import { describe, it, expect, beforeEach, vi } from 'vitest';
import fc from 'fast-check';
import { Game } from '../src/Game.js';
import { Ball } from '../src/entities/Ball.js';
import { GameState, GameMode, BALL_SPEED, BALL_RADIUS, LAUNCH_INTERVAL, GRID_COLS, GRID_GAP, TOP_PADDING_ROWS, FIXED_TIMESTEP } from '../src/constants.js';

/**
 * Create a minimal mock canvas for testing
 */
function createMockCanvas() {
  const canvas = {
    width: 375,
    height: 667,
    style: { width: '', height: '' },
    parentElement: { clientWidth: 375, clientHeight: 667 },
    getContext: () => ({
      save: vi.fn(),
      restore: vi.fn(),
      scale: vi.fn(),
      setTransform: vi.fn(),
      clearRect: vi.fn(),
      fillRect: vi.fn(),
      fillText: vi.fn(),
      beginPath: vi.fn(),
      arc: vi.fn(),
      fill: vi.fn(),
      stroke: vi.fn(),
      moveTo: vi.fn(),
      lineTo: vi.fn(),
      setLineDash: vi.fn(),
      translate: vi.fn(),
      fillStyle: '',
      strokeStyle: '',
      lineWidth: 1,
      font: '',
      textAlign: '',
      textBaseline: '',
      globalAlpha: 1,
    }),
    addEventListener: vi.fn(),
    removeEventListener: vi.fn(),
    getBoundingClientRect: () => ({ left: 0, top: 0, width: 375, height: 667 }),
  };
  return canvas;
}

describe('Game', () => {
  let canvas;
  let game;

  beforeEach(() => {
    // Mock window for devicePixelRatio
    if (typeof globalThis.window === 'undefined') {
      globalThis.window = { devicePixelRatio: 1 };
    } else {
      globalThis.window.devicePixelRatio = 1;
    }
    // Mock performance.now for animations
    if (typeof globalThis.performance === 'undefined') {
      globalThis.performance = { now: () => Date.now() };
    }

    canvas = createMockCanvas();
    game = new Game(canvas, GameMode.CLASSIC);
  });

  describe('constructor', () => {
    it('initializes with correct default state', () => {
      expect(game.state).toBe(GameState.AIMING);
      expect(game.round).toBe(1);
      expect(game.ballCount).toBe(1);
      expect(game.pendingBalls).toBe(0);
      expect(game.balls).toEqual([]);
      expect(game.mode).toBe(GameMode.CLASSIC);
    });

    it('calculates blockSize from canvas width', () => {
      const expectedBlockSize = (375 - GRID_GAP * (GRID_COLS + 1)) / GRID_COLS;
      expect(game.blockSize).toBeCloseTo(expectedBlockSize, 2);
    });

    it('sets board dimensions', () => {
      expect(game.boardWidth).toBe(375);
      expect(game.boardHeight).toBe(667);
    });

    it('creates subsystems', () => {
      expect(game.renderer).toBeDefined();
      expect(game.inputHandler).toBeDefined();
      expect(game.boardManager).toBeDefined();
    });
  });

  describe('start()', () => {
    it('generates first row of blocks', () => {
      game.start();
      const blocks = game.boardManager.getBlocks();
      expect(blocks.length).toBeGreaterThan(0);
    });

    it('enables input after start', () => {
      game.inputHandler.disable();
      game.start();
      // InputHandler._enabled should be true after start
      expect(game.inputHandler._enabled).toBe(true);
    });
  });

  describe('update() - state machine', () => {
    it('does nothing in AIMING state', () => {
      game.state = GameState.AIMING;
      game.update(16);
      expect(game.state).toBe(GameState.AIMING);
    });

    it('does nothing in GAME_OVER state', () => {
      game.state = GameState.GAME_OVER;
      game.update(16);
      expect(game.state).toBe(GameState.GAME_OVER);
    });

    it('calls nextRound in ROUND_END state', () => {
      game.start();
      game.state = GameState.ROUND_END;
      const initialRound = game.round;
      game.update(16);
      // After nextRound, round should increment and state should change
      expect(game.round).toBe(initialRound + 1);
      // State should be AIMING, SLIDING_DOWN, or GAME_OVER
      expect([GameState.AIMING, GameState.SLIDING_DOWN, GameState.GAME_OVER]).toContain(game.state);
    });
  });

  describe('launch logic', () => {
    it('transitions from LAUNCHING to RUNNING after all balls launched', () => {
      game.start();
      game.launchAngle = 90;
      game.state = GameState.LAUNCHING;
      game.launchIndex = 0;
      game.launchTimer = 0;
      game.ballCount = 1;
      game.balls = [];

