import { Metadata } from 'next';
import { getSiteInfo } from './i18n';
import type { Locale } from './i18n';

export interface SEOParams {
  title?: string;
  description?: string;
  locale?: Locale;
  canonical?: string;
  ogType?: 'website' | 'article' | 'product';
  ogImages?: string[];
  publishedTime?: string;
  updatedTime?: string;
  author?: string;
}

export function generateSEOMetadata({
  title,
  description,
  locale = 'en',
  canonical,
  ogType = 'website',
  ogImages = [],
  publishedTime,
  updatedTime,
  author,
}: SEOParams): Metadata {
  const site = getSiteInfo(locale);
  
  const pageTitle = title ? `${title} | ${site.title}` : site.title;
  const pageDescription = description || site.description;
  
  const baseUrl = process.env.NEXT_PUBLIC_SITE_URL || site.baseUrl;
  const path = canonical || '/';
  const fullUrl = `${baseUrl}${path}`;
  
  // Generate alternate URLs for both locales
  const alternates = {
    canonical: fullUrl,
    languages: {
      'en': `${baseUrl}${path.replace('/de/', '/')}`,
      'de': `${baseUrl}${path.startsWith('/de') ? path : `/de${path}`}`,
    },
  };

  const openGraph = {
    title: pageTitle,
    description: pageDescription,
    url: fullUrl,
    siteName: site.title,
    locale: locale === 'de' ? 'de_DE' : 'en_US',
    type: ogType,
    ...(ogImages.length > 0 && { images: ogImages }),
    ...(publishedTime && { publishedTime }),
    ...(updatedTime && { updatedTime }),
    ...(author && { authors: [author] }),
  };

  const twitter = {
    card: 'summary_large_image',
    title: pageTitle,
    description: pageDescription,
    ...(ogImages.length > 0 && { images: ogImages }),
  };

  return {
    title: pageTitle,
    description: pageDescription,
    alternates,
    openGraph,
    twitter,
    authors: author ? [{ name: author }] : undefined,
    metadataBase: new URL(baseUrl),
  };
}

// Helper for blog posts
export function getPostSEO(post: any, locale: Locale): Metadata {
  return generateSEOMetadata({
    title: post.title,
    description: post.excerptHtml?.replace(/<[^>]*>/g, '') || '',
    canonical: post.path,
    locale: locale,
    ogType: 'article',
    ogImages: post.featuredImage ? [post.featuredImage] : [],
    publishedTime: post.datePublished,
    updatedTime: post.updatedAt,
    author: 'KLZ Cables Team',
  });
}

// Helper for products
export function getProductSEO(product: any, locale: Locale): Metadata {
  return generateSEOMetadata({
    title: product.name,
    description: product.shortDescriptionHtml?.replace(/<[^>]*>/g, '') || '',
    canonical: product.path,
    locale: locale,
    ogType: 'product',
    ogImages: product.images || [],
  });
}

// Helper for categories
export function getCategorySEO(category: any, locale: Locale): Metadata {
  return generateSEOMetadata({
    title: category.name,
    description: category.description || `Products in ${category.name}`,
    canonical: category.path,
    locale: locale,
    ogType: 'website',
  });
}

export function generateSitemapItem({
  path,
  lastmod,
  priority = 0.7,
}: {
  path: string;
  lastmod?: string;
  priority?: number;
}) {
  return {
    url: path,
    lastmod: lastmod || new Date().toISOString().split('T')[0],
    changefreq: 'weekly',
    priority,
  };
}