def generate_gcode(cad_file):
    """
    Generates a simple G-Code and saves it to a file.
    Returns the file path of the generated G-Code file.
    """
    try:
        # Ensure the output directory exists
        output_dir = "/mnt/data/"
        os.makedirs(output_dir, exist_ok=True)

        # Define the G-Code content
        gcode_content = """
        G21 ; Set units to millimeters
        G17 ; Select XY plane
        G90 ; Absolute positioning
        G1 F1500 ; Set feed rate

        G0 Z5 ; Raise Z-axis to safe height
        G0 X0 Y0 ; Move to start position
        G1 Z-1 F300 ; Lower Z-axis to cutting depth

        G1 X10 Y0 ; Cut to the first corner
        G1 X10 Y10 ; Cut to the second corner
        G1 X0 Y10 ; Cut to the third corner
        G1 X0 Y0 ; Return to the start position

        G0 Z5 ; Raise Z-axis to safe height
        M30 ; End program
        """

        # Save the G-Code to a file
        gcode_file = os.path.join(output_dir, "generated_gcode.nc")
        with open(gcode_file, "w") as f:
            f.write(gcode_content)

        return gcode_file
    except Exception as e:
        return f"Error in G-Code generation: {e}"