import { sanitizeHtml } from './dom-sanitizer';

/**
 * Format and standardize email content for display following email industry standards.
 * This function handles various email content formats and ensures proper display
 * including support for HTML emails, plain text emails, RTL languages, and email client quirks.
 */
export function formatEmailContent(email: any): string {
  if (!email) {
    console.log('formatEmailContent: No email provided');
    return '';
  }
  
  try {
    // Get the content in order of preference with proper fallbacks
    let content = '';
    let isHtml = false;
    let textContent = '';
    
    // Extract content based on standardized property hierarchy
    if (email.content && typeof email.content === 'object') {
      isHtml = !!email.content.html;
      content = email.content.html || '';
      textContent = email.content.text || '';
    } else if (typeof email.content === 'string') {
      // Check if the string content is HTML
      isHtml = email.content.trim().startsWith('<') && 
               (email.content.includes('<html') || 
                email.content.includes('<body') || 
                email.content.includes('<div') || 
                email.content.includes('<p>'));
      content = email.content;
      textContent = email.content;
    } else if (email.html) {
      isHtml = true;
      content = email.html;
      textContent = email.text || '';
    } else if (email.text) {
      isHtml = false;
      content = '';
      textContent = email.text;
    } else if (email.formattedContent) {
      // Assume formattedContent is already HTML
      isHtml = true;
      content = email.formattedContent;
      textContent = '';
    }
    
    // Log what we found for debugging
    console.log(`Email content detected: isHtml=${isHtml}, contentLength=${content.length}, textLength=${textContent.length}`);
    
    // If we have HTML content, sanitize and standardize it
    if (isHtml && content) {
      // Check if we have a full HTML document or just a fragment
      if (content.includes('<html') && content.includes('</html>')) {
        // Extract the body content from a complete HTML document
        const bodyMatch = content.match(/<body[^>]*>([\s\S]*?)<\/body>/i);
        if (bodyMatch && bodyMatch[1]) {
          // Sanitize just the body content
          const sanitizedContent = sanitizeHtml(bodyMatch[1].trim());
          return sanitizedContent;
        }
      }
      
      // Otherwise sanitize the entire content as a fragment
      const sanitizedContent = sanitizeHtml(content);
      return sanitizedContent;
    } 
    // If we only have text content, format it properly
    else if (textContent) {
      // Check for RTL content and set appropriate direction
      const rtlLangPattern = /[\u0591-\u07FF\uFB1D-\uFDFD\uFE70-\uFEFC]/;
      const containsRtlText = rtlLangPattern.test(textContent);
      const dirAttribute = containsRtlText ? 'dir="rtl"' : 'dir="ltr"';
      
      // Escape HTML characters to prevent XSS
      const escapedText = textContent
        .replace(/&/g, '&amp;')
        .replace(/</g, '&lt;')
        .replace(/>/g, '&gt;')
        .replace(/"/g, '&quot;')
        .replace(/'/g, '&#039;');
      
      // Format plain text with proper line breaks and paragraphs
      const formattedText = escapedText
        .replace(/\r\n|\r|\n/g, '<br>') // Convert all newlines to <br>
        .replace(/((?:<br>){2,})/g, '</p><p>') // Convert multiple newlines to paragraphs
        .replace(/<br><\/p>/g, '</p>') // Fix any <br></p> combinations
        .replace(/<p><br>/g, '<p>'); // Fix any <p><br> combinations
      
      // CRITICAL FIX: Use consistent structure with HTML emails for better compatibility
      return `<div class="email-content plain-text" ${dirAttribute} style="font-family: -apple-system, BlinkMacSystemFont, Menlo, Monaco, Consolas, 'Courier New', monospace; white-space: pre-wrap; line-height: 1.5; color: #333; padding: 15px; max-width: 100%; overflow-wrap: break-word;"><p>${formattedText}</p></div>`;
    }
    
    // Default case: empty or unrecognized content
    return '<div class="email-content-empty" style="padding: 20px; text-align: center; color: #666;">No content available</div>';
  } catch (error) {
    console.error('formatEmailContent: Error formatting email content:', error);
    return `<div class="email-content-error" style="padding: 15px; color: #721c24; background-color: #f8d7da; border: 1px solid #f5c6cb; border-radius: 4px;"><p>Error displaying email content</p><p style="font-size: 12px; margin-top: 10px;">${error instanceof Error ? error.message : 'Unknown error'}</p></div>`;
  }
}