using System;
using System.Collections.Generic;
using System.Net;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;
using System.Threading.Tasks;
using Newtonsoft.Json;
using SpotifyAPI.Web.Models;

namespace SpotifyAPI.Web
{
  internal class SpotifyWebClient : IClient
  {
    public JsonSerializerSettings JsonSettings { get; set; }
    private readonly Encoding _encoding = Encoding.UTF8;
    private readonly HttpClient _client;

    private const string UnknownErrorJson = "{\"error\": { \"status\": 0, \"message\": \"{0}\" }}";

    public SpotifyWebClient(ProxyConfig proxyConfig = null)
    {
      HttpClientHandler clientHandler = ProxyConfig.CreateClientHandler(proxyConfig);
      _client = new HttpClient(clientHandler);
    }

    public Tuple<ResponseInfo, string> Download(string url, Dictionary<string, string> headers = null)
    {
      Tuple<ResponseInfo, byte[]> raw = DownloadRaw(url, headers);
      return new Tuple<ResponseInfo, string>(raw.Item1, raw.Item2.Length > 0 ? _encoding.GetString(raw.Item2) : "{}");
    }

    public async Task<Tuple<ResponseInfo, string>> DownloadAsync(string url, Dictionary<string, string> headers = null)
    {
      Tuple<ResponseInfo, byte[]> raw = await DownloadRawAsync(url, headers).ConfigureAwait(false);
      return new Tuple<ResponseInfo, string>(raw.Item1, raw.Item2.Length > 0 ? _encoding.GetString(raw.Item2) : "{}");
    }

    public Tuple<ResponseInfo, byte[]> DownloadRaw(string url, Dictionary<string, string> headers = null)
    {
      if (headers != null)
      {
        AddHeaders(headers);
      }
      using(HttpResponseMessage response = Task.Run(() => _client.GetAsync(url)).Result)
      {
        return new Tuple<ResponseInfo, byte[]>(new ResponseInfo
        {
          StatusCode = response.StatusCode,
            Headers = ConvertHeaders(response.Headers)
        }, Task.Run(() => response.Content.ReadAsByteArrayAsync()).Result);
      }
    }

    public async Task<Tuple<ResponseInfo, byte[]>> DownloadRawAsync(string url, Dictionary<string, string> headers = null)
    {
      if (headers != null)
      {
        AddHeaders(headers);
      }
      using(HttpResponseMessage response = await _client.GetAsync(url).ConfigureAwait(false))
      {
        return new Tuple<ResponseInfo, byte[]>(new ResponseInfo
        {
          StatusCode = response.StatusCode,
            Headers = ConvertHeaders(response.Headers)
        }, await response.Content.ReadAsByteArrayAsync());
      }
    }

    public Tuple<ResponseInfo, T> DownloadJson<T>(string url, Dictionary<string, string> headers = null)
    {
      Tuple<ResponseInfo, string> response = Download(url, headers);
      try
      {
        return new Tuple<ResponseInfo, T>(response.Item1, JsonConvert.DeserializeObject<T>(response.Item2, JsonSettings));
      }
      catch (JsonException error)
      {
        return new Tuple<ResponseInfo, T>(response.Item1, JsonConvert.DeserializeObject<T>(string.Format(UnknownErrorJson, error.Message), JsonSettings));
      }
    }

    public async Task<Tuple<ResponseInfo, T>> DownloadJsonAsync<T>(string url, Dictionary<string, string> headers = null)
    {
      Tuple<ResponseInfo, string> response = await DownloadAsync(url, headers).ConfigureAwait(false);
      try
      {
        return new Tuple<ResponseInfo, T>(response.Item1, JsonConvert.DeserializeObject<T>(response.Item2, JsonSettings));
      }
      catch (JsonException error)
      {
        return new Tuple<ResponseInfo, T>(response.Item1, JsonConvert.DeserializeObject<T>(string.Format(UnknownErrorJson, error.Message), JsonSettings));
      }
    }

    public Tuple<ResponseInfo, string> Upload(string url, string body, string method, Dictionary<string, string> headers = null)
    {
      Tuple<ResponseInfo, byte[]> data = UploadRaw(url, body, method, headers);
      return new Tuple<ResponseInfo, string>(data.Item1, data.Item2.Length > 0 ? _encoding.GetString(data.Item2) : "{}");
    }

