const LessonModule = require('../base/LessonModule');

class SQLInjectionShopLesson extends LessonModule {
  constructor(config) {
    super(config);
  }

  // Mock database with products
  getMockDatabase() {
    return {
      products: [
        { id: 1, name: 'Laptop Pro 15', price: 1299.99, category: 'Electronics', stock: 15 },
        { id: 2, name: 'Wireless Mouse', price: 29.99, category: 'Accessories', stock: 50 },
        { id: 3, name: 'USB-C Cable', price: 12.99, category: 'Accessories', stock: 100 },
        { id: 4, name: 'Gaming Keyboard', price: 89.99, category: 'Electronics', stock: 25 },
        { id: 5, name: 'Monitor 27"', price: 349.99, category: 'Electronics', stock: 20 },
        { id: 6, name: 'Webcam HD', price: 79.99, category: 'Electronics', stock: 30 },
        { id: 7, name: 'Desk Lamp', price: 34.99, category: 'Office', stock: 40 },
        { id: 8, name: 'Notebook Set', price: 15.99, category: 'Office', stock: 60 }
      ],
      users: [
        { id: 1, username: 'admin', password: 'hashed_admin_password', role: 'admin' },
        { id: 2, username: 'john_doe', password: 'hashed_user_password', role: 'customer' },
        { id: 3, username: 'jane_smith', password: 'hashed_user_password', role: 'customer' }
      ],
      orders: [
        { id: 1, user_id: 2, total: 1329.98, status: 'shipped' },
        { id: 2, user_id: 3, total: 89.99, status: 'processing' }
      ]
    };
  }

  // Simulate vulnerable SQL query
  executeVulnerableQuery(searchTerm) {
    const db = this.getMockDatabase();

    // Build the "vulnerable" query string for educational display
    const vulnerableQuery = `SELECT * FROM products WHERE name LIKE '%${searchTerm}%'`;

    // Detect SQL injection attempts
    const injectionDetected = this.detectInjection(searchTerm);

    let results = [];
    let injectionType = null;
    let explanation = '';

    if (injectionDetected) {
      const injectionInfo = this.analyzeInjection(searchTerm);
      injectionType = injectionInfo.type;
      explanation = injectionInfo.explanation;

      // Simulate different injection results
      if (injectionInfo.type === 'OR_ALWAYS_TRUE') {
        // Return all products (simulating OR '1'='1')
        results = db.products;
      } else if (injectionInfo.type === 'UNION_SELECT') {
        // Simulate UNION attack showing user data
        results = [
          { id: 'INJECTED', name: 'admin', price: 'hashed_admin_password', category: 'LEAKED DATA', stock: 'admin' },
          { id: 'INJECTED', name: 'john_doe', price: 'hashed_user_password', category: 'LEAKED DATA', stock: 'customer' },
          { id: 'INJECTED', name: 'jane_smith', price: 'hashed_user_password', category: 'LEAKED DATA', stock: 'customer' }
        ];
      } else if (injectionInfo.type === 'DROP_TABLE') {
        // Simulate destructive command
        results = [];
        explanation += ' In a real scenario, this could delete the entire products table!';
      } else if (injectionInfo.type === 'COMMENT_INJECTION') {
        // Bypass rest of query
        results = db.products;
      }
    } else {
      // Normal search - filter products by name
      results = db.products.filter(p =>
        p.name.toLowerCase().includes(searchTerm.toLowerCase())
      );
    }

    return {
      query: vulnerableQuery,
      results,
      injectionDetected,
      injectionType,
      explanation,
      recordCount: results.length
    };
  }

  // Detect if input contains SQL injection
  detectInjection(input) {
    const injectionPatterns = [
      /'/,                          // Single quote
      /--/,                         // SQL comment
      /;/,                          // Statement separator
      /union/i,                     // UNION keyword
      /select/i,                    // SELECT keyword
      /drop/i,                      // DROP keyword
      /insert/i,                    // INSERT keyword
      /update/i,                    // UPDATE keyword
      /delete/i,                    // DELETE keyword
      /or\s+['"]?\d+['"]?\s*=\s*['"]?\d+['"]?/i  // OR 1=1 pattern
    ];

    return injectionPatterns.some(pattern => pattern.test(input));
  }

  // Analyze the type of SQL injection
  analyzeInjection(input) {
    const lowerInput = input.toLowerCase();

    if (lowerInput.includes('union') && lowerInput.includes('select')) {
      return {
        type: 'UNION_SELECT',
        explanation: '⚠️ UNION SELECT injection detected! This technique combines results from multiple tables, potentially exposing sensitive data like usernames and passwords.'
      };
    }

    if (lowerInput.includes('drop')) {
      return {
        type: 'DROP_TABLE',
        explanation: '🚨 DROP TABLE injection detected! This is a destructive attack that could delete entire database tables. Critical data loss would occur!'
      };
    }

    if (lowerInput.includes("'") && (lowerInput.includes('or') || lowerInput.includes('||'))) {
      if (lowerInput.match(/or\s+['"]?\d+['"]?\s*=\s*['"]?\d+['"]?/)) {
        return {
          type: 'OR_ALWAYS_TRUE',
          explanation: "⚠️ OR injection detected! The condition '1'='1' is always true, bypassing the intended filter and returning ALL records."
        };
      }
    }

    if (lowerInput.includes('--') || lowerInput.includes('#')) {
      return {
        type: 'COMMENT_INJECTION',
        explanation: '⚠️ Comment injection detected! The -- sequence comments out the rest of the SQL query, potentially bypassing security checks.'
      };
    }

    if (lowerInput.includes(';')) {
      return {
        type: 'MULTIPLE_STATEMENTS',
        explanation: '⚠️ Multiple statement injection detected! The semicolon allows execution of additional SQL commands, enabling complex attacks.'
      };
    }

    // Generic injection
    return {
      type: 'GENERIC',
      explanation: '⚠️ SQL injection attempt detected! Special characters in the input could manipulate the query structure.'
    };
  }

  // Demonstrate safe parameterized query
  executeSafeQuery(searchTerm) {
    const db = this.getMockDatabase();

    // Show the safe query with placeholder
    const safeQuery = `SELECT * FROM products WHERE name LIKE ?`;
    const parameter = `%${searchTerm}%`;

    // Execute safe search (treats all input as literal data)
    const results = db.products.filter(p =>
      p.name.toLowerCase().includes(searchTerm.toLowerCase())
    );

    return {
      query: safeQuery,
      parameter,
      results,
      explanation: '✅ Parameterized query used! User input is treated as data only, never as SQL code. Injection is impossible.',
      recordCount: results.length
    };
  }

  // Get interactive data for the SQL shop demo
  getInteractiveData(stepId) {
    if (stepId === 'shop-demo') {
      return {
        database: this.getMockDatabase(),
        examples: [
          {
            label: 'Normal Search',
            input: 'laptop',
            description: 'Search for products containing "laptop"'
          },
          {
            label: 'View All Products (OR injection)',
            input: "' OR '1'='1",
            description: 'Exploit: Returns all products by making condition always true'
          },
          {
            label: 'Extract User Data (UNION)',
            input: "' UNION SELECT id, username, password, role, 'LEAKED' FROM users--",
            description: 'Exploit: Combines product results with user table data'
          },
          {
            label: 'Destructive Attack (DROP)',
            input: "'; DROP TABLE products--",
            description: 'Exploit: Attempts to delete the products table'
          }
        ]
      };
    }
    return null;
  }
}

module.exports = SQLInjectionShopLesson;