feat: added services, model and environment

src/app/core/services/cart.service.ts

@@ -0,0 +1,38 @@
+import { Injectable, inject, signal } from '@angular/core';
+import { HttpClient } from '@angular/common/http';
+import { firstValueFrom } from 'rxjs';
+
+import { AddCartRequest, AddCartResponse } from '../models/product.model';
+import { environment } from '../../../environments/environment';
+
+const API_BASE_URL = environment.apiBaseUrl;
+const CART_COUNT_STORAGE_KEY = environment.cartCountStorageKey;
+
+// Add cart implementation (just for visualization, not used in the app)
+@Injectable({ providedIn: 'root' })
+export class CartService {
+  private readonly http = inject(HttpClient);
+
+  //total items on cart
+  readonly count = signal<number>(this.readPersistedCount());
+
+  async addToCart(request: AddCartRequest): Promise<number> {
+    const response = await firstValueFrom(
+      this.http.post<AddCartResponse>(`${API_BASE_URL}/cart`, request)
+    );
+    this.setCount(response.count);
+    return response.count;
+  }
+
+  // reloads counter from localstorage
+  private readPersistedCount(): number {
+    const raw = localStorage.getItem(CART_COUNT_STORAGE_KEY);
+    const parsed = raw ? Number(raw) : 0;
+    return Number.isFinite(parsed) ? parsed : 0;
+  }
+
+  private setCount(count: number): void {
+    this.count.set(count);
+    localStorage.setItem(CART_COUNT_STORAGE_KEY, String(count));
+  }
+}