      // Need enough fixed-timestep ticks for launchTimer to exceed LAUNCH_INTERVAL
      const ticksNeeded = Math.ceil(LAUNCH_INTERVAL / FIXED_TIMESTEP) + 1;
      game.update(ticksNeeded * FIXED_TIMESTEP);

      // After launching 1 ball, should transition to RUNNING
      expect(game.state).toBe(GameState.RUNNING);
      expect(game.balls.length).toBe(1);
    });

    it('launches balls at correct intervals', () => {
      game.start();
      game.launchAngle = 90;
      game.state = GameState.LAUNCHING;
      game.launchIndex = 0;
      game.launchTimer = 0;
      game.ballCount = 3;
      game.balls = [];

      // Enough ticks for first ball launch
      const ticksForOneLaunch = Math.ceil(LAUNCH_INTERVAL / FIXED_TIMESTEP) + 1;
      game.update(ticksForOneLaunch * FIXED_TIMESTEP);
      expect(game.balls.length).toBe(1);

      // Another interval for second ball
      game.update(ticksForOneLaunch * FIXED_TIMESTEP);
      expect(game.balls.length).toBe(2);
    });

    it('sets correct velocity on launched balls', () => {
      game.start();
      game.launchAngle = 90; // straight up
      game.state = GameState.LAUNCHING;
      game.launchIndex = 0;
      game.launchTimer = 0;
      game.ballCount = 1;
      game.balls = [];

      const ticksNeeded = Math.ceil(LAUNCH_INTERVAL / FIXED_TIMESTEP) + 1;
      game.update(ticksNeeded * FIXED_TIMESTEP);

      const ball = game.balls[0];
      const rad = 90 * Math.PI / 180;
      expect(ball.vx).toBeCloseTo(BALL_SPEED * Math.cos(rad), 5);
      expect(ball.vy).toBeCloseTo(-BALL_SPEED * Math.sin(rad), 5);
    });
  });

  describe('running state - round end detection', () => {
    it('transitions to ROUND_END when all balls are inactive', () => {
      game.start();
      game.state = GameState.RUNNING;

      // Create a ball that is already inactive
      const { Ball } = require('../src/entities/Ball.js');
      const ball = new Ball(100, 600, BALL_RADIUS);
      ball.active = false;
      game.balls = [ball];

      // Need at least one fixed-timestep tick
      game.update(FIXED_TIMESTEP);
      expect(game.state).toBe(GameState.ROUND_END);
    });

    it('stays in RUNNING when some balls are still active', () => {
      game.start();
      game.state = GameState.RUNNING;

      const { Ball } = require('../src/entities/Ball.js');
      const ball1 = new Ball(100, 300, BALL_RADIUS);
      ball1.vx = 0;
      ball1.vy = 5;
      ball1.active = true;
      const ball2 = new Ball(100, 600, BALL_RADIUS);
      ball2.active = false;
      game.balls = [ball1, ball2];

      game.update(16);
      expect(game.state).toBe(GameState.RUNNING);
    });
  });

  describe('nextRound()', () => {
    it('adds pending balls to ball count', () => {
      game.start();
      game.pendingBalls = 3;
      game.ballCount = 2;
      game.nextRound();
      expect(game.ballCount).toBe(5);
      expect(game.pendingBalls).toBe(0);
    });

    it('increments round number', () => {
      game.start();
      const initialRound = game.round;
      game.nextRound();
      expect(game.round).toBe(initialRound + 1);
    });

    it('transitions to AIMING state', () => {
      game.start();
      game.state = GameState.ROUND_END;
      game.nextRound();
      // nextRound now transitions to SLIDING_DOWN first
      if (game.state === GameState.SLIDING_DOWN) {
        // Force slide animation to complete
        game._slideStartTime = performance.now() - game._slideDuration - 1;
        game._updateSlideDown();
      }
      // Should be AIMING unless game over
      if (game.state !== GameState.GAME_OVER) {
        expect(game.state).toBe(GameState.AIMING);
      }
    });

    it('enables input after round transition', () => {
      game.start();
      game.inputHandler.disable();
      game.nextRound();
      // Force slide animation to complete
      if (game.state === GameState.SLIDING_DOWN) {
        game._slideStartTime = performance.now() - game._slideDuration - 1;
        game._updateSlideDown();
      }
      if (game.state !== GameState.GAME_OVER) {
        expect(game.inputHandler._enabled).toBe(true);
      }
    });
  });

  describe('addPendingBall()', () => {
    it('increments pending balls', () => {
      expect(game.pendingBalls).toBe(0);
      game.addPendingBall();
      expect(game.pendingBalls).toBe(1);
      game.addPendingBall();
      expect(game.pendingBalls).toBe(2);
    });
  });

