import type { Metadata } from 'next';

/**
 * Clean HTML entities from text (e.g., & -> &, " -> ")
 */
function cleanHtmlEntities(text: string): string {
  if (!text) return '';
  return text
    .replace(/&/g, '&')
    .replace(/"/g, '"')
    .replace(/'/g, "'")
    .replace(/&lt;/g, '<')
    .replace(/&gt;/g, '>')
    .replace(/&nbsp;/g, ' ')
    .trim();
}

export interface SEOData {
  title: string;
  description: string;
  excerpt?: string;
  date?: string;
  modified?: string;
  image?: string;
}

/**
 * Generate SEO metadata for a WordPress page/post
 */
export function generateSEOMetadata(data: SEOData): Metadata {
  const { title, description, excerpt, date, modified, image } = data;

  // Clean title (max 60 chars for SEO)
  const cleanTitle = cleanHtmlEntities(title);
  const seoTitle = cleanTitle.length > 60 
    ? cleanTitle.substring(0, 57) + '...' 
    : cleanTitle;
  
  const fullTitle = `${seoTitle} | Rocky Mountain Vending`;

  // Clean description (150-160 chars)
  let seoDescription = description || excerpt || '';
  if (seoDescription.length > 160) {
    seoDescription = seoDescription.substring(0, 157) + '...';
  } else if (seoDescription.length < 120) {
    seoDescription = seoDescription || 'Rocky Mountain Vending provides quality vending machine services in Utah.';
  }

  // Default image
  const ogImage = image || '/images/rocky-mountain-vending-service-area-926x1024.webp';

  const metadata: Metadata = {
    title: fullTitle,
    description: seoDescription,
    openGraph: {
      title: fullTitle,
      description: seoDescription,
      type: 'website',
      images: [
        {
          url: ogImage,
          width: 1200,
          height: 630,
          alt: cleanTitle,
        },
      ],
      siteName: 'Rocky Mountain Vending',
    },
    twitter: {
      card: 'summary_large_image',
      title: fullTitle,
      description: seoDescription,
      images: [ogImage],
    },
  };

  // Add dates if available (via openGraph)
  if (date || modified) {
    metadata.openGraph = {
      ...metadata.openGraph,
      ...(date && { publishedTime: date }),
      ...(modified && { modifiedTime: modified }),
    };
  }

  return metadata;
}

/**
 * Generate structured data (JSON-LD) for a page
 */
export function generateStructuredData(data: {
  title: string;
  description: string;
  url: string;
  datePublished?: string;
  dateModified?: string;
  type?: 'Article' | 'WebPage';
}) {
  const { title, description, url, datePublished, dateModified, type = 'WebPage' } = data;

  const structuredData: any = {
    '@context': 'https://schema.org',
    '@type': type,
    headline: cleanHtmlEntities(title),
    description: cleanHtmlEntities(description),
    url: url,
  };

  if (datePublished) {
    structuredData.datePublished = datePublished;
  }
  if (dateModified) {
    structuredData.dateModified = dateModified;
  }

  if (type === 'Article') {
    structuredData.author = {
      '@type': 'Organization',
      name: 'Rocky Mountain Vending',
      url: 'https://rockymountainvending.com',
    };
    structuredData.publisher = {
      '@type': 'Organization',
      name: 'Rocky Mountain Vending',
      legalName: 'Rocky Mountain Vending LLC',
      url: 'https://rockymountainvending.com',
      logo: {
        '@type': 'ImageObject',
        url: 'https://rockymountainvending.com/rmv-logo.png',
        width: 180,
        height: 45,
      },
    };
    structuredData.mainEntityOfPage = {
      '@type': 'WebPage',
      '@id': url,
    };
  }

  return structuredData;
}