module.exports = io => {
  io.on('connection', async socket => {
    console.log(`A socket connection to the server has been made: ${socket.id}`)
    socket.join('#chat', () => {
      sendAllRooms()
      sendAllUsers()
    })

    socket.on('message', message => {
      console.log(`send a message to room ${message.room}: ${message}`)
      io.of(message.room).emit('message', message)
    })

    socket.on('get all users', () => {
      console.log('get all users')
      sendAllUsers()
    })

    socket.on('get my rooms', () => {
      console.log('get my rooms')
      sendAllRooms()
    })

    socket.on('join', roomName => {
      console.log('join:', roomName)
      socket.join(roomName, () => {
        sendAllRooms()
      })
    })

    socket.on('part', () => {
      console.log('part')
    })

    socket.on('get all rooms', () => sendAllRooms())
    socket.on('send all clients', () => {
      // https://socket.io/docs/server-api/#namespace-clients-callback
      io.clients((error, clients) => {
        if (error) throw error
        console.log(clients)
      })
    })

    const sendAllRooms = () => {
      console.log('get all rooms')
      const allRooms = Object.keys(io.sockets.adapter.rooms)
        .filter(r => r[0] === '#')
        .map(k => ({
          roomName: k,
          sockets: Object.keys(io.sockets.adapter.rooms[k]['sockets']),
        }))
      io.emit('got all rooms', allRooms)
    }

    const sendAllUsers = () =>
      socket.emit('got all users', Object.keys(io.sockets.sockets))

    socket.on('disconnect', async () => {
      io.emit('user disconnected', { socketId: socket.id })
      console.log(`${socket.id} has disconnected.`)
    })
  })
}