using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace Sony.Filtr.SpotifyWebAPI
{
    //This class exist to correct the invalid etag-values sent by Spotify
    public class SpotifyHttpMessageHandler : DelegatingHandler 
    {
        protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
        {
            var result = await base.SendAsync(request, cancellationToken);
            if (result.Headers.Contains("ETag") && result.Headers.ETag == null)
            {
                IEnumerable<string> etagValues;
                if (result.Headers.TryGetValues("ETag", out etagValues))
                {
                    var etag = etagValues.FirstOrDefault();
                    if (etag != null)
                    {
                        string realEtag = etag.Replace("%22", "\"");
                        result.Headers.ETag = new EntityTagHeaderValue(realEtag);
                    }
                }
            }
            return result;
        }
    }

}