created for each personalization context (e.g. 
//									the current course, or a specific syllabus item).
//
//	@parm String	| strContext| A URL indicating the context for the LMSAPI object.  For example,
//									the caller would supply the URL of a course to retrieve and
//									modify properties related to the current user in the specified
//									course.
//	@parm Object	| oUserData	| An object with the userData behavior to load and save the offline
//									personalization XML cache.  This parameter is optional and may
//									be null.
//
//	@rdesc		Returns a newly created LMSAPI object on success.  On failure, returns null.
//				Failure is only caused by passing invalid arguments.
//
//	@ex	Usage: |
//				// Create an LMSAPI object for installation-wide personalization properties
//				var g_oInstallationLMSAPI = new LMSAPI_Instance(g_strInstallationURL, oUserData);
//				
//				// Now, create an LMSAPI object for personalization properties related to the
//				// current course.
//				var g_oCourseLMSAPI = new LMSAPI_Instance(g_strCourseURL, oUserData);
//
//	@comm 
//	@end
//
///////////////////////////////////////////////////////////////////////////////////////////////////
function LMSAPI_Instance
(
strContext,
strSaveName,
oUserData
)
{
	Trace("Entering LMSAPI_Instance context=" + strContext + " savename=" + strSaveName + " userData=" + oUserData);
	try
	{
		// Make nominal checks of the validity of the inputs
		if("string" != typeof(strContext) || "" == strContext)
		{
			Trace("Invalid context string");
			return null;
		}

		// Make nominal checks of the validity of the inputs
		if("string" != typeof(strSaveName) || "" == strSaveName)
		{
			Trace("Invalid context string");
			return null;
		}

		if("undefined" == typeof(oUserData))
		{
			if(null == oUserData)
			{
				// $ TODO: M2: Uncommented, the next line will alert.
				// $ TODO: M2: Figure out how to allow the caller to specify not to use user data.
				//alert("null is not an object");
			}
			oUserData = oDefaultUserData;
		}
		
		if("object" != typeof(oUserData) && null != oUserData)
		{
			Trace("Invalid user data object");
			return null;
		}

		this.strContextURL	= strContext;
		this.strSaveName	= strSaveName;
		this.oUserData		= oUserData;

		// Add private methods
		this.LRNInitialize		= LRNInitialize;
		this.LRNTerminate		= LRNTerminate;
		
		// Add LMS functions as our methods
		this.LMSInitialize		= LMSInitialize;
		this.LMSGetValue		= LMSGetValue;
		this.LMSSetValue		= LMSSetValue;
		this.LMSCommit			= LMSCommit;
		this.LMSGetLastError	= LMSGetLastError;
		this.LMSGetErrorString	= LMSGetErrorString;
		this.LMSGetDiagnostic	= LMSGetDiagnostic;
		this.LMSFinish			= LMSFinish;

		Trace("Returning a new LMSAPI object");
		return this;
	}
	catch(e)
	{
		Trace("LMSAPI_Instance error: " + e.description);
		return null;
	}
}

///////////////////////////////////////////////////////////////////////////////////////////////////
//
//  @doc Internal
//
//	@jsfunc		LRNInitialize | LRN initialization method for LMSAPI objects.  This function loads
//								the personalization XML from the server, if the user is online, or
//								from the client-side userData cache, if the user is offline.  This
//								method must be called before calling any LMS methods.  If this
//								method returns false, only the LMS error methods may be called on
//								the LMSAPI object.
//
//	@rdesc		Returns true to indicate that the initialization was successful or false to
//				indicate a failure.
//
//	@ex	Usage: |
//				// Initialize the Interface & check for any errors.
//
//				if(!LMSAPI.LRNInitialize())
//				{
//					alert(LMSAPI.LMSGetErrorString(LMSAPI.LMSGetLastError()));
//				}
//
//	@end
//
///////////////////////////////////////////////////////////////////////////////////////////////////
function LRNInitialize
(
)
{
	Trace("Entering LRNInitialize");
	try
	{
		if(this.bInitialized)
		{
			// We're already initialized.
			Trace("Already initialized -- returning");
			return;
		}

		// Reset the API's last error so the current call starts clean.
		this.oLastError = null;

