using MAX.Core.DependencyInjection;
using MAX.Core.Interfaces;
using MAX.Core.Logger;
using MAX.Framework.Commons;
using MAX.Framework.Dtos;
using MAX.Framework.Interfaces;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Win32;
using System.Configuration;
using System.Diagnostics;
using System.Reflection;
using MAX.Plugins;

namespace MAX.Framework.DependencyInjection
{
	/// <summary>
	/// IOC 注册入口（由宿主 Program.cs 调用）
	/// </summary>
	public static class ServiceCollectionExtensions
	{
		private static readonly Type[] DependencyMarkers =
		[
			typeof(ISingletonDependency),
			typeof(IScopedDependency),
			typeof(ITransientDependency),
		];

		/// <summary>
		/// 添加框架注册
		/// </summary>
		public static IServiceCollection AddStore(this IHostApplicationBuilder host)
		{
			Debug.WriteLine("[Store] 开始注册应用服务");
			RunDebugStep("Logger", "注册日志服务", () => host.AddLogger());
			//host.Services.AddSingleton<ILoggerFacade>(NLogger.Instance);//注册log

			IEnumerable<Assembly> assemblies = StoreAppTypeFinder.Current.GetAssemblies(host.Configuration["Plugins:Path"]).ToArray();
			foreach (var assembly in assemblies)
				Debug.WriteLine($"[Assembly] 已发现：{assembly.FullName}");
			// 同一个类可能同时实现 IStartup 与 IModule，这里缓存实例，保证两个阶段拿到的是同一个对象
			Dictionary<Type, object> instances = [];
			return AddStoreCore(host, assemblies, instances);
		}





		/// <summary>
		/// 注册应用服务的公共实现：宿主入口（<c>builder.AddStoreHub()</c>）与 <see cref="IServiceCollection"/> 入口共用。
		/// </summary>
		internal static IServiceCollection AddStoreCore(
			IHostApplicationBuilder host,
			IEnumerable<Assembly> assemblies,
			IDictionary<Type, object> instances)
		{
			RunDebugStep("DI", "注册依赖标记服务", () => RegisterDependencyMarkers(host.Services, assemblies));

			RunDebugStep("Module", "注册全部模块", () => RunModules(host, assemblies, instances));
			RunDebugStep("Plugin", "注册全部插件", () => RunPlugins(host, assemblies, instances));

			RunDebugStep("Startup", "初始化并注册启动服务", () => RunStartups(host.Services, assemblies, instances));
            RunDebugStep("MediatR", "按命令特性注册管道", () => host.Services.AddMediatRAttributedBehaviors(assemblies.ToArray()));



			Debug.WriteLine("[MVC] 开始注册控制器和全局过滤器");
			var mvc = host.Services.AddControllers(options =>
			{
				options.Filters.Add<GlobalExceptionFilter>();
				options.Filters.Add<UnifyResultFilter>();
			}).ConfigureApiBehaviorOptions(options =>
			{
				options.InvalidModelStateResponseFactory = context =>
				{
					// 取出所有校验错误信息，拼成一个字符串（或者只取第一个）
					var errors = context.ModelState
						.Where(e => e.Value?.Errors.Count > 0)
						.SelectMany(e => e.Value!.Errors.Select(err => err.ErrorMessage))
						.ToList();

					var msg = string.Join("; ", errors);

					var result = ApiResult.Fail(msg, ResultCode.ValidationError);

					return new ObjectResult(result)
					{
						StatusCode = 200 // 和其他接口保持一致，用Code表达失败，而不是HTTP 400
					};
				};

			});
			foreach (var assembly in assemblies)
			{
				mvc.AddApplicationPart(assembly);
				Debug.WriteLine($"[MVC] 已添加 ApplicationPart：{assembly.GetName().Name}");
			}
			Debug.WriteLine($"[Store] 应用服务注册完成，共 {host.Services.Count} 个服务描述");
			return host.Services;
		}

		/// <summary>
		/// 自动注册标记接口（ISingletonDependency / IScopedDependency / ITransientDependency）的实现类型
		/// </summary>
		private static void RegisterDependencyMarkers(IServiceCollection services, IEnumerable<Assembly> assemblies)
		{
			foreach (Type type in GetConcreteTypes(assemblies))
			{
				Type? marker = DependencyMarkers.FirstOrDefault(m => m.IsAssignableFrom(type));
				if (marker is null)
				{
					continue;
				}

				ServiceLifetime lifetime = marker == typeof(ISingletonDependency) ? ServiceLifetime.Singleton
					: marker == typeof(IScopedDependency) ? ServiceLifetime.Scoped
					: ServiceLifetime.Transient;

