using FastGithub.Configuration;
using FastGithub.DomainResolve;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Threading;
using System.Threading.Tasks;

namespace FastGithub.Http
{
 /// <summary>
 /// 表示http客户端
 /// </summary>
 public class HttpClient : HttpMessageInvoker
 {
 /// <summary>
 /// 插入的UserAgent标记
 /// </summary>
 private readonly static ProductInfoHeaderValue userAgent = new(new ProductHeaderValue(nameof(FastGithub), "1.0"));

 /// <summary>
 /// http客户端
 /// </summary>
 /// <param name="domainConfig"></param>
 /// <param name="domainResolver"></param>
 public HttpClient(DomainConfig domainConfig, IDomainResolver domainResolver)
 : this(new HttpClientHandler(domainConfig, domainResolver), disposeHandler: true)
 {
 }

 /// <summary>
 /// http客户端
 /// </summary> 
 /// <param name="handler"></param>
 /// <param name="disposeHandler"></param>
 public HttpClient(HttpMessageHandler handler, bool disposeHandler)
 : base(handler, disposeHandler)
 {
 }

 /// <summary>
 /// 发送请求
 /// </summary>
 /// <param name="request"></param>
 /// <param name="cancellationToken"></param>
 /// <returns></returns>
 public override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
 {
 if (request.Headers.UserAgent.Contains(userAgent))
 {
 throw new FastGithubException($"由于{request.RequestUri}实际指向了{nameof(FastGithub)}自身,{nameof(FastGithub)}已中断本次转发");
 }
 request.Headers.UserAgent.Add(userAgent);
 var response = await base.SendAsync(request, cancellationToken);
 response.Headers.Server.TryParseAdd(nameof(FastGithub));
 return response;
 }
 }
}