Fastify Server

import Fastify, { FastifyInstance } from "fastify";
import cors from "@fastify/cors";
import helmet from "@fastify/helmet";

export interface ServerOptions {
  port?: number;
  host?: string;
  corsOrigins?: string[];
}

const getEnvConfig = () => ({
  port: parseInt(process.env.PORT ?? "3000", 10),
  host: process.env.HOST ?? "0.0.0.0",
  corsOrigins: (process.env.CORS_ORIGINS ?? "")
    .split(",")
    .map((o) => o.trim())
    .filter((o) => o.length > 0),
});

export async function createServer(options?: ServerOptions): Promise<FastifyInstance> {
  const config = { ...getEnvConfig(), ...options };
  
  const app = Fastify({
    logger: {
      level: process.env.LOG_LEVEL ?? "info",
      transport:
        process.env.NODE_ENV === "development"
          ? { target: "pino-pretty", options: { colorize: true } }
          : undefined,
    },
    requestIdHeader: "x-request-id",
    requestIdLogLabel: "requestId",
    disableRequestLogging: false,
  });

  // Security headers
  await app.register(helmet, {
    contentSecurityPolicy: process.env.NODE_ENV === "production",
  });

  // CORS
  await app.register(cors, {
    origin: config.corsOrigins.length > 0 ? config.corsOrigins : true,
    credentials: true,
  });

  // Health check endpoints
  app.get("/health", async () => ({
    status: "healthy",
    timestamp: new Date().toISOString(),
    uptime: process.uptime(),
    memoryUsage: process.memoryUsage(),
  }));

  app.get("/ready", async () => ({
    status: "ready",
    timestamp: new Date().toISOString(),
  }));

  app.get("/live", async () => ({
    status: "live",
    timestamp: new Date().toISOString(),
  }));

  return app;
}

export async function startServer(app: FastifyInstance, options?: ServerOptions): Promise<void> {
  const config = { ...getEnvConfig(), ...options };

  // Graceful shutdown
  const shutdown = async (signal: string) => {
    app.log.info(`Received ${signal}, shutting down gracefully...`);
    try {
      await app.close();
      app.log.info("Server closed successfully");
      process.exit(0);
    } catch (err) {
      app.log.error(err, "Error during shutdown");
      process.exit(1);
    }
  };

  process.on("SIGTERM", () => shutdown("SIGTERM"));
  process.on("SIGINT", () => shutdown("SIGINT"));

  try {
    await app.listen({ port: config.port, host: config.host });
    app.log.info(`Server listening on http://${config.host}:${config.port}`);
  } catch (err) {
    app.log.error(err);
    process.exit(1);
  }
}

// Usage example:
// const app = await createServer();
// await startServer(app);