/**
 * Strapi Admin Configuration for Preview Feature
 * 
 * This file should be placed in your Strapi project at: config/admin.js
 * 
 * Environment Variables Required in Strapi .env:
 * CLIENT_URL=https://takerofnotes.com
 * PREVIEW_SECRET=preview-secret-key-change-this-in-production
 */

/**
 * Generate preview pathname based on content type and document
 * @param {string} uid - Content type identifier (e.g., 'api::article.article')
 * @param {object} options - Options containing locale and document data
 * @returns {string|null} - The preview pathname or null if no preview available
 */
const getPreviewPathname = (uid, { locale, document }) => {
  const { slug } = document || {};
  
  switch (uid) {
    // Global single type - preview on homepage
    case "api::global.global":
      return "/";
      
    // Generic pages with slugs
    case "api::page.page":
      if (!slug) {
        return null; // No slug, no preview
      }
      return `/${slug}`;
      
    // Articles/blog posts
    case "api::article.article":
      if (!slug) {
        return "/articles"; // Could redirect to articles index
      }
      return `/articles/${slug}`;
      
    // Products (example)
    case "api::product.product":
      if (!slug) {
        return "/products";
      }
      return `/products/${slug}`;
      
    // Add more content types as needed
    default:
      // Return null for content types that shouldn't have previews
      // (e.g., configuration, metadata, components)
      return null;
  }
};

// Main Strapi admin configuration
export default ({ env }) => {
  // Get environment variables
  const clientUrl = env("CLIENT_URL");
  const previewSecret = env("PREVIEW_SECRET");
  
  return {
    // Other admin configurations can go here
    // auth: { ... },
    // apiToken: { ... },
    
    preview: {
      enabled: true,
      config: {
        // Allow preview iframe to load from your frontend domain
        allowedOrigins: clientUrl,
        
        /**
         * Preview handler - generates preview URLs for content
         * @param {string} uid - Content type UID
         * @param {object} context - Preview context
         * @param {string} context.documentId - Document ID being previewed
         * @param {string} context.locale - Document locale
         * @param {string} context.status - Document status ('draft' or 'published')
         * @returns {string|null} - Preview URL or null to disable preview
         */
        async handler(uid, { documentId, locale, status }) {
          try {
            // Fetch the complete document from Strapi
            const document = await strapi.documents(uid).findOne({ 
              documentId,
              // Ensure we get the correct version based on status
              ...(status === 'draft' && { status: 'draft' })
            });
            
            // Generate the preview pathname
            const pathname = getPreviewPathname(uid, { locale, document });
            
            // If no pathname is generated, disable preview for this content type
            if (!pathname) {
              return null;
            }
            
            // Build preview URL with all necessary parameters
            const urlSearchParams = new URLSearchParams({
              path: pathname,
              secret: previewSecret,
              status: status || 'draft',
              documentId,
              uid,
              ...(locale && { locale })
            });
            
            // Return the complete preview URL pointing to your Vike app's preview page
            return `${clientUrl}/preview?${urlSearchParams}`;
            
          } catch (error) {
            console.error('Preview handler error:', error);
            return null;
          }
        },
      },
    },
  };
};