# Copyright (C) 2015-2016 Andrew Hamilton. All rights reserved.
# Licensed under the Artistic License 2.0.

import optparse
import os.path
import shutil
import subprocess
import sys
import tempfile
import unittest


def _accept_actual(failed):
    for actual_str, golden_path in failed:
        with open(golden_path, "w") as golden_file:
            golden_file.write(actual_str)
        print("Changed golden file: %s" % golden_path)


def _run_meld_gui(failed):
    temp_dir = tempfile.mkdtemp()
    try:
        golden_dir = os.path.join(temp_dir, "golden")
        actual_dir = os.path.join(temp_dir, "actual")
        os.mkdir(golden_dir)
        os.mkdir(actual_dir)
        for actual_str, golden_file in failed:
            name = os.path.basename(golden_file)
            actual_path = os.path.join(actual_dir, name)
            with open(actual_path, "w") as actual:
                actual.write(actual_str)
            os.symlink(os.path.abspath(golden_file),
                       os.path.join(golden_dir, name))
        subprocess.call(["meld", actual_dir, golden_dir])
    finally:
        shutil.rmtree(temp_dir)


_FAILED = set()


def assertGolden(actual, golden_path):
    with open(golden_path, "r") as golden_file:
        expected = golden_file.read()
    if actual != expected:
        _FAILED.add((actual, golden_path))
        raise unittest.TestCase.failureException(
            'Output does not match golden file: %r\nUse "--diff" or'
            ' "--accept" to update the golden file.' % golden_path)


def main():
    parser = optparse.OptionParser()
    parser.add_option("-a", "--accept", action="store_true",
                      dest="should_accept_actual")
    parser.add_option("-d", "--diff", action="store_true", dest="should_diff")
    options, args = parser.parse_args()
    # unitest.main doesn't expect these arguments, so remove them.
    for argument in ["-a", "--accept", "-d", "--diff"]:
        if argument in sys.argv:
            sys.argv.remove(argument)
    try:
        unittest.main()
    finally:
        if len(_FAILED) > 0:
            if options.should_accept_actual:
                _accept_actual(_FAILED)
            if options.should_diff:
                _run_meld_gui(_FAILED)