import argparse
import pathlib
import os
import sys
import time

import patch
from tmux import TmuxSession


def parse_args():
    """ Parse command-line arguments """
    parser = argparse.ArgumentParser(prog="patch2vimedit")
    parser.add_argument(
        "-C",
        "--directory",
        metavar="DIR",
        help="Change to DIR before performing any operations.",
    )
    parser.add_argument(
        "patch",
        help=(
            "The patch file to be applied. If '-' is supplied, reads from STDIN "
            "instead."
        ),
    )
    return parser.parse_args()


def get_patch(patch_path):
    if patch_path == "-":
        return patch.PatchSet(sys.stdin)
    with open(patch_path, "rb") as stream:
        return patch.PatchSet(stream)


def main():
    """ Entry-point function """
    args = parse_args()

    if args.directory:
        chdir_to = pathlib.Path(args.directory)
        if not chdir_to.is_dir():
            print(
                (
                    "The required working directory '{}' does not exist, or is not a "
                    "directory."
                ).format(str(chdir_to)),
                file=sys.stderr,
            )
            sys.exit(1)
        os.chdir(chdir_to)

    patchset = get_patch(args.patch)

    tmux_session = TmuxSession.create_detached()
    tmux_fg_process = tmux_session.process_attach(read_only=True)

    time.sleep(0.2)
    tmux_session.send_keys('echo "Hello, world!"', "enter")
    time.sleep(1)
    tmux_session.send_keys('echo "Bye, world!"', "enter")
    time.sleep(1)
    tmux_session.send_keys("exit", "enter")

    tmux_fg_process.join(1)
    if tmux_fg_process.exitcode is None:  # Did not terminate -- kill it
        tmux_fg_process.kill()
    if tmux_session.session_exists():
        tmux_session.session.kill_session()


if __name__ == "__main__":
    main()