(function() {
    // ====== CONSTANTS & STATE ======
    const suits = ['♥', '♦', '♣', '♠'];
    const values = ['A','2','3','4','5','6','7','8','9','10','J','Q','K'];
    const PILE_BORDER_WIDTH = 2;

    let deck, stock, waste, pyramid, discard;
    let cardElements = {};
    let selectedCard = null;
    let score = 0;
    let highScore = 0;
    let isActive = false;

    // DOM Elements
    const gameBoard = document.getElementById('pyramid-board');
    const pyramidLayout = gameBoard.querySelector('.pyramid-layout');
    const stockEl = document.getElementById('pyramid-stock');
    const wasteEl = document.getElementById('pyramid-waste');
    const discardEl = document.getElementById('pyramid-discard');
    const scoreEl = document.getElementById('current-score');
    const highScoreEl = document.getElementById('high-score');
    const winMessage = document.getElementById('win-message');

    // ====== HELPERS ======
    function getValueRank(v) { 
        if (v === 'A') return 1; 
        if (v === 'K') return 13; 
        if (v === 'Q') return 12; 
        if (v === 'J') return 11; 
        if (v === '10') return 10;
        return parseInt(v, 10); 
    }

    function createCardElement(cardData) {
        const el = document.createElement('div');
        el.classList.add('card');
        el.dataset.id = cardData.id;
        const cardInner = document.createElement('div');
        cardInner.classList.add('card-inner');
        const color = (cardData.suit === '♥' || cardData.suit === '♦') ? 'red' : 'black';
        const front = document.createElement('div');
        front.className = `card-face card-face--front ${color}`;
        front.innerHTML = `
            <div class="card-value-display--top"><span class="card-rank">${cardData.value}</span><span class="card-suit">${cardData.suit}</span></div>
            <div class="card-value-display--bottom"><span class="card-rank">${cardData.value}</span><span class="card-suit">${cardData.suit}</span></div>
            <div class="card-watermark">${cardData.suit}</div>`;
        const back = document.createElement('div');
        back.className = 'card-face card-face--back';
        cardInner.append(front, back);
        el.appendChild(cardInner);
        return el;
    }

    function isExposed(cardId) {
        // A card in the pyramid is exposed if no cards in the row below it are still present in the slots it covers.
        // Pyramid indexing: 
        // Row 0: 0
        // Row 1: 1, 2
        // Row 2: 3, 4, 5
        // Row 3: 6, 7, 8, 9
        // Row 4: 10, 11, 12, 13, 14
        // Row 5: 15, 16, 17, 18, 19, 20
        // Row 6: 21, 22, 23, 24, 25, 26, 27
        
        const index = pyramid.findIndex(c => c && c.id === cardId);
        if (index === -1) return true; // Not in pyramid (waste/stock)

        // Find which row it's in
        let row = 0;
        let count = 0;
        for (let r = 0; r < 7; r++) {
            if (index >= count && index < count + r + 1) {
                row = r;
                break;
            }
            count += r + 1;
        }

        if (row === 6) return true; // Bottom row is always exposed if present

        // Check the two cards below it
        // Row r, index i (within row) covers Row r+1, index i and i+1
        const indexInRow = index - count;
        const nextRowStart = count + row + 1;
        const leftBelow = nextRowStart + indexInRow;
        const rightBelow = nextRowStart + indexInRow + 1;

        return !pyramid[leftBelow] && !pyramid[rightBelow];
    }

    // ====== CORE LOGIC ======
    function initPyramid() {
        score = 0;
        highScore = parseInt(localStorage.getItem('pyramid-high-score'), 10) || 0;
        winMessage.classList.add('hidden');
        
        // Clean up
        Object.values(cardElements).forEach(el => el.remove());
        cardElements = {};
        deck = [];
        pyramid = Array(28).fill(null);
        stock = [];
        waste = [];
        discard = [];
        selectedCard = null;

        // Create deck
        suits.forEach(suit => values.forEach(value => {
            deck.push({ suit, value, faceUp: false, id: `p-${value}${suit}-${Math.random().toString(36).slice(2,8)}` });
        }));

        // Shuffle
        for (let i = deck.length - 1; i > 0; i--) {
            const j = Math.floor(Math.random() * (i + 1));
            [deck[i], deck[j]] = [deck[j], deck[i]];
        }

        // Create elements
        deck.forEach(cardData => {
            const el = createCardElement(cardData);
            cardElements[cardData.id] = el;
            gameBoard.appendChild(el);
            
            // Set initial position (will be updated by renderBoard)
            el.style.top = '0px';
            el.style.left = '0px';
        });

