#!/usr/bin/env python3
"""Run Claude on an exact PR head and publish an independent Gitea approval."""
from __future__ import annotations
import argparse
import json
import os
from pathlib import Path
import re
import subprocess
import sys
import urllib.error
import urllib.request

API = "https://code.cubecraftlabs.com/api/v1"
REPO = "/repos/Maniacs_Mansion/NestQuest"
CREDENTIALS = Path("/home/overseer/.llms/credentials.env")
CLAUDE = "/home/overseer/.local/bin/claude"
SHA = re.compile(r"^[0-9a-f]{40}$")

def git(worktree: Path, *args: str) -> str:
    return subprocess.check_output(["git", "-C", str(worktree), *args], text=True).strip()

def token() -> str:
    for line in CREDENTIALS.read_text().splitlines():
        if line.startswith("GITEA_REVIEW_AGENT_TOKEN="):
            return line.split("=", 1)[1].strip().strip("\"'")
    raise RuntimeError("review_agent credential is unavailable")

def api(path: str, credential: str, payload: dict | None = None) -> dict:
    body = None if payload is None else json.dumps(payload).encode()
    headers = {"Authorization": "token " + credential, "Accept": "application/json"}
    if body is not None:
        headers["Content-Type"] = "application/json"
    call = urllib.request.Request(API + path, data=body, headers=headers)
    try:
        with urllib.request.urlopen(call, timeout=20) as response:
            return json.loads(response.read())
    except urllib.error.HTTPError as error:
        raise RuntimeError(f"Gitea returned HTTP {error.code}") from None

def verdict(output: str, head: str) -> str:
    reviewed = re.findall(r"(?m)^REVIEWED_HEAD:\s*([0-9a-f]{40})\s*$", output)
    decisions = re.findall(r"(?m)^REVIEW_VERDICT:\s*(APPROVED|CHANGES_REQUIRED)\s*$", output)
    if reviewed != [head] or len(decisions) != 1:
        raise RuntimeError("Claude did not return one verdict for the exact reviewed head")
    return decisions[0]

def main() -> int:
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("worktree", type=Path)
    parser.add_argument("base_ref")
    parser.add_argument("head_ref")
    parser.add_argument("prompt_file", type=Path)
    parser.add_argument("pr", type=int)
    parser.add_argument("output_file", type=Path)
    args = parser.parse_args()
    if not args.worktree.is_dir() or not args.prompt_file.is_file() or args.pr < 1:
        parser.error("valid worktree, prompt file, and PR number required")
    if not args.output_file.resolve().is_relative_to(Path("/tmp/opencode").resolve()):
        parser.error("review output must be under /tmp/opencode")
    base = git(args.worktree, "rev-parse", "--verify", args.base_ref + "^{commit}")
    head = git(args.worktree, "rev-parse", "--verify", args.head_ref + "^{commit}")
    if not SHA.fullmatch(head) or git(args.worktree, "rev-parse", "HEAD") != head:
        raise RuntimeError("worktree HEAD differs from requested head")
    subprocess.run(["git", "-C", str(args.worktree), "merge-base", "--is-ancestor", base, head], check=True)
    prompt = args.prompt_file.read_text() + (
        f"\n\nReview only the delta from base {base} to exact head {head}. "
        "Verify current HEAD before issuing a verdict. Read only; do not modify files. "
        "End with two plain lines: REVIEWED_HEAD: <full 40-character SHA> "
        "and REVIEW_VERDICT: APPROVED or REVIEW_VERDICT: CHANGES_REQUIRED."
    )
    result = subprocess.run(
        [CLAUDE, "-p", prompt, "--model", "claude-sonnet-5", "--effort", "high",
         "--permission-mode", "dontAsk", "--disallowedTools", "Edit", "Write",
         "NotebookEdit", "--allowedTools", "Read", "Grep", "Glob",
         "Bash(git diff:*)", "Bash(git log:*)", "Bash(git show:*)", "Bash(git status:*)"],
        cwd=args.worktree, text=True, capture_output=True, timeout=1200,
    )
    args.output_file.parent.mkdir(parents=True, exist_ok=True)
    args.output_file.write_text(result.stdout)
    os.chmod(args.output_file, 0o600)
    if result.returncode:
        raise RuntimeError(f"Claude exited {result.returncode}: {result.stderr[-300:]}")
    decision = verdict(result.stdout, head)
    if git(args.worktree, "rev-parse", "HEAD") != head:
        raise RuntimeError("worktree HEAD changed during review")
    print(result.stdout, end="")
    if decision != "APPROVED":
        return 2
    credential = token()
    if api("/user", credential).get("login") != "review_agent":
        raise RuntimeError("review credential belongs to wrong account")
    pr = api(f"{REPO}/pulls/{args.pr}", credential)
    if pr.get("state") != "open" or (pr.get("head") or {}).get("sha") != head:
        raise RuntimeError("PR head changed before review publication")
    published = api(
        f"{REPO}/pulls/{args.pr}/reviews", credential,
        {"body": "Independent Claude Sonnet 5 review completed for this exact commit.",
         "commit_id": head, "event": "APPROVED"},
    )
    if published.get("state") != "APPROVED" or published.get("commit_id") != head:
        raise RuntimeError("Gitea did not confirm exact-head approval")
    return 0

if __name__ == "__main__":
    try:
        raise SystemExit(main())
    except (OSError, ValueError, RuntimeError, subprocess.CalledProcessError,
            subprocess.TimeoutExpired) as error:
        print(f"review gate failed: {error}", file=sys.stderr)
        raise SystemExit(1)