				// 注册为自身
				services.Add(new ServiceDescriptor(type, type, lifetime));
				Debug.WriteLine($"[DI] 注册自身：{type.FullName}，Lifetime={lifetime}");

				// 注册为实现的接口（排除标记接口与系统接口）
				foreach (Type iface in type.GetInterfaces())
				{
					if (DependencyMarkers.Contains(iface) || IsSystemInterface(iface))
					{
						continue;
					}

					services.Add(new ServiceDescriptor(iface, type, lifetime));
					Debug.WriteLine($"[DI] 注册接口：{iface.FullName} -> {type.FullName}，Lifetime={lifetime}");
				}
			}
		}
		private static IEnumerable<IStartup> Startups = [];
		/// <summary>
		/// 发现所有 <see cref="IStartup"/> 实现，按 <see cref="IStartup.Priority"/> 降序执行
		/// </summary>
		private static void RunStartups(IServiceCollection services, IEnumerable<Assembly> assemblies, IDictionary<Type, object> instances)
		{
			IServiceRegistrar registrar = new ServiceRegistrarProxy(services);
			Startups = CreateInstances<IStartup>(assemblies, instances).Where(s => s is not IPlugin).OrderByDescending(s => s.Priority);
			foreach (IStartup startup in Startups)
			{
				RunDebugStep("Startup", $"初始化 {startup.GetType().FullName}，Priority={startup.Priority}", startup.Initialize);
				RunDebugStep("Startup", $"注册服务 {startup.GetType().FullName}", () => startup.Register(registrar));
			}
		}

		private static IEnumerable<IModule> Modules = [];
		/// <summary>
		/// 执行所有模块的服务注册阶段（<see cref="IModule.AddModule"/>）
		/// </summary>
		private static void RunModules(IHostApplicationBuilder host, IEnumerable<Assembly> assemblies, IDictionary<Type, object> instances)
		{
			Modules = CreateInstances<IModule>(assemblies, instances).Where(m => m is not IPlugin).OrderByDescending(s => s.Priority);
			foreach (IModule module in Modules)
			{
				try
				{
					RunDebugStep("Module", $"注册 {module.GetType().FullName}，Priority={module.Priority}", () => module.AddModule(host));
				}
				catch (Exception ex)
				{
					// 带上模块名，避免只看到一个没有上下文的异常
					throw new InvalidOperationException($"模块 {module.GetType().FullName} 的 AddModule 执行失败：{ex.Message}", ex);
				}
			}
		}

		/// <summary>
		/// 反射创建（或复用）所有实现 <typeparamref name="T"/> 的具体类型实例
		/// </summary>
		private static IEnumerable<T> CreateInstances<T>(IEnumerable<Assembly> assemblies, IDictionary<Type, object> instances) where T : class
		{
			foreach (Type type in GetConcreteTypes(assemblies).Where(t => typeof(T).IsAssignableFrom(t)))
			{
				if (!instances.TryGetValue(type, out object? instance))
				{
					instance = Activator.CreateInstance(type, true)
						?? throw new InvalidOperationException($"无法创建 {type.FullName} 的实例（需要有参数量为 0 的构造函数）。");
					instances[type] = instance;
					Debug.WriteLine($"[Instance] 已创建：{type.FullName}");
				}
				else
				{
					Debug.WriteLine($"[Instance] 复用实例：{type.FullName}");
				}

				yield return (T)instance;
			}
		}

		private static IEnumerable<Type> GetConcreteTypes(IEnumerable<Assembly> assemblies)
		{
			return assemblies
				.SelectMany(SafeGetTypes)
				.Where(t => t.IsClass && !t.IsAbstract && !t.IsGenericTypeDefinition);
		}

		private static IEnumerable<Type> SafeGetTypes(Assembly assembly)
		{
			try
			{
				return assembly.GetTypes();
			}
			catch (ReflectionTypeLoadException ex)
			{
				Debug.WriteLine($"[Assembly] 部分类型加载失败：{assembly.FullName}");
				foreach (var error in ex.LoaderExceptions)
					Debug.WriteLine($"[Assembly] 类型加载错误：{error?.Message}");
				return ex.Types.OfType<Type>();
			}
		}

