const { send, broadcast } = require("./utils");

const rooms = new Map(); // roomCode -> { host: ws, participants: Set<ws> }

function generateRoomCode() {
  const chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
  let code = "";
  for (let i = 0; i < 6; i++) code += chars[Math.floor(Math.random() * chars.length)];
  return code;
}

function getRoom(roomCode) {
  return rooms.get(roomCode);
}

function createRoom(ws) {
  removeFromRoom(ws);
  let roomCode = generateRoomCode();
  while (rooms.has(roomCode)) roomCode = generateRoomCode();
  const room = { host: ws, participants: new Set([ws]) };
  rooms.set(roomCode, room);
  ws._roomCode = roomCode;
  return roomCode;
}

function joinRoom(ws, roomCode) {
  const room = rooms.get(roomCode);
  if (!room) return null;
  removeFromRoom(ws);
  room.participants.add(ws);
  ws._roomCode = roomCode;
  return room;
}

function removeFromRoom(ws) {
  const roomCode = ws._roomCode;
  if (!roomCode) return;
  const room = rooms.get(roomCode);
  if (!room) return;

  room.participants.delete(ws);
  ws._roomCode = null;

  if (room.participants.size === 0) {
    rooms.delete(roomCode);
    return;
  }

  // Reassign host if the host left
  if (room.host === ws) {
    room.host = room.participants.values().next().value;
    send(room.host, { type: "promoted-to-host" });
  }

  broadcast(room, { type: "participant-update", count: room.participants.size, members: getParticipantList(room) });
}

function getParticipantList(room) {
  const members = [];
  for (const p of room.participants) {
    members.push({ url: p._url || null });
  }
  return members;
}

module.exports = { rooms, generateRoomCode, createRoom, joinRoom, removeFromRoom, getRoom, getParticipantList };