using System.Reflection;
using Mapster;
using MapsterMapper;
using MongoDB.Bson;

namespace Dpz.Core.Entity.Base.MapperConfig;

public static class GlobalConfigMapper
{
    private static readonly Lazy<TypeAdapterConfig> CachedConfig = new(CreateTypeAdapterConfig);

    private static readonly Lazy<IMapper> CachedMapper = new(() =>
        CreateMapper(CachedConfig.Value)
    );

    public static TypeAdapterConfig GetTypeAdapterConfig()
    {
        return CachedConfig.Value;
    }

    public static IMapper GetMapper()
    {
        return CachedMapper.Value;
    }

    private static TypeAdapterConfig CreateTypeAdapterConfig()
    {
        var config = new TypeAdapterConfig();

        // 获取所有需要扫描的程序集
        var assemblies = GetRelevantAssemblies();

        // 1. 扫描所有程序集中的类型
        var allTypes = assemblies.SelectMany(a => a.GetExportedTypes()).ToArray();

        // 2. 基于 IHaveCustomMapping 接口，自定义规则映射
        ConfigureStaticInterfaceMappings(allTypes, config);

        // 3. 内置映射规则
        ConfigureBuiltInMappings(config);

        return config;
    }

    public static IMapper CreateMapper(TypeAdapterConfig config)
    {
        return new Mapper(config);
    }

    /// <summary>
    /// 获取所有相关的程序集
    /// 只扫描项目相关的程序集，避免扫描系统程序集提升性能
    /// </summary>
    private static Assembly[] GetRelevantAssemblies()
    {
        var assemblies = AppDomain
            .CurrentDomain.GetAssemblies()
            .Where(a =>
            {
                var name = a.GetName().Name;
                // 只扫描项目相关的程序集
                return name != null
                    && name.StartsWith("Dpz.Core", StringComparison.OrdinalIgnoreCase);
            })
            .Where(a => !a.IsDynamic)
            .ToArray();

        return assemblies;
    }

    /// <summary>
    /// 配置静态接口映射（C# 11+）
    /// </summary>
    private static void ConfigureStaticInterfaceMappings(Type[] types, TypeAdapterConfig config)
    {
        var customMappingTypes = types.Where(x =>
            x.GetInterfaces().Any(i => i == typeof(IHaveCustomMapping))
            && x is { IsAbstract: false, IsInterface: false }
        );

        foreach (var type in customMappingTypes)
        {
            // 调用静态 CreateMappings 方法
            var method = type.GetMethod(
                nameof(IHaveCustomMapping.CreateMappings),
                BindingFlags.Static | BindingFlags.Public,
                null,
                [typeof(TypeAdapterConfig)],
                null
            );
            method?.Invoke(null, [config]);
        }
    }

    /// <summary>
    /// 配置内置映射规则
    /// </summary>
    private static void ConfigureBuiltInMappings(TypeAdapterConfig config)
    {
        config.NewConfig<string, ObjectId>().MapWith(x => ToObjectId(x));
    }

    private static ObjectId ToObjectId(string source)
    {
        return !string.IsNullOrEmpty(source) && ObjectId.TryParse(source, out var oid)
            ? oid
            : ObjectId.Empty;
    }
}