ECommerce.RCL/Services/ShopStateService.cs

using Blazored.LocalStorage;

namespace ECommerceModule.Services;

public class ShopStateService
{
    private readonly ILocalStorageService _localStorage;
    
    // keys
    private const string FavoritesKey = "shop_favorites";
    private const string CategoryIdKey = "shop_category_id";

    // events
    public event Action? OnChange;

    public ShopStateService(ILocalStorageService localStorage)
    {
        _localStorage = localStorage;
    }

    public List<string> Favorites { get; private set; } = new();
    public Guid? CategoryId { get; private set; }

    public async Task InitializeAsync()
    {
        Favorites = await _localStorage.GetItemAsync<List<string>>(FavoritesKey) ?? new List<string>();
        CategoryId = await _localStorage.GetItemAsync<Guid?>(CategoryIdKey);
        NotifyStateChanged();
    }

    public async Task ToggleFavorite(string productId)
    {
        if (Favorites.Contains(productId))
        {
            Favorites.Remove(productId);
        }
        else
        {
            Favorites.Add(productId);
        }

        await _localStorage.SetItemAsync(FavoritesKey, Favorites);
        NotifyStateChanged();
    }

    public bool IsFavorite(string productId)
    {
        return Favorites.Contains(productId);
    }

    public async Task SetCategoryId(Guid? categoryId)
    {
        CategoryId = categoryId;
        await _localStorage.SetItemAsync(CategoryIdKey, CategoryId);
        NotifyStateChanged();
    }

    private void NotifyStateChanged() => OnChange?.Invoke();
}