/**
 * Documentation Link Fixer
 *
 * Reads the audit report generated by audit-doc-links.js and applies fixes
 * to broken links where a single match was found.
 *
 * Usage:
 *   node tools/fix-doc-links.js          # Dry-run (preview changes)
 *   node tools/fix-doc-links.js --apply  # Apply changes
 */

const { readFileSync, writeFileSync, existsSync } = require('node:fs');
const { resolve, relative } = require('node:path');

const REPORT_PATH = resolve(__dirname, '.link-audit-report.json');

// Colors for console output
const colors = {
  reset: '\u001B[0m',
  red: '\u001B[31m',
  green: '\u001B[32m',
  yellow: '\u001B[33m',
  cyan: '\u001B[36m',
  dim: '\u001B[2m',
};

/**
 * Load the audit report.
 */
function loadReport() {
  if (!existsSync(REPORT_PATH)) {
    console.error(`\n  ${colors.red}Error:${colors.reset} No audit report found.`);
    console.error(`  Run 'node tools/audit-doc-links.js' first.\n`);
    process.exit(1);
  }

  try {
    const content = readFileSync(REPORT_PATH, 'utf-8');
    return JSON.parse(content);
  } catch (error) {
    console.error(`\n  ${colors.red}Error:${colors.reset} Failed to parse audit report.`);
    console.error(`  ${error.message}\n`);
    process.exit(1);
  }
}

/**
 * Apply a fix to a file by replacing the original link with the suggested fix.
 */
function applyFix(filePath, originalLink, suggestedFix) {
  const content = readFileSync(filePath, 'utf-8');

  // Create the replacement pattern - we need to match the exact link in markdown syntax
  // Original might have anchor, so we need to handle that
  const originalWithoutAnchor = originalLink.split('#')[0];
  const suggestedWithoutAnchor = suggestedFix.split('#')[0];

  // Also preserve any anchor from the original if the fix doesn't include one
  let finalFix = suggestedFix;
  if (originalLink.includes('#') && !suggestedFix.includes('#')) {
    const anchor = originalLink.slice(originalLink.indexOf('#'));
    finalFix = suggestedFix + anchor;
  }

  // Replace the link - be careful to only replace inside markdown link syntax
  const linkPattern = new RegExp(`\\]\\(${escapeRegex(originalLink)}\\)`, 'g');

  const newContent = content.replace(linkPattern, `](${finalFix})`);

  if (newContent === content) {
    return false; // No change made
  }

  writeFileSync(filePath, newContent);
  return true;
}

/**
 * Escape special regex characters in a string.
 */
function escapeRegex(string) {
  return string.replaceAll(/[.*+?^${}()|[\]\\]/g, String.raw`\$&`);
}

/**
 * Main function.
 */
async function main() {
  const args = process.argv.slice(2);
  const applyChanges = args.includes('--apply');

  console.log('\n  Documentation Link Fixer');
  console.log('  ========================\n');

  if (applyChanges) {
    console.log(`  ${colors.green}APPLYING CHANGES${colors.reset}\n`);
  } else {
    console.log(`  ${colors.yellow}DRY RUN${colors.reset} - No files will be modified.`);
    console.log(`  Use --apply to apply changes.\n`);
  }

  const report = loadReport();

  if (report.autoFixable.length === 0) {
    console.log(`  ${colors.green}✓${colors.reset} No auto-fixable links found.\n`);
    process.exit(0);
  }

  console.log(`  Found ${report.autoFixable.length} auto-fixable link(s).\n`);

  const fixed = [];
  const failed = [];

  // Group fixes by file for efficiency
  const byFile = {};
  for (const item of report.autoFixable) {
    if (!byFile[item.sourceFileAbsolute]) {
      byFile[item.sourceFileAbsolute] = [];
    }
    byFile[item.sourceFileAbsolute].push(item);
  }

  for (const [filePath, items] of Object.entries(byFile)) {
    const displayPath = relative(process.cwd(), filePath);
    console.log(`  ${colors.cyan}${displayPath}${colors.reset}`);

    for (const item of items) {
      console.log(`    Line ${item.line}:`);
      console.log(`      ${colors.dim}Old:${colors.reset} ${item.originalLink}`);
      console.log(`      ${colors.dim}New:${colors.reset} ${item.suggestedFix}`);

      if (applyChanges) {
        try {
          const success = applyFix(filePath, item.originalLink, item.suggestedFix);
          if (success) {
            console.log(`      ${colors.green}✓ Fixed${colors.reset}`);
            fixed.push(item);
          } else {
            console.log(`      ${colors.yellow}⚠ No match found (may have been fixed already)${colors.reset}`);
          }
        } catch (error) {
          console.log(`      ${colors.red}✗ Error: ${error.message}${colors.reset}`);
          failed.push({ ...item, error: error.message });
        }
      }
      console.log();
    }
  }

  // Summary
  console.log('  ' + '─'.repeat(50));
  console.log('\n  SUMMARY\n');

  if (applyChanges) {
    console.log(`  Fixed:  ${colors.green}${fixed.length}${colors.reset}`);
    if (failed.length > 0) {
      console.log(`  Failed: ${colors.red}${failed.length}${colors.reset}`);
    }
    console.log(`\n  Run 'node tools/audit-doc-links.js' to verify remaining issues.\n`);
  } else {
    console.log(`  Would fix: ${colors.yellow}${report.autoFixable.length}${colors.reset} link(s)`);
    console.log(`\n  To apply these fixes, run:`);
    console.log(`    node tools/fix-doc-links.js --apply\n`);
  }

  process.exit(failed.length > 0 ? 1 : 0);
}

main().catch((error) => {
  console.error('Error:', error.message);
  process.exit(1);
});