"""Build a standalone rein-aharness runtime for the fixed bwrap mount path.

Only package installation occurs here. No credentials or model calls are used.
Run with the sand-boxer Python environment; uv must be available on PATH.
"""

from __future__ import annotations

import argparse
import json
import subprocess
from pathlib import Path

from sandboxer.extensions.runtime import RUNTIME_MOUNT, runtime_digest


def checked(command: list[str]) -> str:
    result = subprocess.run(command, capture_output=True, text=True, timeout=300)
    if result.returncode:
        raise RuntimeError(f"runtime build command failed: {Path(command[0]).name}")
    return result.stdout.strip()


def build(output: Path, rein_source: Path, llm_source: Path) -> dict:
    revisions = {}
    for name, source in (("rein-aharness", rein_source), ("llm-connect", llm_source)):
        if checked(["git", "-C", str(source), "status", "--porcelain"]):
            raise ValueError(f"{name} source must be committed before building")
        revisions[name] = checked(["git", "-C", str(source), "rev-parse", "HEAD"])
    output.mkdir(parents=True, exist_ok=False)
    checked(["/usr/bin/python3", "-m", "venv", "--copies", "--without-pip", str(output)])
    checked(["uv", "pip", "install", "--python", str(output / "bin/python3"),
             str(rein_source), str(llm_source)])
    # Console entrypoints must reference the in-sandbox mount, not the build host.
    for path in (output / "bin").iterdir():
        if not path.is_file() or path.is_symlink():
            continue
        with path.open("rb") as stream:
            first_line = stream.readline(4096)
        if first_line.startswith(f"#!{output}/bin/python".encode()):
            body = path.read_bytes().partition(b"\n")[2]
            path.write_bytes(f"#!{RUNTIME_MOUNT}/bin/python3\n".encode() + body)
    metadata = json.loads(checked([
        str(output / "bin/python3"), "-c",
        "import importlib.metadata,json,platform; "
        "print(json.dumps({'python':platform.python_version(),'packages':"
        "{d.metadata['Name']:d.version for d in importlib.metadata.distributions()}}))",
    ]))
    metadata["source_revisions"] = revisions
    (output / "build-info.json").write_text(json.dumps(metadata, indent=2) + "\n")
    return {"runtime": {"path": str(output), "sha256": runtime_digest(output)},
            "build": metadata}


def main() -> int:
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("--output", type=Path, required=True)
    parser.add_argument("--rein-source", type=Path, required=True)
    parser.add_argument("--llm-source", type=Path, required=True)
    args = parser.parse_args()
    result = build(args.output.resolve(), args.rein_source.resolve(), args.llm_source.resolve())
    print(json.dumps(result, indent=2))
    return 0


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