  describe('clearRow() and clearColumn()', () => {
    it('delegates clearRow to boardManager', () => {
      game.start();
      const spy = vi.spyOn(game.boardManager, 'clearRow').mockReturnValue([]);
      game.clearRow(2);
      expect(spy).toHaveBeenCalledWith(2);
    });

    it('delegates clearColumn to boardManager', () => {
      game.start();
      const spy = vi.spyOn(game.boardManager, 'clearColumn').mockReturnValue([]);
      game.clearColumn(3);
      expect(spy).toHaveBeenCalledWith(3);
    });
  });

  describe('restart()', () => {
    it('resets game state to initial values', () => {
      game.start();
      game.round = 5;
      game.ballCount = 10;
      game.pendingBalls = 3;
      game.state = GameState.GAME_OVER;

      game.restart();

      expect(game.state).toBe(GameState.AIMING);
      expect(game.round).toBe(1);
      expect(game.ballCount).toBe(1);
      expect(game.pendingBalls).toBe(0);
      expect(game.balls).toEqual([]);
    });

    it('generates new blocks after restart', () => {
      game.start();
      game.restart();
      const blocks = game.boardManager.getBlocks();
      expect(blocks.length).toBeGreaterThan(0);
    });
  });

  describe('gameOver()', () => {
    it('sets state to GAME_OVER', () => {
      game.gameOver();
      expect(game.state).toBe(GameState.GAME_OVER);
    });
  });

  describe('render()', () => {
    it('does not throw when rendering in AIMING state', () => {
      game.start();
      game.state = GameState.AIMING;
      expect(() => game.render()).not.toThrow();
    });

    it('does not throw when rendering in GAME_OVER state', () => {
      game.start();
      game.state = GameState.GAME_OVER;
      expect(() => game.render()).not.toThrow();
    });

    it('does not throw when rendering with active balls', () => {
      game.start();
      game.state = GameState.RUNNING;
      const { Ball } = require('../src/entities/Ball.js');
      const ball = new Ball(100, 300, BALL_RADIUS);
      ball.active = true;
      game.balls = [ball];
      expect(() => game.render()).not.toThrow();
    });
  });

  describe('input disabled during RUNNING', () => {
    it('disables input when launching starts', () => {
      game.start();
      game.inputHandler.enable();
      // Simulate _startLaunch
      game._startLaunch();
      expect(game.inputHandler._enabled).toBe(false);
    });

    it('re-enables input after round ends', () => {
      game.start();
      game.inputHandler.disable();
      game.nextRound();
      // Force slide animation to complete
      if (game.state === GameState.SLIDING_DOWN) {
        game._slideStartTime = performance.now() - game._slideDuration - 1;
        game._updateSlideDown();
      }
      if (game.state !== GameState.GAME_OVER) {
        expect(game.inputHandler._enabled).toBe(true);
      }
    });
  });

  describe('collision handling', () => {
    it('removes destroyed blocks during physics step', () => {
      game.start();
      // Add a block with count=1 that will be destroyed on hit
      const { Block } = require('../src/entities/Block.js');
      const block = new Block(3, 3, 1, game.blockSize);
      game.boardManager.blocks = [block];

      // Create a ball above the block, moving downward toward it
      const { Ball } = require('../src/entities/Ball.js');
      const blockRect = block.getRect();
      const ball = new Ball(
        blockRect.x + blockRect.width / 2,
        blockRect.y - BALL_RADIUS - 2,
        BALL_RADIUS
      );
      ball.vx = 0;
      ball.vy = BALL_SPEED;
      ball.active = true;
      game.balls = [ball];

      game.state = GameState.RUNNING;
      game._stepPhysics();

      // Block should be destroyed and removed
      expect(game.boardManager.getBlocks().length).toBe(0);
    });
  });

  /**
   * Feature: ball-block-breaker, Property 4: 球到底部停止
   * **Validates: Requirements 3.3**
   *
   * 对于任意小球，当其 y 坐标到达或超过 Game_Board 底部时，
   * 该球应被标记为非活跃状态（active = false）。
   */
  describe('Property 4: 球到底部停止', () => {
    it('balls at or beyond the bottom become inactive after update', () => {
      fc.assert(
        fc.property(
          // Generate a y position at or beyond the bottom of the board
          fc.float({ min: 0, max: 200, noNaN: true, noDefaultInfinity: true }),
          // Generate an x position within the board
          fc.float({ min: BALL_RADIUS + 1, max: 375 - BALL_RADIUS - 1, noNaN: true, noDefaultInfinity: true }),
          // Generate a downward vy (positive = moving down)
          fc.float({ min: 1, max: BALL_SPEED, noNaN: true, noDefaultInfinity: true }),
          (yOffset, x, vy) => {
            const boardHeight = game.boardHeight;
            // Place ball at or past the bottom boundary
            const y = boardHeight - BALL_RADIUS + yOffset;

            const ball = new Ball(x, y, BALL_RADIUS);
            ball.vx = 0;
            ball.vy = vy;
            ball.active = true;

            game.state = GameState.RUNNING;
            game.balls = [ball];

