Add product data domain layer

src/app/facades/platform/product.facade.ts

@@ -0,0 +1,70 @@
+import { Injectable, signal } from '@angular/core';
+import { ProductDataService } from '../../core/products/product-data.service';
+import { Product, ProductCategory, ProductListQuery, ProductListResult, ProductSearchQuery, RelatedProductsQuery } from '../../core/products/models/product-domain.model';
+
+@Injectable({ providedIn: 'root' })
+export class ProductFacade {
+  readonly categories = signal<ProductCategory[]>([]);
+  readonly products = signal<Product[]>([]);
+  readonly selectedProduct = signal<Product | null>(null);
+  readonly relatedProducts = signal<Product[]>([]);
+  readonly total = signal(0);
+  readonly loading = signal(false);
+  readonly error = signal<string | null>(null);
+
+  constructor(private readonly productData: ProductDataService) {}
+
+  loadCategories(): void {
+    this.loading.set(true);
+    this.error.set(null);
+
+    this.productData.getCategories().subscribe({
+      next: (categories) => {
+        this.categories.set(categories);
+        this.loading.set(false);
+      },
+      error: () => {
+        this.categories.set([]);
+        this.error.set('Failed to load categories');
+        this.loading.set(false);
+      }
+    });
+  }
+
+  getCategories() {
+    return this.productData.getCategories();
+  }
+
+  getProducts(query?: ProductListQuery) {
+    return this.productData.getProducts(query);
+  }
+
+  getProduct(productID: number) {
+    return this.productData.getProduct(productID);
+  }
+
+  searchProducts(query: ProductSearchQuery) {
+    return this.productData.searchProducts(query);
+  }
+
+  getFeaturedProducts(query?: ProductListQuery) {
+    return this.productData.getFeaturedProducts(query);
+  }
+
+  getLatestProducts(query?: ProductListQuery) {
+    return this.productData.getLatestProducts(query);
+  }
+
+  getProductsByCategory(categoryID: number, query?: ProductListQuery) {
+    return this.productData.getProductsByCategory(categoryID, query);
+  }
+
+  getRelatedProducts(query: RelatedProductsQuery) {
+    return this.productData.getRelatedProducts(query);
+  }
+
+  setListResult(result: ProductListResult): void {
+    this.products.set(result.items);
+    this.total.set(result.total);
+  }
+}