#! /usr/bin/python

import argparse
import re

"""
Simple translation of command arguments in an G-code file.

This script will rewrite all X, Y and Z argument values in a G-code file,
incrementing them by the supplied offset values. It does simple text
substitution and has no notion of, e.g. relative and absolute positioning
modes.
"""

def make_coordinate_translator(coordinate, offset):
    regex = re.compile(r'{0}([\d\.]+)'.format(coordinate))

    def process_match(match):
        return '{0}{1}'.format(coordinate, float(match.group(1)) + offset)

    def process_line(line):
        return regex.sub(process_match, line)

    if offset:
        return process_line
    return lambda x: x


def translate(input_file, output_file, x, y, z):
    translators = [make_coordinate_translator(axis, value) for axis, value in zip(('X', 'Y', 'Z'), (x, y ,z))]

    for line in input_file:
        if not line.startswith(';'):
            for translator in translators:
                line = translator(line)
        output_file.write(line)


def main():
    description = """
    This script will rewrite all X, Y and Z argument values in a G-code file,
    incrementing them by the supplied offset values. It does simple text
    substitution and has no notion of, e.g. relative and absolute positioning
    modes.
    """

    parser = argparse.ArgumentParser(description=description)
    parser.add_argument('-x', type=float, default=0)
    parser.add_argument('-y', type=float, default=0)
    parser.add_argument('-z', type=float, default=0)
    parser.add_argument('input_file', type=file)
    parser.add_argument('output_file', type=argparse.FileType('w'))
    args = parser.parse_args()
    translate(**vars(args))

if __name__ == '__main__':
    main()