einvoice/test/suite/einvoice_edge-cases/test.edge-03.deep-nesting.ts

import { tap } from '@git.zone/tstest/tapbundle';
import * as plugins from '../plugins.js';
import { EInvoice } from '../../../ts/index.js';
import { PerformanceTracker } from '../performance.tracker.js';

const performanceTracker = new PerformanceTracker('EDGE-03: Deeply Nested XML Structures');

tap.test('EDGE-03: Deeply Nested XML Structures - should handle extremely nested XML', async (t) => {
  const einvoice = new EInvoice();

  // Test 1: Linear deep nesting
  const linearDeepNesting = await performanceTracker.measureAsync(
    'linear-deep-nesting',
    async () => {
      const testDepths = [10, 100, 1000, 5000, 10000];
      const results = [];
      
      for (const depth of testDepths) {
        let xml = '<?xml version="1.0" encoding="UTF-8"?>\n';
        
        // Build deeply nested structure
        for (let i = 0; i < depth; i++) {
          xml += ' '.repeat(i) + `<Level${i}>\n`;
        }
        
        xml += ' '.repeat(depth) + '<Data>Invoice Data</Data>\n';
        
        // Close all tags
        for (let i = depth - 1; i >= 0; i--) {
          xml += ' '.repeat(i) + `</Level${i}>\n`;
        }
        
        const startTime = Date.now();
        const startMemory = process.memoryUsage();
        
        try {
          const result = await einvoice.parseXML(xml);
          
          const endTime = Date.now();
          const endMemory = process.memoryUsage();
          
          results.push({
            depth,
            success: true,
            timeTaken: endTime - startTime,
            memoryUsed: endMemory.heapUsed - startMemory.heapUsed,
            hasData: !!result
          });
        } catch (error) {
          results.push({
            depth,
            success: false,
            error: error.message,
            isStackOverflow: error.message.includes('stack') || error.message.includes('depth')
          });
        }
      }
      
      return results;
    }
  );

  linearDeepNesting.forEach(result => {
    if (result.depth <= 1000) {
      t.ok(result.success, `Depth ${result.depth} should be handled`);
    } else {
      t.ok(!result.success || result.isStackOverflow, `Extreme depth ${result.depth} should be limited`);
    }
  });

  // Test 2: Recursive element nesting
  const recursiveElementNesting = await performanceTracker.measureAsync(
    'recursive-element-nesting',
    async () => {
      const createRecursiveStructure = (depth: number): string => {
        if (depth === 0) {
          return '<Amount>100.00</Amount>';
        }
        
        return `<Item>
          <ID>ITEM-${depth}</ID>
          <SubItems>
            ${createRecursiveStructure(depth - 1)}
          </SubItems>
        </Item>`;
      };
      
      const testDepths = [5, 10, 20, 50];
      const results = [];
      
      for (const depth of testDepths) {
        const xml = `<?xml version="1.0" encoding="UTF-8"?>
<Invoice>
  <ID>RECURSIVE-001</ID>
  <Items>
    ${createRecursiveStructure(depth)}
  </Items>
</Invoice>`;
        
        try {
          const startTime = Date.now();
          const parsed = await einvoice.parseXML(xml);
          const endTime = Date.now();
          
          // Count actual depth
          let actualDepth = 0;
          let current = parsed;
          while (current?.Items || current?.SubItems) {
            actualDepth++;
            current = current.Items || current.SubItems;
          }
          
          results.push({
            requestedDepth: depth,
            actualDepth,
            success: true,
            timeTaken: endTime - startTime
          });
        } catch (error) {
          results.push({
            requestedDepth: depth,
            success: false,
            error: error.message
          });
        }
      }
      
      return results;
    }
  );

  recursiveElementNesting.forEach(result => {
    t.ok(result.success || result.error, `Recursive depth ${result.requestedDepth} was processed`);
  });

  // Test 3: Namespace nesting complexity
  const namespaceNesting = await performanceTracker.measureAsync(
    'namespace-nesting-complexity',
    async () => {
      const createNamespaceNesting = (depth: number): string => {
        let xml = '<?xml version="1.0" encoding="UTF-8"?>\n';
        
