(function (global) {
  'use strict';

  const PATTERNS = {
    glider: {
      name: 'Glider',
      cells: [
        [0, 1],
        [1, 2],
        [2, 0],
        [2, 1],
        [2, 2],
      ],
    },
    pulsar: {
      name: 'Pulsar',
      cells: [
        [0, 2], [0, 3], [0, 4], [0, 8], [0, 9], [0, 10],
        [2, 0], [2, 5], [2, 7], [2, 12],
        [3, 0], [3, 5], [3, 7], [3, 12],
        [4, 0], [4, 5], [4, 7], [4, 12],
        [5, 2], [5, 3], [5, 4], [5, 8], [5, 9], [5, 10],
        [7, 2], [7, 3], [7, 4], [7, 8], [7, 9], [7, 10],
        [8, 0], [8, 5], [8, 7], [8, 12],
        [9, 0], [9, 5], [9, 7], [9, 12],
        [10, 0], [10, 5], [10, 7], [10, 12],
        [12, 2], [12, 3], [12, 4], [12, 8], [12, 9], [12, 10],
      ],
    },
    gosperGliderGun: {
      name: 'Gosper Glider Gun',
      cells: [
        [0, 24],
        [1, 22], [1, 24],
        [2, 12], [2, 13], [2, 20], [2, 21], [2, 34], [2, 35],
        [3, 11], [3, 15], [3, 20], [3, 21], [3, 34], [3, 35],
        [4, 0], [4, 1], [4, 10], [4, 16], [4, 20], [4, 21],
        [5, 0], [5, 1], [5, 10], [5, 14], [5, 16], [5, 17], [5, 22], [5, 24],
        [6, 10], [6, 16], [6, 24],
        [7, 11], [7, 15],
        [8, 12], [8, 13],
      ],
    },
  };

  function createEmptyGrid(rows, cols) {
    return Array.from({ length: rows }, function () {
      return Array(cols).fill(0);
    });
  }

  function cloneGrid(grid) {
    return grid.map(function (row) {
      return row.slice();
    });
  }

  function countLiveNeighbors(grid, row, col) {
    let total = 0;

    for (let rowOffset = -1; rowOffset <= 1; rowOffset += 1) {
      for (let colOffset = -1; colOffset <= 1; colOffset += 1) {
        if (rowOffset === 0 && colOffset === 0) {
          continue;
        }

        const nextRow = row + rowOffset;
        const nextCol = col + colOffset;

        if (
          nextRow >= 0 &&
          nextRow < grid.length &&
          nextCol >= 0 &&
          nextCol < grid[0].length
        ) {
          total += grid[nextRow][nextCol];
        }
      }
    }

    return total;
  }

  function stepGrid(grid) {
    return grid.map(function (cells, rowIndex) {
      return cells.map(function (cell, colIndex) {
        const neighbors = countLiveNeighbors(grid, rowIndex, colIndex);

        if (cell === 1) {
          return neighbors === 2 || neighbors === 3 ? 1 : 0;
        }

        return neighbors === 3 ? 1 : 0;
      });
    });
  }

  function stampPattern(grid, pattern, offsetRow, offsetCol) {
    pattern.cells.forEach(function (cell) {
      const row = cell[0] + offsetRow;
      const col = cell[1] + offsetCol;

      if (row >= 0 && row < grid.length && col >= 0 && col < grid[0].length) {
        grid[row][col] = 1;
      }
    });

    return grid;
  }

  function countLiveCells(grid) {
    return grid.reduce(function (total, row) {
      return total + row.reduce(function (rowTotal, cell) {
        return rowTotal + cell;
      }, 0);
    }, 0);
  }

  function centerPattern(grid, pattern) {
    const lastRow = pattern.cells.reduce(function (maxRow, cell) {
      return Math.max(maxRow, cell[0]);
    }, 0);
    const lastCol = pattern.cells.reduce(function (maxCol, cell) {
      return Math.max(maxCol, cell[1]);
    }, 0);
    const offsetRow = Math.max(0, Math.floor((grid.length - (lastRow + 1)) / 2));
    const offsetCol = Math.max(0, Math.floor((grid[0].length - (lastCol + 1)) / 2));

    return stampPattern(grid, pattern, offsetRow, offsetCol);
  }

  function createInitialState(options) {
    const rows = options.rows;
    const cols = options.cols;
    const defaultPattern = options.defaultPattern || 'pulsar';
    const grid = createEmptyGrid(rows, cols);

