import argparse
import os
import tempfile
import shlex
import subprocess


def parse_args():
    parser = argparse.ArgumentParser()
    parser.add_argument("--split-factor", type=int, default=0)
    parser.add_argument("--shard", type=int, default=0)
    parser.add_argument("--fork-mode", type=str, default="SEQUENTIAL")
    parser.add_argument("command", nargs=argparse.REMAINDER)
    return parser.parse_args()


def get_sequential_chunk(tests, modulo, modulo_index):
    chunk_size = len(tests) // modulo
    not_used = len(tests) % modulo
    shift = chunk_size + (modulo_index < not_used)
    start = chunk_size * modulo_index + min(modulo_index, not_used)
    end = start + shift
    return [] if end > len(tests) else tests[start:end]


def get_shuffled_chunk(tests, modulo, modulo_index):
    result_tests = []
    for i, test in enumerate(tests):
        if i % modulo == modulo_index:
            result_tests.append(test)
    return result_tests


def list_tests(binary):
    # can't use NamedTemporaryFile or mkstemp because of child process access issues on Windows
    # https://stackoverflow.com/questions/66744497/python-tempfile-namedtemporaryfile-cant-use-generated-tempfile
    with tempfile.TemporaryDirectory() as tmp_dir:
        list_file = os.path.join(tmp_dir, 'list')
        cmd = [binary, "--list-verbose", "--list-path", list_file]
        subprocess.check_call(cmd)

        with open(list_file) as afile:
            lines = afile.read().strip().split("\n")
            lines = [x.strip() for x in lines]
            return [x for x in lines if x]


def get_shard_tests(args):
    test_names = list_tests(args.command[0])
    test_names = sorted(test_names)

    if args.fork_mode == "MODULO":
        return get_shuffled_chunk(test_names, args.split_factor, args.shard)
    elif args.fork_mode == "SEQUENTIAL":
        return get_sequential_chunk(test_names, args.split_factor, args.shard)
    else:
        raise ValueError("detected unknown partition mode: {}".format(args.fork_mode))


def get_shard_cmd_args(args):
    return ["+{}".format(x) for x in get_shard_tests(args)]


def main():
    args = parse_args()

    if args.split_factor:
        shard_cmd = get_shard_cmd_args(args)
        if shard_cmd:
            cmd = args.command + shard_cmd
        else:
            print("No tests for {} shard".format(args.shard))
            return 0
    else:
        cmd = args.command

    rc = subprocess.call(cmd)
    if rc:
        print("Some tests failed. To reproduce run: {}".format(shlex.join(cmd)))
    return rc


if __name__ == "__main__":
    exit(main())