#!/usr/bin/python3

import re
import sys

node_version_file = sys.argv[1]
out_file = sys.argv[2]
NMV = None
if len(sys.argv) > 3:
    NMV = sys.argv[3]

with open(node_version_file, 'r', encoding='utf-8') as in_file:
    with open(out_file, 'w', encoding='utf-8') as out_file:
        changed = False
        contents = in_file.read()
        new_contents = re.sub(r'^#define NODE_MODULE_VERSION [0-9]+$',
                              '#define NODE_MODULE_VERSION ' + NMV,
                              contents, flags=re.MULTILINE)

        changed = contents != new_contents

        if not changed and NMV is not None:
            raise Exception('NMV must differ from current value in Node.js')

        out_file.writelines(new_contents)