const http = require('http')
const url = require('url')

const clients = new Map()

// HTTP-Server starten
const server = http.createServer((req, res) => {
  const parsedUrl = url.parse(req.url, true)

  // CORS & SSE-Header
  res.setHeader('Access-Control-Allow-Origin', '*')
  res.setHeader('Access-Control-Allow-Methods', 'GET, POST, OPTIONS')
  res.setHeader('Access-Control-Allow-Headers', 'Content-Type')

  if (req.method === 'OPTIONS') {
    res.writeHead(204)
    res.end()
    return
  }

  // Verbindung zu einem Client (SSE)
  if (req.method === 'GET' && req.url.startsWith('/events')) {
    const steamId = parsedUrl.query.steamId
    if (!steamId) {
      res.writeHead(400)
      res.end('steamId fehlt')
      return
    }

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

    res.write('\n') // Verbindung offen halten
    clients.set(steamId, res)
    //console.log(`[SSE] Verbunden: steamId=${steamId}`)

    req.on('close', () => {
      clients.delete(steamId)
      //console.log(`[SSE] Verbindung geschlossen: steamId=${steamId}`)
    })
    return
  }

  // Nachricht senden (POST)
  if (req.method === 'POST' && req.url === '/send') {
    let body = ''
    req.on('data', chunk => body += chunk)
    req.on('end', () => {
      const message = JSON.parse(body)
      const isBroadcast = !Array.isArray(message.targetUserIds)
      const type = message.type || 'notification'

      let sentCount = 0

      for (const [steamId, clientRes] of clients.entries()) {
        const shouldSend =
          isBroadcast || (
            Array.isArray(message.targetUserIds) &&
            message.targetUserIds.includes(steamId)
          )

        if (shouldSend) {
          clientRes.write(`event: ${type}\n`)
          clientRes.write(`data: ${JSON.stringify(message)}\n\n`)
          sentCount++
        }
      }

      //console.log(`[SSE] Nachricht vom Typ "${type}" an ${sentCount} Client(s) gesendet.`)
      res.writeHead(200)
      res.end('Nachricht gesendet.')
    })
    return
  }

  // Unbekannte Route
  res.writeHead(404)
  res.end()
})

server.listen(3001, () => {
  console.log('✅ SSE-Server läuft auf Port 3001')
})