import Connect from 'connect'
import { ServerResponse } from 'node:http';
import { parse } from 'cookie'

interface Massage {
  type: string;
  value: string;
  time: number;
}

let sessionList: {[session: string]: Set<ServerResponse<Connect.IncomingMessage>>} = {}

export default async function SseMid(req: Connect.IncomingMessage, res: ServerResponse<Connect.IncomingMessage>, next: Connect.NextFunction) {
  const BaseUrl = process.env.BASE_URL

  // 检查session_id
  let session_id: string | undefined = undefined
  const cookies = parse(req.headers.cookie ?? '')
  if (!cookies.session_id) {
    session_id = crypto.randomUUID()
    res.setHeader('Set-Cookie', `session_id=${session_id}; HttpOnly; Path=/`)
  } else {
    session_id = cookies.session_id
  }

  // 处理SSE
  if (req.url === BaseUrl + 'sse') {
    res.writeHead(200, {
      'Content-Type': 'text/event-stream',
      'Cache-Control': 'no-cache',
      Connection: 'keep-alive',
    })
  
    const interval = setInterval(() => {
      const msg = {
        type: 'pending',
        value: session_id,
        time: Date.now()
      }
      res.write(`data: ${JSON.stringify(msg)}\n\n`)
    }, 60 * 1000)
  
    req.on('close', () => {
      clearInterval(interval)
      res.end()
      if (sessionList[session_id]) {
        sessionList[session_id].delete(res)
      }
    })

    // 插入res
    if (!sessionList[session_id]) {
      sessionList[session_id] = new Set<ServerResponse<Connect.IncomingMessage>>
    }
    sessionList[session_id].add(res)

    return
  }

  // 继续执行下一个中间件
  next();
}

export function sendReLogin(session_id: string): boolean {
  if (!sessionList[session_id]) return false

  console.log("send relogin: ", session_id)
  sessionList[session_id].forEach(res => {
    const msg: Massage = {
      type: 'command',
      value: 'Re-login',
      time: Date.now()
    }
    res.write(`data: ${JSON.stringify(msg)}\n\n`)
  });

  return true
}