import express from "express";
import crypto from "node:crypto";
import { postPRComment } from "./gitea.js";
import { reviewPullRequest } from "./runner.js";
import { startMatrixBot } from "./matrixBot.js";

const app = express();
app.use(
  express.json({
    verify: (req, _res, buf) => {
      req.rawBody = buf;
    },
  })
);

const PORT = process.env.PORT || 3001;
const WEBHOOK_SECRET = process.env.GITEA_WEBHOOK_SECRET;

function verifySignature(req) {
  if (!WEBHOOK_SECRET) return false;
  const sig = req.get("X-Gitea-Signature");
  if (!sig) return false;
  const expected = crypto.createHmac("sha256", WEBHOOK_SECRET).update(req.rawBody).digest("hex");
  const sigBuf = Buffer.from(sig, "hex");
  const expBuf = Buffer.from(expected, "hex");
  return sigBuf.length === expBuf.length && crypto.timingSafeEqual(sigBuf, expBuf);
}

app.get("/healthz", (_req, res) => res.send("ok"));

app.post("/webhooks/gitea", async (req, res) => {
  if (!verifySignature(req)) {
    return res.status(401).send("bad signature");
  }
  // Ack immediately — Gitea has a short webhook timeout and the review itself takes a while.
  res.status(202).send("accepted");

  const event = req.get("X-Gitea-Event");
  const body = req.body;

  try {
    if (event === "pull_request" && ["opened", "synchronize"].includes(body.action)) {
      const { repository, pull_request: pr } = body;
      const [owner, repo] = repository.full_name.split("/");
      const review = await reviewPullRequest({
        owner,
        repo,
        ref: pr.head.sha,
        cloneUrl: repository.clone_url,
        prTitle: pr.title,
        prBody: pr.body || "",
      });
      await postPRComment(owner, repo, pr.number, review);
    }
  } catch (err) {
    console.error("webhook handling failed:", err);
  }
});

app.listen(PORT, () => {
  console.log(`claude-agent listening on :${PORT}`);
});

startMatrixBot().catch((err) => {
  console.error("matrix bot failed to start:", err);
});