        // Create nested elements with different namespaces
        for (let i = 0; i < depth; i++) {
          xml += ' '.repeat(i) + `<ns${i}:Element xmlns:ns${i}="http://example.com/ns${i}">\n`;
        }
        
        xml += ' '.repeat(depth) + '<Data>Content</Data>\n';
        
        // Close all namespace elements
        for (let i = depth - 1; i >= 0; i--) {
          xml += ' '.repeat(i) + `</ns${i}:Element>\n`;
        }
        
        return xml;
      };
      
      const testDepths = [5, 10, 25, 50, 100];
      const results = [];
      
      for (const depth of testDepths) {
        const xml = createNamespaceNesting(depth);
        
        try {
          const startTime = Date.now();
          const parsed = await einvoice.parseXML(xml);
          const endTime = Date.now();
          
          results.push({
            depth,
            success: true,
            timeTaken: endTime - startTime,
            namespacesPreserved: true // Check if namespaces were preserved
          });
        } catch (error) {
          results.push({
            depth,
            success: false,
            error: error.message
          });
        }
      }
      
      return results;
    }
  );

  namespaceNesting.forEach(result => {
    if (result.depth <= 50) {
      t.ok(result.success, `Namespace depth ${result.depth} should be handled`);
    }
  });

  // Test 4: Mixed content deep nesting
  const mixedContentNesting = await performanceTracker.measureAsync(
    'mixed-content-deep-nesting',
    async () => {
      const createMixedNesting = (depth: number): string => {
        let xml = '';
        
        for (let i = 0; i < depth; i++) {
          xml += `<Level${i}>Text before `;
        }
        
        xml += '<Value>Core Value</Value>';
        
        for (let i = depth - 1; i >= 0; i--) {
          xml += ` text after</Level${i}>`;
        }
        
        return xml;
      };
      
      const testCases = [10, 50, 100, 500];
      const results = [];
      
      for (const depth of testCases) {
        const xml = `<?xml version="1.0" encoding="UTF-8"?>
<Invoice>
  <MixedContent>
    ${createMixedNesting(depth)}
  </MixedContent>
</Invoice>`;
        
        try {
          const parsed = await einvoice.parseXML(xml);
          
          results.push({
            depth,
            success: true,
            hasMixedContent: true
          });
        } catch (error) {
          results.push({
            depth,
            success: false,
            error: error.message
          });
        }
      }
      
      return results;
    }
  );

  mixedContentNesting.forEach(result => {
    t.ok(result.success || result.error, `Mixed content depth ${result.depth} was handled`);
  });

  // Test 5: Attribute-heavy deep nesting
  const attributeHeavyNesting = await performanceTracker.measureAsync(
    'attribute-heavy-nesting',
    async () => {
      const createAttributeNesting = (depth: number, attrsPerLevel: number): string => {
        let xml = '';
        
        for (let i = 0; i < depth; i++) {
          xml += `<Element${i}`;
          
          // Add multiple attributes at each level
          for (let j = 0; j < attrsPerLevel; j++) {
            xml += ` attr${j}="value${i}_${j}"`;
          }
          
          xml += '>';
        }
        
        xml += 'Content';
        
        for (let i = depth - 1; i >= 0; i--) {
          xml += `</Element${i}>`;
        }
        
        return xml;
      };
      
      const testCases = [
        { depth: 10, attrs: 10 },
        { depth: 50, attrs: 5 },
        { depth: 100, attrs: 3 },
        { depth: 500, attrs: 1 }
      ];
      
      const results = [];
      
      for (const test of testCases) {
        const xml = `<?xml version="1.0" encoding="UTF-8"?>
<Invoice>
  ${createAttributeNesting(test.depth, test.attrs)}
</Invoice>`;
        
        const startTime = Date.now();
        const startMemory = process.memoryUsage();
        
        try {
          await einvoice.parseXML(xml);
          
          const endTime = Date.now();
          const endMemory = process.memoryUsage();
          
          results.push({
            depth: test.depth,
            attributesPerLevel: test.attrs,
            totalAttributes: test.depth * test.attrs,
            success: true,
            timeTaken: endTime - startTime,
            memoryUsed: endMemory.heapUsed - startMemory.heapUsed
          });
        } catch (error) {
          results.push({
            depth: test.depth,
            attributesPerLevel: test.attrs,
            success: false,
            error: error.message
          });
        }
      }
      
      return results;
    }
  );

  attributeHeavyNesting.forEach(result => {
    t.ok(result.success || result.error, 
      `Attribute-heavy nesting (depth: ${result.depth}, attrs: ${result.attributesPerLevel}) was processed`);
  });

