/**
 * Integration Tests: Storage Service (S3/R2)
 *
 * Epic: OQI-002 - Módulo Educativo
 * Service: storage.service.ts
 *
 * Tests validate:
 * - Multipart upload flow
 * - Presigned URL generation
 * - Object operations (upload, delete, copy, metadata)
 * - S3/R2 API integration
 * - Error handling
 */

import { StorageService, type StorageConfig } from '../../shared/services/storage.service';
import { S3Client } from '@aws-sdk/client-s3';
import { getSignedUrl } from '@aws-sdk/s3-request-presigner';

// Mock AWS SDK
jest.mock('@aws-sdk/client-s3');
jest.mock('@aws-sdk/s3-request-presigner');

describe('Integration: Storage Service', () => {
  let service: StorageService;
  let mockS3Client: jest.Mocked<S3Client>;

  const testConfig: StorageConfig = {
    provider: 's3',
    bucket: 'test-bucket',
    region: 'us-east-1',
    accessKeyId: 'test-key',
    secretAccessKey: 'test-secret',
    cdnUrl: 'https://cdn.example.com',
  };

  beforeEach(() => {
    // Create mock S3 client
    mockS3Client = {
      send: jest.fn(),
    } as any;

    // Mock S3Client constructor
    (S3Client as jest.Mock).mockImplementation(() => mockS3Client);

    service = new StorageService(testConfig);
  });

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

  // ==========================================================================
  // Multipart Upload Flow
  // ==========================================================================

  describe('Multipart Upload', () => {
    it('should initialize multipart upload', async () => {
      mockS3Client.send.mockResolvedValue({
        UploadId: 'upload-123',
      });

      const result = await service.initMultipartUpload(
        'videos/test.mp4',
        'video/mp4',
        { title: 'Test Video', userId: 'user-123' }
      );

      expect(result).toEqual({
        uploadId: 'upload-123',
        key: 'videos/test.mp4',
      });

      expect(mockS3Client.send).toHaveBeenCalledWith(
        expect.objectContaining({
          input: expect.objectContaining({
            Bucket: 'test-bucket',
            Key: 'videos/test.mp4',
            ContentType: 'video/mp4',
            Metadata: { title: 'Test Video', userId: 'user-123' },
          }),
        })
      );
    });

    it('should throw error if uploadId is missing', async () => {
      mockS3Client.send.mockResolvedValue({
        UploadId: undefined, // Missing
      });

      await expect(service.initMultipartUpload('videos/test.mp4')).rejects.toThrow(
        'Failed to get uploadId from multipart upload init'
      );
    });

    it('should upload a part', async () => {
      const partData = Buffer.from('video chunk data');

      mockS3Client.send.mockResolvedValue({
        ETag: '"etag-abc123"',
      });

      const result = await service.uploadPart('videos/test.mp4', 'upload-123', 1, partData);

      expect(result).toEqual({
        etag: '"etag-abc123"',
        partNumber: 1,
      });

      expect(mockS3Client.send).toHaveBeenCalledWith(
        expect.objectContaining({
          input: expect.objectContaining({
            Bucket: 'test-bucket',
            Key: 'videos/test.mp4',
            UploadId: 'upload-123',
            PartNumber: 1,
            Body: partData,
          }),
        })
      );
    });

    it('should throw error if ETag is missing from part upload', async () => {
      mockS3Client.send.mockResolvedValue({
        ETag: undefined,
      });

      await expect(
        service.uploadPart('videos/test.mp4', 'upload-123', 1, Buffer.from('data'))
      ).rejects.toThrow('Failed to get ETag from part upload');
    });

    it('should complete multipart upload', async () => {
      mockS3Client.send.mockResolvedValue({});

      const parts = [
        { PartNumber: 1, ETag: '"etag-1"' },
        { PartNumber: 2, ETag: '"etag-2"' },
      ];

      const result = await service.completeMultipartUpload('videos/test.mp4', 'upload-123', parts);

      expect(result).toEqual({
        key: 'videos/test.mp4',
        url: 'https://cdn.example.com/videos/test.mp4',
      });

