#!/usr/bin/env node

/**
 * CSP Violations Checker
 * Enforces Content Security Policy compliance (inst_008)
 *
 * Checks staged files for:
 * - Inline scripts (<script> tags with code)
 * - Inline event handlers (onclick, onload, etc.)
 * - Inline styles in HTML
 *
 * Does NOT check:
 * - Non-HTML files (JS, CSS, MD, etc.)
 * - <script src="..."> external scripts
 */

const { execSync } = require('child_process');
const fs = require('fs');
const path = require('path');

/**
 * Scan for CSP violations in HTML files
 * @param {Array<string>} files - Optional array of files to scan (defaults to staged files)
 * @returns {Array} Array of violation objects
 */
function scanForViolations(files = null) {
  let htmlFiles;

  if (files) {
    // Use provided files
    htmlFiles = files.filter(f => f.endsWith('.html'));
  } else {
    // Get list of staged files
    try {
      const stagedFiles = execSync('git diff --cached --name-only --diff-filter=ACMR', { encoding: 'utf8' })
        .split('\n')
        .filter(f => f.trim() !== '');
      htmlFiles = stagedFiles.filter(f => f.endsWith('.html'));
    } catch (error) {
      console.error('Error getting staged files:', error.message);
      return []; // Return empty array if can't check
    }
  }

  if (htmlFiles.length === 0) {
    return [];
  }

  const violations = [];

  // Check each HTML file
  htmlFiles.forEach(file => {
    const filePath = path.join(process.cwd(), file);

    if (!fs.existsSync(filePath)) {
      return; // File deleted, skip
    }

    const content = fs.readFileSync(filePath, 'utf8');
    const lines = content.split('\n');

    lines.forEach((line, index) => {
      const lineNum = index + 1;

      // Check for inline scripts (but not <script src="...">)
      if (/<script(?!.*src=)[^>]*>[\s\S]*?<\/script>/i.test(line)) {
        if (line.includes('<script>') || (line.includes('<script ') && !line.includes('src='))) {
          violations.push({
            file,
            line: lineNum,
            type: 'inline-script',
            content: line.trim().substring(0, 80)
          });
        }
      }

      // Check for inline event handlers
      const inlineHandlers = ['onclick', 'onload', 'onmouseover', 'onsubmit', 'onerror', 'onchange'];
      inlineHandlers.forEach(handler => {
        if (new RegExp(`\\s${handler}=`, 'i').test(line)) {
          violations.push({
            file,
            line: lineNum,
            type: 'inline-handler',
            handler,
            content: line.trim().substring(0, 80)
          });
        }
      });

      // Check for inline styles (style attribute)
      if (/\sstyle\s*=\s*["'][^"']*["']/i.test(line)) {
        // Allow Tailwind utility classes pattern (common false positive)
        if (!line.includes('class=') || line.match(/style\s*=\s*["'][^"']{20,}/)) {
          violations.push({
            file,
            line: lineNum,
            type: 'inline-style',
            content: line.trim().substring(0, 80)
          });
        }
      }
    });
  });

  return violations;
}

/**
 * Display violations to console
 * @param {Array} violations - Array of violation objects
 */
function displayViolations(violations) {
  if (violations.length === 0) {
    return;
  }

  console.error('\nCSP Violations Found:\n');
  violations.forEach(v => {
    console.error(`  ${v.file}:${v.line}`);
    console.error(`    Type: ${v.type}${v.handler ? ' (' + v.handler + ')' : ''}`);
    console.error(`    Content: ${v.content}`);
    console.error('');
  });

  console.error(`Total violations: ${violations.length}\n`);
  console.error('Fix these violations or use --no-verify to bypass (not recommended)\n');
}

// Export functions for use as a module
module.exports = { scanForViolations, displayViolations };

// Run as CLI if called directly
if (require.main === module) {
  const violations = scanForViolations();

  if (violations.length === 0) {
    process.exit(0); // No violations, allow commit
  }

  displayViolations(violations);
  process.exit(1); // Block commit
}