        // Fill Pyramid
        for (let i = 0; i < 28; i++) {
            pyramid[i] = deck.pop();
            pyramid[i].faceUp = true;
        }

        stock = deck;
        updateScoreDisplay();
        requestAnimationFrame(renderBoard);
        saveGame();
    }

    function renderBoard() {
        if (!isActive) return;

        const boardRect = gameBoard.getBoundingClientRect();
        const layoutRect = pyramidLayout.getBoundingClientRect();
        
        // If the board isn't visible yet or dimensions aren't ready, wait for the next frame
        if (boardRect.width === 0 || layoutRect.width === 0) {
            requestAnimationFrame(renderBoard);
            return;
        }

        const rootStyle = getComputedStyle(document.documentElement);
        let cardWidth = parseFloat(rootStyle.getPropertyValue('--card-width'));
        if (isNaN(cardWidth) || cardWidth === 0) cardWidth = 80;

        const cardHeight = cardWidth * 1.4;
        const rowOverlap = 0.45;
        const horizontalGap = cardWidth * 0.15; // Proportional gap

        const boardTop = boardRect.top;
        const boardLeft = boardRect.left;

        // Position Pyramid Cards
        let index = 0;
        for (let row = 0; row < 7; row++) {
            // Calculate total width of this row to center it
            const numCards = row + 1;
            const totalRowWidth = numCards * cardWidth + (numCards - 1) * horizontalGap;
            const startX = (layoutRect.width - totalRowWidth) / 2;
            const y = row * (cardHeight * rowOverlap);

            for (let i = 0; i <= row; i++) {
                const card = pyramid[index];
                if (card) {
                    const el = cardElements[card.id];
                    // Absolute position relative to the gameBoard
                    const finalTop = y + (layoutRect.top - boardTop);
                    const finalLeft = startX + i * (cardWidth + horizontalGap) + (layoutRect.left - boardLeft);
                    
                    el.style.top = `${finalTop}px`;
                    el.style.left = `${finalLeft}px`;
                    el.style.zIndex = 100 + index;
                    el.classList.add('is-flipped');
                    
                    // Mark if it's currently playable for visual feedback
                    const exposed = isExposed(card.id);
                    el.classList.toggle('is-exposed', exposed);
                    el.style.opacity = exposed ? '1' : '0.85';
                    // el.style.filter = exposed ? 'none' : 'brightness(0.8)'; // Optional: dim unexposed cards
                }
                index++;
            }
        }

        // Position Stock
        const sRect = stockEl.getBoundingClientRect();
        stock.forEach((card, i) => {
            const el = cardElements[card.id];
            el.style.top = `${sRect.top - boardTop + PILE_BORDER_WIDTH}px`;
            el.style.left = `${sRect.left - boardLeft + PILE_BORDER_WIDTH}px`;
            el.style.zIndex = 10 + i;
            el.classList.remove('is-flipped');
            el.classList.remove('is-selected');
            el.classList.remove('is-exposed');
        });

        // Position Waste
        const wRect = wasteEl.getBoundingClientRect();
        waste.forEach((card, i) => {
            const el = cardElements[card.id];
            const isTop = (i === waste.length - 1);
            el.style.top = `${wRect.top - boardTop + PILE_BORDER_WIDTH}px`;
            el.style.left = `${wRect.left - boardLeft + PILE_BORDER_WIDTH}px`;
            // Base z-index for waste is 500, +i to stack correctly
            el.style.zIndex = 500 + i;
            el.classList.add('is-flipped');
            el.classList.toggle('is-exposed', isTop);
        });

        // Position Discard
        const dRect = discardEl.getBoundingClientRect();
        discard.forEach((card, i) => {
            const el = cardElements[card.id];
            el.style.top = `${dRect.top - boardTop + PILE_BORDER_WIDTH}px`;
            el.style.left = `${dRect.left - boardLeft + PILE_BORDER_WIDTH}px`;
            el.style.zIndex = 10 + i;
            el.classList.add('is-flipped');
            el.classList.remove('is-selected');
            el.classList.remove('is-exposed');
        });
        
        checkWin();
    }

    function handleCardClick(cardId) {
        if (!isActive) return;

        // Find card
        let card = null;
        let source = '';
        let pIdx = pyramid.findIndex(c => c && c.id === cardId);
        if (pIdx !== -1) {
            card = pyramid[pIdx];
            source = 'pyramid';
        } else if (waste.length > 0 && waste[waste.length - 1].id === cardId) {
            card = waste[waste.length - 1];
            source = 'waste';
        }

        if (!card) return;
        if (source === 'pyramid' && !isExposed(cardId)) return;

        const el = cardElements[card.id];

