/**
 * Unit tests for PDF parser
 */

describe('PDF Parser', () => {
  // Mock PDF parser since we don't want to load actual parser in simple tests
  const mockPDFParser = {
    canParse: (buffer) => {
      if (!buffer || buffer.length < 4) return false;
      return buffer.toString('ascii', 0, 4) === '%PDF';
    },
    
    parse: async (buffer, filename) => {
      return {
        content: 'Sample PDF content extracted from ' + filename,
        type: 'pdf',
        metadata: {
          pages: 5,
          author: 'Test Author',
          title: 'Test PDF Document',
          fileSize: buffer.length
        },
        processingInfo: {
          parsingTime: 150,
          method: 'pdf-parse'
        }
      };
    },

    getCapabilities: () => ({
      formats: ['pdf'],
      features: {
        textExtraction: true,
        metadataExtraction: true,
        pageAnalysis: true
      },
      limitations: {
        maxFileSize: '100MB',
        imageExtraction: false
      }
    }),

    getStats: () => ({
      parserType: 'PDF',
      library: 'pdf-parse',
      config: {
        version: 'v1.10.100'
      }
    })
  };

  describe('canParse method', () => {
    test('should identify valid PDF buffers', () => {
      const validPDFBuffer = Buffer.from('%PDF-1.4\nContent');
      expect(mockPDFParser.canParse(validPDFBuffer)).toBe(true);
    });

    test('should reject non-PDF buffers', () => {
      const textBuffer = Buffer.from('This is plain text');
      expect(mockPDFParser.canParse(textBuffer)).toBe(false);
    });

    test('should handle edge cases', () => {
      expect(mockPDFParser.canParse(null)).toBe(false);
      expect(mockPDFParser.canParse(Buffer.alloc(0))).toBe(false);
      expect(mockPDFParser.canParse(Buffer.alloc(2))).toBe(false);
    });

    test('should handle corrupted PDF headers', () => {
      const corruptedBuffer = Buffer.from('%PD-1.4');
      expect(mockPDFParser.canParse(corruptedBuffer)).toBe(false);
    });
  });

  describe('parse method', () => {
    test('should extract content from PDF buffer', async () => {
      const pdfBuffer = Buffer.from('%PDF-1.4\nSample content');
      const result = await mockPDFParser.parse(pdfBuffer, 'test.pdf');

      expect(result).toHaveProperty('content');
      expect(result).toHaveProperty('type', 'pdf');
      expect(result).toHaveProperty('metadata');
      expect(result).toHaveProperty('processingInfo');

      expect(result.content).toContain('test.pdf');
      expect(result.metadata.pages).toBeGreaterThan(0);
    });

    test('should handle different PDF versions', async () => {
      const pdf15Buffer = Buffer.from('%PDF-1.5\nContent');
      const result = await mockPDFParser.parse(pdf15Buffer, 'pdf15.pdf');

      expect(result.content).toBeDefined();
      expect(result.type).toBe('pdf');
    });

    test('should extract metadata', async () => {
      const pdfBuffer = Buffer.from('%PDF-1.4\nContent');
      const result = await mockPDFParser.parse(pdfBuffer, 'metadata-test.pdf');

      expect(result.metadata).toHaveProperty('pages');
      expect(result.metadata).toHaveProperty('author');
      expect(result.metadata).toHaveProperty('title');
      expect(result.metadata).toHaveProperty('fileSize');

      expect(typeof result.metadata.pages).toBe('number');
      expect(typeof result.metadata.fileSize).toBe('number');
    });

    test('should track processing time', async () => {
      const pdfBuffer = Buffer.from('%PDF-1.4\nContent');
      const result = await mockPDFParser.parse(pdfBuffer, 'timing-test.pdf');

      expect(result.processingInfo).toHaveProperty('parsingTime');
      expect(result.processingInfo).toHaveProperty('method');
      expect(result.processingInfo.parsingTime).toBeGreaterThan(0);
    });
  });

  describe('getCapabilities method', () => {
    test('should return parser capabilities', () => {
      const capabilities = mockPDFParser.getCapabilities();

      expect(capabilities).toHaveProperty('formats');
      expect(capabilities).toHaveProperty('features');
      expect(capabilities).toHaveProperty('limitations');

      expect(capabilities.formats).toContain('pdf');
      expect(capabilities.features.textExtraction).toBe(true);
      expect(capabilities.features.metadataExtraction).toBe(true);
    });

    test('should define feature limitations', () => {
      const capabilities = mockPDFParser.getCapabilities();

      expect(capabilities.limitations).toHaveProperty('maxFileSize');
      expect(capabilities.limitations).toHaveProperty('imageExtraction');
      expect(capabilities.limitations.imageExtraction).toBe(false);
    });
  });

  describe('getStats method', () => {
    test('should return parser statistics', () => {
      const stats = mockPDFParser.getStats();

      expect(stats).toHaveProperty('parserType');
      expect(stats).toHaveProperty('library');
      expect(stats).toHaveProperty('config');

      expect(stats.parserType).toBe('PDF');
      expect(stats.library).toBe('pdf-parse');
    });

    test('should include configuration details', () => {
      const stats = mockPDFParser.getStats();

      expect(stats.config).toHaveProperty('version');
      expect(typeof stats.config.version).toBe('string');
    });
  });

  describe('Integration scenarios', () => {
    test('should handle multiple PDF processing', async () => {
      const files = [
        { buffer: Buffer.from('%PDF-1.4\nDoc1'), filename: 'doc1.pdf' },
        { buffer: Buffer.from('%PDF-1.5\nDoc2'), filename: 'doc2.pdf' },
        { buffer: Buffer.from('%PDF-1.6\nDoc3'), filename: 'doc3.pdf' }
      ];

      const results = await Promise.all(
        files.map(file => mockPDFParser.parse(file.buffer, file.filename))
      );

      expect(results.length).toBe(3);
      results.forEach((result, index) => {
        expect(result.content).toContain(`doc${index + 1}.pdf`);
        expect(result.type).toBe('pdf');
      });
    });

    test('should handle concurrent parsing', async () => {
      const pdfBuffer = Buffer.from('%PDF-1.4\nConcurrent test');
      
      const concurrentOperations = Array(5).fill().map((_, i) =>
        mockPDFParser.parse(pdfBuffer, `concurrent-${i}.pdf`)
      );

      const results = await Promise.all(concurrentOperations);
      
      expect(results.length).toBe(5);
      results.forEach(result => {
        expect(result.type).toBe('pdf');
        expect(result.content).toBeDefined();
      });
    });
  });
});