import express, { Request, Response } from 'express'
import type { ApiResponse } from '../../../shared/types.js'
import { eventBus } from '../../events/eventBus.js'

const router = express.Router()

router.get('/', (req: Request, res: Response) => {
  if (process.env.VERCEL) {
    const response: ApiResponse<null> = {
      success: false,
      error: { code: 'SSE_UNSUPPORTED', message: 'SSE在无服务器运行时中不受支持' },
    }
    return res.status(501).json(response)
  }

  const headers = {
    'Content-Type': 'text/event-stream',
    'Connection': 'keep-alive',
    'Cache-Control': 'no-cache'
  }
  res.writeHead(200, headers)

  res.write(`data: ${JSON.stringify({ event: 'connected' })}\n\n`)

  eventBus.addClient(res)

  req.on('close', () => {
    eventBus.removeClient(res)
  })
})

export default router