  // Test 6: CDATA section nesting
  const cdataNesting = await performanceTracker.measureAsync(
    'cdata-section-nesting',
    async () => {
      const depths = [5, 10, 20, 50];
      const results = [];
      
      for (const depth of depths) {
        let xml = '<?xml version="1.0" encoding="UTF-8"?><Invoice>';
        
        // Create nested elements with CDATA
        for (let i = 0; i < depth; i++) {
          xml += `<Level${i}><![CDATA[Data at level ${i} with <special> characters & symbols]]>`;
        }
        
        // Close all elements
        for (let i = depth - 1; i >= 0; i--) {
          xml += `</Level${i}>`;
        }
        
        xml += '</Invoice>';
        
        try {
          const parsed = await einvoice.parseXML(xml);
          
          results.push({
            depth,
            success: true,
            cdataPreserved: true
          });
        } catch (error) {
          results.push({
            depth,
            success: false,
            error: error.message
          });
        }
      }
      
      return results;
    }
  );

  cdataNesting.forEach(result => {
    t.ok(result.success, `CDATA nesting depth ${result.depth} should be handled`);
  });

  // Test 7: Processing instruction nesting
  const processingInstructionNesting = await performanceTracker.measureAsync(
    'processing-instruction-nesting',
    async () => {
      const createPINesting = (depth: number): string => {
        let xml = '<?xml version="1.0" encoding="UTF-8"?>\n';
        
        for (let i = 0; i < depth; i++) {
          xml += `<?process-level-${i} instruction="value"?>\n`;
          xml += `<Level${i}>\n`;
        }
        
        xml += '<Data>Content</Data>\n';
        
        for (let i = depth - 1; i >= 0; i--) {
          xml += `</Level${i}>\n`;
        }
        
        return xml;
      };
      
      const depths = [10, 25, 50];
      const results = [];
      
      for (const depth of depths) {
        const xml = createPINesting(depth);
        
        try {
          const parsed = await einvoice.parseXML(xml);
          
          results.push({
            depth,
            success: true,
            processingInstructionsHandled: true
          });
        } catch (error) {
          results.push({
            depth,
            success: false,
            error: error.message
          });
        }
      }
      
      return results;
    }
  );

  processingInstructionNesting.forEach(result => {
    t.ok(result.success, `PI nesting depth ${result.depth} should be handled`);
  });

  // Test 8: Real invoice format deep structures
  const realFormatDeepStructures = await performanceTracker.measureAsync(
    'real-format-deep-structures',
    async () => {
      const formats = ['ubl', 'cii'];
      const results = [];
      
      for (const format of formats) {
        // Create deeply nested invoice structure
        let invoice;
        
        if (format === 'ubl') {
          invoice = `<?xml version="1.0" encoding="UTF-8"?>
<Invoice xmlns="urn:oasis:names:specification:ubl:schema:xsd:Invoice-2">
  <ID>DEEP-UBL-001</ID>
  <Note>
    <SubNote>
      <SubSubNote>
        <Content>
          <Detail>
            <SubDetail>
              <Information>Deeply nested note</Information>
            </SubDetail>
          </Detail>
        </Content>
      </SubSubNote>
    </SubNote>
  </Note>
  <InvoiceLine>
    <Item>
      <AdditionalItemProperty>
        <Value>
          <SubValue>
            <Detail>
              <SubDetail>
                <Information>Deep item property</Information>
              </SubDetail>
            </Detail>
          </SubValue>
        </Value>
      </AdditionalItemProperty>
    </Item>
  </InvoiceLine>
</Invoice>`;
        } else {
          invoice = `<?xml version="1.0" encoding="UTF-8"?>
<rsm:CrossIndustryInvoice xmlns:rsm="urn:un:unece:uncefact:data:standard:CrossIndustryInvoice:100">
  <rsm:ExchangedDocument>
    <ram:ID>DEEP-CII-001</ram:ID>
    <ram:IncludedNote>
      <ram:Content>
        <ram:SubContent>
          <ram:Detail>
            <ram:SubDetail>
              <ram:Information>Deep CII structure</ram:Information>
            </ram:SubDetail>
          </ram:Detail>
        </ram:SubContent>
      </ram:Content>
    </ram:IncludedNote>
  </rsm:ExchangedDocument>
</rsm:CrossIndustryInvoice>`;
        }
        
