# CNFR33D v 0.5
# A Free CNC GCode converter for 3D CNC Files
# Created By Peter Kenna 2016

targetFileName = raw_input("Please enter file name: ")
targetFile = open(targetFileName+".gcode", 'r')
newFileName = targetFileName+"_CNF33D.gcode"
newFile = open(newFileName, 'w')
currentZ = "Z0.0"
startChanges = False


for line in targetFile:
    fastMove = line.find("G0 ")
    zMove = line.find("Z")

    if startChanges == False: # Don't invert Z Moves until routing starts
        newFile.write(line) # Add the line to the new file as-is
        if line.find("M117"):
            startChanges = True

    if startChanges == True: # Start inverting Z Moves
        if fastMove == -1: # If it's not a fast move
            newFile.write(line) # Add the line to the new file as-is
        if fastMove != -1 and zMove == -1: # If it's a fast move, but not a Z move
            newFile.write("G0 Z0.0\n") # Raise the bit before moving to avoid hitting uncut sections
            newFile.write(newLine) # Move to a new section
            newFile.write("G0 "+currentZ) # Lower the bit back to the correct height
            
        if fastMove != -1 and zMove != -1: # If it's a fast move and a Z move
            newLine = ""
            prevLetter = ""
            newZ = ""
            startZ = False
            
            for letter in line:
                if letter != "Z" and prevLetter != "G": # If it's not something we're changing
                    newLine = newLine+letter # Add it to the new line as-is
                if startZ:
                    newZ = newZ+letter
                if letter == "Z": # If its a Z move
                    newLine = newLine+"Z-" # Invert it
                    startZ = True
                    newZ = "Z-"
                if prevLetter == "G" and letter == "0": # If this is a fast move
                    newLine = newLine+"1" # make it a normal move
                prevLetter = letter
            currentZ = newZ
            newFile.write(newLine)

targetFile.close
newFile.close