		// Check that the context URL has been set.
		if(null == this.strContextURL)
		{
			Trace("Context string was null!");
			// $ TODO: M2: Create a constant for 302.
			throw new PersError(302);
		}

		if(null != this.oUserData)
		{
			// Load the personalization userData store.
			Trace("Attempting to load user data");
			this.oUserData.load(gc_strUserDataPrefix + this.strSaveName);

			this.oMainXML = new ActiveXObject("Microsoft.XMLDOM");
			if(null == this.oMainXML)
			{
				throw new PersError(304);
			}

			var strMainXML = this.oUserData.getAttribute(gc_strMainXMLAttribute);
			if("string" != typeof(strMainXML) || "" == strMainXML)
			{
				Trace("No XML in user data.  Starting fresh.");
				this.oMainXML = oMainBaseXML.XMLDocument.cloneNode(true);
			}
			else
			{
				this.oMainXML.loadXML(strMainXML);
			}

			if(0 != this.oMainXML.parseError.errorCode)
			{
				// $ TODO: M2: Better error ID.
				throw new PersError(101, gc_strParseError, this.oMainXML.parseError);
			}
		}
		else
		{
			throw new PersError(304);
		}

		Trace("LRNInitialize succeeded.");

		// Successful initialization
		this.bInitialized = true;
		return true;
	}
	catch(oPersError)
	{
		Trace("Failed in LRNInitialize because " + oPersError.description);
		this.oLastError = oPersError;
		return false;
	}
}

////////////////////////////////////////////////////////////////////////////////////////////////////
//	@doc Internal
//
//	@jsfunc LRNTerminate	| Commits the changes made to personalization data since calling
//								LRNInitialize.
//
//	@rdesc  none
//
//	@ex Usage: |
//				// Set the last visited page to our current location and commit the change.
//				// (error checking omitted for clarity)
//				LMSAPI.LRNInitialize();
//				LMSAPI.LMSInitialize(null);
//				LMSAPI.LMSSetValue("LastPageVisited", location.href);
//				LMSAPI.LMSFinish();
//				LMSAPI.LRNTerminate();
//		
//	@end
//
////////////////////////////////////////////////////////////////////////////////////////////////////
function LRNTerminate
(
oLMSAPI
)
{
	try
	{
		this.LMSCommit();
		this.bInitialized = false;
	}
	catch(e)
	{
		this.oLastError = new PersError(101, gc_strJScriptError, e);
	}
}

///////////////////////////////////////////////////////////////////////////////////////////////////
//
//  @doc External
//
//	@jsfunc		LMSInitialize | LRN implementation of LMSInitialize, which initializes the LMS API
//								for use by the personalization client.  The real work of
//								initializing the LMSAPI object is done in LRNInitialize, which is
//								a private method.  This function does little or no initialization.
//
//	@parm Object	| null	|	A null must be passed for conformance to the current LMS standard.  
//
//	@rdesc		Returns true to indicate that the initialization was successful or false to indicate
//				a failure.
//
//	@ex	Usage: |
//				// Initialize the Interface & check for any errors.
//
//				if(!LMSAPI.LMSInitialize())
//				{
//					alert(LMSAPI.LMSGetErrorString(LMSAPI.LMSGetLastError()));
//				}
//
//	@comm 
//				This function should not be called directly.  It is meant to be called through an
//				instance of the LMSImplentation object that is returned by FindLMSAPI().  
//	@end
//
///////////////////////////////////////////////////////////////////////////////////////////////////
function LMSInitialize()
{
	Trace("Entering LMSInitialize");
	try
	{
		// Reset the API's last error so the current call starts clean.
		this.oLastError = null;
	
		if(!this.bInitialized)
		{
			Trace("LRNInitialize has not been called successfully!");
			// $ TODO: M2: Better error ID
			throw PersError(101);
		}

		Trace("LMSInitialize succeeded.");
		return true;
	}
	catch(oPersError)
	{
		Trace("Failed in LMSInitialize because " + oPersError.description);
		this.oLastError = oPersError;
		return false;
	}
}

////////////////////////////////////////////////////////////////////////////////////////////////////
//
//	@doc External
//
//	@jsfunc LMSGetValue | LRN implementation of LMSGetValue, which retrieves the value of the named
//							personalization property. 
//
//	@parm String | strPropertyName	|	The name of the property to retrieve.
//
//	@rdesc  If the property exists, its value is returned as a string.  Otherwise, null is returned.
//
//	@ex Usage: |
//				// Get a value (error checking ommited for clarity)
//				var strScore	= LMSAPI.LMSGetValue("Assessment1_Score");
//
//	@comm 
//				This function should not be called directly.  It is meant to be called through an
//				initialized instance of the LMSImplementation object that is returned by
//				FindLMSAPI().
//				Note:  The current LRN implementation of the LMS API does not support datamodels or
//				the _children, _count, or _version keywords.
//	@end
//
////////////////////////////////////////////////////////////////////////////////////////////////////
function LMSGetValue
(
strPropertyName
)
{
	try
	{
		Trace("Entering LMSGetValue for " + strPropertyName);
		