        try {
          const parsed = await einvoice.parseDocument(invoice);
          const validated = await einvoice.validate(parsed);
          
          results.push({
            format,
            parsed: true,
            valid: validated?.isValid || false,
            deepStructureSupported: true
          });
        } catch (error) {
          results.push({
            format,
            parsed: false,
            error: error.message
          });
        }
      }
      
      return results;
    }
  );

  realFormatDeepStructures.forEach(result => {
    t.ok(result.parsed, `${result.format} deep structure should be parsed`);
  });

  // Test 9: Stack overflow protection
  const stackOverflowProtection = await performanceTracker.measureAsync(
    'stack-overflow-protection',
    async () => {
      const extremeDepths = [10000, 50000, 100000];
      const results = [];
      
      for (const depth of extremeDepths) {
        // Create extremely deep structure efficiently
        const parts = [];
        parts.push('<?xml version="1.0" encoding="UTF-8"?>');
        
        // Opening tags
        for (let i = 0; i < Math.min(depth, 1000); i++) {
          parts.push(`<L${i}>`);
        }
        
        parts.push('<Data>Test</Data>');
        
        // Closing tags
        for (let i = Math.min(depth - 1, 999); i >= 0; i--) {
          parts.push(`</L${i}>`);
        }
        
        const xml = parts.join('');
        
        const startTime = Date.now();
        
        try {
          await einvoice.parseXML(xml, { maxDepth: 1000 });
          
          const endTime = Date.now();
          
          results.push({
            depth,
            protected: true,
            method: 'depth-limit',
            timeTaken: endTime - startTime
          });
        } catch (error) {
          const endTime = Date.now();
          
          results.push({
            depth,
            protected: true,
            method: error.message.includes('depth') ? 'depth-check' : 'stack-guard',
            timeTaken: endTime - startTime,
            error: error.message
          });
        }
      }
      
      return results;
    }
  );

  stackOverflowProtection.forEach(result => {
    t.ok(result.protected, `Stack overflow protection active for depth ${result.depth}`);
  });

  // Test 10: Performance impact of nesting
  const nestingPerformanceImpact = await performanceTracker.measureAsync(
    'nesting-performance-impact',
    async () => {
      const depths = [1, 10, 50, 100, 500, 1000];
      const results = [];
      
      for (const depth of depths) {
        // Create invoice with specific nesting depth
        let xml = '<?xml version="1.0" encoding="UTF-8"?><Invoice>';
        
        // Create structure at depth
        let current = xml;
        for (let i = 0; i < depth; i++) {
          current += `<Item${i}>`;
        }
        
        current += '<ID>TEST</ID><Amount>100</Amount>';
        
        for (let i = depth - 1; i >= 0; i--) {
          current += `</Item${i}>`;
        }
        
        current += '</Invoice>';
        
        // Measure parsing time
        const iterations = 10;
        const times = [];
        
        for (let i = 0; i < iterations; i++) {
          const startTime = process.hrtime.bigint();
          
          try {
            await einvoice.parseXML(current);
          } catch (error) {
            // Ignore errors for performance testing
          }
          
          const endTime = process.hrtime.bigint();
          times.push(Number(endTime - startTime) / 1000000); // Convert to ms
        }
        
        const avgTime = times.reduce((a, b) => a + b, 0) / times.length;
        const minTime = Math.min(...times);
        const maxTime = Math.max(...times);
        
        results.push({
          depth,
          avgTime,
          minTime,
          maxTime,
          complexity: avgTime / depth // Time per nesting level
        });
      }
      
      return results;
    }
  );

  // Verify performance doesn't degrade exponentially
  const complexities = nestingPerformanceImpact.map(r => r.complexity);
  const avgComplexity = complexities.reduce((a, b) => a + b, 0) / complexities.length;
  
  nestingPerformanceImpact.forEach(result => {
    t.ok(result.complexity < avgComplexity * 10, 
      `Nesting depth ${result.depth} has reasonable performance`);
  });

  // Print performance summary
  performanceTracker.printSummary();
});

// Run the test
tap.start();