      expect(mockS3Client.send).toHaveBeenCalledWith(
        expect.objectContaining({
          input: expect.objectContaining({
            Bucket: 'test-bucket',
            Key: 'videos/test.mp4',
            UploadId: 'upload-123',
            MultipartUpload: {
              Parts: parts,
            },
          }),
        })
      );
    });

    it('should abort multipart upload', async () => {
      mockS3Client.send.mockResolvedValue({});

      await service.abortMultipartUpload('videos/test.mp4', 'upload-123');

      expect(mockS3Client.send).toHaveBeenCalledWith(
        expect.objectContaining({
          input: expect.objectContaining({
            Bucket: 'test-bucket',
            Key: 'videos/test.mp4',
            UploadId: 'upload-123',
          }),
        })
      );
    });

    it('should handle S3 errors in multipart operations', async () => {
      mockS3Client.send.mockRejectedValue(new Error('S3 Access Denied'));

      await expect(service.initMultipartUpload('videos/test.mp4')).rejects.toThrow(
        'Multipart upload init failed'
      );
    });
  });

  // ==========================================================================
  // Presigned URLs
  // ==========================================================================

  describe('Presigned URLs', () => {
    it('should generate presigned upload URL', async () => {
      (getSignedUrl as jest.Mock).mockResolvedValue('https://s3.example.com/presigned-upload?signature=abc');

      const result = await service.getPresignedUploadUrl({
        key: 'videos/test.mp4',
        expiresIn: 3600,
        contentType: 'video/mp4',
      });

      expect(result).toBe('https://s3.example.com/presigned-upload?signature=abc');
      expect(getSignedUrl).toHaveBeenCalledWith(
        mockS3Client,
        expect.anything(),
        { expiresIn: 3600 }
      );
    });

    it('should generate presigned download URL', async () => {
      (getSignedUrl as jest.Mock).mockResolvedValue('https://s3.example.com/presigned-download?signature=xyz');

      const result = await service.getPresignedDownloadUrl('videos/test.mp4', 1800);

      expect(result).toBe('https://s3.example.com/presigned-download?signature=xyz');
      expect(getSignedUrl).toHaveBeenCalledWith(
        mockS3Client,
        expect.anything(),
        { expiresIn: 1800 }
      );
    });

    it('should use default expiration (3600s) for presigned URLs', async () => {
      (getSignedUrl as jest.Mock).mockResolvedValue('https://s3.example.com/presigned');

      await service.getPresignedUploadUrl({ key: 'videos/test.mp4' });

      expect(getSignedUrl).toHaveBeenCalledWith(
        mockS3Client,
        expect.anything(),
        { expiresIn: 3600 }
      );
    });

    it('should handle presigned URL generation errors', async () => {
      (getSignedUrl as jest.Mock).mockRejectedValue(new Error('Invalid credentials'));

      await expect(service.getPresignedUploadUrl({ key: 'videos/test.mp4' })).rejects.toThrow(
        'Presigned URL generation failed'
      );
    });
  });

  // ==========================================================================
  // Simple Upload
  // ==========================================================================

  describe('Simple Upload', () => {
    it('should upload object with buffer', async () => {
      mockS3Client.send.mockResolvedValue({});

      const buffer = Buffer.from('file content');

      const result = await service.upload({
        key: 'documents/test.pdf',
        body: buffer,
        contentType: 'application/pdf',
        metadata: { userId: 'user-123' },
        acl: 'private',
      });

      expect(result).toEqual({
        key: 'documents/test.pdf',
        url: 'https://cdn.example.com/documents/test.pdf',
      });

      expect(mockS3Client.send).toHaveBeenCalledWith(
        expect.objectContaining({
          input: expect.objectContaining({
            Bucket: 'test-bucket',
            Key: 'documents/test.pdf',
            Body: buffer,
            ContentType: 'application/pdf',
            Metadata: { userId: 'user-123' },
            ACL: 'private',
          }),
        })
      );
    });

    it('should default to private ACL', async () => {
      mockS3Client.send.mockResolvedValue({});

      await service.upload({
        key: 'test.txt',
        body: 'content',
      });

      expect(mockS3Client.send).toHaveBeenCalledWith(
        expect.objectContaining({
          input: expect.objectContaining({
            ACL: 'private',
          }),
        })
      );
    });

    it('should handle upload errors', async () => {
      mockS3Client.send.mockRejectedValue(new Error('Quota exceeded'));

      await expect(
        service.upload({ key: 'test.txt', body: 'content' })
      ).rejects.toThrow('Storage upload failed');
    });
  });

