ECommerce/ECommerce.Domain/Entities/Category.cs

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

namespace Commerce.Domain.Entities;

public class Category
{
    public Guid Id { get; set; }
    public string[] Photos { get; set; } = Array.Empty<string>();
    public Guid? ParentCategoryId { get; set; }
    public Category? ParentCategory { get; set; }
    public ICollection<Category> ChildCategories { get; set; } = new List<Category>();
    public bool IsBundle { get; set; }

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

    public static CategoryVM ToVM(Category category, string? language = null)
    {
        var translations = category.Translations?.ToList() ?? new List<CategoryTranslation>();
        List<CategoryTranslationVM> selectedTranslations;

        if (string.IsNullOrEmpty(language))
        {
            selectedTranslations = translations
                .Select(t => new CategoryTranslationVM
                {
                    Language = t.Language,
                    Info = new CategoryInfoVM
                    {
                        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<CategoryTranslationVM>
                {
                    new CategoryTranslationVM
                    {
                        Language = matchedTranslation.Language,
                        Info = new CategoryInfoVM
                        {
                            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<CategoryTranslationVM>();
        }

        return new CategoryVM
        {
            Id = category.Id,
            Photos = category.Photos,
            ParentCategoryId = category.ParentCategoryId,
            IsBundle = category.IsBundle,
            Translations = selectedTranslations,
            ChildCategories = category.ChildCategories?.Select(x => Category.ToVM(x, language)).ToList() ?? new List<CategoryVM>(),
        };
    }

    public static Category ToEntity(CategoryVM categoryVM)
    {
        return new Category
        {
            Id = categoryVM.Id ?? Guid.NewGuid(),
            Photos = categoryVM.Photos ?? Array.Empty<string>(),
            ParentCategoryId = categoryVM.ParentCategoryId,
            IsBundle = categoryVM.IsBundle,
            Translations = categoryVM.Translations?.Select(t => new CategoryTranslation
            {
                Language = t.Language,
                Info = new CategoryInfo
                {
                    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(),
            ChildCategories = categoryVM.ChildCategories?.Select(x => Category.ToEntity(x)).ToList() ?? new List<Category>(),
        };
    }
}

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

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