#! /usr/bin/python

import os
import sys
import stat
import subprocess

from bzrlib.patiencediff import unified_diff, PatienceSequenceMatcher
try:
    from bzrlib.plugins.bzrtools.colordiff import DiffWriter
except ImportError:
    _have_colordiff = False
else:
    _have_colordiff = True

##

def main():
    path = sys.argv[1]
    file1 = open(sys.argv[2], 'rb')
    file2 = open(sys.argv[5], 'rb')

    if use_color():
        writer = DiffWriter(sys.stdout, check_style=True)
    else:
        writer = sys.stdout

    for line in unified_diff(
            file1.readlines(), file2.readlines(),
            path, path, sequencematcher=PatienceSequenceMatcher):
        writer.write(line)

##

def use_color():
    if not _have_colordiff:
        return False

    for c in ['color.diff', 'color.ui']:
        p = subprocess.Popen(
                ['git', 'config', '--get', c], stdout=subprocess.PIPE)
        if p.wait() == 0:
            when = p.stdout.readline().strip()
            break
    else:
        return False

    if when == 'always':
        return True
    elif when in ['false', 'never']:
        return False
    elif when in ['true', 'auto']:
        stdout = sys.stdout.fileno()
        return (os.isatty(stdout) or
                stat.S_ISFIFO(os.fstat(sys.stdout.fileno()).st_mode))
    else:
        return False

##

if __name__ == '__main__':
    sys.exit(main())