"""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 hashlib
import json
import os
import re
import subprocess
from pathlib import Path

from sandboxer.extensions.runtime import RUNTIME_MOUNT, runtime_digest


def checked(command: list[str], *, env: dict[str, str] | None = None) -> str:
    result = subprocess.run(command, capture_output=True, text=True, timeout=300, env=env)
    if result.returncode:
        raise RuntimeError(f"runtime build command failed: {Path(command[0]).name}")
    return result.stdout.strip()


def install_claude(output: Path, source: Path, sha256: str, version: str) -> dict:
    """Copy only an explicitly pinned native executable, never an interactive HOME."""
    if not re.fullmatch(r"[0-9a-f]{64}", sha256) or not version.strip():
        raise ValueError("Claude requires an exact SHA-256 and expected version")
    if source.is_symlink() or not source.is_file():
        raise ValueError("Claude source must be a regular file, not a symlink")
    content = source.read_bytes()
    if hashlib.sha256(content).hexdigest() != sha256:
        raise ValueError("Claude executable digest mismatch")
    if not content.startswith(b"\x7fELF"):
        raise ValueError("Claude executable must be native ELF, not a host wrapper")
    destination = output / "bin/claude"
    with destination.open("xb") as stream:
        stream.write(content)
    destination.chmod(0o755)
    return {"path": f"{RUNTIME_MOUNT}/bin/claude", "sha256": sha256,
            "expected_version": version, "source": str(source)}


def build(output: Path, rein_source: Path, llm_source: Path,
          claude_binary: Path | None = None, claude_sha256: str | None = None,
          claude_version: str | None = None, *, owner_runtime: bool = False) -> dict:
    supplied = (claude_binary, claude_sha256, claude_version)
    if any(x is not None for x in supplied) and not all(x is not None for x in supplied):
        raise ValueError("Claude binary, SHA-256 and expected version must be supplied together")
    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"])
    lock_report = None
    if owner_runtime:
        lock_report = json.loads(checked([
            "/usr/bin/python3", str(rein_source / "scripts/verify_runtime_lock.py")
        ]))
        if not lock_report.get("ok"):
            raise ValueError("owner runtime requires the verified sibling lock")
        if next(x["commit"] for x in lock_report["dependencies"]
                if x["distribution"] == "llm-connect") != revisions["llm-connect"]:
            raise ValueError("owner runtime llm source does not match sibling lock")
        revisions.update({x["distribution"]: x["commit"] for x in lock_report["dependencies"]})
    output.mkdir(parents=True, exist_ok=False)
    checked(["/usr/bin/python3", "-m", "venv", "--copies", "--without-pip", str(output)])
    if owner_runtime:
        checked(["uv", "sync", "--project", str(rein_source), "--frozen", "--no-editable",
                 "--no-dev", "--extra", "glas", "--extra", "llm", "--python", "/usr/bin/python3"],
                env={**os.environ, "UV_PROJECT_ENVIRONMENT": str(output)})
    else:
        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()}}))",
    ]))
    if claude_binary is not None:
        metadata["claude"] = install_claude(output, claude_binary, claude_sha256, claude_version)
    metadata["source_revisions"] = revisions
    if owner_runtime:
        metadata["owner_runtime"] = True
        metadata["runtime_contract"] = lock_report
        metadata["uv_lock_sha256"] = hashlib.sha256(
            (rein_source / "uv.lock").read_bytes()
        ).hexdigest()
    (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)
    parser.add_argument("--claude-binary", type=Path)
    parser.add_argument("--claude-sha256")
    parser.add_argument("--claude-version")
    parser.add_argument("--owner-runtime", action="store_true",
                        help="Include the pinned owner packages from rein uv.lock")
    args = parser.parse_args()
    result = build(args.output.resolve(), args.rein_source.resolve(), args.llm_source.resolve(),
                   args.claude_binary, args.claude_sha256, args.claude_version,
                   owner_runtime=args.owner_runtime)
    print(json.dumps(result, indent=2))
    return 0


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