		// Reset the API's last error so the current call starts clean.
		this.oLastError = null;
		
		// Make sure that we were passed a reasonable argument
		if("string" != typeof(strPropertyName) || "" == strPropertyName)
		{
			// $ TODO: M2: Use string replacement tool to replace error IDs too.
			throw new PersError(201);
		}
			
		// Make sure we are initialized
		// $ TODO: M2: Assert that null != this.oMainXML instead.
		if(!this.bInitialized || null == this.oMainXML)
		{
			Trace("The LMSAPI has not been initialized!");
			throw new PersError(301);
		}

		var strScope = null;

		// If it's one of our global properties, do not attach scope
		if (strPropertyName.indexOf(gc_strLRNPrefix) != 0)
			strScope = this.LMSGetValue(gc_strScopeProperty);

		if (null == strScope)
			strScope = "";

		// Find the value of the current property
		var strPattern = "/root/" + gc_strPersDBShortName + "[@" + gc_strPropertyPropName + "=\'" +
						 strPropertyName + "\' && @" + gc_strScopePropName + "=\'" +
						 strScope + "\']";
		Trace("Using the following XSL pattern: " + strPattern);
		var oProperty = this.oMainXML.selectSingleNode(strPattern);

		if(null == oProperty)
		{
			// We don't consider this an error.
			Trace("Could not find the specified property");
			return null;
		}

		return oProperty.attributes.getNamedItem(gc_strXMLValuePropName).value;
		Trace("LMSGetValue succeeded.");
	}
	catch(e)
	{
		if("undefined" == typeof(e.strDetailsType))
		{
			this.oLastError = new PersError(101, gc_strJScriptError, e);
		}
		else
		{
			this.oLastError = e;
		}
		Trace("LMSGetValue failed because " + this.oLastError.description);
	}
}

////////////////////////////////////////////////////////////////////////////////////////////////////
//	@doc External
//
//	@jsfunc LMSSetValue | LRN implementation of LMSSetValue, which sets the value of the named
//							personalization property.  The change is not commited to the store until
//							LMSCommit or LMSFinish is called.
//
//	@parm String | strPropertyName	|	The name of the property to modify.
//	@parm String | strPropertyValue	|	The value to set.  This must be a number, a boolean, or a
//										string.  We will convert the value to a string before
//										setting it.
//
//	@rdesc  none
//
//	@ex Usage: |
//				// Set the last visited page to our current location.
//				// (error checking omitted for clarity)
//				LMSAPI.LMSSetValue("LastPageVisited", location.href);
//		
//	@comm 
//				This function should not be called directly.  It is meant to be called through an
//				initialized instance of the LMSImplementation object that is returned by
//				FindLMSApI().
//	@end
//
////////////////////////////////////////////////////////////////////////////////////////////////////
function LMSSetValue
(
strPropertyName,
strPropertyValue
)
{
	Trace("Entering LMSSetValue to set " + strPropertyName + " to " + strPropertyValue);
	try
	{
		// Reset the API's last error so the current call starts clean.
		this.oLastError = null;
		
		// Make sure that we were passed reasonable inputs
		if("string" != typeof(strPropertyName) || "" == strPropertyName)
		{
			Trace("Bad property name");
			throw new PersError(201);
		}

		if("string" != typeof(strPropertyValue))
		{
			if("number" == typeof(strPropertyValue) || "boolean" == typeof(strPropertyValue))
			{
				Trace("Converting value from " + typeof(strPropertyValue) + " to a string.");
				strPropertyValue = strPropertyValue.toString();
				// $ TODO: M2: Assert that the value is now a string
			}
			else if(null != strPropertyValue)
			{
				Trace("Bad property value");
				throw new PersError(201);
			}
		}

		// Make sure we are initialized
		// $ TODO: M2: Assert that null != this.oMainXML instead.
		if(!this.bInitialized || null == this.oMainXML)
		{
			Trace("LMSAPI has not been initialized");
			throw new PersError(301);
		}

		var strScope = null;

		// If it's one of our global properties, do not attach scope
		if (strPropertyName.indexOf(gc_strLRNPrefix) != 0)
			strScope = this.LMSGetValue(gc_strScopeProperty);

		if (null == strScope)
			strScope = "";