  // ==========================================================================
  // Object Operations
  // ==========================================================================

  describe('Object Operations', () => {
    it('should get object as buffer', async () => {
      const mockStream = {
        [Symbol.asyncIterator]: async function* () {
          yield Buffer.from('chunk1');
          yield Buffer.from('chunk2');
        },
      };

      mockS3Client.send.mockResolvedValue({
        Body: mockStream,
      });

      const result = await service.getObject('documents/test.pdf');

      expect(result).toBeInstanceOf(Buffer);
      expect(result.toString()).toBe('chunk1chunk2');
      expect(mockS3Client.send).toHaveBeenCalledWith(
        expect.objectContaining({
          input: expect.objectContaining({
            Bucket: 'test-bucket',
            Key: 'documents/test.pdf',
          }),
        })
      );
    });

    it('should throw error if object body is empty', async () => {
      mockS3Client.send.mockResolvedValue({
        Body: undefined,
      });

      await expect(service.getObject('test.txt')).rejects.toThrow('Empty response body');
    });

    it('should delete object', async () => {
      mockS3Client.send.mockResolvedValue({});

      await service.deleteObject('documents/old.pdf');

      expect(mockS3Client.send).toHaveBeenCalledWith(
        expect.objectContaining({
          input: expect.objectContaining({
            Bucket: 'test-bucket',
            Key: 'documents/old.pdf',
          }),
        })
      );
    });

    it('should copy object', async () => {
      mockS3Client.send.mockResolvedValue({});

      await service.copyObject('source/file.txt', 'destination/file.txt');

      expect(mockS3Client.send).toHaveBeenCalledWith(
        expect.objectContaining({
          input: expect.objectContaining({
            Bucket: 'test-bucket',
            CopySource: 'test-bucket/source/file.txt',
            Key: 'destination/file.txt',
          }),
        })
      );
    });

    it('should get object metadata', async () => {
      mockS3Client.send.mockResolvedValue({
        ContentLength: 1024,
        LastModified: new Date('2026-01-27T10:00:00Z'),
        ContentType: 'application/pdf',
        ETag: '"abc123"',
        Metadata: { userId: 'user-123' },
      });

      const result = await service.getObjectMetadata('documents/test.pdf');

      expect(result).toEqual({
        key: 'documents/test.pdf',
        size: 1024,
        lastModified: new Date('2026-01-27T10:00:00Z'),
        contentType: 'application/pdf',
        etag: '"abc123"',
        metadata: { userId: 'user-123' },
      });
    });

    it('should list objects with prefix', async () => {
      mockS3Client.send.mockResolvedValue({
        Contents: [
          {
            Key: 'videos/test1.mp4',
            Size: 1024000,
            LastModified: new Date('2026-01-27T10:00:00Z'),
            ETag: '"etag1"',
          },
          {
            Key: 'videos/test2.mp4',
            Size: 2048000,
            LastModified: new Date('2026-01-27T11:00:00Z'),
            ETag: '"etag2"',
          },
        ],
      });

      const result = await service.listObjects('videos/', 100);

      expect(result).toEqual([
        {
          key: 'videos/test1.mp4',
          size: 1024000,
          lastModified: new Date('2026-01-27T10:00:00Z'),
          etag: '"etag1"',
        },
        {
          key: 'videos/test2.mp4',
          size: 2048000,
          lastModified: new Date('2026-01-27T11:00:00Z'),
          etag: '"etag2"',
        },
      ]);

      expect(mockS3Client.send).toHaveBeenCalledWith(
        expect.objectContaining({
          input: expect.objectContaining({
            Bucket: 'test-bucket',
            Prefix: 'videos/',
            MaxKeys: 100,
          }),
        })
      );
    });

    it('should return empty array if no objects found', async () => {
      mockS3Client.send.mockResolvedValue({
        Contents: undefined,
      });

      const result = await service.listObjects('empty/');

      expect(result).toEqual([]);
    });

    it('should use default maxKeys (1000) for listing', async () => {
      mockS3Client.send.mockResolvedValue({ Contents: [] });

      await service.listObjects('prefix/');

      expect(mockS3Client.send).toHaveBeenCalledWith(
        expect.objectContaining({
          input: expect.objectContaining({
            MaxKeys: 1000,
          }),
        })
      );
    });
  });

