using System.Net.Http.Headers;
using System.Security.Cryptography;
using System.Text;
using Dpz.Core.Infrastructure;
using Microsoft.Extensions.Configuration;

namespace Dpz.Core.Service.Network;

public class AuthUpyunHeaderHandler:DelegatingHandler
{
    private readonly IConfiguration _configuration;

    public AuthUpyunHeaderHandler(IConfiguration configuration)
    {
        _configuration = configuration;
        InnerHandler = new HttpClientHandler();
    }

    protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
    {
        var upyunOperator = _configuration.GetSection("upyun").Get<UpyunOperator>();
        if (upyunOperator == null)
            throw new BusinessException("configuration error,need upyun config node.");
        
        
        var utcNow = DateTime.UtcNow;

        var pwd = upyunOperator.Password.GenerateHashMd5();
        var method = request.Method.ToString().ToUpper();
        var uri = request.RequestUri?.AbsolutePath ?? "";


        var message = $"{method}&{uri}&{utcNow:R}";
        // if (!string.IsNullOrEmpty(contentMd5))
        // {
        //     message += "&" + contentMd5;
        // }

        var keyBytes = Encoding.UTF8.GetBytes(pwd);
        var sha1 = new HMACSHA1(keyBytes);
        var byteArray = Encoding.UTF8.GetBytes(message);
        var stream = new MemoryStream(byteArray);
        var sha1Result = await sha1.ComputeHashAsync(stream, cancellationToken);
        var signBase64 = Convert.ToBase64String(sha1Result);
        request.Headers.Authorization =
            AuthenticationHeaderValue.Parse($"UPYUN {upyunOperator.Operator}:{signBase64}");
        request.Headers.Date = utcNow;
        
        return await base.SendAsync(request, cancellationToken);
    }
}