#!/usr/bin/env python3
import argparse
import logging
import plistlib
import sys
import typing
from pathlib import Path


def parse_args(argv: list[str]) -> typing.Tuple[argparse.Namespace, list[str]]:
    def parse_env(env: str) -> typing.Tuple[str, str]:
        return env.split("=", maxsplit=1)

    def parse_path(path: str) -> Path:
        return Path(path).expanduser().resolve()

    arger = argparse.ArgumentParser(formatter_class=argparse.ArgumentDefaultsHelpFormatter)
    arger.add_argument(
        "-e", "--env", dest="env", metavar="ENVVAR", type=parse_env, nargs="+", help="Environment variables as K=V list"
    )
    arger.add_argument("-w", "--cwd", dest="cwd", default=Path.cwd(), type=parse_path, help="Working directory")
    arger.add_argument("-l", "--label", required=True, help="Label")
    arger.add_argument(
        "--install",
        action="store_true",
        help="Install the plist to ~/Library/LaunchAgents/",
    )

    if not argv:
        arger.print_help()
        sys.exit(1)

    args, unknown = arger.parse_known_args()
    if unknown and unknown[0] == "--":
        unknown = unknown[1:]

    if not unknown:
        arger.print_help()
        sys.exit(1)

    return args, unknown


def generate_plist(label: str, args: list[str], env: dict, cwd: Path) -> str:
    doc = {
        "Label": label,
        "ProgramArguments": args,
        "EnvironmentVariables": env,
        "WorkingDirectory": str(cwd),
        "RunAtLoad": True,
        "StandardOutPath": str(cwd / f"{label}.stdout.log"),
        "StandardErrorPath": str(cwd / f"{label}.stderr.log"),
    }
    return plistlib.dumps(
        doc,
        fmt=plistlib.FMT_XML,
        sort_keys=True,
    ).decode()


def main():
    args, unknown = parse_args(sys.argv[1:])
    print(args, unknown)
    plist_doc = generate_plist(
        label=args.label,
        args=unknown,
        env=dict(args.env),
        cwd=args.cwd,
    )
    print(plist_doc)

    if args.install:
        install_dir: Path = Path("~/Library/LaunchAgents/").expanduser()
        logging.info(f"Installing plist to {install_dir}")

        install_path = install_dir / f"{args.label}.plist"
        install_path.write_text(plist_doc)

        logging.info(f'Run "launchctl load -w {install_path}" to start the service')


if __name__ == "__main__":
    logging.basicConfig(level=logging.INFO)
    main()