// Type-safe Shopify Storefront API integration
import { createStorefrontApiClient } from '@shopify/storefront-api-client';

const storefront = createStorefrontApiClient({
  storeDomain: 'https://your-shop.myshopify.com',
  apiVersion: '2024-01',
  publicAccessToken: process.env.SHOPIFY_STOREFRONT_TOKEN,
});

// React Router loader with headless data fetching
export async function loader({ params }: LoaderArgs) {
  const { handle } = params;

  const query = `
    query GetProduct($handle: String!) {
      product(handle: $handle) {
        id
        title
        description
        images(first: 10) {
          edges {
            node {
              url
              altText
              width
              height
            }
          }
        }
        variants(first: 250) {
          edges {
            node {
              id
              title
              price {
                amount
                currencyCode
              }
              availableForSale
            }
          }
        }
      }
    }
  `;

  const response = await storefront.request(query, { variables: { handle } });

  if (!response.data?.product) {
    throw new Response('Product not found', { status: 404 });
  }

  return { product: response.data.product };
}

// Complex headless commerce queries
const PRODUCT_COLLECTION_QUERY = `
  query ProductCollection(
    $handle: String!
    $first: Int!
    $filters: [ProductFilter!]
    $sortKey: ProductCollectionSortKeys!
  ) {
    collection(handle: $handle) {
      id
      title
      description
      products(
        first: $first
        filters: $filters
        sortKey: $sortKey
      ) {
        edges {
          node {
            ...ProductFragment
          }
        }
        pageInfo {
          hasNextPage
          hasPreviousPage
          startCursor
          endCursor
        }
        filters {
          id
          label
          type
          values {
            id
            label
            count
            input
          }
        }
      }
    }
  }

  fragment ProductFragment on Product {
    id
    handle
    title
    description
    priceRange {
      minVariantPrice {
        amount
        currencyCode
      }
      maxVariantPrice {
        amount
        currencyCode
      }
    }
    compareAtPriceRange {
      minVariantPrice {
        amount
        currencyCode
      }
    }
    images(first: 5) {
      edges {
        node {
          url
          altText
          width
          height
        }
      }
    }
  }
`;

// Type-safe data fetching with caching
export async function getProductCollection({
  handle,
  first = 24,
  filters = [],
  sortKey = 'BEST_SELLING'
}: CollectionQueryParams): Promise<Collection> {
  const response = await storefront.request(PRODUCT_COLLECTION_QUERY, {
    variables: { handle, first, filters, sortKey }
  });

  return response.data.collection;
}

// Shared commerce logic across channels
interface CommerceChannel {
  id: string;
  name: string;
  platform: 'web' | 'mobile' | 'pos' | 'iot' | 'social';
  capabilities: ChannelCapability[];
}

// Universal cart management
export class UniversalCart {
  private cartId: string;
  private channel: CommerceChannel;

  async addLineItem(
    variantId: string,
    quantity: number,
    channel: CommerceChannel
  ): Promise<Cart> {
    // Channel-specific optimizations
    const optimizedRequest = this.optimizeForChannel(
      { variantId, quantity },
      channel
    );

    // Universal Shopify Cart API
    const response = await fetch('/api/cart/add', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        ...optimizedRequest,
        cartId: this.cartId,
        channel: channel.id,
      }),
    });

    return response.json();
  }

  // Real-time synchronization across channels
  async syncAcrossChannels(): Promise<void> {
    const channels = await this.getActiveChannels();

    await Promise.all(
      channels.map(channel =>
        this.syncCartToChannel(this.cartId, channel)
      )
    );
  }
}

// WebSocket-based real-time inventory
import { useEffect, useState } from 'react';

interface InventoryUpdate {
  variantId: string;
  availableQuantity: number;
  timestamp: string;
}

export function useRealTimeInventory(variantIds: string[]) {
  const [inventory, setInventory] = useState<Map<string, number>>(new Map());
  const [socket, setSocket] = useState<WebSocket | null>(null);

  useEffect(() => {
    const ws = new WebSocket('wss://inventory.your-app.com/subscribe');

    ws.onopen = () => {
      // Subscribe to variant inventory updates
      ws.send(JSON.stringify({
        type: 'SUBSCRIBE',
        variantIds,
      }));
    };

    ws.onmessage = (event) => {
      const update: InventoryUpdate = JSON.parse(event.data);

      setInventory(prev => new Map(prev).set(
        update.variantId,
        update.availableQuantity
      ));

      // Trigger UI updates for low stock warnings
      if (update.availableQuantity < 5) {
        showLowStockNotification(update.variantId);
      }
    };

    setSocket(ws);

    return () => {
      ws.close();
    };
  }, [variantIds]);

  return { inventory, isConnected: socket?.readyState === WebSocket.OPEN };
}

// Component usage
export function ProductPage() {
  const { product } = useLoaderData<typeof loader>();
  const variantIds = product.variants.edges.map(edge => edge.node.id);
  const { inventory } = useRealTimeInventory(variantIds);

  return (
    <div>
      {product.variants.edges.map(({ node: variant }) => (
        <VariantOption
          key={variant.id}
          variant={variant}
          availableQuantity={inventory.get(variant.id)}
          showLowStock={inventory.get(variant.id) < 5}
        />
      ))}
    </div>
  );
}

// Headless personalization service
interface UserBehavior {
  userId: string;
  sessionId: string;
  viewedProducts: string[];
  cartActions: CartAction[];
  purchaseHistory: Purchase[];
  preferences: UserPreferences;
}

export class PersonalizationEngine {
  async getPersonalizedRecommendations(
    userId: string,
    context: CommerceContext
  ): Promise<PersonalizedContent> {
    // Fetch user behavior data
    const behavior = await this.getUserBehavior(userId);

    // AI-powered recommendation generation
    const recommendations = await fetch('/api/ai/recommendations', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        userId,
        behavior,
        context,
        algorithm: 'collaborative-filtering-v2',
      }),
    }).then(res => res.json());

    // Real-time A/B testing
    const optimizedContent = await this.applyABTesting(
      recommendations,
      userId
    );

    return {
      products: optimizedContent.products,
      collections: optimizedContent.collections,
      content: optimizedContent.content,
      confidence: optimizedContent.confidence,
    };
  }
}

// Centralized API gateway for headless services
export class CommerceAPIGateway {
  private services = {
    shopify: new ShopifyStorefrontClient(),
    inventory: new InventoryService(),
    reviews: new ReviewsService(),
    recommendations: new RecommendationEngine(),
    analytics: new AnalyticsService(),
  };

  async aggregateProductData(productId: string): Promise<EnrichedProduct> {
    // Parallel API calls for optimal performance
    const [product, inventory, reviews, recommendations] = await Promise.all([
      this.services.shopify.getProduct(productId),
      this.services.inventory.getAvailability(productId),
      this.services.reviews.getProductReviews(productId),
      this.services.recommendations.getRelatedProducts(productId),
    ]);

    // Merge data from multiple services
    return {
      ...product,
      realTimeInventory: inventory,
      customerReviews: reviews,
      relatedProducts: recommendations,
      aggregatedAt: new Date().toISOString(),
    };
  }
}