  // ==========================================================================
  // URL Generation
  // ==========================================================================

  describe('URL Generation', () => {
    it('should generate CDN URL if configured', () => {
      const url = service.getPublicUrl('videos/test.mp4');

      expect(url).toBe('https://cdn.example.com/videos/test.mp4');
    });

    it('should generate R2 URL for Cloudflare R2', () => {
      const r2Service = new StorageService({
        provider: 'r2',
        bucket: 'test-bucket',
        endpoint: 'https://r2.example.com',
        accessKeyId: 'key',
        secretAccessKey: 'secret',
      });

      const url = r2Service.getPublicUrl('videos/test.mp4');

      expect(url).toBe('https://r2.example.com/test-bucket/videos/test.mp4');
    });

    it('should generate S3 URL for AWS S3', () => {
      const s3Service = new StorageService({
        provider: 's3',
        bucket: 'my-bucket',
        region: 'us-west-2',
        accessKeyId: 'key',
        secretAccessKey: 'secret',
      });

      const url = s3Service.getPublicUrl('documents/file.pdf');

      expect(url).toBe('https://my-bucket.s3.us-west-2.amazonaws.com/documents/file.pdf');
    });

    it('should prefer CDN URL over S3/R2 URL', () => {
      const serviceWithCdn = new StorageService({
        provider: 'r2',
        bucket: 'test-bucket',
        region: 'auto',
        endpoint: 'https://r2.example.com',
        accessKeyId: 'key',
        secretAccessKey: 'secret',
        cdnUrl: 'https://cdn.example.com',
      });

      const url = serviceWithCdn.getPublicUrl('test.mp4');

      expect(url).toBe('https://cdn.example.com/test.mp4');
    });
  });

  // ==========================================================================
  // Helper Methods
  // ==========================================================================

  describe('Helper Methods', () => {
    it('should generate unique storage key', () => {
      const key1 = service.generateKey('videos', 'test.mp4');
      const key2 = service.generateKey('videos', 'test.mp4');

      // Should start with prefix
      expect(key1).toMatch(/^videos\//);
      expect(key2).toMatch(/^videos\//);

      // Should include timestamp
      expect(key1).toMatch(/videos\/\d+-[a-z0-9]+-test\.mp4/);

      // Should be unique (different random component)
      expect(key1).not.toBe(key2);
    });

    it('should sanitize filename in generated key', () => {
      const key = service.generateKey('documents', 'my file (copy) #1.pdf');

      // Special characters should be replaced with underscores
      expect(key).toMatch(/^documents\/\d+-[a-z0-9]+-my_file__copy___1\.pdf$/);
    });

    it('should preserve file extension', () => {
      const key = service.generateKey('images', 'photo.jpg');

      expect(key).toMatch(/\.jpg$/);
    });
  });

  // ==========================================================================
  // Error Handling
  // ==========================================================================

  describe('Error Handling', () => {
    it('should wrap S3 errors with context', async () => {
      mockS3Client.send.mockRejectedValue(new Error('AccessDenied: Insufficient permissions'));

      await expect(
        service.upload({ key: 'test.txt', body: 'content' })
      ).rejects.toThrow('Storage upload failed: AccessDenied: Insufficient permissions');
    });

    it('should handle network errors', async () => {
      mockS3Client.send.mockRejectedValue(new Error('ECONNREFUSED'));

      await expect(service.deleteObject('test.txt')).rejects.toThrow('Delete object failed');
    });

    it('should handle unknown errors', async () => {
      mockS3Client.send.mockRejectedValue('Unknown error');

      await expect(service.getObject('test.txt')).rejects.toThrow('Get object failed');
    });
  });
});