const express = require('express');
const http = require('http');
const { Server } = require('socket.io');
const path = require('path');

const app = express();
const server = http.createServer(app);
const io = new Server(server, {
  pingTimeout: 60000,
  pingInterval: 25000,
});

app.use(express.static(path.join(__dirname, 'public')));

// pin -> { issuedCount, calledCount }
const sessions = {};

function sessionState(pin) {
  const s = sessions[pin] || { issuedCount: 0, calledCount: 0 };
  return {
    issuedCount: s.issuedCount,
    calledCount: s.calledCount,
    waitingCount: s.issuedCount - s.calledCount,
  };
}

io.on('connection', (socket) => {
  let pin = null;

  socket.on('join', ({ pin: p }) => {
    if (!p || typeof p !== 'string' || p.length < 4) {
      socket.emit('join_error', 'PIN은 최소 4자리 이상이어야 합니다.');
      return;
    }
    pin = p.trim();
    if (!sessions[pin]) {
      sessions[pin] = { issuedCount: 0, calledCount: 0 };
    }
    socket.join(pin);
    socket.emit('join_ok', sessionState(pin));
  });

  socket.on('issue_ticket', () => {
    if (!pin || !sessions[pin]) return;
    sessions[pin].issuedCount += 1;
    const ticketNumber = sessions[pin].issuedCount;
    const state = sessionState(pin);
    socket.emit('ticket_issued', { ticketNumber, waitingCount: state.waitingCount });
    io.to(pin).emit('state_update', state);
  });

  socket.on('call_next', () => {
    if (!pin || !sessions[pin]) return;
    const s = sessions[pin];
    if (s.calledCount >= s.issuedCount) return;
    s.calledCount += 1;
    io.to(pin).emit('state_update', sessionState(pin));
  });

  socket.on('reset', () => {
    if (!pin || !sessions[pin]) return;
    sessions[pin] = { issuedCount: 0, calledCount: 0 };
    io.to(pin).emit('state_update', sessionState(pin));
    io.to(pin).emit('reset_done');
  });
});

const PORT = process.env.PORT || 3000;
server.listen(PORT, '0.0.0.0', () => {
  console.log(`Queue server running on port ${PORT}`);
});