type WebsocketData = {
  clientId: string
}

type Message =
  | { type: 'welcome', id: string }
  | { type: 'presence-information', others: number }
  | { type: 'ripple', position: [number, number], maxRadius: number }

const clients: Map<WebsocketData['clientId'], WebSocket> = new Map()

const _server = Deno.serve({
  port: Number.parseInt(Deno.env.get('PORT') || '8000', 10),
  handler: (req) => {
   if (req.headers.get("upgrade") !== "websocket") {
     return new Response(null, { status: 501 })
   }

    const { socket, response } = Deno.upgradeWebSocket(req)

    // TODO Allow creating private ponds
    const clientId = crypto.randomUUID()
    console.log('generated clientId', clientId)

    socket.addEventListener("open", () => {
      // register newly connected client and tell them how many other people are there
      console.log('Connection opened', clientId, clients)
      socket.send(JSON.stringify(<Message>{
        type: 'welcome',
        id: clientId
      }))
      const enterNotice = JSON.stringify(<Message>{
        type: 'presence-information',
        others: clients.size,
      })
      clients.set(clientId, socket)
      for (const client of clients.values()) {
        client.send(enterNotice)
      }
    })

    socket.addEventListener("message", (event) => {
      const message = `${event.data}`
      // broadcast message to all other clients
      // TODO: Validate message shape
      const msg = JSON.parse(`${message}`)
      console.log('Relaying message from', clientId, msg)
      for (const [uuid, client] of clients.entries()) {
        if (uuid !== clientId) {
          client.send(message)
        }
      }
    })

    socket.addEventListener("close", () => {
      // remove client from list of registered clients and tell other clients how many people are there
      console.log('Connection closed', clientId, clients)
      clients.delete(clientId)
      const leaveNotice = JSON.stringify(<Message>{
        type: 'presence-information',
        others: clients.size - 1,
      })
      for (const [uuid, client] of clients.entries()) {
        if (uuid !== clientId) {
          client.send(leaveNotice)
        }
      }
    })

    return response
  }
})