    public async Task<Tuple<ResponseInfo, string>> UploadAsync(string url, string body, string method, Dictionary<string, string> headers = null)
    {
      Tuple<ResponseInfo, byte[]> data = await UploadRawAsync(url, body, method, headers).ConfigureAwait(false);
      return new Tuple<ResponseInfo, string>(data.Item1, data.Item2.Length > 0 ? _encoding.GetString(data.Item2) : "{}");
    }

    public Tuple<ResponseInfo, byte[]> UploadRaw(string url, string body, string method, Dictionary<string, string> headers = null)
    {
      if (headers != null)
      {
        AddHeaders(headers);
      }

      HttpRequestMessage message = new HttpRequestMessage(new HttpMethod(method), url)
      {
        Content = new StringContent(body, _encoding)
      };
      using(HttpResponseMessage response = Task.Run(() => _client.SendAsync(message)).Result)
      {
        return new Tuple<ResponseInfo, byte[]>(new ResponseInfo
        {
          StatusCode = response.StatusCode,
            Headers = ConvertHeaders(response.Headers)
        }, Task.Run(() => response.Content.ReadAsByteArrayAsync()).Result);
      }
    }

    public async Task<Tuple<ResponseInfo, byte[]>> UploadRawAsync(string url, string body, string method, Dictionary<string, string> headers = null)
    {
      if (headers != null)
      {
        AddHeaders(headers);
      }

      HttpRequestMessage message = new HttpRequestMessage(new HttpMethod(method), url)
      {
        Content = new StringContent(body, _encoding)
      };
      using(HttpResponseMessage response = await _client.SendAsync(message))
      {
        return new Tuple<ResponseInfo, byte[]>(new ResponseInfo
        {
          StatusCode = response.StatusCode,
            Headers = ConvertHeaders(response.Headers)
        }, await response.Content.ReadAsByteArrayAsync());
      }
    }

    public Tuple<ResponseInfo, T> UploadJson<T>(string url, string body, string method, Dictionary<string, string> headers = null)
    {
      Tuple<ResponseInfo, string> response = Upload(url, body, method, headers);
      try
      {
        return new Tuple<ResponseInfo, T>(response.Item1, JsonConvert.DeserializeObject<T>(response.Item2, JsonSettings));
      }
      catch (JsonException error)
      {
        return new Tuple<ResponseInfo, T>(response.Item1, JsonConvert.DeserializeObject<T>(string.Format(UnknownErrorJson, error.Message), JsonSettings));
      }
    }

    public async Task<Tuple<ResponseInfo, T>> UploadJsonAsync<T>(string url, string body, string method, Dictionary<string, string> headers = null)
    {
      Tuple<ResponseInfo, string> response = await UploadAsync(url, body, method, headers).ConfigureAwait(false);
      try
      {
        return new Tuple<ResponseInfo, T>(response.Item1, JsonConvert.DeserializeObject<T>(response.Item2, JsonSettings));
      }
      catch (JsonException error)
      {
        return new Tuple<ResponseInfo, T>(response.Item1, JsonConvert.DeserializeObject<T>(string.Format(UnknownErrorJson, error.Message), JsonSettings));
      }
    }

    public void Dispose()
    {
      _client.Dispose();
      GC.SuppressFinalize(this);
    }

    private static WebHeaderCollection ConvertHeaders(HttpResponseHeaders headers)
    {
      WebHeaderCollection newHeaders = new WebHeaderCollection();
      foreach (KeyValuePair<string, IEnumerable<string>> headerPair in headers)
      {
        foreach (string headerValue in headerPair.Value)
        {
          newHeaders.Add(headerPair.Key, headerValue);
        }
      }
      return newHeaders;
    }

    private void AddHeaders(Dictionary<string, string> headers)
    {
      _client.DefaultRequestHeaders.Clear();
      foreach (KeyValuePair<string, string> headerPair in headers)
      {
        _client.DefaultRequestHeaders.TryAddWithoutValidation(headerPair.Key, headerPair.Value);
      }
    }
  }
}