using LubanHub.Core.Attributes;
using Microsoft.Extensions.DependencyInjection;
using System;
using System.Linq;
using System.Net.Http;
using System.Reflection;

namespace LubanHub.Core;

/// <summary>
/// Core服务依赖注入扩展
/// </summary>
public static class ServiceCollectionExtensions
{
    /// <summary>
    /// 添加Core服务 - 通过反射自动发现并注册带有RegistService特性的服务
    /// </summary>
    public static IServiceCollection AddCoreServices(this IServiceCollection services)
    {
        // 注册HttpClient（Core服务的依赖）
        services.AddSingleton<HttpClient>();
        
        // 获取当前程序集
        var assembly = Assembly.GetExecutingAssembly();
        
        // 发现所有带有RegistService特性的类型
        var serviceTypes = assembly.GetTypes()
            .Where(type => type.IsClass && !type.IsAbstract && type.GetCustomAttribute<RegistServiceAttribute>() != null)
            .Select(type => new
            {
                Type = type,
                Attribute = type.GetCustomAttribute<RegistServiceAttribute>()!
            })
            .OrderBy(x => x.Attribute.Priority) // 按优先级排序
            .ToList();

        // 注册服务
        foreach (var serviceInfo in serviceTypes)
        {
            var implementationType = serviceInfo.Type;
            var attribute = serviceInfo.Attribute;
            
            // 确定服务接口类型
            Type serviceType;
            if (attribute.ServiceType != null)
            {
                // 使用特性指定的服务类型
                serviceType = attribute.ServiceType;
            }
            else
            {
                // 自动推断：查找实现的第一个接口
                var interfaceType = implementationType.GetInterfaces().FirstOrDefault();
                if (interfaceType == null)
                {
                    throw new InvalidOperationException($"服务 {implementationType.Name} 没有实现任何接口，且未在RegistService特性中指定ServiceType");
                }
                serviceType = interfaceType;
            }
            
            // 根据生命周期注册服务
            switch (attribute.Lifetime)
            {
                case ServiceLifetime.Singleton:
                    services.AddSingleton(serviceType, implementationType);
                    break;
                case ServiceLifetime.Scoped:
                    services.AddScoped(serviceType, implementationType);
                    break;
                case ServiceLifetime.Transient:
                    services.AddTransient(serviceType, implementationType);
                    break;
                default:
                    throw new ArgumentOutOfRangeException(nameof(attribute.Lifetime), attribute.Lifetime, "不支持的服务生命周期");
            }
        }
        
        return services;
    }
}