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

// Mock the @huggingface/transformers module before importing the providers
vi.mock('@huggingface/transformers', () => ({
  pipeline: vi.fn(),
}));

// Mock the providerRegistry to prevent actual cleanup registration
vi.mock('../../src/providers/providerRegistry', () => ({
  providerRegistry: {
    register: vi.fn(),
  },
}));

import {
  disposePipelines,
  pipelineCache,
  TransformersEmbeddingProvider,
  TransformersTextGenerationProvider,
} from '../../src/providers/transformers';

describe('TransformersEmbeddingProvider', () => {
  let mockPipeline: ReturnType<typeof vi.fn>;
  let mockExtractor: ReturnType<typeof vi.fn>;
  let mockDispose: ReturnType<typeof vi.fn>;

  beforeEach(async () => {
    vi.resetAllMocks();

    // Clear pipeline cache between tests
    pipelineCache.clear();

    // Setup mock extractor that returns tensor-like object
    mockExtractor = vi.fn().mockResolvedValue({
      data: new Float32Array([0.1, 0.2, 0.3, 0.4]),
      dims: [1, 4],
    });

    mockDispose = vi.fn().mockResolvedValue(undefined);

    // Mock pipeline factory
    mockPipeline = vi
      .fn()
      .mockResolvedValue(Object.assign(mockExtractor, { dispose: mockDispose }));

    // Get the mocked module and set up the pipeline mock
    // Use 'as any' to avoid complex generic type resolution issues with the library's types
    const transformers = await import('@huggingface/transformers');
    vi.mocked(transformers.pipeline).mockImplementation(mockPipeline as any);
  });

  afterEach(async () => {
    await disposePipelines();
    vi.clearAllMocks();
  });

  describe('constructor', () => {
    it('should construct with model name and default options', () => {
      const provider = new TransformersEmbeddingProvider('Xenova/all-MiniLM-L6-v2');
      expect(provider.modelName).toBe('Xenova/all-MiniLM-L6-v2');
      expect(provider.id()).toBe('transformers:feature-extraction:Xenova/all-MiniLM-L6-v2');
    });

    it('should use custom id when provided', () => {
      const provider = new TransformersEmbeddingProvider('model', { id: 'custom-id' });
      expect(provider.id()).toBe('custom-id');
    });

    it('should store config options', () => {
      const provider = new TransformersEmbeddingProvider('model', {
        config: { pooling: 'cls', normalize: false, prefix: 'query: ' },
      });
      expect(provider.config.pooling).toBe('cls');
      expect(provider.config.normalize).toBe(false);
      expect(provider.config.prefix).toBe('query: ');
    });

    it('should have correct toString', () => {
      const provider = new TransformersEmbeddingProvider('Xenova/all-MiniLM-L6-v2');
      expect(provider.toString()).toBe('[Transformers Embedding Provider Xenova/all-MiniLM-L6-v2]');
    });
  });

  describe('callApi', () => {
    it('should return error for callApi (text generation not supported)', async () => {
      const provider = new TransformersEmbeddingProvider('model');
      const result = await provider.callApi('test');

      expect(result.error).toContain('Cannot use an embedding provider for text generation');
    });
  });

  describe('callEmbeddingApi', () => {
    it('should call embedding API and return normalized embedding', async () => {
      const provider = new TransformersEmbeddingProvider('Xenova/all-MiniLM-L6-v2');
      const result = await provider.callEmbeddingApi('test text');

      expect(mockPipeline).toHaveBeenCalledWith(
        'feature-extraction',
        'Xenova/all-MiniLM-L6-v2',
        expect.objectContaining({
          progress_callback: expect.any(Function),
        }),
      );

      expect(mockExtractor).toHaveBeenCalledWith('test text', {
        pooling: 'mean',
        normalize: true,
      });

      // Float32Array values have floating point precision differences
      expect(result.embedding).toHaveLength(4);
      expect(result.embedding![0]).toBeCloseTo(0.1, 5);
      expect(result.embedding![1]).toBeCloseTo(0.2, 5);
      expect(result.embedding![2]).toBeCloseTo(0.3, 5);
      expect(result.embedding![3]).toBeCloseTo(0.4, 5);
      expect(result.error).toBeUndefined();
      expect(result.latencyMs).toBeGreaterThanOrEqual(0);
    });

    it('should apply prefix to input text', async () => {
      const provider = new TransformersEmbeddingProvider('BAAI/bge-small-en-v1.5', {
        config: { prefix: 'query: ' },
      });

      await provider.callEmbeddingApi('test text');

      expect(mockExtractor).toHaveBeenCalledWith('query: test text', expect.any(Object));
    });

    it('should use custom pooling options', async () => {
      const provider = new TransformersEmbeddingProvider('model', {
        config: { pooling: 'cls', normalize: false },
      });

      await provider.callEmbeddingApi('test');

      expect(mockExtractor).toHaveBeenCalledWith('test', {
        pooling: 'cls',
        normalize: false,
      });
    });

    it('should cache pipeline instances', async () => {
      const provider = new TransformersEmbeddingProvider('model');

      await provider.callEmbeddingApi('text 1');
      await provider.callEmbeddingApi('text 2');

