def post_process_gcode(input_file, output_file):
    add_custom_command = True
    add_M5_before_M9 = True

    # Open the input file in read mode
    with open(input_file, 'r') as f:
        lines = f.readlines()

    # Open the output file in write mode
    with open(output_file, 'w') as f:
        for line in lines:
            # Check if the line is a rapid move command (G0) with Z10
            if add_M5_before_M9 == False:
                f.write(line)
            elif line.startswith('G0') and 'Z10' in line:
                # Change rapid move command to linear move (G1) with Z10
                modified_line = line.replace('G0', 'G1')
                if(add_custom_command==True):
                    for newline in lines:
                        if newline.startswith('G1'):
                            spindle_speed = "S" + newline.split('S', 1)[-1].strip()  # Extracting all characters after "S" including "S"
                            print(spindle_speed)
                            break
                    #modified_line+=spindle_speed
                    modified_line = "M3" + "\n" + modified_line.strip() + spindle_speed + "\n"
                    print(modified_line)
                f.write(modified_line)
                add_custom_command = False

            elif line.startswith('G1') and 'S' in line:
                no_spindle_g1 = newline.split('S', 1)[0].strip() + "\n" # Extracting all characters after "S" including "S"
                f.write(no_spindle_g1)
            # Check if the line is a spindle stop command (M5) or spindle start command (M3)
            elif line.startswith('M5') or line.startswith('M3'):
                # Ignore these commands until M9
                pass
            # Check if the line is the spindle stop command (M9)
            elif line.startswith('M9'):
                # Add M5 before M9
                if add_M5_before_M9:
                    f.write('M5\n')
                    add_M5_before_M9 = False
                # Write the line as it is
                f.write(line)
            else:
                # Write the line as it is
                f.write(line)

# Example usage
if __name__ == "__main__":
    input_file = 'Cutting_samples_2S_100p.gc'
    output_file = 'PP_Cutting_samples_2S_100p.gc'
    post_process_gcode(input_file, output_file)
    print("G-code post-processing complete!")