ECommerce/ECommerce.Domain/Entities/Product.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.ComponentModel.DataAnnotations.Schema;
using Commerce.Contracts.DTOs;

namespace Commerce.Domain.Entities;

public class Product
{
    public Guid Id { get; set; }
    public double Price { get; set; }
    public double Discount { get; set; }
    public DateTime Created { get; set; }
    public string CodeName { get; set; } = string.Empty;
    public bool IsBundle { get; set; }
    public string? CategoryName { get; set; }
    public Guid? CategoryId { get; set; }

    public string[] Photos { get; set; } = Array.Empty<string>();

    [ForeignKey("CategoryId")]
    public virtual Category Category { get; set; } = null!;

    public virtual List<Product> ChildProducts { get; set; } = new();
    public virtual List<Product>? ParentBundles { get; set; }

    // New nested structure for JSONB
    public List<ProductTranslation> Translations { get; set; } = new();

    public static ProductVM ToVM(Product product, string? language = null)
    {
        var translations = product.Translations?.ToList() ?? new List<ProductTranslation>();
        List<ProductTranslationVM> selectedTranslations;

        if (string.IsNullOrEmpty(language))
        {
            selectedTranslations = translations
                .Select(t => new ProductTranslationVM
                {
                    Language = t.Language,
                    Info = new ProductInfoVM
                    {
                        Name = t.Info.Name,
                        Description = t.Info.Description,
                        TechnicalDetails = t.Info.TechnicalDetails?.Select(td => new TechnicalDetailVM { Key = td.Key, Value = td.Value }).ToList() ?? new()
                    }
                }).ToList();
        }
        else
        {
            var matchedTranslation = translations
                .FirstOrDefault(t => t.Language == language)
                ?? translations.FirstOrDefault(t => t.Language == "en");

            selectedTranslations = matchedTranslation != null
                ? new List<ProductTranslationVM>
                {
                    new ProductTranslationVM
                    {
                        Language = matchedTranslation.Language,
                        Info = new ProductInfoVM
                        {
                            Name = matchedTranslation.Info.Name,
                            Description = matchedTranslation.Info.Description,
                            TechnicalDetails = matchedTranslation.Info.TechnicalDetails?.Select(td => new TechnicalDetailVM { Key = td.Key, Value = td.Value }).ToList() ?? new()
                        }
                    }
                }
                : new List<ProductTranslationVM>();
        }

        return new ProductVM
        {
            Id = product.Id,
            Price = product.Price,
            Discount = product.Discount,
            Created = product.Created,
            CodeName = product.CodeName,
            CategoryName = product.CategoryName,
            IsBundle = product.IsBundle,
            CategoryId = product.CategoryId,
            Photos = product.Photos,
            Translations = selectedTranslations,
            ChildProducts = product.ChildProducts?.Select(x => Product.ToVM(x, language)).ToList() ?? new List<ProductVM>(),
        };
    }

    public static Product ToEntity(ProductVM productVM)
    {
        return new Product
        {
            Id = productVM.Id ?? Guid.NewGuid(),
            Price = productVM.Price ?? 0,
            Discount = productVM.Discount ?? 0,
            Created = productVM.Created ?? DateTime.UtcNow,
            CodeName = productVM.CodeName ?? string.Empty,
            CategoryName = productVM.CategoryName,
            IsBundle = productVM.IsBundle,
            CategoryId = productVM.CategoryId ?? Guid.Empty,
            Photos = productVM.Photos ?? Array.Empty<string>(),
            Translations = productVM.Translations?.Select(t => new ProductTranslation
            {
                Language = t.Language,
                Info = new ProductInfo
                {
                    Name = t.Info.Name,
                    Description = t.Info.Description,
                    TechnicalDetails = t.Info.TechnicalDetails?.Select(td => new TechnicalDetail { Key = td.Key, Value = td.Value }).ToList() ?? new()
                }
            }).ToList() ?? new(),
            ChildProducts = new List<Product>(),
        };
    }
}

public class ProductTranslation
{
    public string Language { get; set; } = string.Empty;
    public ProductInfo Info { get; set; } = new();
}

public class ProductInfo
{
    public string Name { get; set; } = string.Empty;
    public string Description { get; set; } = string.Empty;
    public List<TechnicalDetail> TechnicalDetails { get; set; } = new();
}

public class TechnicalDetail
{
    public string Key { get; set; } = string.Empty;
    public string Value { get; set; } = string.Empty;
}