using Microsoft.Extensions.DependencyInjection;
using Polly;
using Polly.Extensions.Http;
using System;
using System.Net.Http;
using Polly.Retry;
using Polly.Timeout;
using Polly.CircuitBreaker;
using Microsoft.Extensions.Http.Resilience;

namespace medical.transfomer.business
{
    /// <summary>
    /// 应用程序启动扩展方法
    /// </summary>
    public static class StartupExtensions
    {
        /// <summary>
        /// 注册医保服务所需的服务
        /// </summary>
        public static IServiceCollection AddMedicalInsuranceServices(this IServiceCollection services, string baseUrl)
        {
            // 注册HttpClient工厂
            services.AddHttpClient("MedicalInsurance", client =>
            {
                client.BaseAddress = new Uri(baseUrl);
                client.DefaultRequestHeaders.Add("Accept", "application/json");
                client.DefaultRequestHeaders.Add("User-Agent", "MedicalInsuranceClient");
                client.Timeout = TimeSpan.FromSeconds(30);
            })
            .AddResilienceHandler("MedicalInsuranceResilienceHandler", builder =>
            {
                // 添加重试策略
                builder.AddRetry(new RetryStrategyOptions<HttpResponseMessage>
                {
                    ShouldHandle = new PredicateBuilder<HttpResponseMessage>()
                        .Handle<HttpRequestException>()
                        .HandleResult(r => !r.IsSuccessStatusCode),
                    MaxRetryAttempts = 3,
                    Delay = TimeSpan.FromSeconds(1),
                    BackoffType = DelayBackoffType.Exponential
                });

                // 添加断路器策略
                builder.AddCircuitBreaker(new CircuitBreakerStrategyOptions<HttpResponseMessage>
                {
                    ShouldHandle = new PredicateBuilder<HttpResponseMessage>()
                        .Handle<HttpRequestException>()
                        .HandleResult(r => !r.IsSuccessStatusCode),
                    FailureRatio = 0.5, // 50%失败率
                    MinimumThroughput = 10, // 最小样本数
                    SamplingDuration = TimeSpan.FromSeconds(30), // 采样时间窗口
                    BreakDuration = TimeSpan.FromMinutes(1) // 断路时间
                });

                // 添加超时策略
                builder.AddTimeout(TimeSpan.FromSeconds(30));
            });

            // 注册转换工厂
            services.AddScoped<TransformerFactory>();

            return services;
        }
    }
}