// McGonagall's Wizard Chess (Zauberschach) Mini-Game
(function() {
    const boardEl = document.getElementById('chessBoard');
    if (!boardEl) return;

    const statusMsg = document.getElementById('chessStatus');
    const moveHistoryEl = document.getElementById('moveHistory');
    const modalBackdrop = document.getElementById('modalBackdrop');
    const modalTitle = document.getElementById('modalTitle');
    const modalText = document.getElementById('modalText');
    const modalBtn = document.getElementById('modalBtn');
    const btnResetChess = document.getElementById('btnResetChess');

    // Piece Unicode Symbols
    const PIECES = {
        'wK': '♔', 'wQ': '♕', 'wR': '♖', 'wB': '♗', 'wN': '♘', 'wP': '♙',
        'bK': '♚', 'bQ': '♛', 'bR': '♜', 'bB': '♝', 'bN': '♞', 'bP': '♟'
    };

    // Initial Board State for "Rons Meisterzug" (Smothered Mate / Zauberschach-Taktik)
    // Black to move: Knight on g4 and Queen on h4 attack White's castled King on h1!
    let initialPosition = {
        'h1': 'wK', 'g2': 'wP', 'h2': 'wP', 'f1': 'wR', 'd2': 'wQ', 'b2': 'wP', 'a1': 'wR',
        'g8': 'bK', 'g7': 'bP', 'h7': 'bP', 'f8': 'bR', 'h4': 'bQ', 'g4': 'bN', 'c6': 'bP'
    };

    let boardState = {};
    let selectedSquare = null;
    let isSolved = false;

    function initBoard() {
        boardState = Object.assign({}, initialPosition);
        selectedSquare = null;
        isSolved = false;
        if (statusMsg) {
            statusMsg.innerHTML = "🧙‍♂️ <strong>Du führst Schwarz (Rons Springer & Hermines Figuren)!</strong> Finde den vernichtenden Zug gegen den weißen König!";
            statusMsg.style.color = "var(--gold)";
        }
        if (moveHistoryEl) moveHistoryEl.innerHTML = "<li>Partie eröffnet: Schwarz am Zug!</li>";
        renderBoard();
    }

    // Valid moves for Black pieces in this tactical puzzle
    function getValidMoves(square) {
        const piece = boardState[square];
        if (!piece || !piece.startsWith('b')) return [];

        const file = square.charCodeAt(0) - 97; // 0 to 7 (a-h)
        const rank = parseInt(square[1], 10) - 1; // 0 to 7 (1-8)
        const moves = [];

        if (piece === 'bN') {
            // Knight moves: L-shape
            const offsets = [
                [-2, -1], [-2, 1], [-1, -2], [-1, 2],
                [1, -2], [1, 2], [2, -1], [2, 1]
            ];
            offsets.forEach(([df, dr]) => {
                const nf = file + df;
                const nr = rank + dr;
                if (nf >= 0 && nf < 8 && nr >= 0 && nr < 8) {
                    const targetSq = String.fromCharCode(97 + nf) + (nr + 1);
                    const targetPiece = boardState[targetSq];
                    if (!targetPiece || targetPiece.startsWith('w')) {
                        moves.push(targetSq);
                    }
                }
            });
        } else if (piece === 'bQ') {
            // Queen moves: orthogonal + diagonal
            const directions = [
                [0, 1], [0, -1], [1, 0], [-1, 0],
                [1, 1], [1, -1], [-1, 1], [-1, -1]
            ];
            directions.forEach(([df, dr]) => {
                let step = 1;
                while (true) {
                    const nf = file + df * step;
                    const nr = rank + dr * step;
                    if (nf < 0 || nf >= 8 || nr < 0 || nr >= 8) break;
                    const targetSq = String.fromCharCode(97 + nf) + (nr + 1);
                    const targetPiece = boardState[targetSq];
                    if (!targetPiece) {
                        moves.push(targetSq);
                    } else {
                        if (targetPiece.startsWith('w')) moves.push(targetSq);
                        break;
                    }
                    step++;
                }
            });
        }
        return moves;
    }

    function renderBoard() {
        boardEl.innerHTML = '';
        // 8 ranks (from 8 down to 1), 8 files (a to h)
        for (let r = 8; r >= 1; r--) {
            for (let f = 0; f < 8; f++) {
                const sq = String.fromCharCode(97 + f) + r;
                const isLight = (f + r) % 2 !== 0;

                const tile = document.createElement('div');
                tile.className = `chess-sq ${isLight ? 'light' : 'dark'}`;
                tile.dataset.sq = sq;

                if (selectedSquare === sq) {
                    tile.classList.add('selected');
                }

                const piece = boardState[sq];
                if (piece) {
                    const pSpan = document.createElement('span');
                    pSpan.className = `chess-piece ${piece.startsWith('w') ? 'white-piece' : 'black-piece'}`;
                    pSpan.innerText = PIECES[piece] || '';
                    tile.appendChild(pSpan);
                }

