/**
 * Tracker Service — Fastify server entry point.
 *
 * Modules: items, comments, votes.
 * Port: 4004 (configurable via PORT env var).
 * Product-agnostic: all data scoped by productId.
 */

import { randomUUID } from "node:crypto";
import Fastify from "fastify";
import cors from "@fastify/cors";
import swagger from "@fastify/swagger";
import metricsPlugin from "fastify-metrics";
import { ServiceError } from "./lib/errors.js";
import { itemRoutes } from "./modules/items/routes.js";
import { commentRoutes } from "./modules/comments/routes.js";
import { voteRoutes } from "./modules/votes/routes.js";
import { publicRoutes } from "./modules/public/routes.js";
import { config } from "./lib/config.js";

const PORT = config.PORT;
const HOST = config.HOST;

const app = Fastify({ logger: true });

// CORS — restrict to specific origins in production via CORS_ORIGIN (comma-separated)
const corsOrigin = config.CORS_ORIGIN;
await app.register(cors, {
  origin: corsOrigin ? corsOrigin.split(",").map((o) => o.trim()) : true,
});

// OpenAPI spec auto-generation (GET /api/docs/json)
await app.register(swagger, {
  openapi: {
    info: { title: "Tracker Service", version: "0.1.0", description: "Feature requests, bugs, tasks — product-agnostic" },
    servers: [{ url: `http://localhost:${PORT}` }],
  },
});

// Prometheus metrics
await app.register(metricsPlugin, { endpoint: "/metrics" });

// x-request-id: propagate incoming header or generate a new one
app.addHook("onRequest", async (req, reply) => {
  const requestId = (req.headers["x-request-id"] as string) || randomUUID();
  req.headers["x-request-id"] = requestId;
  reply.header("x-request-id", requestId);
  req.log = req.log.child({ requestId });
});

// Health check
app.get("/health", async (req) => ({
  status: "ok",
  service: "tracker-service",
  version: "0.1.0",
  timestamp: new Date().toISOString(),
  requestId: req.headers["x-request-id"],
}));

// Custom error handler
app.setErrorHandler((error, _req, reply) => {
  if (error instanceof ServiceError) {
    reply.code(error.statusCode).send({ error: error.message });
    return;
  }
  app.log.error(error);
  reply.code(500).send({ error: "Internal server error" });
});

// Register route modules
await app.register(itemRoutes, { prefix: "/api" });
await app.register(commentRoutes, { prefix: "/api" });
await app.register(voteRoutes, { prefix: "/api" });
await app.register(publicRoutes, { prefix: "/api" });

// Start
try {
  await app.listen({ port: PORT, host: HOST });
  app.log.info(`Tracker Service listening on ${HOST}:${PORT}`);
} catch (err) {
  app.log.error(err);
  process.exit(1);
}