#!/usr/bin/env python3
"""Build the dependency-free ICT login zipapp and its checksum."""

from __future__ import annotations

import argparse
import hashlib
import os
import shutil
import tempfile
from pathlib import Path
from zipapp import create_archive


ROOT = Path(__file__).resolve().parents[1]
DEFAULT_OUTPUT = ROOT / "dist" / "ictlogin.pyz"


def _copy_source(source: Path, target: Path) -> None:
    target.mkdir(parents=True, exist_ok=True)
    shutil.copytree(
        source,
        target / "ictlogin",
        ignore=shutil.ignore_patterns("__pycache__", "*.pyc", "*.pyo", "*.egg-info"),
    )


def _sha256(path: Path) -> str:
    digest = hashlib.sha256()
    with path.open("rb") as handle:
        for chunk in iter(lambda: handle.read(1024 * 1024), b""):
            digest.update(chunk)
    return digest.hexdigest()


def build(output: Path, checksum_path: Path) -> None:
    output.parent.mkdir(parents=True, exist_ok=True)
    staging_root = Path(tempfile.mkdtemp(prefix="ictlogin-build-"))
    temporary_output = output.with_name(output.name + ".tmp")
    try:
        _copy_source(ROOT / "src" / "ictlogin", staging_root)
        create_archive(
            staging_root,
            temporary_output,
            interpreter="/usr/bin/env python3",
            main="ictlogin.cli:main",
            compressed=True,
        )
        os.chmod(temporary_output, 0o755)
        os.replace(temporary_output, output)
        digest = _sha256(output)
        checksum_path.parent.mkdir(parents=True, exist_ok=True)
        checksum_path.write_text(f"{digest}  {output.name}\n", encoding="ascii")
        os.chmod(checksum_path, 0o644)
    finally:
        if temporary_output.exists():
            temporary_output.unlink()
        shutil.rmtree(staging_root, ignore_errors=True)


def main() -> None:
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument(
        "--output", type=Path, default=DEFAULT_OUTPUT, help="output .pyz path"
    )
    parser.add_argument(
        "--checksum", type=Path, help="checksum path (defaults to OUTPUT.sha256)"
    )
    args = parser.parse_args()
    checksum_path = args.checksum or Path(str(args.output) + ".sha256")
    build(args.output.resolve(), checksum_path.resolve())
    print(f"built {args.output}")
    print(f"sha256 {checksum_path}")


if __name__ == "__main__":
    main()