import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';

import { AGENT_FLOAT_COUNT } from '../pipelines/agents/agent-generation/agent';
import { createIntroTitleAgents } from './intro-title-agents';

const installCanvasMask = () => {
  Object.defineProperty(globalThis, 'document', {
    configurable: true,
    value: {
      createElement: vi.fn(() => {
        const canvas = {
          width: 0,
          height: 0,
          getContext: vi.fn(() => ({
            clearRect: vi.fn(),
            fillStyle: '',
            fillText: vi.fn(),
            font: '',
            getImageData: vi.fn(() => {
              const data = new Uint8ClampedArray(canvas.width * canvas.height * 4);
              for (let i = 3; i < data.length; i += 4) {
                data[i] = 255;
              }
              return { data };
            }),
            lineJoin: '',
            lineWidth: 0,
            measureText: vi.fn((text: string) => ({
              actualBoundingBoxAscent: 10,
              actualBoundingBoxDescent: 4,
              width: text.length * 10,
            })),
            strokeStyle: '',
            strokeText: vi.fn(),
            textAlign: '',
            textBaseline: '',
          })),
        };

        return canvas;
      }),
    },
  });
};

describe('createIntroTitleAgents', () => {
  beforeEach(() => {
    installCanvasMask();
  });

  afterEach(() => {
    Reflect.deleteProperty(globalThis, 'document');
  });

  it('creates deterministic agents for the same seed and progress', () => {
    const first = createIntroTitleAgents({
      count: 4,
      height: 32,
      progress: 0.4,
      seed: 123,
      width: 64,
    });
    const second = createIntroTitleAgents({
      count: 4,
      height: 32,
      progress: 0.4,
      seed: 123,
      width: 64,
    });

    expect(Array.from(first)).toEqual(Array.from(second));
  });

  it('preserves targets while advancing positions for a later intro progress', () => {
    const initial = createIntroTitleAgents({
      count: 1,
      height: 32,
      progress: 0,
      seed: 456,
      width: 64,
    });
    const later = createIntroTitleAgents({
      count: 1,
      height: 32,
      progress: 0.8,
      seed: 456,
      width: 64,
    });

    expect(later[0]).not.toBe(initial[0]);
    expect(later[1]).not.toBe(initial[1]);
    expect(later[4]).toBe(initial[4]);
    expect(later[5]).toBe(initial[5]);
    expect(later[7]).toBe(initial[7]);
    expect(later.length).toBe(AGENT_FLOAT_COUNT);
  });
});