            // Need at least one fixed-timestep tick
            game.update(FIXED_TIMESTEP);

            // Ball that was at or beyond the bottom should now be inactive
            expect(ball.active).toBe(false);
          }
        ),
        { numRuns: 100 }
      );
    });
  });
});

/**
 * Feature: ball-block-breaker, Property 5: 所有球到底部则回合结束
 * **Validates: Requirements 3.4**
 *
 * 对于任意球列表，当且仅当所有球的 active 状态均为 false 时，
 * 回合应结束（状态转为 ROUND_END）。
 */
describe('Property 5: 所有球到底部则回合结束', () => {
  let canvas;
  let game;

  beforeEach(() => {
    if (typeof globalThis.window === 'undefined') {
      globalThis.window = { devicePixelRatio: 1 };
    } else {
      globalThis.window.devicePixelRatio = 1;
    }
    if (typeof globalThis.performance === 'undefined') {
      globalThis.performance = { now: () => Date.now() };
    }
    canvas = createMockCanvas();
    game = new Game(canvas, GameMode.CLASSIC);
    game.start();
  });

  it('transitions to ROUND_END when all balls are inactive', () => {
    fc.assert(
      fc.property(
        fc.integer({ min: 1, max: 20 }),
        (numBalls) => {
          game.state = GameState.RUNNING;

          // Create numBalls balls, all inactive
          game.balls = Array.from({ length: numBalls }, (_, i) => {
            const ball = new Ball(50 + i * 10, game.boardHeight - BALL_RADIUS, BALL_RADIUS);
            ball.vx = 0;
            ball.vy = 0;
            ball.active = false;
            return ball;
          });

          game._updateRunning(16);

          expect(game.state).toBe(GameState.ROUND_END);
        }
      ),
      { numRuns: 100 }
    );
  });

  it('stays in RUNNING when at least one ball is still active', () => {
    fc.assert(
      fc.property(
        fc.integer({ min: 1, max: 20 }),
        fc.integer({ min: 0, max: 19 }),
        (numBalls, activeIndexRaw) => {
          const activeIndex = activeIndexRaw % numBalls;
          game.state = GameState.RUNNING;

          // Create numBalls balls, all inactive except one at safe position
          game.balls = Array.from({ length: numBalls }, (_, i) => {
            const ball = new Ball(50 + i * 10, 300, BALL_RADIUS);
            ball.vx = 0;
            ball.vy = 0;
            ball.active = (i === activeIndex);
            return ball;
          });

          game._updateRunning(16);

          expect(game.state).toBe(GameState.RUNNING);
        }
      ),
      { numRuns: 100 }
    );
  });
});


/**
 * Feature: ball-block-breaker, Property 13: BallItem碰撞效果
 * **Validates: Requirements 6.1, 6.3**
 *
 * 对于任意游戏状态，当小球触碰 BallItem 后，下一轮的球数应比当前多1，
 * 且该 BallItem 应被标记为已收集（从面板移除）。
 */
describe('Property 13: BallItem碰撞效果', () => {
  let canvas;
  let game;

  beforeEach(() => {
    if (typeof globalThis.window === 'undefined') {
      globalThis.window = { devicePixelRatio: 1 };
    } else {
      globalThis.window.devicePixelRatio = 1;
    }
    if (typeof globalThis.performance === 'undefined') {
      globalThis.performance = { now: () => Date.now() };
    }
    canvas = createMockCanvas();
    game = new Game(canvas, GameMode.CLASSIC);
    game.start();
  });

  it('collecting a BallItem increases pendingBalls by 1 and removes the item', () => {
    const { BallItem } = require('../src/entities/Item.js');

    fc.assert(
      fc.property(
        // Random grid position for the BallItem
        fc.integer({ min: 0, max: GRID_COLS - 1 }),
        fc.integer({ min: 1, max: 5 }),
        // Random initial pendingBalls count
        fc.integer({ min: 0, max: 10 }),
        (gridX, gridY, initialPending) => {
          // Set up game state
          game.state = GameState.RUNNING;
          game.pendingBalls = initialPending;

          // Create a BallItem at the given grid position
          const ballItem = new BallItem(gridX, gridY, game.blockSize);

          // Clear existing items and add only our BallItem
          game.boardManager.blocks = [];
          game.boardManager.items = [ballItem];

          // Position a ball overlapping the BallItem (guaranteed collision)
          const itemRect = ballItem.getRect();
          const ball = new Ball(
            itemRect.x + itemRect.width / 2,
            itemRect.y + itemRect.height / 2,
            BALL_RADIUS
          );
          ball.vx = 0;
          ball.vy = -0.001;
          ball.active = true;
          game.balls = [ball];

