Timer.vbs - limit a user account's total usage time.

Option Explicit

Dim objFSO, objShell, objTextFile
Dim strText
Dim prevDate
Dim prevTime
Dim timeLeft
Const strDirectory = "C:"
Const strFile = "\timelog.txt"
Const checkTimeLeftVbs = "C:\checktimeleft.vbs"
Const ForAppending = 8
Const ForReading = 1
Const ForWriting = 2
Dim usageTime       'in minutes

Set objFSO = CreateObject("Scripting.FileSystemObject")
Set objShell = WScript.CreateObject ("WScript.Shell")

Function openLogFile(N)
Set objTextFile = objFSO.OpenTextFile(strDirectory & strFile, N, True)
End Function

Function checkPrevInst()
Call openLogFile(ForReading)
prevDate = objTextFile.ReadLine
prevTime = CInt(objTextFile.ReadLine)
objTextFile.Close
If prevDate <> "" Then
    If DateDiff("d", prevDate, Date) >= 1 Then
        Call logStartTime()
    Else
        'Continue monitoring
        Call logTime()
    End If
Else
    'Log file compromised...
    Call logStartTime()
End If
End Function

Function logStartTime()
Call openLogFile(ForWriting)
objTextFile.WriteLine(Date)
objTextFile.WriteLine("0")
objTextFile.Close
prevDate = Date
prevTime = 0
Call logTime()
End Function

Function checkforChanges()
Dim tempPrevDate
Dim tempPrevTime
Call openLogFile(ForReading)
tempPrevDate = objTextFile.ReadLine
tempPrevTime = CInt(objTextFile.ReadLine)
objTextFile.Close
If tempPrevDate = PrevDate Then
    If tempPrevTime <> prevTime Then
        prevTime = tempPrevTime
        timeLeft = usageTime - prevTime
        objShell.Run checkTimeLeftVbs
    End If
End If
End Function

Function logTime()
timeLeft = usageTime - prevTime
objShell.Run checkTimeLeftVbs
Do While timeLeft > 0
    Call openLogFile(ForWriting)
    objTextFile.WriteLine(prevDate)
    objTextFile.WriteLine(prevTime)
        objTextFile.WriteLine(timeLeft)
    objTextFile.Close
    WScript.Sleep 60000
    Call checkforChanges()
    prevTime = prevTime + 1
    timeLeft = usageTime - prevTime
    If timeLeft <= 5 Or timeLeft = 10 Or timeLeft = 15 Then
        objShell.Run checkTimeLeftVbs
    End If
Loop
'Time exceeded
Call timeExceeded()
End Function

Function timeExceeded()
Do While timeLeft <= 0
Call endSession()
WScript.Sleep 10000
Loop
End Function

Function endSession()
objShell.Run "%windir%\SYSTEM32\rundll32.exe user32.dll,LockWorkStation", 0, False
End Function

Function checkDay()
If Weekday(Date, 1) <> "1" And Weekday(Date, 1) <> "6" And Weekday(Date, 1) <> "7" Then
    usageTime = 60      'weekday time, in minutes
Else
    usageTime = 90      'weekend time, in minutes
End If
Call checkPrevInst()
End Function

'Main program
Call checkDay()