    centerPattern(grid, PATTERNS[defaultPattern]);

    return {
      cols: cols,
      defaultPattern: defaultPattern,
      generation: 0,
      grid: grid,
      liveCount: countLiveCells(grid),
      rows: rows,
      running: false,
      selectedPattern: defaultPattern,
      speed: 1,
    };
  }

  function randomizeGrid(grid, probability) {
    const chance = typeof probability === 'number' ? probability : 0.28;

    return grid.map(function (row) {
      return row.map(function () {
        return Math.random() < chance ? 1 : 0;
      });
    });
  }

  function toggleCell(grid, row, col, forcedValue) {
    const next = cloneGrid(grid);

    if (row < 0 || row >= next.length || col < 0 || col >= next[0].length) {
      return next;
    }

    next[row][col] = typeof forcedValue === 'number' ? forcedValue : next[row][col] ? 0 : 1;
    return next;
  }

  function applyPreset(state, patternName) {
    const grid = createEmptyGrid(state.rows, state.cols);
    const nextPattern = PATTERNS[patternName] ? patternName : state.defaultPattern;

    centerPattern(grid, PATTERNS[nextPattern]);

    return {
      cols: state.cols,
      defaultPattern: state.defaultPattern,
      generation: 0,
      grid: grid,
      liveCount: countLiveCells(grid),
      rows: state.rows,
      running: false,
      selectedPattern: nextPattern,
      speed: state.speed,
    };
  }

  function advanceState(state) {
    const nextGrid = stepGrid(state.grid);

    return Object.assign({}, state, {
      generation: state.generation + 1,
      grid: nextGrid,
      liveCount: countLiveCells(nextGrid),
    });
  }

  function setSpeed(state, speed) {
    return Object.assign({}, state, {
      speed: Math.max(1, Math.min(6, speed)),
    });
  }

  function getSpeedLabel(speed) {
    if (speed <= 1) {
      return 'Drift';
    }

    if (speed <= 3) {
      return 'Pulse';
    }

    if (speed <= 5) {
      return 'Hyper';
    }

    return 'Lightstorm';
  }

  function getSpeedDelay(speed) {
    const delays = {
      1: 520,
      2: 340,
      3: 220,
      4: 140,
      5: 90,
      6: 60,
    };

    return delays[Math.max(1, Math.min(6, speed))];
  }

  function getPatternLabel(patternName) {
    return PATTERNS[patternName] ? PATTERNS[patternName].name : 'Custom';
  }

  function createEmptyLike(state) {
    return createEmptyGrid(state.rows, state.cols);
  }

  function replaceGrid(state, grid, selectedPattern) {
    return Object.assign({}, state, {
      generation: 0,
      grid: grid,
      liveCount: countLiveCells(grid),
      running: false,
      selectedPattern: selectedPattern || 'custom',
    });
  }

  function getCanvasPoint(event, canvas, state) {
    const rect = canvas.getBoundingClientRect();
    const col = Math.floor(((event.clientX - rect.left) / rect.width) * state.cols);
    const row = Math.floor(((event.clientY - rect.top) / rect.height) * state.rows);

    if (row < 0 || row >= state.rows || col < 0 || col >= state.cols) {
      return null;
    }

    return { row: row, col: col };
  }

  function resizeCanvas(canvas) {
    const ratio = global.devicePixelRatio || 1;
    const bounds = canvas.getBoundingClientRect();
    const width = Math.max(1, Math.floor(bounds.width * ratio));
    const height = Math.max(1, Math.floor(bounds.height * ratio));

    if (canvas.width !== width || canvas.height !== height) {
      canvas.width = width;
      canvas.height = height;
    }
  }

  function drawSimulation(canvas, state) {
    const context = canvas.getContext('2d');
    const width = canvas.width;
    const height = canvas.height;
    const cellWidth = width / state.cols;
    const cellHeight = height / state.rows;
    const inset = Math.max(1.5, Math.min(cellWidth, cellHeight) * 0.12);

    context.clearRect(0, 0, width, height);

    const background = context.createLinearGradient(0, 0, width, height);
    background.addColorStop(0, '#081321');
    background.addColorStop(1, '#040a13');
    context.fillStyle = background;
    context.fillRect(0, 0, width, height);