          // Run physics step (handles item collisions)
          game._stepPhysics();

          // pendingBalls should have increased by exactly 1
          expect(game.pendingBalls).toBe(initialPending + 1);

          // BallItem should be removed from items array
          expect(game.boardManager.getItems().length).toBe(0);

          // BallItem should be marked as collected
          expect(ballItem.collected).toBe(true);
        }
      ),
      { numRuns: 100 }
    );
  });
});


/**
 * Feature: ball-block-breaker, Property 15: LineClearItem碰撞效果
 * **Validates: Requirements 6.4, 6.5**
 *
 * 对于任意方块布局和 LineClearItem 位置，触发后该行或列的所有方块应被移除，
 * 且 LineClearItem 本身不被移除。
 */
describe('Property 15: LineClearItem碰撞效果', () => {
  let canvas;
  let game;

  beforeEach(() => {
    if (typeof globalThis.window === 'undefined') {
      globalThis.window = { devicePixelRatio: 1 };
    } else {
      globalThis.window.devicePixelRatio = 1;
    }
    if (typeof globalThis.performance === 'undefined') {
      globalThis.performance = { now: () => Date.now() };
    }
    canvas = createMockCanvas();
    game = new Game(canvas, GameMode.ENHANCED);
    game.start();
  });

  it('collecting a LineClearItem decrements count of blocks in its row or column by 1', () => {
    const { LineClearItem } = require('../src/entities/Item.js');
    const { Block } = require('../src/entities/Block.js');

    fc.assert(
      fc.property(
        // LineClearItem grid position
        fc.integer({ min: 0, max: GRID_COLS - 1 }),
        fc.integer({ min: 1, max: 5 }),
        // Direction
        fc.constantFrom('horizontal', 'vertical'),
        // Generate blocks that won't overlap with the ball position
        fc.array(
          fc.record({
            gridX: fc.integer({ min: 0, max: GRID_COLS - 1 }),
            gridY: fc.integer({ min: 0, max: 7 }),
            count: fc.integer({ min: 2, max: 20 })
          }),
          { minLength: 1, maxLength: 20 }
        ),
        (itemGridX, itemGridY, direction, blockDefs) => {
          game.state = GameState.RUNNING;

          // Create LineClearItem with explicit direction
          const lineClearItem = new LineClearItem(itemGridX, itemGridY, game.blockSize, direction);

          // Filter out blocks that would overlap with the item's grid cell
          // or are adjacent (ball physics might hit nearby blocks)
          const safeBlockDefs = blockDefs.filter(def =>
            !(def.gridX === itemGridX && def.gridY === itemGridY) &&
            Math.abs(def.gridY - itemGridY) > 1 &&
            Math.abs(def.gridX - itemGridX) > 1
          );
          if (safeBlockDefs.length === 0) return; // skip if no safe blocks

          // Create blocks from definitions
          const blocks = safeBlockDefs.map(def =>
            new Block(def.gridX, def.gridY, def.count, game.blockSize)
          );
          const originalCounts = blocks.map(b => b.count);

          // Set up board
          game.boardManager.blocks = [...blocks];
          game.boardManager.items = [lineClearItem];

          // Position a ball overlapping the LineClearItem for guaranteed collision
          const itemRect = lineClearItem.getRect();
          const ball = new Ball(
            itemRect.x + itemRect.width / 2,
            itemRect.y + itemRect.height / 2,
            BALL_RADIUS
          );
          ball.vx = 0;
          ball.vy = -0.001;
          ball.active = true;
          game.balls = [ball];

          // Run physics step (handles item collisions)
          game._stepPhysics();

          // LineClearItem should be marked as collected
          expect(lineClearItem.collected).toBe(true);

          // LineClearItem should NOT be removed (stays on board)
          expect(game.boardManager.getItems()).toContain(lineClearItem);

          // Check that affected blocks had count decremented by 1
          // (blocks not overlapping with ball, so only clearRow/clearColumn hit them)
          for (let i = 0; i < blocks.length; i++) {
            const block = blocks[i];
            const wasAffected = direction === 'horizontal'
              ? block.gridY === itemGridY
              : block.gridX === itemGridX;

            if (wasAffected && !block.isDestroyed()) {
              expect(block.count).toBe(originalCounts[i] - 1);
            } else if (!wasAffected) {
              expect(block.count).toBe(originalCounts[i]);
            }
          }
        }
      ),
      { numRuns: 100 }
    );
  });
});


