import { describe, it, expect } from 'vitest';
import * as fc from 'fast-check';
import { Block } from '../src/entities/Block.js';
import { GRID_GAP } from '../src/constants.js';

describe('Block', () => {
  describe('constructor', () => {
    it('initializes with correct properties', () => {
      const block = new Block(3, 2, 5, 40);
      expect(block.gridX).toBe(3);
      expect(block.gridY).toBe(2);
      expect(block.count).toBe(5);
      expect(block.size).toBe(40);
      expect(block.destroyed).toBe(false);
    });
  });

  describe('hit()', () => {
    it('decrements count by 1', () => {
      const block = new Block(0, 0, 5, 40);
      block.hit();
      expect(block.count).toBe(4);
    });

    it('returns false when count > 0 after hit', () => {
      const block = new Block(0, 0, 3, 40);
      expect(block.hit()).toBe(false);
    });

    it('marks destroyed and returns true when count reaches 0', () => {
      const block = new Block(0, 0, 1, 40);
      expect(block.hit()).toBe(true);
      expect(block.destroyed).toBe(true);
      expect(block.count).toBe(0);
    });

    it('marks destroyed when count goes below 0', () => {
      const block = new Block(0, 0, 0, 40);
      expect(block.hit()).toBe(true);
      expect(block.destroyed).toBe(true);
      expect(block.count).toBe(-1);
    });
  });

  describe('getRect()', () => {
    it('converts grid coordinates to pixel coordinates', () => {
      const size = 40;
      const block = new Block(2, 3, 5, size);
      const rect = block.getRect();
      expect(rect.x).toBe(2 * (size + GRID_GAP) + GRID_GAP);
      expect(rect.y).toBe(3 * (size + GRID_GAP) + GRID_GAP);
      expect(rect.width).toBe(size);
      expect(rect.height).toBe(size);
    });

    it('returns correct rect for origin block (0,0)', () => {
      const size = 50;
      const block = new Block(0, 0, 1, size);
      const rect = block.getRect();
      expect(rect.x).toBe(GRID_GAP);
      expect(rect.y).toBe(GRID_GAP);
      expect(rect.width).toBe(size);
      expect(rect.height).toBe(size);
    });
  });

  describe('getColor()', () => {
    it('returns a valid hex color string', () => {
      const block = new Block(0, 0, 10, 40);
      const color = block.getColor();
      expect(color).toMatch(/^#[0-9a-f]{6}$/);
    });

    it('returns different colors for different counts', () => {
      const block1 = new Block(0, 0, 1, 40);
      const block2 = new Block(0, 0, 50, 40);
      expect(block1.getColor()).not.toBe(block2.getColor());
    });
  });

  describe('isDestroyed()', () => {
    it('returns false when count > 0', () => {
      const block = new Block(0, 0, 5, 40);
      expect(block.isDestroyed()).toBe(false);
    });

    it('returns true when count is 0', () => {
      const block = new Block(0, 0, 0, 40);
      expect(block.isDestroyed()).toBe(true);
    });

    it('returns true when count is negative', () => {
      const block = new Block(0, 0, -1, 40);
      expect(block.isDestroyed()).toBe(true);
    });
  });

  describe('moveDown()', () => {
    it('increments gridY by 1', () => {
      const block = new Block(3, 2, 5, 40);
      block.moveDown();
      expect(block.gridY).toBe(3);
    });

    it('can be called multiple times', () => {
      const block = new Block(0, 0, 5, 40);
      block.moveDown();
      block.moveDown();
      block.moveDown();
      expect(block.gridY).toBe(3);
    });
  });

  // Feature: ball-block-breaker, Property 7: 碰撞方块数字减1
  // **Validates: Requirements 4.1**
  describe('Property 7: 碰撞方块数字减1', () => {
    it('hit() decrements count by exactly 1 for any block with count > 0', () => {
      fc.assert(
        fc.property(
          fc.integer({ min: 1, max: 10000 }),
          fc.integer({ min: 0, max: 6 }),
          fc.integer({ min: 0, max: 20 }),
          fc.constantFrom(30, 40, 50),
          (count, gridX, gridY, size) => {
            const block = new Block(gridX, gridY, count, size);
            const originalCount = block.count;
            block.hit();
            expect(block.count).toBe(originalCount - 1);
          }
        ),
        { numRuns: 100 }
      );
    });
  });
});