import "reflect-metadata";
import { NestFactory } from "@nestjs/core";
import { AppModule } from "./app.module.js";
import { GlobalErrorFilter } from "./shared/errors/global-error.filter.js";
import { initTracer, shutdownTracer } from "./shared/observability/tracer.js";
import { env } from "./config/env.js";
import { closeDb } from "./config/database.js";
import { closeNeo4j } from "./config/neo4j.js";
import { logger } from "./shared/observability/logger.js";
import { metricsRegistry } from "./shared/observability/metrics.js";

async function bootstrap(): Promise<void> {
  initTracer();

  const app = await NestFactory.create(AppModule, {
    logger: ["log", "error", "warn"],
  });

  app.useGlobalFilters(new GlobalErrorFilter());
  app.enableShutdownHooks();

  // Prometheus 指标端点：不鉴权，供 Prometheus 抓取。
  // 返回 register.metrics()（Promise<string>，含 Content-Type text/plain; version=0.0.4; charset=utf-8）。
  app.getHttpAdapter().get("/metrics", async (req, res) => {
    res.set("Content-Type", metricsRegistry.contentType);
    res.end(await metricsRegistry.metrics());
  });

  await app.listen(env.PORT);
  logger.info({ port: env.PORT }, "Content service started");

  process.on("SIGTERM", async () => {
    logger.info("SIGTERM received, shutting down gracefully...");
    await closeNeo4j();
    await closeDb();
    await shutdownTracer();
    await app.close();
    process.exit(0);
  });

  process.on("SIGINT", async () => {
    logger.info("SIGINT received, shutting down gracefully...");
    await closeNeo4j();
    await closeDb();
    await shutdownTracer();
    await app.close();
    process.exit(0);
  });
}

bootstrap().catch((err: unknown) => {
  logger.error({ err }, "Failed to start content service");
  process.exit(1);
});