/**
 * Feature: ball-block-breaker, Property 18: 运行中忽略输入
 * **Validates: Requirements 9.3**
 *
 * 对于任意游戏状态为 RUNNING 或 LAUNCHING 时，输入事件不应改变游戏的瞄准角度或触发新的发射。
 */
describe('Property 18: 运行中忽略输入', () => {
  let canvas;
  let game;

  beforeEach(() => {
    if (typeof globalThis.window === 'undefined') {
      globalThis.window = { devicePixelRatio: 1 };
    } else {
      globalThis.window.devicePixelRatio = 1;
    }
    if (typeof globalThis.performance === 'undefined') {
      globalThis.performance = { now: () => Date.now() };
    }
    canvas = createMockCanvas();
    game = new Game(canvas, GameMode.CLASSIC);
    game.start();
  });

  it('input callbacks do not change aimAngle or trigger launch in RUNNING/LAUNCHING state', () => {
    fc.assert(
      fc.property(
        // Random state: RUNNING or LAUNCHING
        fc.constantFrom(GameState.RUNNING, GameState.LAUNCHING),
        // Random initial aimAngle
        fc.float({ min: 15, max: 165, noNaN: true, noDefaultInfinity: true }),
        // Random angle from input event
        fc.float({ min: -360, max: 360, noNaN: true, noDefaultInfinity: true }),
        (state, initialAimAngle, inputAngle) => {
          // Set game to the target state
          game.state = state;
          game.aimAngle = initialAimAngle;

          // Record state before input
          const aimAngleBefore = game.aimAngle;
          const stateBefore = game.state;
          const ballsBefore = game.balls.length;

          const eventData = { x: 100, y: 100, angle: inputAngle };

          // Trigger all three input callbacks directly
          game.inputHandler._onAimStart(eventData);
          game.inputHandler._onAimMove(eventData);
          game.inputHandler._onAimEnd(eventData);

          // aimAngle must not change
          expect(game.aimAngle).toBe(aimAngleBefore);

          // State must not change (no launch triggered)
          expect(game.state).toBe(stateBefore);

          // No new balls should be created
          expect(game.balls.length).toBe(ballsBefore);
        }
      ),
      { numRuns: 100 }
    );
  });
});


/**
 * Game Over UI Tests
 * **Validates: Requirements 7.2, 7.3**
 *
 * Tests for the game over overlay: showing the overlay with round number,
 * restart button functionality, and hiding the overlay on restart.
 */
describe('Game Over UI (Requirements 7.2, 7.3)', () => {
  let canvas;
  let game;
  let overlay;
  let scoreEl;
  let restartBtn;

  function createMockCanvasLocal() {
    return {
      width: 375,
      height: 667,
      style: { width: '', height: '' },
      parentElement: { clientWidth: 375, clientHeight: 667 },
      getContext: () => ({
        save: vi.fn(),
        restore: vi.fn(),
        scale: vi.fn(),
        setTransform: vi.fn(),
        clearRect: vi.fn(),
        fillRect: vi.fn(),
        fillText: vi.fn(),
        beginPath: vi.fn(),
        arc: vi.fn(),
        fill: vi.fn(),
        stroke: vi.fn(),
        moveTo: vi.fn(),
        lineTo: vi.fn(),
        setLineDash: vi.fn(),
        translate: vi.fn(),
        fillStyle: '',
        strokeStyle: '',
        lineWidth: 1,
        font: '',
        textAlign: '',
        textBaseline: '',
        globalAlpha: 1,
      }),
      addEventListener: vi.fn(),
      removeEventListener: vi.fn(),
      getBoundingClientRect: () => ({ left: 0, top: 0, width: 375, height: 667 }),
    };
  }

  beforeEach(() => {
    if (typeof globalThis.window === 'undefined') {
      globalThis.window = { devicePixelRatio: 1 };
    } else {
      globalThis.window.devicePixelRatio = 1;
    }
    if (typeof globalThis.performance === 'undefined') {
      globalThis.performance = { now: () => Date.now() };
    }

    canvas = createMockCanvasLocal();
    game = new Game(canvas, GameMode.CLASSIC);

    // Create mock DOM elements for game over UI
    overlay = { style: { display: 'none' } };
    scoreEl = { textContent: '' };
    restartBtn = {
      _listeners: [],
      addEventListener(event, handler) {
        this._listeners.push({ event, handler });
      },
    };

    game.setGameOverUI(overlay, scoreEl, restartBtn);
    game.start();
  });

  describe('setGameOverUI()', () => {
    it('stores references to DOM elements', () => {
      expect(game.gameOverOverlay).toBe(overlay);
      expect(game.gameOverScoreEl).toBe(scoreEl);
      expect(game.gameOverRestartBtn).toBe(restartBtn);
    });

    it('binds click handler to restart button', () => {
      expect(restartBtn._listeners.length).toBe(1);
      expect(restartBtn._listeners[0].event).toBe('click');
    });
  });

