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

const app = express();
const server = http.createServer(app);
const io = new Server(server);

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

const FINISH_LINE = 10;
const COLORS = ['#e74c3c', '#3498db', '#2ecc71', '#f39c12', '#9b59b6', '#1abc9c', '#e67e22', '#e91e63',
                '#ff6b6b', '#54a0ff', '#5f27cd', '#01CBC6', '#ffd32a', '#0be881', '#f8b739'];

const rooms = {};

function genRoomId() {
  const chars = 'ABCDEFGHJKLMNPQRSTUVWXYZ23456789';
  let id = '';
  for (let i = 0; i < 6; i++) id += chars[Math.floor(Math.random() * chars.length)];
  return id;
}

function shuffle(arr) {
  const a = [...arr];
  for (let i = a.length - 1; i > 0; i--) {
    const j = Math.floor(Math.random() * (i + 1));
    [a[i], a[j]] = [a[j], a[i]];
  }
  return a;
}

function getOrdinal(n) {
  const s = ['th', 'st', 'nd', 'rd'];
  const v = n % 100;
  return n + (s[(v - 20) % 10] || s[v] || s[0]);
}

function normalizeAnswer(ans) {
  return ans.toLowerCase().trim().replace(/^(a |an |the )/, '').replace(/[^a-z0-9\s]/g, '').replace(/\s+/g, ' ');
}

function checkAnswer(playerAns, riddleIndex) {
  const riddle = riddles[riddleIndex];
  const norm = normalizeAnswer(playerAns);
  return riddle.answers.some(a => normalizeAnswer(a) === norm);
}

function publicPlayers(room) {
  return Object.entries(room.players).map(([id, p]) => ({
    id,
    name: p.name,
    position: p.position,
    color: p.color,
    finished: p.finished,
    finishPosition: p.finishPosition
  }));
}

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

  socket.on('createRoom', ({ name }) => {
    if (!name || name.trim().length === 0) return;
    roomId = genRoomId();
    // Make sure room ID is unique
    while (rooms[roomId]) roomId = genRoomId();

    const color = COLORS[0];
    rooms[roomId] = {
      host: socket.id,
      state: 'lobby',
      finishCount: 0,
      players: {
        [socket.id]: {
          name: name.trim().slice(0, 20),
          color,
          position: 0,
          queue: shuffle(Array.from({ length: riddles.length }, (_, i) => i)),
          queuePos: 0,
          finished: false,
          finishPosition: null
        }
      }
    };

    socket.join(roomId);
    socket.emit('roomCreated', { roomId });
    socket.emit('lobbyState', {
      players: publicPlayers(rooms[roomId]),
      isHost: true,
      roomId
    });
  });

  socket.on('joinRoom', ({ name, code }) => {
    if (!name || name.trim().length === 0) return socket.emit('joinError', 'Please enter your name.');
    const upperCode = (code || '').trim().toUpperCase();
    const room = rooms[upperCode];
    if (!room) return socket.emit('joinError', 'Room not found. Check the code and try again.');
    if (room.state !== 'lobby') return socket.emit('joinError', 'That race already started. Wait for the next one!');
    if (Object.keys(room.players).length >= 15) return socket.emit('joinError', 'Room is full (max 15 racers).');

    const usedColors = new Set(Object.values(room.players).map(p => p.color));
    const color = COLORS.find(c => !usedColors.has(c)) || COLORS[Object.keys(room.players).length % COLORS.length];

    room.players[socket.id] = {
      name: name.trim().slice(0, 20),
      color,
      position: 0,
      queue: shuffle(Array.from({ length: riddles.length }, (_, i) => i)),
      queuePos: 0,
      finished: false,
      finishPosition: null
    };

    roomId = upperCode;
    socket.join(upperCode);

    socket.emit('joinedRoom', { roomId: upperCode });
    socket.emit('lobbyState', {
      players: publicPlayers(room),
      isHost: false,
      roomId: upperCode
    });

    // Tell everyone else a new racer joined
    socket.to(upperCode).emit('playerUpdate', {
      players: publicPlayers(room),
      message: `${room.players[socket.id].name} joined the race!`
    });
  });

  socket.on('startGame', () => {
    if (!roomId) return;
    const room = rooms[roomId];
    if (!room || room.host !== socket.id || room.state !== 'lobby') return;
    if (Object.keys(room.players).length < 1) return;

    room.state = 'playing';

