import { randomUUID } from 'node:crypto';
import cors from '@fastify/cors';
import rateLimit from '@fastify/rate-limit';
import Fastify, { type FastifyInstance } from 'fastify';
import { loadConfig, type AppConfig } from './config.js';
import { registerHealthRoutes } from './routes/health.js';
import {
  registerPlatformBootstrapRoutes,
  type PlatformConfigResolver
} from './routes/platform-bootstrap.js';
import { registerAuthRoutes, type AuthRouteOptions } from './routes/auth.js';
import {
  registerUserManagementRoutes,
  type UserManagementRouteOptions
} from './routes/user-management.js';

export interface BuildAppOptions {
  config?: AppConfig;
  platformConfigRepository?: PlatformConfigResolver;
  auth?: AuthRouteOptions;
  userManagement?: UserManagementRouteOptions;
}

declare module 'fastify' {
  interface FastifyRequest {
    traceId: string;
  }
}

export async function buildApp(options: BuildAppOptions = {}): Promise<FastifyInstance> {
  const config = options.config ?? loadConfig();
  const app = Fastify({
    logger: {
      level: config.nodeEnv === 'test' ? 'silent' : 'info'
    },
    genReqId: () => randomUUID()
  });

  app.decorateRequest('traceId', '');
  app.addHook('onRequest', async (request, reply) => {
    const traceHeader = request.headers['x-trace-id'];
    request.traceId = Array.isArray(traceHeader) ? traceHeader[0] : traceHeader || request.id;
    reply.header('x-trace-id', request.traceId);
  });

  await app.register(cors, {
    origin: config.corsOrigins
  });
  await app.register(rateLimit, {
    max: 120,
    timeWindow: '1 minute'
  });

  app.setErrorHandler((error, request, reply) => {
    request.log.error({ err: error, traceId: request.traceId }, 'request failed');
    reply.status(500).send({
      code: 'INTERNAL_ERROR',
      message: 'Internal server error',
      traceId: request.traceId
    });
  });

  await registerHealthRoutes(app, config);
  if (options.platformConfigRepository) {
    await registerPlatformBootstrapRoutes(app, options.platformConfigRepository);
  }
  if (options.auth) {
    await registerAuthRoutes(app, options.auth);
  }
  if (options.userManagement) {
    await registerUserManagementRoutes(app, options.userManagement);
  }

  return app;
}