  describe('gameOver()', () => {
    it('sets state to GAME_OVER', () => {
      game.round = 5;
      game.gameOver();
      expect(game.state).toBe(GameState.GAME_OVER);
    });

    it('displays the current round number in the score element', () => {
      game.round = 7;
      game.gameOver();
      expect(scoreEl.textContent).toBe('第 7 轮');
    });

    it('shows the game over overlay', () => {
      game.gameOver();
      expect(overlay.style.display).toBe('flex');
    });

    it('works without UI elements set (no errors)', () => {
      const game2 = new Game(createMockCanvasLocal(), GameMode.CLASSIC);
      expect(() => game2.gameOver()).not.toThrow();
      expect(game2.state).toBe(GameState.GAME_OVER);
    });
  });

  describe('restart via button', () => {
    it('clicking restart button resets game state', () => {
      game.round = 10;
      game.gameOver();

      // Simulate clicking the restart button
      const clickHandler = restartBtn._listeners.find(l => l.event === 'click').handler;
      clickHandler();

      expect(game.state).toBe(GameState.AIMING);
      expect(game.round).toBe(1);
      expect(game.ballCount).toBe(1);
    });

    it('clicking restart button hides the overlay', () => {
      game.gameOver();
      expect(overlay.style.display).toBe('flex');

      const clickHandler = restartBtn._listeners.find(l => l.event === 'click').handler;
      clickHandler();

      expect(overlay.style.display).toBe('none');
    });
  });

  describe('nextRound triggers gameOver with UI', () => {
    it('shows overlay when blocks reach bottom during nextRound', () => {
      // Force checkGameOver to return true
      vi.spyOn(game.boardManager, 'checkGameOver').mockReturnValue(true);
      game.round = 12;

      game.nextRound();
      // Force slide animation to complete
      if (game.state === GameState.SLIDING_DOWN) {
        game._slideStartTime = performance.now() - game._slideDuration - 1;
        game._updateSlideDown();
      }

      // round increments before gameOver is called
      expect(game.state).toBe(GameState.GAME_OVER);
      expect(overlay.style.display).toBe('flex');
      expect(scoreEl.textContent).toBe('第 13 轮');
    });
  });
});


/**
 * 集成单元测试 - 任务 11.2
 * 测试模式选择后游戏正确初始化，以及完整回合流程
 * **Validates: Requirements 1.1-1.4, 3.4, 5.1, 5.2**
 */
describe('Integration: Mode selection and game initialization', () => {
  beforeEach(() => {
    if (typeof globalThis.window === 'undefined') {
      globalThis.window = { devicePixelRatio: 1 };
    } else {
      globalThis.window.devicePixelRatio = 1;
    }
    if (typeof globalThis.performance === 'undefined') {
      globalThis.performance = { now: () => Date.now() };
    }
  });

  it('CLASSIC mode initializes correctly (state=AIMING, round=1, ballCount=1)', () => {
    const canvas = createMockCanvas();
    const game = new Game(canvas, GameMode.CLASSIC);

    expect(game.mode).toBe(GameMode.CLASSIC);
    expect(game.state).toBe(GameState.AIMING);
    expect(game.round).toBe(1);
    expect(game.ballCount).toBe(1);
  });

  it('ENHANCED mode initializes correctly (state=AIMING, round=1, ballCount=1)', () => {
    const canvas = createMockCanvas();
    const game = new Game(canvas, GameMode.ENHANCED);

    expect(game.mode).toBe(GameMode.ENHANCED);
    expect(game.state).toBe(GameState.AIMING);
    expect(game.round).toBe(1);
    expect(game.ballCount).toBe(1);
  });

  it('start() generates blocks on the board', () => {
    const canvas = createMockCanvas();
    const game = new Game(canvas, GameMode.CLASSIC);
    game.start();

    const blocks = game.boardManager.getBlocks();
    expect(blocks.length).toBeGreaterThan(0);
    // All initial blocks should be at TOP_PADDING_ROWS
    for (const block of blocks) {
      expect(block.gridY).toBe(TOP_PADDING_ROWS);
    }
  });

  it('start() in ENHANCED mode generates blocks on the board', () => {
    const canvas = createMockCanvas();
    const game = new Game(canvas, GameMode.ENHANCED);
    game.start();

    const blocks = game.boardManager.getBlocks();
    expect(blocks.length).toBeGreaterThan(0);
  });
});

describe('Integration: Full round flow (launch → collision → round end → new row)', () => {
  let canvas;
  let game;

  beforeEach(() => {
    if (typeof globalThis.window === 'undefined') {
      globalThis.window = { devicePixelRatio: 1 };
    } else {
      globalThis.window.devicePixelRatio = 1;
    }
    if (typeof globalThis.performance === 'undefined') {
      globalThis.performance = { now: () => Date.now() };
    }

    canvas = createMockCanvas();
    game = new Game(canvas, GameMode.CLASSIC);
    game.start();
  });

  it('transitions AIMING → LAUNCHING → RUNNING when launching', () => {
    expect(game.state).toBe(GameState.AIMING);

