(function() {
  var SIZE = 6;
  var NUM_CHECKPOINTS = 6;
  var TOTAL_CELLS = SIZE * SIZE;
  var WALL_PROBABILITY = 0.55;

  function mulberry32(seed) {
    return function() {
      seed |= 0; seed = (seed + 0x6D2B79F5) | 0;
      var t = Math.imul(seed ^ (seed >>> 15), 1 | seed);
      t = (t + Math.imul(t ^ (t >>> 7), 61 | t)) ^ t;
      return ((t ^ (t >>> 14)) >>> 0) / 4294967296;
    };
  }
  function hashSeed(str) {
    var h = 0;
    for (var i = 0; i < str.length; i++) h = (Math.imul(31, h) + str.charCodeAt(i)) | 0;
    return h;
  }
  function shuffle(arr, rng) {
    for (var i = arr.length - 1; i > 0; i--) {
      var j = Math.floor(rng() * (i + 1));
      var tmp = arr[i]; arr[i] = arr[j]; arr[j] = tmp;
    }
    return arr;
  }
  function generateHamiltonianPath(size, rng) {
    var total = size * size;
    var visited = new Array(total).fill(false);
    var path = [];
    var attempts = 0, MAX_ATTEMPTS = 300000, aborted = false;
    function idx(r,c){ return r*size+c; }
    function neighbors(r,c) {
      var dirs = [[0,1],[0,-1],[1,0],[-1,0]], result = [];
      dirs.forEach(function(d){
        var nr=r+d[0], nc=c+d[1];
        if (nr>=0 && nr<size && nc>=0 && nc<size && !visited[idx(nr,nc)]) result.push([nr,nc]);
      });
      return shuffle(result, rng);
    }
    function dfs(r,c) {
      attempts++;
      if (attempts > MAX_ATTEMPTS) { aborted = true; return false; }
      visited[idx(r,c)] = true; path.push(idx(r,c));
      if (path.length === total) return true;
      var nbrs = neighbors(r,c);
      for (var i=0;i<nbrs.length;i++) {
        if (dfs(nbrs[i][0], nbrs[i][1])) return true;
        if (aborted) return false;
      }
      visited[idx(r,c)] = false; path.pop();
      return false;
    }
    var sR = Math.floor(rng()*size), sC = Math.floor(rng()*size);
    var ok = dfs(sR, sC);
    if (!ok || aborted) {
      path = [];
      for (var r=0;r<size;r++) {
        if (r%2===0) { for (var c=0;c<size;c++) path.push(idx(r,c)); }
        else { for (var c=size-1;c>=0;c--) path.push(idx(r,c)); }
      }
    }
    return path;
  }

  function edgeKey(a, b) { return a < b ? a + '_' + b : b + '_' + a; }

  function allGridEdges(size) {
    var edges = [];
    for (var r = 0; r < size; r++) {
      for (var c = 0; c < size; c++) {
        var idx = r*size+c;
        if (c+1 < size) edges.push([idx, idx+1]);
        if (r+1 < size) edges.push([idx, idx+size]);
      }
    }
    return edges;
  }

  function buildPuzzle(seedStr) {
    var rng = mulberry32(hashSeed(seedStr));
    var hamPath = generateHamiltonianPath(SIZE, rng);
    var checkpoints = {};
    var step = (TOTAL_CELLS - 1) / (NUM_CHECKPOINTS - 1);
    for (var k = 0; k < NUM_CHECKPOINTS; k++) {
      var pos = Math.round(k * step);
      checkpoints[hamPath[pos]] = k + 1;
    }
    var usedEdges = new Set();
    for (var i = 0; i < hamPath.length - 1; i++) usedEdges.add(edgeKey(hamPath[i], hamPath[i+1]));

    var walls = new Set();
    allGridEdges(SIZE).forEach(function(e) {
      var key = edgeKey(e[0], e[1]);
      if (usedEdges.has(key)) return;
      if (rng() < WALL_PROBABILITY) walls.add(key);
    });

    return { hamPath: hamPath, checkpoints: checkpoints, walls: walls };
  }
  function isAdjacent(a, b) {
    var ra = Math.floor(a/SIZE), ca = a%SIZE, rb = Math.floor(b/SIZE), cb = b%SIZE;
    return (Math.abs(ra-rb)===1 && ca===cb) || (Math.abs(ca-cb)===1 && ra===rb);
  }
  function hasWall(walls, a, b) { return walls.has(edgeKey(a, b)); }
  function todayStr() {
    var d = new Date();
    return d.getFullYear() + '-' + String(d.getMonth()+1).padStart(2,'0') + '-' + String(d.getDate()).padStart(2,'0');
  }

