#!/usr/bin/env python3
"""
Review Gate — Poka-yoke for unreviewed merges.
Fails if the current PR has fewer than 1 approving review.

Usage in Gitea workflow:
  - name: Review Approval Gate
    run: python scripts/review_gate.py
    env:
      GITEA_TOKEN: ${{ secrets.GITEA_TOKEN }}
"""

import os
import sys
import json
import subprocess
from urllib import request, error

GITEA_TOKEN = os.environ.get("GITEA_TOKEN", "")
GITEA_URL = os.environ.get("GITEA_URL", "https://forge.alexanderwhitestone.com")
REPO = os.environ.get("GITEA_REPO", "")
PR_NUMBER = os.environ.get("PR_NUMBER", "")


def api_call(method, path):
    url = f"{GITEA_URL}/api/v1{path}"
    headers = {"Authorization": f"token {GITEA_TOKEN}"}
    req = request.Request(url, method=method, headers=headers)
    try:
        with request.urlopen(req, timeout=30) as resp:
            return json.loads(resp.read().decode())
    except error.HTTPError as e:
        return {"error": e.read().decode(), "status": e.code}


def main():
    if not GITEA_TOKEN:
        print("ERROR: GITEA_TOKEN not set")
        sys.exit(1)

    if not REPO:
        print("ERROR: GITEA_REPO not set")
        sys.exit(1)

    pr_number = PR_NUMBER
    if not pr_number:
        # Try to infer from Gitea Actions environment
        pr_number = os.environ.get("GITEA_PULL_REQUEST_INDEX", "")

    if not pr_number:
        print("ERROR: Could not determine PR number")
        sys.exit(1)

    reviews = api_call("GET", f"/repos/{REPO}/pulls/{pr_number}/reviews")
    if isinstance(reviews, dict) and "error" in reviews:
        print(f"ERROR fetching reviews: {reviews}")
        sys.exit(1)

    approvals = [r for r in reviews if r.get("state") == "APPROVED"]
    if len(approvals) >= 1:
        print(f"OK: PR #{pr_number} has {len(approvals)} approving review(s).")
        sys.exit(0)
    else:
        print(f"BLOCKED: PR #{pr_number} has no approving reviews.")
        print("Merges are not permitted without at least one approval.")
        sys.exit(1)


if __name__ == "__main__":
    main()