#!/usr/bin/env python3
"""
CI Auto-Revert — Poka-yoke for broken merges.
Monitors the main branch post-merge and auto-reverts via local git if CI fails.

Usage:
    python ci_auto_revert.py <repo_owner>/<repo_name>
    python ci_auto_revert.py Timmy_Foundation/hermes-agent

Recommended cron: */10 * * * *
"""

import os
import sys
import json
import subprocess
import tempfile
from datetime import datetime, timedelta, timezone
from urllib import request, error

GITEA_TOKEN = os.environ.get("GITEA_TOKEN", "")
GITEA_URL = os.environ.get("GITEA_URL", "https://forge.alexanderwhitestone.com")
REVERT_WINDOW_MINUTES = 10


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 get_recent_commits(owner, repo, since):
    since_iso = since.strftime("%Y-%m-%dT%H:%M:%SZ")
    return api_call("GET", f"/repos/{owner}/{repo}/commits?sha=main&since={since_iso}&limit=20")


def get_commit_status(owner, repo, sha):
    return api_call("GET", f"/repos/{owner}/{repo}/commits/{sha}/status")


def revert_via_git(clone_url, sha, msg, owner, repo):
    with tempfile.TemporaryDirectory() as tmpdir:
        # Clone with token
        auth_url = clone_url.replace("https://", f"https://bezalel:{GITEA_TOKEN}@")
        subprocess.run(["git", "clone", "--depth", "10", auth_url, tmpdir], check=True, capture_output=True)

        # Configure git
        subprocess.run(["git", "-C", tmpdir, "config", "user.email", "bezalel@timmy.foundation"], check=True, capture_output=True)
        subprocess.run(["git", "-C", tmpdir, "config", "user.name", "Bezalel"], check=True, capture_output=True)

        # Revert the commit
        revert_msg = f"[auto-revert] {msg}\n\nOriginal commit {sha} failed CI."
        result = subprocess.run(
            ["git", "-C", tmpdir, "revert", "--no-edit", "-m", revert_msg, sha],
            capture_output=True,
            text=True,
        )
        if result.returncode != 0:
            return {"error": f"git revert failed: {result.stderr}"}

        # Push
        push_result = subprocess.run(
            ["git", "-C", tmpdir, "push", "origin", "main"],
            capture_output=True,
            text=True,
        )
        if push_result.returncode != 0:
            return {"error": f"git push failed: {push_result.stderr}"}

        return {"ok": True, "reverted_sha": sha}


def main():
    if len(sys.argv) < 2:
        print(f"Usage: {sys.argv[0]} <owner/repo>")
        sys.exit(1)

    repo_full = sys.argv[1]
    owner, repo = repo_full.split("/", 1)

    since = datetime.now(timezone.utc) - timedelta(minutes=REVERT_WINDOW_MINUTES + 5)
    commits = get_recent_commits(owner, repo, since)

    if not isinstance(commits, list):
        print(f"ERROR fetching commits: {commits}")
        sys.exit(1)

    reverted = 0
    for commit in commits:
        sha = commit.get("sha", "")
        msg = commit.get("commit", {}).get("message", "").split("\n")[0]
        commit_time = commit.get("commit", {}).get("committer", {}).get("date", "")
        if not commit_time:
            continue

        commit_dt = datetime.fromisoformat(commit_time.replace("Z", "+00:00"))
        age_min = (datetime.now(timezone.utc) - commit_dt).total_seconds() / 60

        if age_min > REVERT_WINDOW_MINUTES:
            continue

        status = get_commit_status(owner, repo, sha)
        state = status.get("state", "")

        if state == "failure":
            print(f"ALERT: Commit {sha[:8]} '{msg}' failed CI ({age_min:.1f}m old). Initiating revert...")
            repo_info = api_call("GET", f"/repos/{owner}/{repo}")
            clone_url = repo_info.get("clone_url", "")
            if not clone_url:
                print(f"  Cannot find clone URL")
                continue
            result = revert_via_git(clone_url, sha, msg, owner, repo)
            if "error" in result:
                print(f"  Revert failed: {result['error']}")
            else:
                print(f"  Reverted successfully.")
                reverted += 1
        elif state == "success":
            print(f"OK: Commit {sha[:8]} '{msg}' passed CI.")
        elif state == "pending":
            print(f"PENDING: Commit {sha[:8]} '{msg}' still running CI.")
        else:
            print(f"UNKNOWN: Commit {sha[:8]} '{msg}' has CI state '{state}'.")

    if reverted == 0:
        print("No broken merges found in the last 10 minutes.")


if __name__ == "__main__":
    main()