    // Send each player their first riddle individually
    Object.entries(room.players).forEach(([pid, player]) => {
      const riddleIdx = player.queue[player.queuePos];
      io.to(pid).emit('gameStarted', {
        players: publicPlayers(room),
        riddle: {
          question: riddles[riddleIdx].question,
          hint: riddles[riddleIdx].hint
        },
        riddleNum: 1,
        total: FINISH_LINE
      });
    });
  });

  socket.on('submitAnswer', ({ answer }) => {
    if (!roomId) return;
    const room = rooms[roomId];
    if (!room || room.state !== 'playing') return;

    const player = room.players[socket.id];
    if (!player || player.finished) return;
    if (!answer || answer.trim().length === 0) return;

    const riddleIdx = player.queue[player.queuePos];

    if (!checkAnswer(answer, riddleIdx)) {
      return socket.emit('answerResult', { correct: false });
    }

    // Correct answer!
    player.position++;
    player.queuePos++;

    if (player.position >= FINISH_LINE) {
      room.finishCount++;
      player.finished = true;
      player.finishPosition = room.finishCount;

      // Update track for all
      io.to(roomId).emit('positionUpdate', { players: publicPlayers(room) });

      // Announce finish to all
      io.to(roomId).emit('playerFinished', {
        name: player.name,
        place: player.finishPosition
      });

      // Tell this player they're done
      socket.emit('answerResult', {
        correct: true,
        finished: true,
        finishPosition: player.finishPosition
      });

      // Check if everyone is done
      if (Object.values(room.players).every(p => p.finished)) {
        room.state = 'finished';
        const results = Object.values(room.players)
          .sort((a, b) => a.finishPosition - b.finishPosition)
          .map(p => ({ name: p.name, color: p.color, place: p.finishPosition }));
        setTimeout(() => io.to(roomId).emit('gameOver', { results }), 1500);
      }
    } else {
      const nextRiddleIdx = player.queue[player.queuePos];
      const nextRiddle = riddles[nextRiddleIdx];

      // Update track for all
      io.to(roomId).emit('positionUpdate', { players: publicPlayers(room) });

      // Send next riddle to this player
      socket.emit('answerResult', {
        correct: true,
        finished: false,
        riddle: {
          question: nextRiddle.question,
          hint: nextRiddle.hint
        },
        riddleNum: player.position + 1,
        total: FINISH_LINE
      });
    }
  });

  socket.on('getHint', () => {
    if (!roomId) return;
    const room = rooms[roomId];
    if (!room || room.state !== 'playing') return;
    const player = room.players[socket.id];
    if (!player || player.finished) return;

    const riddle = riddles[player.queue[player.queuePos]];
    socket.emit('hint', { hint: riddle.hint });
  });

  socket.on('playAgain', () => {
    if (!roomId) return;
    const room = rooms[roomId];
    if (!room || room.host !== socket.id) return;

    room.state = 'lobby';
    room.finishCount = 0;

    Object.values(room.players).forEach(p => {
      p.position = 0;
      p.queue = shuffle(Array.from({ length: riddles.length }, (_, i) => i));
      p.queuePos = 0;
      p.finished = false;
      p.finishPosition = null;
    });

    io.to(roomId).emit('returnToLobby', { players: publicPlayers(room) });
  });

  socket.on('disconnect', () => {
    if (!roomId || !rooms[roomId]) return;
    const room = rooms[roomId];
    const player = room.players[socket.id];
    if (!player) return;

    const name = player.name;
    const wasHost = room.host === socket.id;
    delete room.players[socket.id];

    if (Object.keys(room.players).length === 0) {
      delete rooms[roomId];
      return;
    }

    if (wasHost) {
      room.host = Object.keys(room.players)[0];
    }

    io.to(roomId).emit('playerUpdate', {
      players: publicPlayers(room),
      message: `${name} left the race.`,
      newHost: wasHost ? room.host : null
    });

    // If game was in progress and all remaining players finished, end it
    if (room.state === 'playing') {
      const allDone = Object.values(room.players).every(p => p.finished);
      if (allDone && Object.keys(room.players).length > 0) {
        room.state = 'finished';
        const results = Object.values(room.players)
          .sort((a, b) => a.finishPosition - b.finishPosition)
          .map(p => ({ name: p.name, color: p.color, place: p.finishPosition }));
        io.to(roomId).emit('gameOver', { results });
      }
    }
  });
});

const PORT = process.env.PORT || 3000;
server.listen(PORT, () => {
  console.log(`\n🏎️  Riddle Racer is running!`);
  console.log(`   Open http://localhost:${PORT} in your browser\n`);
});