        // King is special (13) - remove immediately
        if (getValueRank(card.value) === 13) {
            if (selectedCard) {
                cardElements[selectedCard.id].classList.remove('is-selected');
                selectedCard = null;
            }
            removeCards([card]);
            return;
        }

        if (!selectedCard) {
            selectedCard = card;
            el.classList.add('is-selected');
        } else {
            if (selectedCard.id === card.id) {
                // Deselect if clicking the same card
                el.classList.remove('is-selected');
                selectedCard = null;
            } else {
                // Try to match
                if (getValueRank(selectedCard.value) + getValueRank(card.value) === 13) {
                    removeCards([selectedCard, card]);
                    selectedCard = null;
                } else {
                    // Invalid pair: switch selection to the new card
                    cardElements[selectedCard.id].classList.remove('is-selected');
                    selectedCard = card;
                    el.classList.add('is-selected');
                }
            }
        }
    }

    function removeCards(cards) {
        cards.forEach(card => {
            // Remove from pyramid
            const pIdx = pyramid.findIndex(c => c && c.id === card.id);
            if (pIdx !== -1) pyramid[pIdx] = null;

            // Remove from waste
            const wIdx = waste.findIndex(c => c && c.id === card.id);
            if (wIdx !== -1) waste.splice(wIdx, 1);

            discard.push(card);
            cardElements[card.id].classList.remove('is-selected');
            score += 5;
        });
        updateScoreDisplay();
        renderBoard();
        saveGame();
    }

    function handleStockClick() {
        // Clear current selection when drawing/recycling
        if (selectedCard) {
            cardElements[selectedCard.id].classList.remove('is-selected');
            selectedCard = null;
        }

        if (stock.length > 0) {
            const card = stock.pop();
            card.faceUp = true;
            waste.push(card);
        } else if (waste.length > 0) {
            // Recycle waste back to stock
            stock = waste.reverse();
            stock.forEach(c => c.faceUp = false);
            waste = [];
        }
        renderBoard();
        saveGame();
    }

    function updateScoreDisplay() {
        if (!isActive) return;
        scoreEl.textContent = score;
        highScoreEl.textContent = highScore;
    }

    function checkWin() {
        if (pyramid.every(c => c === null)) {
            if (score > highScore) {
                highScore = score;
                localStorage.setItem('pyramid-high-score', highScore);
                updateScoreDisplay();
            }
            winMessage.classList.remove('hidden');
            // Trigger bouncing cards - reuse logic if available or implement local
            if (window.triggerBouncingCards) window.triggerBouncingCards();
        }
    }

    function saveGame() {
        const state = { pyramid, stock, waste, discard, score };
        localStorage.setItem('pyramid-save', JSON.stringify(state));
    }

    function loadGame() {
        const saved = localStorage.getItem('pyramid-save');
        if (!saved) return false;
        try {
            const state = JSON.parse(saved);
            pyramid = state.pyramid;
            stock = state.stock;
            waste = state.waste;
            discard = state.discard;
            score = state.score || 0;
            
            // Rebuild elements
            Object.values(cardElements).forEach(el => el.remove());
            cardElements = {};
            const all = [...pyramid.filter(c => c), ...stock, ...waste, ...discard];
            all.forEach(c => {
                const el = createCardElement(c);
                cardElements[c.id] = el;
                gameBoard.appendChild(el);
            });
            renderBoard();
            updateScoreDisplay();
            return true;
        } catch (e) {
            return false;
        }
    }

    // ====== EVENT LISTENERS ======
    gameBoard.addEventListener('click', (e) => {
        if (!isActive) return;

        const cardEl = e.target.closest('.card');
        const pileEl = e.target.closest('.pile');

        // Check if we clicked the stock pile OR a card that is currently in the stock
        const isStockClick = (pileEl && pileEl.id === 'pyramid-stock') || 
                            (cardEl && stock.some(c => c.id === cardEl.dataset.id));

        if (isStockClick) {
            handleStockClick();
            return;
        }

        if (cardEl) {
            handleCardClick(cardEl.dataset.id);
            return;
        }

        // If we click the board background but NOT a card or a pile, clear selection
        if (selectedCard && !cardEl && !pileEl) {
            cardElements[selectedCard.id].classList.remove('is-selected');
            selectedCard = null;
        }
    });

    document.addEventListener('gameModeChanged', (e) => {
        isActive = (e.detail === 'pyramid');
        if (isActive) {
            if (!pyramid) {
                if (!loadGame()) initPyramid();
            } else {
                updateScoreDisplay();
                requestAnimationFrame(renderBoard);
            }
        }
    });

    // Handle New Game button from topbar
    document.getElementById('restart-btn').addEventListener('click', () => {
        if (isActive) initPyramid();
    });

    window.addEventListener('resize', () => {
        if (isActive) renderBoard();
    });

    // Initial check
    if (localStorage.getItem('solitaire-mode') === 'pyramid') {
        isActive = true;
        if (!loadGame()) initPyramid();
    }
})();