		// If the named property already exists, get a handle to its row in the main XML.
		var strPattern = "/root/" + gc_strPersDBShortName + "[@" + gc_strPropertyPropName + "=\'" +
						 strPropertyName + "\' && @" + gc_strScopePropName + "=\'" +
						 strScope + "\']";
		Trace("Using the following XSL pattern: " + strPattern);
		var oOldRow = this.oMainXML.selectSingleNode(strPattern);

		// If a property is being modified or deleted, add the appropriate row to the before
		// section of the update gram.  If the property is being deleted, also delete the old row
		// from the main XML.
		if(null != oOldRow)
		{
			Trace("Updating an existing row");
			oOldRow.attributes.getNamedItem(gc_strXMLValuePropName).value = strPropertyValue;
		}
		else
		{
			// Create a new after row from scratch.
			oNewRow = this.oMainXML.createElement(gc_strPersDBShortName);

			// Set the property and value on the new after row.
			var oProperty		= this.oMainXML.createAttribute(gc_strPropertyPropName);
			var oPropertyValue	= this.oMainXML.createAttribute(gc_strXMLValuePropName);
			var oScope              = this.oMainXML.createAttribute(gc_strScopePropName);

			oProperty.value			= strPropertyName;
			oPropertyValue.value	= strPropertyValue;
			oScope.value = strScope;

			oNewRow.attributes.setNamedItem(oProperty);
			oNewRow.attributes.setNamedItem(oPropertyValue);
			oNewRow.attributes.setNamedItem(oScope);

			var oRootNode = this.oMainXML.selectSingleNode("/root");
			if(null == oRootNode)
			{
				// $ TODO: M2: Assert here.  This is unexpected.
				Trace("Could not find root node in main XML!");
				throw new PersError(101);
			}

			oRootNode.appendChild(oNewRow);
		}
		Trace("LMSSetValue succeeded.");
	}
	catch(e)
	{
		if("undefined" == e.strDetailsType)
		{
			// Return a general error, because we don't know exactly what happened.
			this.oLastError = new PersError(101, gc_strJScriptError, e);
		}
		else
		{
			this.oLastError = e;
		}
		Trace("LMSSetValue error: " + e.description);
	}
}

////////////////////////////////////////////////////////////////////////////////////////////////////
//	@doc External
//
//	@jsfunc LMSCommit	| LRN implementation of LMSCommit, which saves the current set of
//							personalization data to the personalization store.
//
//	@rdesc  none
//
//	@ex Usage: |
//				// Set the last visited page to our current location and commit the change.
//				// (error checking omitted for clarity)
//				LMSAPI.LMSSetValue("LastPageVisited", location.href);
//				LMSAPI.LMSCommit();
//		
//	@comm 
//				This function should not be called directly.  It is meant to be called through an
//				initialized instance of the LMSImplementation object that is returned by
//				FindLMSAPI().
//	@end
//
////////////////////////////////////////////////////////////////////////////////////////////////////
function LMSCommit
(
)
{
	try
	{
		Trace("Entering LMSCommit");
		
		// Reset the last error
		this.oLastError = null;

		if(null != this.oUserData)
		{		
			// Try saving to user data
			Trace("Attempting to save to userData.");
				
			this.oUserData.setAttribute(gc_strMainXMLAttribute, this.oMainXML.xml);
				
			this.oUserData.save(gc_strUserDataPrefix + this.strSaveName);
		}
	}
	catch(e)
	{
		Trace("LMSCommit failed because " + e.description);
		this.oLastError = new PersError(101, gc_strJScriptError, e);
	}
}

////////////////////////////////////////////////////////////////////////////////////////////////////
//	@doc External
//
//	@jsfunc LMSFinish	| LRN implementation of LMSFinish, which saves the current set of
//							personalization data to the personalization store and terminates the
//							connection to the personalization store.
//
//	@rdesc  none
//
//	@ex Usage: |
//				// Set the last visited page to our current location and commit the change.
//				// (error checking omitted for clarity)
//				LMSAPI.LMSInitialize(null);
//				LMSAPI.LMSSetValue("LastPageVisited", location.href);
//				LMSAPI.LMSFinish();
//		
//	@comm 
//				This function should not be called directly.  It is meant to be called through an
//				initialized instance of the LMSImplementation object that is returned by
//				FindLMSAPI().
//	@end
//
////////////////////////////////////////////////////////////////////////////////////////////////////
function LMSFinish()
{
	this.oLastError = null;
	