  // ---- State ----
  var puzzle = null;
  var path = [];
  var isDragging = false;
  var timerInterval = null;
  var elapsedSeconds = 0;
  var isDaily = true;

  var gridEl = document.getElementById('mm-zip-grid');
  var svgEl = document.getElementById('mm-zip-svg');
  var polylineEl = document.getElementById('mm-zip-polyline');
  var timerEl = document.getElementById('mm-zip-timer');
  var progressEl = document.getElementById('mm-zip-progress');
  var titleEl = document.getElementById('mm-zip-title');
  var modeTagEl = document.getElementById('mm-zip-mode-tag');
  var playArea = document.getElementById('mm-zip-play-area');
  var winArea = document.getElementById('mm-zip-win-area');
  var cellEls = [];

  gridEl.style.gridTemplateColumns = 'repeat(' + SIZE + ', 1fr)';
  gridEl.style.gridTemplateRows = 'repeat(' + SIZE + ', 1fr)';

  function buildGridDOM() {
    gridEl.innerHTML = '';
    cellEls = [];
    for (var i = 0; i < TOTAL_CELLS; i++) {
      var cell = document.createElement('div');
      cell.className = 'mm-zip-cell';
      cell.dataset.idx = i;
      if (puzzle.checkpoints[i] !== undefined) {
        cell.classList.add('mm-checkpoint');
        cell.textContent = puzzle.checkpoints[i];
      }
      var r = Math.floor(i/SIZE), c = i%SIZE;
      var up = i - SIZE, down = i + SIZE, left = c > 0 ? i-1 : null, right = c < SIZE-1 ? i+1 : null;
      if (r > 0 && hasWall(puzzle.walls, i, up)) cell.classList.add('mm-wall-top');
      if (r < SIZE-1 && hasWall(puzzle.walls, i, down)) cell.classList.add('mm-wall-bottom');
      if (left !== null && hasWall(puzzle.walls, i, left)) cell.classList.add('mm-wall-left');
      if (right !== null && hasWall(puzzle.walls, i, right)) cell.classList.add('mm-wall-right');
      gridEl.appendChild(cell);
      cellEls.push(cell);
    }
  }

  function cellCenter(idx) {
    var cellEl = cellEls[idx];
    var gridRect = gridEl.getBoundingClientRect();
    var cellRect = cellEl.getBoundingClientRect();
    return { x: cellRect.left - gridRect.left + cellRect.width/2, y: cellRect.top - gridRect.top + cellRect.height/2 };
  }

  function updateVisuals() {
    cellEls.forEach(function(cell) { cell.classList.remove('mm-filled', 'mm-current', 'mm-checkpoint-done'); });
    path.forEach(function(idx) {
      cellEls[idx].classList.add('mm-filled');
      if (puzzle.checkpoints[idx] !== undefined) cellEls[idx].classList.add('mm-checkpoint-done');
    });
    if (path.length) cellEls[path[path.length-1]].classList.add('mm-current');
    var pts = path.map(function(idx) { var c = cellCenter(idx); return c.x + ',' + c.y; }).join(' ');
    polylineEl.setAttribute('points', pts);
    progressEl.textContent = path.length + '/' + TOTAL_CELLS;
  }

  function nextExpectedCheckpoint() {
    var maxSeen = 0;
    path.forEach(function(idx) { if (puzzle.checkpoints[idx] !== undefined) maxSeen = Math.max(maxSeen, puzzle.checkpoints[idx]); });
    return maxSeen + 1;
  }

  function tryExtend(cellIdx) {
    if (path.indexOf(cellIdx) !== -1) {
      var pos = path.indexOf(cellIdx);
      path = path.slice(0, pos + 1);
      updateVisuals();
      return;
    }
    if (path.length === 0) {
      path.push(cellIdx);
      startTimerIfNeeded();
      updateVisuals();
      return;
    }
    var last = path[path.length - 1];
    if (!isAdjacent(last, cellIdx)) return;
    if (hasWall(puzzle.walls, last, cellIdx)) return;
    if (puzzle.checkpoints[cellIdx] !== undefined && puzzle.checkpoints[cellIdx] !== nextExpectedCheckpoint()) return;
    path.push(cellIdx);
    updateVisuals();
    checkWin();
  }

  function startTimerIfNeeded() {
    if (timerInterval) return;
    var start = Date.now() - elapsedSeconds * 1000;
    timerInterval = setInterval(function() {
      elapsedSeconds = Math.floor((Date.now() - start) / 1000);
      var m = Math.floor(elapsedSeconds / 60), s = elapsedSeconds % 60;
      timerEl.textContent = m + ':' + String(s).padStart(2, '0');
    }, 250);
  }
  function stopTimer() { if (timerInterval) { clearInterval(timerInterval); timerInterval = null; } }

