const PORT = parseInt(Deno.env.get("PORT") || "80");

const randomInt = (low: number, high: number) =>
  Math.floor(Math.random() * (high - low + 1) + low);

const randomSecret = () => new Array(8).map(() => randomInt(0, 10)).join("");

interface Client {
  socket: WebSocket;
}

// TODO: version comparison

interface Lobby {
  name: string;
  clients: Client[];
  // TODO: private vs public lobbies?
}

const lobbies = new Set<Lobby>();
const clients = new Set<Client>();

console.log("Listening on port", PORT);
const listener = Deno.listen({ port: PORT });
for await (const conn of listener) {
  console.debug("Connection received:", conn);
  (async () => {
    const server = Deno.serveHttp(conn);
    for await (const { respondWith, request } of server) {
      console.debug("HTTP Request Received", request);
      try {
        const { socket, response } = Deno.upgradeWebSocket(request);
        const client: Client = { socket };
        socket.onmessage = (ev) => {
          console.log("Client Message Received", ev);
        };
        socket.onopen = (ev) => {
          console.log("New Client:", ev);
          if (!clients.has(client)) clients.add(client);
          socket.send("lobbies_start");
          lobbies.forEach(({ name, clients }) => {
            socket.send(JSON.stringify({ name, numClients: clients.length }));
          });
          socket.send("lobbies_end");
        };
        socket.onclose = (ev) => {
          console.log("Client Socket Close:", ev);
          if (clients.has(client)) clients.delete(client);
        };
        socket.onerror = (ev) => {
          console.log("Client Socket Error:", ev);
          if (clients.has(client)) clients.delete(client);
        };
        respondWith(response);
      } catch (e) {
        let body = "400 Bad Request";
        if (e instanceof TypeError) {
          body += " - Expected to be able to upgrade to WebSocket connection";
          console.log("Could not add client:", e);
        } else {
          console.log("Could not add client for unhandled reason:", e);
        }
        respondWith(
          new Response(body, {
            status: 400,
            headers: { "content-type": "text/html" },
          }),
        );
      }
    }
  })();
}

/*
function peerCreatesLobby(peer: Peer, lobbyName: string) {
  // TODO: ensure we can create a lobby
  lobbies.add({
  })
}
  */

/*
function peerJoinsLobby(peer: Peer, lobby: Lobby) {
      lobbyName = randomSecret();
      lobbies.set(lobbyName, new Lobby(lobbyName, this.id));
      console.log(`Peer ${this.id} created lobby ${lobbyName}`);
      console.log(`Open lobbies: ${lobbies.size}`);
    }
    const lobby = lobbies.get(lobbyName);
    if (!lobby) throw new ProtoError(4000, STR_LOBBY_DOES_NOT_EXIST);
    if (lobby.sealed) throw new ProtoError(4000, STR_LOBBY_IS_SEALED);
    this.lobby = lobbyName;
    console.log(
      `Peer ${this.id} joining lobby ${lobbyName} ` +
        `with ${lobby.peers.length} peers`,
    );
    lobby.join(this);
    this.ws.send(`J: ${lobbyName}\n`);
  }
  // TODO: ensure peer not already in a lobby
  const assigned = this.getPeerId(peer);
  peer.ws.send(`I: ${assigned}\n`);
  this.peers.forEach((p) => {
    p.ws.send(`N: ${assigned}\n`);
    peer.ws.send(`N: ${this.getPeerId(p)}\n`);
  });
  this.peers.push(peer);
}
  */

/*
function peerLeavesLobby(peer: Peer) {
  const idx = this.peers.findIndex((p) => peer === p);
  if (idx === -1) return false;
  const assigned = this.getPeerId(peer);
  const close = assigned === 1;
  this.peers.forEach((p) => {
    try {
      // room host disconnected
      if (close) p.ws.close(4000, STR_HOST_DISCONNECTED);
      // notify peers
      else p.ws.send(`D: ${assigned}\n`);
    } catch (e) {
      console.error(`Error when leaving: ${e}`);
    }
  });
  this.peers.splice(idx, 1);
  if (close && this.closeTimer >= 0) {
    // we are closing already.
    clearTimeout(this.closeTimer);
    this.closeTimer = -1;
  }
  return close;
}
  */

/*
function graduateLobby(lobby: Lobby) {
    // only host can seal
    if (peer.id !== this.host) {
      throw new ProtoError(4000, STR_ONLY_HOST_CAN_SEAL);
    }
    this.sealed = true;
    this.peers.forEach((p) => {
      p.ws.send("S: \n");
    });
    console.log(
      `Peer ${peer.id} sealed lobby ${this.name} ` +
        `with ${this.peers.length} peers`,
    );
    this.closeTimer = setTimeout(() => {
      // close peer connection to host (and thus the lobby)
      this.peers.forEach((p) => {
        p.ws.close(1000, STR_SEAL_COMPLETE);
      });
    }, SEAL_CLOSE_TIMEOUT);
}

}
  */

/*
function parseMsg(peer: Peer, msg: string) {
  // TODO: modify this?
  // O: Client is sending an offer.
  // A: Client is sending an answer.
  // C: Client is sending a candidate.
  let destId = parseInt(cmd.substr(3).trim());
  // Dest is not an ID.
  if (!destId) throw new ProtoError(4000, STR_INVALID_DEST);
  if (destId === 1) destId = lobby.host;
  const dest = lobby.peers.find((p: Peer) => p.id === destId);
  // Dest is not in this room.
  if (!dest) throw new ProtoError(4000, STR_INVALID_DEST);

  function isCmd(what: string) {
    return cmd.startsWith(`${what}: `);
  }
  if (isCmd("O") || isCmd("A") || isCmd("C")) {
    dest.ws.send(cmd[0] + ": " + lobby.getPeerId(peer) + data);
    return;
  }
  throw new ProtoError(4000, STR_INVALID_CMD);
}
  */