#!/usr/bin/env python3
"""Generate Fold's C++ embedded skill header from the canonical SKILL.md."""

from __future__ import annotations

import argparse
from pathlib import Path

DELIMITER = "FOLDSKILL"


def render(skill: str) -> str:
    terminator = f'){DELIMITER}"'
    if terminator in skill:
        raise ValueError(
            f"skill contains reserved raw-string terminator {terminator!r}"
        )
    return (
        "#pragma once\n\n"
        "namespace fold::cli {\n\n"
        f'inline constexpr const char* kEmbeddedFoldSkill = R"{DELIMITER}('
        f"{skill}"
        f'){DELIMITER}";\n\n'
        "} // namespace fold::cli\n"
    )


def main() -> int:
    parser = argparse.ArgumentParser()
    parser.add_argument("--input", type=Path, required=True)
    parser.add_argument("--output", type=Path, required=True)
    parser.add_argument("--check", action="store_true")
    args = parser.parse_args()

    generated = render(args.input.read_text(encoding="utf-8"))
    if args.check:
        if (
            not args.output.exists()
            or args.output.read_text(encoding="utf-8") != generated
        ):
            print(f"generated embedded skill is stale: {args.output}")
            return 1
        return 0

    args.output.parent.mkdir(parents=True, exist_ok=True)
    args.output.write_text(generated, encoding="utf-8")
    return 0


if __name__ == "__main__":
    raise SystemExit(main())