      // Pipeline should only be created once
      expect(mockPipeline).toHaveBeenCalledTimes(1);
    });

    it('should return error when model is not found', async () => {
      mockPipeline.mockRejectedValue(new Error('Could not locate file for model'));

      const provider = new TransformersEmbeddingProvider('non-existent/model');
      const result = await provider.callEmbeddingApi('test');

      expect(result.error).toContain('Model not found');
      expect(result.error).toContain('non-existent/model');
    });

    it('should handle general errors', async () => {
      mockPipeline.mockRejectedValue(new Error('Some unexpected error'));

      const provider = new TransformersEmbeddingProvider('model');
      const result = await provider.callEmbeddingApi('test');

      expect(result.error).toContain('Transformers.js embedding error');
      expect(result.error).toContain('Some unexpected error');
    });
  });
});

describe('TransformersTextGenerationProvider', () => {
  let mockPipeline: ReturnType<typeof vi.fn>;
  let mockGenerator: ReturnType<typeof vi.fn>;
  let mockDispose: ReturnType<typeof vi.fn>;

  beforeEach(async () => {
    vi.resetAllMocks();

    // Clear pipeline cache between tests
    pipelineCache.clear();

    // Setup mock generator
    mockGenerator = vi.fn().mockResolvedValue([{ generated_text: 'Generated output' }]);
    mockDispose = vi.fn().mockResolvedValue(undefined);

    mockPipeline = vi
      .fn()
      .mockResolvedValue(Object.assign(mockGenerator, { dispose: mockDispose }));

    const transformers = await import('@huggingface/transformers');
    vi.mocked(transformers.pipeline).mockImplementation(mockPipeline as any);
  });

  afterEach(async () => {
    await disposePipelines();
    vi.clearAllMocks();
  });

  describe('constructor', () => {
    it('should construct with model name and default options', () => {
      const provider = new TransformersTextGenerationProvider('Xenova/gpt2');
      expect(provider.modelName).toBe('Xenova/gpt2');
      expect(provider.id()).toBe('transformers:text-generation:Xenova/gpt2');
    });

    it('should use custom id when provided', () => {
      const provider = new TransformersTextGenerationProvider('model', { id: 'custom-id' });
      expect(provider.id()).toBe('custom-id');
    });

    it('should store config options', () => {
      const provider = new TransformersTextGenerationProvider('model', {
        config: { temperature: 0.7, maxNewTokens: 100 },
      });
      expect(provider.config.temperature).toBe(0.7);
      expect(provider.config.maxNewTokens).toBe(100);
    });

    it('should have correct toString', () => {
      const provider = new TransformersTextGenerationProvider('Xenova/gpt2');
      expect(provider.toString()).toBe('[Transformers Text Generation Provider Xenova/gpt2]');
    });
  });

  describe('callApi', () => {
    it('should generate text with default options', async () => {
      const provider = new TransformersTextGenerationProvider('Xenova/gpt2');
      const result = await provider.callApi('Hello');

      expect(mockPipeline).toHaveBeenCalledWith(
        'text-generation',
        'Xenova/gpt2',
        expect.objectContaining({
          progress_callback: expect.any(Function),
        }),
      );

      expect(mockGenerator).toHaveBeenCalledWith('Hello', {
        max_new_tokens: 256,
        return_full_text: false,
      });

      expect(result.output).toBe('Generated output');
      expect(result.error).toBeUndefined();
      expect(result.latencyMs).toBeGreaterThanOrEqual(0);
    });

    it('should respect generation parameters', async () => {
      const provider = new TransformersTextGenerationProvider('model', {
        config: {
          temperature: 0.7,
          maxNewTokens: 100,
          topK: 40,
          topP: 0.9,
          doSample: true,
          repetitionPenalty: 1.2,
        },
      });

      await provider.callApi('test');

      expect(mockGenerator).toHaveBeenCalledWith('test', {
        max_new_tokens: 100,
        return_full_text: false,
        temperature: 0.7,
        top_k: 40,
        top_p: 0.9,
        do_sample: true,
        repetition_penalty: 1.2,
      });
    });

    it('should handle chat format output', async () => {
      mockGenerator.mockResolvedValue([
        {
          generated_text: [
            { role: 'user', content: 'Hello' },
            { role: 'assistant', content: 'Hi there!' },
          ],
        },
      ]);

      const provider = new TransformersTextGenerationProvider('model');
      const result = await provider.callApi('Hello');

      expect(result.output).toBe('Hi there!');
    });

    it('should cache pipeline instances', async () => {
      const provider = new TransformersTextGenerationProvider('model');

      await provider.callApi('prompt 1');
      await provider.callApi('prompt 2');

      expect(mockPipeline).toHaveBeenCalledTimes(1);
    });

    it('should handle empty output', async () => {
      mockGenerator.mockResolvedValue([{ generated_text: undefined }]);

      const provider = new TransformersTextGenerationProvider('model');
      const result = await provider.callApi('test');

      expect(result.error).toBe('No output generated');
    });

    it('should return error when model is not found', async () => {
      mockPipeline.mockRejectedValue(new Error('Could not locate file for model'));

