# Example Follow line program
# Python port of C follow line program by Jan-Klaas Kollhof
# Same copy right as the original program

global LightThreshold, Speed

# A simple spiral search
def findLineSpiral():
   ratio=30;
   while(SENSOR_3 >= LightThreshold):
        OnFwdSync(OUT_BC, Speed, ratio);
        Wait(200);
        if ratio > 20:
            ratio -= 1
           
# A simple left right search for the line
def findLine():
    tvar = lineFound = turnLeft = 0

    if Random(2) > 0:
        turnLeft = 1

    longTimeout = 10
    longStartTime = 0
    
    while not lineFound:
        longStartTime = CurrentTick()        
        tvar = 100          
        if turnLeft:
            tvar *= -1
        OnFwdSync(OUT_BC, Speed, tvar)

        #turn until we find a line or time is up
        while (CurrentTick() - longStartTime < longTimeout) or lineFound:
            if SENSOR_3 < LightThreshold:
                lineFound = 1
                            
        if not lineFound:
            turnLeft = not turnLeft            
            if longTimeout > 1000:
                # lets give up and search with a spiral
                findLineSpiral()
                lineFound = 1
            else:
                # lets give the bot a bit more time to turn
                longTimeout += 100


LightThreshold = Speed = 50
SetSensorLight(IN_3)
findLineSpiral()
OnFwd(OUT_BC, Speed)

while(true):
   if(SENSOR_3 > LightThreshold):
      findLine()
      OnFwd(OUT_BC, Speed)