using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using Microsoft.Extensions.Caching.Memory;
using CoreAgent.WebSocketTransport.Interfaces;
using CoreAgent.WebSocketTransport.Services;
using CoreAgent.WebSocketTransport.Middleware;
using CoreAgent.WebSocketTransport.Models;

namespace CoreAgent.WebSocketTransport.Extensions
{
    /// <summary>
    /// WebSocket 传输服务扩展
    /// </summary>
    public static class WebSocketTransportExtensions
    {
        /// <summary>
        /// 添加 WebSocket 传输服务
        /// </summary>
        /// <param name="services">服务集合</param>
        /// <param name="configuration">配置</param>
        /// <param name="configSection">配置节名称</param>
        /// <returns>服务集合</returns>
        public static IServiceCollection AddWebSocketTransport(
            this IServiceCollection services,
            IConfiguration configuration,
            string configSection = "WebSocket")
        {
            if (services == null)
                throw new ArgumentNullException(nameof(services));
            if (configuration == null)
                throw new ArgumentNullException(nameof(configuration));

            // 注册配置
            services.Configure<WebSocketConfig>(options => 
            {
                configuration.GetSection(configSection).Bind(options);
            });

            // 注册默认中间件（在核心服务之前）
            RegisterDefaultMiddleware(services);

            // 注册核心服务
            RegisterCoreServices(services);

            return services;
        }

        /// <summary>
        /// 添加 WebSocket 中间件
        /// </summary>
        /// <typeparam name="T">中间件类型</typeparam>
        /// <param name="services">服务集合</param>
        /// <returns>服务集合</returns>
        public static IServiceCollection AddWebSocketMiddleware<T>(this IServiceCollection services)
            where T : class, IMessageMiddleware
        {
            if (services == null)
                throw new ArgumentNullException(nameof(services));

            services.AddTransient<IMessageMiddleware, T>();
            return services;
        }

        /// <summary>
        /// 注册核心服务
        /// </summary>
        /// <param name="services">服务集合</param>
        private static void RegisterCoreServices(IServiceCollection services)
        {
            // 注册核心组件
            services.AddSingleton<IWebSocketConnection, WebSocketConnection>();
            services.AddSingleton<IMessageSerializer, JsonMessageSerializer>();

            // 注册消息通道管理器
            services.AddSingleton<IMessageChannelManager>(provider =>
            {
                var logger = provider.GetRequiredService<ILogger<MessageChannelManager>>();
                var config = provider.GetRequiredService<IOptions<WebSocketConfig>>().Value;
                
                return new MessageChannelManager(
                    logger, 
                    config.SendChannelCapacity, 
                    config.ReceiveChannelCapacity, 
                    config.PriorityChannelCapacity);
            });

            // 注册 WebSocket 传输
            services.AddSingleton<IWebSocketTransport>(provider =>
            {
                var logger = provider.GetRequiredService<ILogger<CoreAgent.WebSocketTransport.Services.WebSocketTransport>>();
                var connection = provider.GetRequiredService<IWebSocketConnection>();
                var serializer = provider.GetRequiredService<IMessageSerializer>();
                var middlewares = provider.GetServices<IMessageMiddleware>();
                var config = provider.GetRequiredService<IOptions<WebSocketConfig>>().Value;
                var channelManager = provider.GetRequiredService<IMessageChannelManager>();
                
                return new CoreAgent.WebSocketTransport.Services.WebSocketTransport(
                    logger, 
                    connection, 
                    serializer, 
                    middlewares, 
                    config, 
                    channelManager);
            });
        }

        /// <summary>
        /// 注册默认中间件
        /// </summary>
        /// <param name="services">服务集合</param>
        private static void RegisterDefaultMiddleware(IServiceCollection services)
        {
            // 注册日志中间件
            services.AddWebSocketMiddleware<LoggingMiddleware>();

            // 注册缓存中间件（使用正确的注册方式）
            services.AddWebSocketMiddleware<CacheMiddleware>();
        }
    }
}