/**
 * events.routes.ts
 *
 * Endpoint SSE (Server-Sent Events).
 * Mantém a conexão aberta e repassa eventos do `fastify.events` para o cliente.
 */

import fp from 'fastify-plugin';
import type { FastifyInstance, FastifyRequest, FastifyReply } from 'fastify';

async function eventsRoutes(fastify: FastifyInstance): Promise<void> {
  fastify.get('/', {
    schema: {
      tags: ['Dashboard'],
      summary: 'Stream de eventos em tempo real (SSE)',
    },
    preHandler: [fastify.authenticate],
    handler: (request: FastifyRequest, reply: FastifyReply) => {
      // 1. Configura os headers para SSE
      reply.raw.writeHead(200, {
        'Content-Type': 'text/event-stream',
        'Cache-Control': 'no-cache',
        'Connection': 'keep-alive',
      });
      reply.raw.write('\n'); // Garante envio do header imediato

      // Helper para formatar pacote SSE
      const sendEvent = (event: string, data: any) => {
        reply.raw.write(`event: ${event}\n`);
        reply.raw.write(`data: ${JSON.stringify(data)}\n\n`);
      };

      // 2. Registra os listeners
      const onTicketCreated = (data: any) => sendEvent('ticket.created', data);
      const onTicketUpdated = (data: any) => sendEvent('ticket.updated', data);
      const onCommentAdded  = (data: any) => sendEvent('comment.added', data);

      fastify.events.on('ticket.created', onTicketCreated);
      fastify.events.on('ticket.updated', onTicketUpdated);
      fastify.events.on('comment.added', onCommentAdded);

      // Ping a cada 30s para manter a conexão ativa (evitar timeout do LB/Nginx)
      const pingInterval = setInterval(() => {
        reply.raw.write(':\n\n'); // SSE comment block serve como heartbeat
      }, 30000);

      // 3. Limpeza quando o cliente desconecta
      request.raw.on('close', () => {
        clearInterval(pingInterval);
        fastify.events.off('ticket.created', onTicketCreated);
        fastify.events.off('ticket.updated', onTicketUpdated);
        fastify.events.off('comment.added', onCommentAdded);
      });
    },
  });
}

export default eventsRoutes;