    // Simulate launch
    game.launchAngle = 90;
    game.state = GameState.LAUNCHING;
    game.launchIndex = 0;
    game.launchTimer = 0;
    game.balls = [];

    // Provide enough fixed-timestep ticks to launch all balls (ballCount=1)
    const ticksNeeded = Math.ceil(LAUNCH_INTERVAL / FIXED_TIMESTEP) + 1;
    game.update(ticksNeeded * FIXED_TIMESTEP);

    expect(game.state).toBe(GameState.RUNNING);
    expect(game.balls.length).toBe(1);
    expect(game.balls[0].active).toBe(true);
  });

  it('transitions RUNNING → ROUND_END when all balls become inactive', () => {
    game.state = GameState.RUNNING;

    // Create a ball that is already inactive (simulating it reached bottom)
    const ball = new Ball(game.boardWidth / 2, game.boardHeight - BALL_RADIUS);
    ball.active = false;
    game.balls = [ball];

    game.update(FIXED_TIMESTEP);

    expect(game.state).toBe(GameState.ROUND_END);
  });

  it('ROUND_END triggers nextRound: round increments, new blocks generated, blocks moved down', () => {
    // Record initial blocks
    const initialBlocks = game.boardManager.getBlocks();
    const initialBlockCount = initialBlocks.length;
    const initialGridYs = initialBlocks.map(b => b.gridY);

    expect(game.round).toBe(1);

    // Trigger round end
    game.state = GameState.ROUND_END;
    game.update(16);

    // Round should have incremented (nextRound increments after generating)
    if (game.state !== GameState.GAME_OVER) {
      expect(game.round).toBe(2);
      // Complete slide animation if in SLIDING_DOWN
      if (game.state === GameState.SLIDING_DOWN) {
        game._slideStartTime = performance.now() - game._slideDuration - 1;
        game._updateSlideDown();
      }
      expect(game.state).toBe(GameState.AIMING);

      // Blocks should have been moved down and new ones generated
      const newBlocks = game.boardManager.getBlocks();
      expect(newBlocks.length).toBeGreaterThan(0);

      // There should be blocks at TOP_PADDING_ROWS (newly generated)
      const topRowBlocks = newBlocks.filter(b => b.gridY === TOP_PADDING_ROWS);
      expect(topRowBlocks.length).toBeGreaterThan(0);

      // Original blocks should have moved down by 1 row
      const movedBlocks = newBlocks.filter(b => b.gridY > 0);
      expect(movedBlocks.length).toBeGreaterThanOrEqual(initialBlockCount);
    }
  });

  it('complete flow: launch → all balls inactive → round end → new round', () => {
    const round1Blocks = [...game.boardManager.getBlocks()];
    expect(game.round).toBe(1);

    // Step 1: Start launching
    game.launchAngle = 90;
    game.state = GameState.LAUNCHING;
    game.launchIndex = 0;
    game.launchTimer = 0;
    game.balls = [];

    // Step 2: Launch all balls
    const ticksNeeded = Math.ceil(LAUNCH_INTERVAL / FIXED_TIMESTEP) + 1;
    game.update(ticksNeeded * FIXED_TIMESTEP);
    expect(game.state).toBe(GameState.RUNNING);

    // Step 3: Set all balls to inactive (simulate reaching bottom)
    for (const ball of game.balls) {
      ball.active = false;
    }

    // Step 4: Update triggers ROUND_END detection
    game.update(FIXED_TIMESTEP);
    expect(game.state).toBe(GameState.ROUND_END);

    // Step 5: Update triggers nextRound
    game.update(16);

    if (game.state !== GameState.GAME_OVER) {
      expect(game.round).toBe(2);
      // Complete slide animation if in SLIDING_DOWN
      if (game.state === GameState.SLIDING_DOWN) {
        game._slideStartTime = performance.now() - game._slideDuration - 1;
        game._updateSlideDown();
      }
      expect(game.state).toBe(GameState.AIMING);

      // New blocks should exist at TOP_PADDING_ROWS
      const blocks = game.boardManager.getBlocks();
      const topRowBlocks = blocks.filter(b => b.gridY === TOP_PADDING_ROWS);
      expect(topRowBlocks.length).toBeGreaterThan(0);

      // Original round 1 blocks should now be at TOP_PADDING_ROWS + 1 (moved down)
      const row1Blocks = blocks.filter(b => b.gridY === TOP_PADDING_ROWS + 1);
      expect(row1Blocks.length).toBeGreaterThanOrEqual(round1Blocks.length);
    }
  });
});