	// We don't actually commit the changes until LRNTerminate is called.
	return;
}

////////////////////////////////////////////////////////////////////////////////////////////////////
//	@doc External
//
//	@jsfunc LMSGetLastError	| LRN implementation of LMSGetLastError, which returns the ID of the
//								last error to occur.  A return value of zero indicates that the
//								last operation was successful.  Multiple consecutive calls to this
//								method will return the same value.
//
//	@rdesc  none
//
//	@ex Usage: |
//				// Set the last visited page to our current location and check for errors.
//				LMSAPI.LMSSetValue("LastPageVisited", location.href);
//				lErrorNumber = LMSAPI.LMSGetLastError();
//				if(0 != lErrorNumber)
//				{
//					alert(LMSAPI.LMSGetErrorString(lErrorNumber));
//				}
//		
//	@comm 
//				This function should not be called directly.  It is meant to be called through an
//				initialized instance of the LMSImplementation object that is returned by
//				FindLMSAPI().
//	@end
//
////////////////////////////////////////////////////////////////////////////////////////////////////
function LMSGetLastError()
{
	if(null == this.oLastError)
	{
		return 0;
	}
	return this.oLastError.number;
}

////////////////////////////////////////////////////////////////////////////////////////////////////
//	@doc External
//
//	@jsfunc LMSGetErrorString	| LRN implementation of LMSGetErrorString, which returns the string
//									associated with a specific error ID.
//
//	@parm	Integer	| iErrorNumber	| ID of the error for which to return a description.
//
//	@rdesc  none
//
//	@ex Usage: |
//				// Set the last visited page to our current location and check for errors.
//				LMSAPI.LMSSetValue("LastPageVisited", location.href);
//				lErrorNumber = LMSAPI.LMSGetLastError();
//				if(0 != lErrorNumber)
//				{
//					alert(LMSAPI.LMSGetErrorString(lErrorNumber));
//				}
//		
//	@comm 
//				This function should not be called directly.  It is meant to be called through an
//				initialized instance of the LMSImplementation object that is returned by
//				FindLMSAPI().
//	@end
//
////////////////////////////////////////////////////////////////////////////////////////////////////
function LMSGetErrorString
(
iErrorNumber
)
{
	if(0 == iErrorNumber)
	{
		return L_Success_Message;
	}
	else
	{
		var strErrorMessage = ErrorStringFromID(iErrorNumber);
		if(null == strErrorMessage)
		{
			return "";
		}
		return strErrorMessage;
	}
}

////////////////////////////////////////////////////////////////////////////////////////////////////
//	@doc External
//
//	@jsfunc LMSGetDiagnostic	| LRN implementation of LMSGetErrorString, which returns additional
//									information regarding a specific error.  The LRN implementation
//									will only return additional information about the last error to
//									occur.
//
//	@parm	Integer	| iErrorNumber	| ID of the error for which to return a description.  Any value
//										other than null will cause an empty string to be returned.
//
//	@rdesc  none
//
//	@ex Usage: |
//				// Set the last visited page to our current location and check for errors.
//				LMSAPI.LMSSetValue("LastPageVisited", location.href);
//				lErrorNumber = LMSAPI.LMSGetLastError();
//				if(0 != lErrorNumber)
//				{
//					alert(LMSAPI.LMSGetErrorString(lErrorNumber));
//					alert(LMSAPI.LMSGetDiagnostic(null));
//				}
//		
//	@comm 
//				This function should not be called directly.  It is meant to be called through an
//				initialized instance of the LMSImplementation object that is returned by
//				FindLMSAPI().
//	@end
//
////////////////////////////////////////////////////////////////////////////////////////////////////
function LMSGetDiagnostic
(
iErrorNumber
)
{
	try
	{
		if(null != iErrorNumber)
		{
			return "";
		}

		if(null == this.oLastError || 0 == this.oLastError.number)
		{
			return L_Success_Message;
		}
		
		switch(this.oLastError.strDetailsType)
		{
		case gc_strParseError:
			return this.oLastError.oErrorDetails.reason;
		case gc_strJScriptError:
			return this.oLastError.oErrorDetails.description;
		case gc_strMultiStatusError:
			return this.oLastError.oErrorDetails.xml;
		case gc_strString:
			return this.oLastError.oErrorDetails;
		default:
			return "";
		}
	}
	catch(e){}
	return "";
}

// This variable can be used to see if the whole script block has been parsed.
var g_bLMSAPIIsLoaded = true;