using AutoMapper;
using AutoMapper.Internal;
using System;
using System.Linq;
using System.Reflection;

namespace Kean.Application.Utilities
{
    /// <summary>
    /// 模型映射配置
    /// </summary>
    public class AutoMapper : Profile
    {
        /// <summary>
        /// 初始化 Kean.Application.Utilities.AutoMapper 类的新实例
        /// </summary>
        public AutoMapper()
        {
            /* 这是一个例子：
             * 只需在 ViewModels 文件夹下创建视图模型，配置与数据表实体的映射即可
             * 注意：在最后 ReverseMap()，确保双向映射处理读写能力
             * 
             * CreateMap<Test, T_TEST>()
             *   .ForMember(entity => entity.TEST_ID, options => options.MapFrom(viewmodel => viewmodel.Id))
             *   .ForMember(entity => entity.TEST_NAME, options => options.MapFrom(viewmodel => viewmodel.Name))
             *   .ReverseMap();
             */
        }
    }

    /// <summary>
    /// AutoMapper 扩展方法
    /// </summary>
    internal static class AutoMapperExtension
    {
        /// <summary>
        /// 获取映射配置
        /// </summary>
        /// <param name="mapper">映射</param>
        /// <param name="type">ViewModel 类型名</param>
        /// <returns>映射配置</returns>
        internal static TypeMap GetMap(this IMapper mapper, string type)
        {
            var assembly = Assembly.GetExecutingAssembly();
            var viewModelType = assembly.GetType($"{assembly.FullName.Split(',')[0]}.ViewModels.{type}", false, true);
            if (viewModelType == null)
            {
                throw new TypeLoadException("ViewModel 不存在。");
            }
            var map = mapper.ConfigurationProvider.Internal().GetAllTypeMaps()
                .FirstOrDefault(m => m.SourceType == viewModelType);
            if (map == null)
            {
                throw new AutoMapperMappingException("未配置 ViewModel 与 Entity 之间的映射。");
            }
            return map;
        }
    }
}