#!/usr/bin/env python

import sys
import re
import os

from subprocess import Popen, PIPE
from argparse import ArgumentParser


GENERATED_INCLUDE_RE = re.compile(
    r'^\s*#\s*include\s*"([/a-z_0-9.]+\.generated\.h)"(\s+//.*)?$')


def main(argv):
    argparser = ArgumentParser()
    argparser.add_argument('--generated-includes-dir', action='append',
                           help='Directory where generated includes are located.')
    argparser.add_argument('--file', type=open, help='File to check.')
    argparser.add_argument('iwyu_args', nargs='*',
                           help='IWYU arguments, must go after --.')
    args = argparser.parse_args(argv)

    with args.file:
        iwyu = Popen(['include-what-you-use', '-xc'] + args.iwyu_args + ['/dev/stdin'],
                     stdin=PIPE, stdout=PIPE, stderr=PIPE)

        for line in args.file:
            match = GENERATED_INCLUDE_RE.match(line)
            if match:
                for d in args.generated_includes_dir:
                    try:
                        f = open(os.path.join(d, match.group(1)))
                    except IOError:
                        continue
                    else:
                        with f:
                            for generated_line in f:
                                iwyu.stdin.write(generated_line)
                            break
                else:
                    raise IOError('Failed to find {0}'.format(match.group(1)))
            else:
                iwyu.stdin.write(line)

    iwyu.stdin.close()

    out = iwyu.stdout.read()
    err = iwyu.stderr.read()

    ret = iwyu.wait()

    if ret != 2:
        print('IWYU failed with exit code {0}:'.format(ret))
        print('{0} stdout {0}'.format('=' * ((80 - len(' stdout ')) // 2)))
        print(out)
        print('{0} stderr {0}'.format('=' * ((80 - len(' stderr ')) // 2)))
        print(err)
        return 1
    return 0


if __name__ == '__main__':
    raise SystemExit(main(sys.argv[1:]))