import Fastify, { FastifyInstance } from 'fastify';
import { AppError } from './utils/errors.js';
import databasePlugin from './plugins/database.js';
import redisPlugin from './plugins/redis.js';
import securityPlugin from './plugins/security.js';
import rateLimitPlugin from './plugins/rateLimit.js';
import { env } from './config/env.js';
import { randomUUID } from 'node:crypto';

export async function buildApp(): Promise<FastifyInstance> {
  const isDev = env.NODE_ENV === 'development';

  const app = Fastify({
    logger: {
      level: isDev ? 'debug' : 'info',
      transport:
        isDev
          ? {
              target: 'pino-pretty',
              options: {
                translateTime: 'HH:MM:ss Z',
                ignore: 'pid,hostname',
              },
            }
          : undefined,
    },
    requestIdHeader: 'x-request-id',
    requestIdLogLabel: 'requestId',
    genReqId: () => randomUUID(),
  });

  app.setErrorHandler((err: unknown, request, reply) => {
    const error = err as Error & { statusCode?: number; validation?: unknown };
    request.log.error({ err }, error.message);

    if (err instanceof AppError) {
      const statusCode = err.statusCode;
      const payload = err.toJSON();
      if (err.code === 'RATE_LIMIT_EXCEEDED' && 'retryAfter' in err) {
        reply.header('Retry-After', String((err as AppError & { retryAfter?: number }).retryAfter ?? 60));
      }
      return reply.status(statusCode).send(payload);
    }

    if (error.validation) {
      return reply.status(422).send({
        error: {
          code: 'VALIDATION_ERROR',
          message: 'Validation failed',
          details: error.validation,
        },
      });
    }

    const statusCode = error.statusCode ?? 500;
    return reply.status(statusCode).send({
      error: {
        code: 'INTERNAL_ERROR',
        message: env.NODE_ENV === 'production' ? 'Internal server error' : error.message,
      },
    });
  });

  app.addHook('onRequest', async (request, reply) => {
    reply.header('x-request-id', request.id);
  });

  await app.register(redisPlugin);
  await app.register(databasePlugin);
  await app.register(securityPlugin);
  await app.register(rateLimitPlugin);

  app.get('/health', async () => ({ status: 'ok', timestamp: new Date().toISOString() }));

  return app;
}