import Fastify, { type FastifyInstance } from 'fastify';
import type { AppConfig } from './config.js';
import { pool } from './db/pool.js';
import { registerSecurityPlugins } from './lib/security.js';
import { registerInstrumentation } from './lib/instrumentation.js';
import { registerAgentRoutes } from './routes/agents.js';
import { registerTokenRoutes } from './routes/tokens.js';
import { registerSessionRoutes } from './routes/sessions.js';
import { registerRoomRoutes } from './routes/rooms.js';
import { registerSocialRoutes } from './routes/social.js';
import { registerDirectoryRoutes } from './routes/directory.js';
import { setupSocketIO } from './socket/index.js';
import { register as metricsRegister } from './lib/metrics.js';
import { startMetricsCollector } from './services/metrics-collector.js';

export interface BuildAppOptions {
  config: AppConfig;
}

export async function buildApp({ config }: BuildAppOptions): Promise<FastifyInstance> {
  const app = Fastify({
    logger: { level: config.LOG_LEVEL },
    disableRequestLogging: config.NODE_ENV === 'test',
  });

  // Register security plugins first
  await registerSecurityPlugins(app, config);

  // Register instrumentation for metrics
  await registerInstrumentation(app);

  app.get('/healthz', async () => {
    return { status: 'ok', uptime: process.uptime() };
  });

  app.get('/readyz', async (_req, reply) => {
    const start = Date.now();
    try {
      // Check DB connectivity
      await pool.query('SELECT 1');

      const elapsed = Date.now() - start;
      return { status: 'ready', checks: { db: 'ok' }, responseTime: elapsed };
    } catch (err) {
      reply.status(503);
      return {
        status: 'not_ready',
        checks: { db: 'failed' },
        error: err instanceof Error ? err.message : 'unknown',
      };
    }
  });

  app.get('/metrics', async (_req, reply) => {
    reply.header('Content-Type', metricsRegister.contentType);
    return metricsRegister.metrics();
  });

  // Register API routes
  await registerAgentRoutes(app, pool);
  await registerTokenRoutes(app, pool);
  await registerSessionRoutes(app, pool, config);
  await registerRoomRoutes(app, pool);
  await registerSocialRoutes(app, pool);
  await registerDirectoryRoutes(app, pool);

  // Setup socket.io after app is ready (if feature enabled)
  await app.ready();
  if (config.FEATURE_MESSAGING_ENABLED) {
    setupSocketIO(app.server, pool, config);
    app.log.info('✅ Socket.IO messaging enabled');
  } else {
    app.log.warn('⚠️  Socket.IO messaging disabled (FEATURE_MESSAGING_ENABLED=false)');
  }

  // Start metrics collector (updates room metrics every 30s)
  startMetricsCollector(pool);
  app.log.info('✅ Metrics collector started');

  return app;
}