    const bloom = context.createRadialGradient(width * 0.18, height * 0.16, 0, width * 0.18, height * 0.16, width * 0.55);
    bloom.addColorStop(0, 'rgba(115, 240, 221, 0.15)');
    bloom.addColorStop(1, 'rgba(115, 240, 221, 0)');
    context.fillStyle = bloom;
    context.fillRect(0, 0, width, height);

    context.beginPath();
    context.strokeStyle = 'rgba(126, 192, 212, 0.1)';
    context.lineWidth = 1;

    for (let row = 0; row <= state.rows; row += 1) {
      const y = Math.round(row * cellHeight) + 0.5;
      context.moveTo(0, y);
      context.lineTo(width, y);
    }

    for (let col = 0; col <= state.cols; col += 1) {
      const x = Math.round(col * cellWidth) + 0.5;
      context.moveTo(x, 0);
      context.lineTo(x, height);
    }

    context.stroke();

    for (let rowIndex = 0; rowIndex < state.rows; rowIndex += 1) {
      for (let colIndex = 0; colIndex < state.cols; colIndex += 1) {
        if (!state.grid[rowIndex][colIndex]) {
          continue;
        }

        const x = colIndex * cellWidth + inset;
        const y = rowIndex * cellHeight + inset;
        const drawWidth = Math.max(2, cellWidth - inset * 2);
        const drawHeight = Math.max(2, cellHeight - inset * 2);
        const fill = context.createLinearGradient(x, y, x + drawWidth, y + drawHeight);

        fill.addColorStop(0, 'rgba(115, 240, 221, 0.98)');
        fill.addColorStop(1, 'rgba(190, 252, 125, 0.94)');
        context.fillStyle = fill;
        context.shadowColor = 'rgba(115, 240, 221, 0.4)';
        context.shadowBlur = Math.max(8, Math.min(cellWidth, cellHeight) * 0.66);
        context.fillRect(x, y, drawWidth, drawHeight);
      }
    }

    context.shadowBlur = 0;
  }

  function renderState(state, refs) {
    resizeCanvas(refs.canvas);
    drawSimulation(refs.canvas, state);

    refs.statusText.textContent = state.running ? 'Running' : 'Paused';
    refs.statusText.classList.toggle('running', state.running);
    refs.speedLabel.textContent = getSpeedLabel(state.speed);
    refs.speedReadout.textContent = state.speed + ' / 6';
    refs.generationValue.textContent = String(state.generation);
    refs.liveValue.textContent = String(state.liveCount);
    refs.presetValue.textContent = getPatternLabel(state.selectedPattern);
    refs.heroGeneration.textContent = String(state.generation);
    refs.heroLive.textContent = String(state.liveCount);
    refs.heroPattern.textContent = getPatternLabel(state.selectedPattern);
    refs.canvasHint.textContent = state.running ? '演化进行中，拖拽会自动暂停' : '点击或拖拽即可绘制细胞';
    refs.playToggle.textContent = state.running ? '暂停演化' : '开始演化';
    refs.stepButton.disabled = state.running;
    refs.speedSlider.value = String(state.speed);

    refs.presetButtons.forEach(function (button) {
      button.classList.toggle('active', button.dataset.pattern === state.selectedPattern);
    });
  }

  function initDemo() {
    const canvas = document.getElementById('life-canvas');

    if (!canvas) {
      return;
    }

    const refs = {
      canvas: canvas,
      canvasHint: document.getElementById('canvas-hint'),
      clearButton: document.getElementById('clear-button'),
      generationValue: document.getElementById('generation-value'),
      heroGeneration: document.getElementById('hero-generation'),
      heroLive: document.getElementById('hero-live'),
      heroPattern: document.getElementById('hero-pattern'),
      liveValue: document.getElementById('live-value'),
      loadDefaultHero: document.getElementById('load-default-hero'),
      playToggle: document.getElementById('play-toggle'),
      presetButtons: Array.from(document.querySelectorAll('[data-pattern]')),
      presetValue: document.getElementById('preset-value'),
      randomButton: document.getElementById('random-button'),
      resetButton: document.getElementById('reset-button'),
      speedLabel: document.getElementById('speed-label'),
      speedReadout: document.getElementById('speed-readout'),
      speedSlider: document.getElementById('speed-slider'),
      statusText: document.getElementById('status-text'),
      stepButton: document.getElementById('step-button'),
    };
    const baseSize = global.innerWidth <= 720 ? 34 : 44;
    let state = createInitialState({
      rows: baseSize,
      cols: baseSize,
      defaultPattern: 'pulsar',
    });
    let lastTick = 0;
    let drawing = false;
    let drawValue = 1;
    let lastCellKey = '';

