class Card {
  constructor(imgPath) {
    this.img = "ASSets/" + imgPath;
    this.name = imgPath.split(".")[0];
    this.pairId = Card.nextPairId++;
  }
  static altText = "Upside-down card";
  static nextPairId = 0;
}

const cards = [
  "card1.jpg",
  "card2.jpg",
  "card3.jpeg",
]

const deck = [];
cards.forEach(card => {
  deck.push(new Card(card));
});

// Fisher-Yates shuffle
const 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]];
  }
  return array;
}

const buildFullDeck = (baseDeck) => {
  return shuffle([...baseDeck, ...baseDeck]);
};

const createCardElement = (backSrc) => {
  const cardElem = document.createElement("div");
  cardElem.className = "card";
  cardElem.dataset.revealed = "false";
  const img = document.createElement("img");
  img.src = backSrc;
  img.alt = Card.altText;
  cardElem.appendChild(img);
  return cardElem;
};

const revealCard = (elem, card) => {
  const img = elem.querySelector("img");
  img.src = card.img;
  elem.dataset.revealed = "true";
};

const hideCard = (elem, backSrc) => {
  const img = elem.querySelector("img");
  img.src = backSrc;
  elem.dataset.revealed = "false";
};

const startGame = () => {
  const container = document.getElementById("cards");
  const backSrc = "ASSets/cardback.jpg";
  const winSfx = new Audio("ASSets/fart.mp3");
  const fullDeck = buildFullDeck(deck);
  container.innerHTML = "";

  let firstPick = null;
  let isLocked = false;
  let matchedCount = 0;

  fullDeck.forEach((card) => {
    const el = createCardElement(backSrc);

    el.addEventListener("click", () => {
      if (isLocked) return;
      if (el.dataset.revealed === "true") return;

      revealCard(el, card);

      if (!firstPick) {
        firstPick = { el, card };
        return;
      }

      if (firstPick.card.pairId === card.pairId && firstPick.el !== el) {
        matchedCount += 2;
        firstPick = null;
        if (matchedCount === fullDeck.length) {
          try { winSfx.currentTime = 0; winSfx.play(); } catch (_) {}
          setTimeout(startGame, 800);
        }
      } else {
        isLocked = true;
        const prev = firstPick;
        firstPick = null;
        setTimeout(() => {
          hideCard(prev.el, backSrc);
          hideCard(el, backSrc);
          isLocked = false;
        }, 700);
      }
    });

    container.appendChild(el);
  });
};