      const provider = new TransformersTextGenerationProvider('non-existent/model');
      const result = await provider.callApi('test');

      expect(result.error).toContain('Model not found');
      expect(result.error).toContain('non-existent/model');
    });

    it('should handle general errors', async () => {
      mockPipeline.mockRejectedValue(new Error('Some unexpected error'));

      const provider = new TransformersTextGenerationProvider('model');
      const result = await provider.callApi('test');

      expect(result.error).toContain('Transformers.js generation error');
      expect(result.error).toContain('Some unexpected error');
    });
  });
});

describe('disposePipelines', () => {
  let mockPipeline: ReturnType<typeof vi.fn>;
  let mockDispose: ReturnType<typeof vi.fn>;

  beforeEach(async () => {
    vi.resetAllMocks();
    pipelineCache.clear();

    mockDispose = vi.fn().mockResolvedValue(undefined);

    mockPipeline = vi.fn().mockResolvedValue(
      Object.assign(vi.fn().mockResolvedValue({ data: new Float32Array([0.1]), dims: [1] }), {
        dispose: mockDispose,
      }),
    );

    const transformers = await import('@huggingface/transformers');
    vi.mocked(transformers.pipeline).mockImplementation(mockPipeline as any);
  });

  afterEach(() => {
    vi.clearAllMocks();
  });

  it('should dispose all cached pipelines', async () => {
    const provider1 = new TransformersEmbeddingProvider('model1');
    const provider2 = new TransformersEmbeddingProvider('model2');

    await provider1.callEmbeddingApi('test');
    await provider2.callEmbeddingApi('test');

    expect(pipelineCache.size).toBe(2);

    await disposePipelines();

    expect(mockDispose).toHaveBeenCalledTimes(2);
    expect(pipelineCache.size).toBe(0);
  });

  it('should handle dispose errors gracefully', async () => {
    mockDispose.mockRejectedValue(new Error('Dispose error'));

    const provider = new TransformersEmbeddingProvider('model');
    await provider.callEmbeddingApi('test');

    // Should not throw
    await expect(disposePipelines()).resolves.not.toThrow();
    expect(pipelineCache.size).toBe(0);
  });
});

describe('Pipeline caching', () => {
  let mockPipeline: ReturnType<typeof vi.fn>;

  beforeEach(async () => {
    vi.resetAllMocks();
    pipelineCache.clear();

    mockPipeline = vi.fn().mockResolvedValue(
      Object.assign(vi.fn().mockResolvedValue({ data: new Float32Array([0.1]), dims: [1] }), {
        dispose: vi.fn(),
      }),
    );

    const transformers = await import('@huggingface/transformers');
    vi.mocked(transformers.pipeline).mockImplementation(mockPipeline as any);
  });

  afterEach(async () => {
    await disposePipelines();
    vi.clearAllMocks();
  });

  it('should create separate pipelines for different models', async () => {
    const provider1 = new TransformersEmbeddingProvider('model1');
    const provider2 = new TransformersEmbeddingProvider('model2');

    await provider1.callEmbeddingApi('test');
    await provider2.callEmbeddingApi('test');

    expect(mockPipeline).toHaveBeenCalledTimes(2);
  });

  it('should create separate pipelines for different tasks', async () => {
    const embeddingProvider = new TransformersEmbeddingProvider('model');
    const textGenProvider = new TransformersTextGenerationProvider('model');

    // Need to setup generator mock for text generation
    const mockGenerator = vi.fn().mockResolvedValue([{ generated_text: 'output' }]);
    mockPipeline
      .mockResolvedValueOnce(
        Object.assign(vi.fn().mockResolvedValue({ data: new Float32Array([0.1]), dims: [1] }), {
          dispose: vi.fn(),
        }),
      )
      .mockResolvedValueOnce(Object.assign(mockGenerator, { dispose: vi.fn() }));

    await embeddingProvider.callEmbeddingApi('test');
    await textGenProvider.callApi('test');

    expect(mockPipeline).toHaveBeenCalledTimes(2);
    expect(mockPipeline).toHaveBeenCalledWith('feature-extraction', 'model', expect.any(Object));
    expect(mockPipeline).toHaveBeenCalledWith('text-generation', 'model', expect.any(Object));
  });

  it('should create separate pipelines for different devices', async () => {
    const provider1 = new TransformersEmbeddingProvider('model', { config: { device: 'cpu' } });
    const provider2 = new TransformersEmbeddingProvider('model', { config: { device: 'webgpu' } });

    await provider1.callEmbeddingApi('test');
    await provider2.callEmbeddingApi('test');

    expect(mockPipeline).toHaveBeenCalledTimes(2);
  });

  it('should create separate pipelines for different dtypes', async () => {
    const provider1 = new TransformersEmbeddingProvider('model', { config: { dtype: 'fp32' } });
    const provider2 = new TransformersEmbeddingProvider('model', { config: { dtype: 'q4' } });

    await provider1.callEmbeddingApi('test');
    await provider2.callEmbeddingApi('test');

    expect(mockPipeline).toHaveBeenCalledTimes(2);
  });
});