    function setState(nextState) {
      state = nextState;
      renderState(state, refs);
    }

    function applyCanvasPoint(event) {
      const point = getCanvasPoint(event, refs.canvas, state);

      if (!point) {
        return;
      }

      const cellKey = point.row + ':' + point.col;

      if (cellKey === lastCellKey) {
        return;
      }

      lastCellKey = cellKey;
      const nextGrid = toggleCell(state.grid, point.row, point.col, drawValue);
      setState(replaceGrid(state, nextGrid, 'custom'));
    }

    refs.playToggle.addEventListener('click', function () {
      setState(Object.assign({}, state, {
        running: !state.running,
      }));
    });

    refs.stepButton.addEventListener('click', function () {
      if (!state.running) {
        setState(advanceState(state));
      }
    });

    refs.clearButton.addEventListener('click', function () {
      setState(replaceGrid(state, createEmptyLike(state), 'custom'));
    });

    refs.randomButton.addEventListener('click', function () {
      setState(replaceGrid(state, randomizeGrid(createEmptyLike(state), 0.22), 'custom'));
    });

    refs.resetButton.addEventListener('click', function () {
      const patternName = PATTERNS[state.selectedPattern] ? state.selectedPattern : state.defaultPattern;
      setState(applyPreset(state, patternName));
    });

    refs.loadDefaultHero.addEventListener('click', function () {
      setState(applyPreset(state, state.defaultPattern));
      document.getElementById('lab').scrollIntoView({ behavior: 'smooth', block: 'start' });
    });

    refs.speedSlider.addEventListener('input', function (event) {
      const speed = Number(event.target.value);
      setState(setSpeed(state, speed));
    });

    refs.presetButtons.forEach(function (button) {
      button.addEventListener('click', function () {
        setState(applyPreset(state, button.dataset.pattern));
      });
    });

    refs.canvas.addEventListener('pointerdown', function (event) {
      const point = getCanvasPoint(event, refs.canvas, state);

      if (!point) {
        return;
      }

      drawing = true;
      lastCellKey = '';
      drawValue = state.grid[point.row][point.col] ? 0 : 1;
      refs.canvas.setPointerCapture(event.pointerId);
      applyCanvasPoint(event);
    });

    refs.canvas.addEventListener('pointermove', function (event) {
      if (!drawing) {
        return;
      }

      applyCanvasPoint(event);
    });

    function stopDrawing(event) {
      if (drawing && event && refs.canvas.hasPointerCapture(event.pointerId)) {
        refs.canvas.releasePointerCapture(event.pointerId);
      }

      drawing = false;
      lastCellKey = '';
    }

    refs.canvas.addEventListener('pointerup', stopDrawing);
    refs.canvas.addEventListener('pointerleave', stopDrawing);

    global.addEventListener('resize', function () {
      renderState(state, refs);
    });

    function animate(timestamp) {
      if (state.running && timestamp - lastTick >= getSpeedDelay(state.speed)) {
        lastTick = timestamp;
        setState(advanceState(state));
      }

      global.requestAnimationFrame(animate);
    }

    renderState(state, refs);
    global.requestAnimationFrame(animate);
  }

  const api = {
    advanceState: advanceState,
    applyPreset: applyPreset,
    PATTERNS: PATTERNS,
    cloneGrid: cloneGrid,
    countLiveNeighbors: countLiveNeighbors,
    countLiveCells: countLiveCells,
    createInitialState: createInitialState,
    createEmptyGrid: createEmptyGrid,
    getSpeedDelay: getSpeedDelay,
    getSpeedLabel: getSpeedLabel,
    randomizeGrid: randomizeGrid,
    setSpeed: setSpeed,
    stampPattern: stampPattern,
    stepGrid: stepGrid,
    toggleCell: toggleCell,
  };

  if (typeof module !== 'undefined' && module.exports) {
    module.exports = api;
  }

  global.LifeDemo = api;

  if (typeof document !== 'undefined') {
    document.addEventListener('DOMContentLoaded', initDemo);
  }
})(typeof window !== 'undefined' ? window : globalThis);