// Shop API, 25.12.04
// Fetch products from Shopify for the products carousel
// Credentials stored in MongoDB to avoid Netlify's 4KB env var limit
// Now with Redis caching (10 min TTL) to avoid Shopify rate limits

import { respond } from "../../backend/http.mjs";
import { connect } from "../../backend/database.mjs";
import { getOrCompute, CACHE_KEYS, CACHE_TTLS } from "../../backend/cache.mjs";

// Collection ID for "Home page" (frontpage)
const HOME_COLLECTION_ID = 369657512117;

// Cache credentials in memory for warm function invocations
let cachedCredentials = null;

async function getShopifyCredentials() {
  if (cachedCredentials) return cachedCredentials;
  
  const { db } = await connect();
  const secrets = await db.collection("secrets").findOne({ _id: "shopify" });
  
  if (!secrets) {
    throw new Error("Shopify credentials not found in database");
  }
  
  cachedCredentials = {
    domain: secrets.storeDomain,
    token: secrets.adminAccessToken,
  };
  
  return cachedCredentials;
}

export async function handler(event, context) {
  // Handle CORS preflight
  if (event.httpMethod === "OPTIONS") {
    return respond(200, {});
  }

  if (event.httpMethod !== "GET") {
    return respond(405, { message: "Method Not Allowed" });
  }

  try {
    // Check if client wants fresh data (bypass cache)
    const bypassCache = event.queryStringParameters?.fresh === 'true';
    
    if (bypassCache) {
      console.log("🛒 Shop: bypassing cache (fresh=true)");
      return respond(200, await computeShopProducts());
    }
    
    // Use cached shop data (10 min TTL)
    const shopData = await getOrCompute(
      CACHE_KEYS.SHOP,
      computeShopProducts,
      CACHE_TTLS.SHOP
    );
    
    return respond(200, shopData);
  } catch (error) {
    console.error(`❌ Shop API error:`, error);
    return respond(500, { message: error.message || String(error) });
  }
}

// Extracted shop computation for caching
async function computeShopProducts() {
  const { domain: SHOPIFY_STORE_DOMAIN, token: SHOPIFY_ADMIN_ACCESS_TOKEN } = 
    await getShopifyCredentials();
    
  // Get products from the Home page collection
  const productsRes = await fetch(
    `https://${SHOPIFY_STORE_DOMAIN}/admin/api/2024-10/collections/${HOME_COLLECTION_ID}/products.json?limit=50`,
    {
      headers: {
        "X-Shopify-Access-Token": SHOPIFY_ADMIN_ACCESS_TOKEN,
      },
    }
  );

  if (!productsRes.ok) {
    throw new Error(`Shopify API error: ${productsRes.status}`);
  }

  const productsData = await productsRes.json();

  // Process products into a simplified format for the carousel
  const products = await Promise.all(
    productsData.products.map(async (p) => {
      // Get inventory for this product
      const variantsRes = await fetch(
        `https://${SHOPIFY_STORE_DOMAIN}/admin/api/2024-10/products/${p.id}/variants.json`,
        {
          headers: {
            "X-Shopify-Access-Token": SHOPIFY_ADMIN_ACCESS_TOKEN,
          },
        }
      );
      const variantsData = await variantsRes.json();
      const totalInventory = variantsData.variants.reduce(
        (sum, v) => sum + (v.inventory_quantity || 0),
        0
      );

      // Get ALL image URLs (not just the first)
      const images = p.images?.map(img => img.src) || [];
      const imageUrl = images[0] || null;

      // Get price from first variant
      const price = variantsData.variants?.[0]?.price || "0.00";
      
      // Strip HTML tags from description for plain text, preserve line breaks
      const descriptionHtml = p.body_html || '';
      const description = descriptionHtml
        .replace(/<br\s*\/?>/gi, '\n')  // Convert <br> to newlines
        .replace(/<\/p>\s*<p[^>]*>/gi, '\n\n')  // Convert </p><p> to double newlines
        .replace(/<\/?(p|div|h[1-6])[^>]*>/gi, '\n')  // Block elements to newlines
        .replace(/<[^>]*>/g, '')  // Remove remaining HTML tags
        .replace(/&nbsp;/g, ' ')   // Replace HTML entities
        .replace(/&amp;/g, '&')
        .replace(/&lt;/g, '<')
        .replace(/&gt;/g, '>')
        .replace(/[ \t]+/g, ' ')   // Collapse horizontal whitespace only
        .replace(/\n\s*\n\s*\n/g, '\n\n')  // Max 2 consecutive newlines
        .trim();

      return {
        id: p.id,
        handle: p.handle,
        title: p.title,
        vendor: p.vendor,
        productType: p.product_type,
        price: `$${parseFloat(price).toFixed(0)} USD`,
        priceRaw: parseFloat(price),
        imageUrl,
        images,  // All product images
        description,  // Plain text description with newlines
        descriptionHtml,  // Raw HTML description
        shopUrl: `https://shop.aesthetic.computer/products/${p.handle}`,
        inventory: totalInventory,
        available: totalInventory > 0,
        tags: p.tags ? p.tags.split(", ") : [],
        createdAt: p.created_at,
        updatedAt: p.updated_at,
      };
    })
  );

  // Separate available and sold products
  const available = products.filter((p) => p.available);
  const sold = products.filter((p) => !p.available);

  return {
    products,
    available,
    sold,
    total: products.length,
    lastUpdated: new Date().toISOString(),
  };
}