// pages/api/webhooks/stripe.ts
import type { NextApiRequest, NextApiResponse } from "next";
import { receiveWebhook, retry } from "hook-engine";
import { config } from "../../../lib/config";
import { processEvent } from "../../../lib/handler";
import { isDuplicate, markSeen } from "../../../lib/dedupe";

export const configRuntime = {
  api: {
    bodyParser: false, // Required for raw body access
  },
};

export default async function handler(req: NextApiRequest, res: NextApiResponse) {
  try {
    const event = await receiveWebhook(req, config);

    if (isDuplicate(event.id)) {
      console.warn(`⚠️ Duplicate skipped: ${event.id}`);
      return res.status(200).send("duplicate");
    }

    markSeen(event.id);
    await retry(event, processEvent);

    res.status(200).send("ok");
  } catch (err: any) {
    console.error("❌ Webhook error:", err.message);
    res.status(400).send("webhook error");
  }
}

// lib/handler.ts
export async function processEvent(event: any) {
  console.log(`🎯 Received ${event.type} for ${event.id}`);

  if (event.type === "invoice.paid") {
    const customer = event.payload.customer;
    console.log(`🎉 Grant premium access to ${customer}`);
    // do something: DB, email, billing...
  }

  if (event.type === "invoice.failed") {
    throw new Error("🔥 Simulated failure for retry");
  }
}

// lib/dedupe.ts
import Database from "better-sqlite3";
import path from "path";
import fs from "fs";

const DB_PATH = path.resolve(process.cwd(), "db/seen.sqlite");
fs.mkdirSync(path.dirname(DB_PATH), { recursive: true });
const db = new Database(DB_PATH);

db.exec(`CREATE TABLE IF NOT EXISTS seen_events (
  id TEXT PRIMARY KEY,
  seen_at INTEGER
);`);

export function isDuplicate(id: string): boolean {
  return !!db.prepare("SELECT 1 FROM seen_events WHERE id = ?").get(id);
}

export function markSeen(id: string) {
  db.prepare("INSERT OR IGNORE INTO seen_events (id, seen_at) VALUES (?, ?)").run(id, Date.now());
}

// lib/config.ts
import { WebhookConfig } from "hook-engine";

export const config: WebhookConfig = {
  source: "stripe",
  secret: process.env.STRIPE_WEBHOOK_SECRET!,
};