ShopSolution-backend/Webshop.Infrastructure/Repositories/ProductRepository.cs

// src/Webshop.Infrastructure/Repositories/ProductRepository.cs
using Microsoft.EntityFrameworkCore;
using Webshop.Domain.Entities;
using Webshop.Domain.Interfaces;
using Webshop.Infrastructure.Data;
using System;
using System.Collections.Generic;
using System.Threading.Tasks;

namespace Webshop.Infrastructure.Repositories
{
    public class ProductRepository : IProductRepository // Implementiert das korrigierte Interface
    {
        private readonly ApplicationDbContext _context;

        public ProductRepository(ApplicationDbContext context)
        {
            _context = context;
        }

        public async Task<IEnumerable<Product>> GetAllProductsAsync()
        {
            return await _context.Products.ToListAsync();
        }

        public async Task<Product?> GetProductByIdAsync(Guid id)
        {
            return await _context.Products.FindAsync(id);
        }

        public async Task<Product?> GetBySlugAsync(string slug)
        {
            return await _context.Products.FirstOrDefaultAsync(p => p.Slug == slug && p.IsActive);
        }

        // --- NEUE METHODE ---
        public async Task<Product?> GetProductByIdForUpdateAsync(Guid id)
        {
            return await _context.Products
                .Include(p => p.Images)
                .Include(p => p.Productcategories)
                .FirstOrDefaultAsync(p => p.Id == id);
        }

        public async Task AddProductAsync(Product product)
        {
            await _context.Products.AddAsync(product);
            await _context.SaveChangesAsync();
        }

        // --- KORRIGIERTE UPDATE-METHODE (OHNE PARAMETER) ---
        public async Task UpdateProductAsync(Product product)
        {
            // Wir sagen dem DbContext explizit, dass der Zustand dieser Entität "Modifiziert" ist.
            // Das zwingt EF Core dazu, ALLE Eigenschaften der Entität in der UPDATE-Anweisung zu berücksichtigen.
            // Es umgeht alle möglichen Probleme mit dem Change Tracking, die durch verschiedene Kontexte 
            // oder komplexe Beziehungs-Updates entstehen können.
            _context.Entry(product).State = EntityState.Modified;

            await _context.SaveChangesAsync();
        }

        public async Task DeleteProductAsync(Guid id)
        {
            var product = await GetProductByIdAsync(id);
            if (product != null)
            {
                _context.Products.Remove(product);
                await _context.SaveChangesAsync();
            }
        }
    }
}