  function checkWin() {
    if (path.length !== TOTAL_CELLS) return;
    var seenCheckpoints = 0;
    path.forEach(function(idx) { if (puzzle.checkpoints[idx] !== undefined) seenCheckpoints++; });
    if (seenCheckpoints !== NUM_CHECKPOINTS) return;
    stopTimer();
    showWin();
    if (isDaily) { try { localStorage.setItem('mm_zip_done_' + todayStr(), String(elapsedSeconds)); } catch(e) {} }
  }

  function showWin() {
    playArea.style.display = 'none';
    winArea.style.display = 'block';
    var m = Math.floor(elapsedSeconds / 60), s = elapsedSeconds % 60;
    winArea.innerHTML = '<div class="mm-zip-win"><div class="mm-zip-win-emoji">🎉</div><h4>Tamamlandı!</h4>' +
      '<p style="opacity:0.8;">Süre: ' + m + ':' + String(s).padStart(2,'0') + '</p>' +
      '<div class="mm-zip-actions" style="justify-content:center;"><button class="mm-btn mm-btn-primary" id="mm-zip-win-random">🎲 Rastgele Bulmaca Oyna</button></div></div>';
    document.getElementById('mm-zip-win-random').addEventListener('click', function() { startPuzzle(false); });
  }

  function showAlreadyDoneToday(savedSeconds) {
    playArea.style.display = 'none';
    winArea.style.display = 'block';
    var m = Math.floor(savedSeconds / 60), s = savedSeconds % 60;
    winArea.innerHTML = '<div class="mm-zip-win"><div class="mm-zip-win-emoji">✅</div><h4>Bugünkü bulmacayı zaten tamamladın!</h4>' +
      '<p style="opacity:0.8;">Süre: ' + m + ':' + String(s).padStart(2,'0') + ' — yarın yeni bulmaca burada olacak.</p>' +
      '<div class="mm-zip-actions" style="justify-content:center;"><button class="mm-btn mm-btn-primary" id="mm-zip-again-random">🎲 Rastgele Bulmaca ile Pratik Yap</button></div></div>';
    document.getElementById('mm-zip-again-random').addEventListener('click', function() { startPuzzle(false); });
  }

  function startPuzzle(daily) {
    isDaily = daily;
    stopTimer();
    elapsedSeconds = 0;
    timerEl.textContent = '0:00';
    path = [];
    var seed = daily ? ('zip-' + todayStr()) : ('zip-random-' + Math.random());
    puzzle = buildPuzzle(seed);
    titleEl.textContent = daily ? 'Bugünün Bulmacası' : 'Rastgele Bulmaca';
    modeTagEl.textContent = daily ? 'GÜNLÜK' : 'PRATİK';
    playArea.style.display = 'block';
    winArea.style.display = 'none';
    buildGridDOM();
    updateVisuals();
  }

  function pointerCellFromEvent(evt) {
    var x = evt.clientX, y = evt.clientY;
    var el = document.elementFromPoint(x, y);
    if (!el) return null;
    var cellEl = el.closest ? el.closest('.mm-zip-cell') : null;
    if (!cellEl) return null;
    return parseInt(cellEl.dataset.idx, 10);
  }

  gridEl.addEventListener('pointerdown', function(evt) {
    var idx = pointerCellFromEvent(evt);
    if (idx === null) return;
    isDragging = true;
    tryExtend(idx);
    evt.preventDefault();
  });
  gridEl.addEventListener('pointermove', function(evt) {
    if (!isDragging) return;
    var idx = pointerCellFromEvent(evt);
    if (idx === null) return;
    tryExtend(idx);
  });
  window.addEventListener('pointerup', function() { isDragging = false; });
  window.addEventListener('resize', updateVisuals);

  document.getElementById('mm-zip-undo').addEventListener('click', function() {
    if (path.length > 0) { path.pop(); updateVisuals(); }
  });
  document.getElementById('mm-zip-clear').addEventListener('click', function() {
    path = []; elapsedSeconds = 0; stopTimer(); timerEl.textContent = '0:00'; updateVisuals();
  });
  document.getElementById('mm-zip-random').addEventListener('click', function() { startPuzzle(false); });

  var savedToday = null;
  try { savedToday = localStorage.getItem('mm_zip_done_' + todayStr()); } catch(e) {}
  startPuzzle(true);
  if (savedToday !== null) showAlreadyDoneToday(parseInt(savedToday, 10));
})();