'use strict';

// Símbolos disponibles (>= 18 únicos para niveles altos)
const SYMBOLS = [
  '🍎','🍌','🍒','🍇','🍉','🍑','🍊','🍓',
  '🥝','🍍','🥥','🍐','🍈','🍏','🍔','🍕',
  '🎈','⭐','🌙','☀️','⚽','🏀','🎲','🎵',
  '🐶','🐱','🐼','🐸','🦊','🦁','🦄','🐯',
  '🚗','🚀','✈️','🚲','🏝️','🏰'
];

const DIFFICULTIES = {
  facil:   { pairs: 6 },
  normal:  { pairs: 8 },
  dificil: { pairs: 12 },
  extremo: { pairs: 18 }
};

// Estado del juego
let deck = [];              // array de símbolos duplicados y mezclados
let firstCard = null;
let secondCard = null;
let lockBoard = false;
let matches = 0;
let moves = 0;
let totalPairs = DIFFICULTIES.normal.pairs;

let timerId = null;
let startTime = 0;

// DOM
const gameBoard = document.getElementById('game-board');
const infoDiv = document.getElementById('info');
const resetBtn = document.getElementById('reset-btn');
const difficultySelect = document.getElementById('difficulty');
const movesSpan = document.getElementById('moves');
const timeSpan = document.getElementById('time');
const bestSpan = document.getElementById('best-score');

// Utils
function shuffle(array) {
  for (let i = array.length - 1; i > 0; i--) {
    const j = Math.floor(Math.random() * (i + 1));
    [array[i], array[j]] = [array[j], array[i]];
  }
}
function pickSymbols(n) {
  const pool = SYMBOLS.slice();
  shuffle(pool);
  return pool.slice(0, n);
}
function formatTime(seconds) {
  const s = Math.max(0, Math.floor(seconds));
  return `${s}s`;
}
function bestKey(diff) {
  return `memory_best_time_${diff}`;
}
function getBest(diff) {
  const v = localStorage.getItem(bestKey(diff));
  return v ? parseInt(v, 10) : null;
}
function setBestIfBetter(diff, timeSec) {
  const prev = getBest(diff);
  if (prev === null || timeSec < prev) {
    localStorage.setItem(bestKey(diff), String(timeSec));
  }
  const best = getBest(diff);
  if (bestSpan) bestSpan.textContent = best !== null ? `${best}s` : '—';
}

function startTimer() {
  stopTimer();
  startTime = Date.now();
  timerId = setInterval(() => {
    const elapsed = (Date.now() - startTime) / 1000;
    if (timeSpan) timeSpan.textContent = formatTime(elapsed);
  }, 250);
}
function stopTimer() {
  if (timerId) {
    clearInterval(timerId);
    timerId = null;
  }
}

function gridColumnsFor(totalCards) {
  // Aproxima columnas en función del total para formar rejilla compacta
  if (totalCards <= 12) return 4;
  if (totalCards <= 16) return 4;
  if (totalCards <= 24) return 6;
  if (totalCards <= 30) return 6;
  return 6;
}

function setupBoard() {
  // Leer dificultad
  const diff = (difficultySelect && difficultySelect.value) || 'normal';
  const conf = DIFFICULTIES[diff] || DIFFICULTIES.normal;
  totalPairs = conf.pairs;

  // Reiniciar estado
  matches = 0;
  moves = 0;
  firstCard = null;
  secondCard = null;
  lockBoard = false;
  if (movesSpan) movesSpan.textContent = String(moves);
  if (infoDiv) infoDiv.textContent = '';

  // Construir mazo
  const chosen = pickSymbols(totalPairs);
  deck = [...chosen, ...chosen];
  shuffle(deck);

  // Render tablero accesible
  gameBoard.textContent = '';
  const totalCards = deck.length;
  const cols = gridColumnsFor(totalCards);
  gameBoard.style.gridTemplateColumns = `repeat(${cols}, 1fr)`;

  deck.forEach((symbol, idx) => {
    const cardEl = document.createElement('button');
    cardEl.type = 'button';
    cardEl.className = 'card';
    cardEl.dataset.index = String(idx);
    cardEl.dataset.symbol = symbol;
    cardEl.textContent = '';
    cardEl.setAttribute('role', 'gridcell');
    cardEl.setAttribute('aria-label', 'Carta de memoria');
    cardEl.setAttribute('aria-disabled', 'false');

    cardEl.addEventListener('click', () => flipCard(cardEl));
    cardEl.addEventListener('keydown', (e) => {
      if (e.key === 'Enter' || e.key === ' ') {
        e.preventDefault();
        flipCard(cardEl);
      }
    });

    gameBoard.appendChild(cardEl);
  });

  // Mostrar mejor tiempo
  const best = getBest(diff);
  if (bestSpan) bestSpan.textContent = best !== null ? `${best}s` : '—';

  // Arrancar temporizador
  startTimer();

  // Foco inicial
  const first = gameBoard.querySelector('.card');
  if (first) first.focus();
}

function flipCard(cardEl) {
  if (lockBoard) return;
  if (cardEl.classList.contains('flipped') || cardEl.classList.contains('matched')) return;

  // Voltear carta
  cardEl.classList.add('flipped');
  cardEl.textContent = cardEl.dataset.symbol;
  cardEl.setAttribute('aria-disabled', 'true');

  if (!firstCard) {
    firstCard = cardEl;
    return;
  }
  if (!secondCard && cardEl !== firstCard) {
    secondCard = cardEl;
    lockBoard = true;
    moves++;
    if (movesSpan) movesSpan.textContent = String(moves);

    if (firstCard.dataset.symbol === secondCard.dataset.symbol) {
      // Pareja encontrada
      firstCard.classList.add('matched');
      secondCard.classList.add('matched');
      matches++;
      setTimeout(() => {
        resetSelection();
        if (matches === totalPairs) {
          // Fin de partida
          const elapsed = Math.floor((Date.now() - startTime) / 1000);
          if (infoDiv) infoDiv.textContent = `¡Felicidades! 🎉 Parejas: ${totalPairs} · Movimientos: ${moves} · Tiempo: ${elapsed}s`;
          stopTimer();
          const diff = (difficultySelect && difficultySelect.value) || 'normal';
          setBestIfBetter(diff, elapsed);
        }
      }, 400);
    } else {
      // No es pareja, desvoltear tras un momento
      setTimeout(() => {
        unflip(firstCard);
        unflip(secondCard);
        resetSelection();
      }, 700);
    }
  }
}

function unflip(el) {
  if (!el) return;
  el.classList.remove('flipped');
  el.textContent = '';
  el.setAttribute('aria-disabled', 'false');
}

function resetSelection() {
  firstCard = null;
  secondCard = null;
  lockBoard = false;
}

// Listeners
resetBtn.addEventListener('click', () => {
  stopTimer();
  setupBoard();
});
if (difficultySelect) {
  difficultySelect.addEventListener('change', () => {
    stopTimer();
    setupBoard();
  });
}

// Init
setupBoard();