"""One-time Windows SDK setup and Windows target linting from Unix hosts."""

import argparse
import os
from pathlib import Path
import shutil
import subprocess
import sys
import tempfile


SDK_ROOT = Path.home() / ".local/share/herdr/windows-cross"
LIBC_ENV = "LIBGHOSTTY_VT_WINDOWS_LIBC"
TARGET = "x86_64-pc-windows-msvc"


def libc_contents(root: Path) -> str:
    paths = {
        "include_dir": root / "sdk/include/ucrt",
        "sys_include_dir": root / "crt/include",
        "crt_dir": root / "sdk/lib/ucrt/x86_64",
        "msvc_lib_dir": root / "crt/lib/x86_64",
        "kernel32_lib_dir": root / "sdk/lib/um/x86_64",
    }
    required = {
        "include_dir": "stdlib.h",
        "sys_include_dir": "vcruntime.h",
        "crt_dir": "ucrt.lib",
        "msvc_lib_dir": "vcruntime.lib",
        "kernel32_lib_dir": "kernel32.lib",
    }
    for key, filename in required.items():
        if not (paths[key] / filename).is_file():
            raise ValueError(f"Windows SDK is incomplete: missing {paths[key] / filename}")
    return "".join(f"{key}={value}\n" for key, value in paths.items()) + "gcc_dir=\n"


def libc_path() -> Path:
    override = os.environ.get(LIBC_ENV)
    path = Path(override).expanduser() if override else SDK_ROOT / "libc.txt"
    if not path.is_file():
        raise ValueError(
            f"Windows cross-check needs SDK configuration at {path}.\n"
            "Run `just setup-windows-cross` once, or set "
            f"{LIBC_ENV} to an existing Zig libc configuration."
        )
    return path.resolve()


def setup(accept_license: bool) -> None:
    if not shutil.which("xwin"):
        raise ValueError("Install xwin first: cargo install xwin --locked")
    if not shutil.which(os.environ.get("ZIG", "zig")):
        raise ValueError("Install Zig 0.16.0 first, or set ZIG to its executable.")
    SDK_ROOT.mkdir(parents=True, exist_ok=True)
    # SDK downloads can be large; /tmp is often RAM-backed on Linux.
    temp_parent = "/var/tmp" if sys.platform.startswith("linux") else None
    with tempfile.TemporaryDirectory(prefix="herdr-windows-sdk-", dir=temp_parent) as cache:
        command = ["xwin", "--arch", "x86_64", "--cache-dir", cache]
        if accept_license:
            command.append("--accept-license")
        subprocess.run(command + ["splat", "--copy", "--output", str(SDK_ROOT)], check=True)
    config = SDK_ROOT / "libc.txt"
    config.write_text(libc_contents(SDK_ROOT))
    subprocess.run(
        [os.environ.get("ZIG", "zig"), "libc", "-target", "x86_64-windows-msvc", str(config)],
        check=True,
    )
    print(f"Windows SDK configured at {config}. Run `just windows-lint` or `just check`.")


def lint() -> None:
    env = {**os.environ, LIBC_ENV: str(libc_path()), "LIBGHOSTTY_VT_SIMD": "false"}
    subprocess.run(["rustup", "target", "add", TARGET], check=True)
    subprocess.run(
        ["cargo", "clippy", "--bin", "herdr", "--locked", "--target", TARGET, "--", "-D", "warnings"],
        env=env,
        check=True,
    )


def main() -> int:
    parser = argparse.ArgumentParser(description=__doc__)
    commands = parser.add_subparsers(dest="command", required=True)
    setup_parser = commands.add_parser("setup", help="Download Microsoft's SDK using xwin")
    setup_parser.add_argument(
        "--accept-license", action="store_true",
        help="Explicitly accept Microsoft's SDK license instead of xwin's interactive prompt",
    )
    commands.add_parser("lint", help="Run Windows clippy with the configured SDK")
    args = parser.parse_args()
    try:
        if args.command == "setup":
            setup(args.accept_license)
        else:
            lint()
    except (ValueError, OSError) as error:
        print(error, file=sys.stderr)
        return 1
    except subprocess.CalledProcessError as error:
        return error.returncode
    return 0


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