                // Show valid moves
                if (selectedSquare) {
                    const validMoves = getValidMoves(selectedSquare);
                    if (validMoves.includes(sq)) {
                        const dot = document.createElement('div');
                        dot.className = piece ? 'move-capture-ring' : 'move-dot';
                        tile.appendChild(dot);
                    }
                }

                tile.addEventListener('click', () => onSquareClick(sq));
                boardEl.appendChild(tile);
            }
        }
    }

    function onSquareClick(sq) {
        if (isSolved) return;

        const piece = boardState[sq];

        if (selectedSquare) {
            const validMoves = getValidMoves(selectedSquare);
            if (validMoves.includes(sq)) {
                // Execute Move!
                executeMove(selectedSquare, sq);
                selectedSquare = null;
                return;
            }
        }

        // Select new piece if black
        if (piece && piece.startsWith('b')) {
            selectedSquare = sq;
            if (window.soundFX) window.soundFX.playStoneSlide();
            renderBoard();
        } else {
            selectedSquare = null;
            renderBoard();
        }
    }

    async function executeMove(fromSq, toSq) {
        const piece = boardState[fromSq];
        const capturedPiece = boardState[toSq];

        delete boardState[fromSq];
        boardState[toSq] = piece;

        if (window.soundFX) {
            window.soundFX.playStoneSlide();
            if (capturedPiece) {
                window.soundFX.playPoisonSizzle(); // Crushing sound
            }
        }

        renderBoard();

        // Check if winning move:
        // Winning move 1: Knight moves to f2+ (Smothered mate / Royal fork!)
        // Winning move 2: Queen captures h2# (Schachmatt!)
        if (piece === 'bN' && toSq === 'f2') {
            if (moveHistoryEl) {
                const li = document.createElement('li');
                li.innerHTML = `<strong>1... ♞f2+</strong> (Springer-Schach! Weißer König erstarrt!)`;
                moveHistoryEl.appendChild(li);
            }
            triggerWin("♞f2+", "Rons Springer zerschellt die weiße Verteidigung! Der weiße König hat kein Feld mehr und die weiße Königin muss kapitulieren!");
        } else if (piece === 'bQ' && toSq === 'h2') {
            if (moveHistoryEl) {
                const li = document.createElement('li');
                li.innerHTML = `<strong>1... ♛xh2#</strong> (Schachmatt! Die schwarze Dame schlägt zu!)`;
                moveHistoryEl.appendChild(li);
            }
            triggerWin("♛xh2#", "Schachmatt! Mit kaltblütiger Präzision fällt der weiße König in Trümmer!");
        } else {
            if (moveHistoryEl) {
                const li = document.createElement('li');
                li.innerHTML = `Zug: ${piece} nach ${toSq}. Weiß pariert den Angriff. Versuche es erneut!`;
                moveHistoryEl.appendChild(li);
            }
            if (statusMsg) {
                statusMsg.innerHTML = "⚠️ <em>Kein Schachmatt! Die weißen Figuren schlagen zurück. Drücke auf 'Zurücksetzen' und versuche es erneut!</em>";
                statusMsg.style.color = "#e67e22";
            }
        }
    }

    async function triggerWin(moveNotation, explanation) {
        isSolved = true;
        if (window.soundFX) window.soundFX.playMagicSuccess();

        if (statusMsg) {
            statusMsg.innerHTML = `🏆 <strong>${moveNotation} — SCHACHMATT!</strong> Die gigantischen weißen Steinfiguren senken ihre Schwerter!`;
            statusMsg.style.color = "#2ecc71";
        }

        try {
            const res = await fetch('/api/chess/complete', { method: 'POST' });
            const data = await res.json();
            if (data.new_item && window.notifyNewItem) {
                window.notifyNewItem(data.new_item);
            }
        } catch (e) {
            console.error(e);
        }

        modalTitle.innerText = "♟️ Zauberschach Gemeistert!";
        modalText.innerHTML = `
            <strong>${moveNotation} — Grandios kombiniert!</strong><br><br>
            ${explanation}<br><br>
            Die weiße Königin wirft ihr Schwert zu Boden. Die Riesen-Schachfiguren weichen zur Seite und die Tür zur <strong>Flammenkammer (Snapes Flaschenrätsel)</strong> steht weit offen!<br><br>
            🎒 <em>Ein massiver schwarzer Springer wurde deinem Zauberbeutel hinzugefügt!</em>
        `;
        modalBtn.innerText = "Weiter zu Snapes Flammenkammer 🧪";
        modalBtn.onclick = () => { window.location.href = '/bottles'; };
        modalBackdrop.classList.add('show');
    }

    if (btnResetChess) {
        btnResetChess.addEventListener('click', () => {
            if (window.soundFX) window.soundFX.playStoneSlide();
            initBoard();
        });
    }

    initBoard();
})();