		/// <summary>
		/// 应用程序集（模块、Startup 都从这里发现）
		/// </summary>
		internal static IEnumerable<Assembly> GetApplicationAssemblies()
		{
			// 使用 AppTypeFinder：扫描应用输出目录 + 已加载程序集，
			return StoreAppTypeFinder.Current.GetAssemblies();
		}

        private sealed class PluginRuntime : IDisposable
        {
            public List<(IPlugin Plugin, PluginContext Context)> Entries { get; } = [];
            public void Dispose()
            {
                foreach (var entry in Entries) entry.Context.Dispose();
            }
        }

        private static void RunPlugins(IHostApplicationBuilder host, IEnumerable<Assembly> assemblies, IDictionary<Type, object> instances)
        {
            var runtime = new PluginRuntime();
            var ids = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
            try
            {
                foreach (var plugin in CreateInstances<IPlugin>(assemblies, instances).OrderByDescending(p => p.Priority))
                {
                    if (plugin is IModule || plugin is IStartup)
                        throw new InvalidOperationException($"插件 {plugin.GetType().FullName} 不能同时实现 IModule/IStartup。");
                    if (string.IsNullOrWhiteSpace(plugin.Id) || !ids.Add(plugin.Id))
                        throw new InvalidOperationException($"插件标识为空或重复：{plugin.Id}");
                    try
                    {
                        var directory = Path.GetDirectoryName(plugin.GetType().Assembly.Location)!;
                        Debug.WriteLine($"[Plugin] 加载独立配置：{plugin.Id}，目录={directory}，环境={host.Environment.EnvironmentName}");
                        var context = new PluginContext(plugin.Id, directory, host.Environment);
                        runtime.Entries.Add((plugin, context));
                        host.Services.AddKeyedSingleton<PluginContext>(plugin.Id, (provider, _) =>
                        {
                            // 只要上下文被解析，就让容器持有并管理全部插件配置的释放。
                            provider.GetRequiredService<PluginRuntime>();
                            return context;
                        });
                        var typedContext = typeof(PluginContext<>).MakeGenericType(plugin.GetType());
                        host.Services.AddSingleton(typedContext, provider =>
                            // 复用键名注册，确保仅解析泛型上下文时也由容器管理配置的释放。
                            Activator.CreateInstance(typedContext, provider.GetRequiredKeyedService<PluginContext>(plugin.Id))!);
                        RunDebugStep("Plugin", $"注册 {plugin.Id} ({plugin.GetType().FullName})，Priority={plugin.Priority}",
                            () => plugin.ConfigureServices(host.Services, context));
                    }
                    catch (Exception ex)
                    {
                        Debug.WriteLine($"[Plugin] 注册失败：{plugin.Id}，{ex.Message}");
                        throw new InvalidOperationException($"插件 {plugin.Id} ({plugin.GetType().Assembly.Location}) 注册失败：{ex.Message}", ex);
                    }
                }
                host.Services.AddSingleton(_ => runtime);
            }
            catch { runtime.Dispose(); throw; }
        }

		private static bool IsSystemInterface(Type type)
		{
			return type.Namespace is null
				|| type.Namespace.StartsWith("System", StringComparison.Ordinal)
				|| type.Namespace.StartsWith("Microsoft", StringComparison.Ordinal);
		}


        private static void RunDebugStep(string category, string description, Action action)
        {
            Debug.WriteLine($"[{category}] 开始：{description}");
            try
            {
                action();
                Debug.WriteLine($"[{category}] 完成：{description}");
            }
            catch (Exception ex)
            {
                Debug.WriteLine($"[{category}] 失败：{description}，{ex.Message}");
                throw;
            }
        }

		public static IApplicationBuilder UseStore(this IApplicationBuilder app)
		{
			Debug.WriteLine("[Store] 开始装配应用管道");
			RunDebugStep("Middleware", "注册统一状态码中间件", () => app.UseMiddleware<UnifyStatusCodeMiddleware>());
            foreach (var (plugin, context) in app.ApplicationServices.GetRequiredService<PluginRuntime>().Entries)
            {
                try { RunDebugStep("Plugin", $"装配管道 {plugin.Id}", () => plugin.Configure(app, context)); }
                catch (Exception ex) { throw new InvalidOperationException($"插件 {plugin.Id} 管道装配失败：{ex.Message}", ex); }
            }
			foreach (IStartup startup in Startups)
			{
				RunDebugStep("Startup", $"执行启动回调 {startup.GetType().FullName}", () => startup.Start((app as IHost).Services));
			}

			foreach (IModule module in Modules)
			{
				RunDebugStep("Module", $"装配管道 {module.GetType().FullName}", () => module.UseModule(app));
			}
			Debug.WriteLine("[Store] 应用管道装配完成");
			return app;
		}

	}
}