using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;
using System.IO;
using System.Web.Script.Serialization;
using Newtonsoft.Json.Linq;

namespace Nuclex.Networking.Gallery3.Requests {

  /// <summary>Implements a gallery request with the WebRequest class</summary>
  /// <remarks>
  ///   Instances of this class are usually constructed by the RequestFactory
  ///   class, providing a WebRequest already prepared with authentication
  ///   options or custom headers.
  /// </remarks>
  public class Request : IRequest {

    /// <summary>Initializes a new request</summary>
    /// <param name="jsonSerializer">
    ///   JSON serializer through which responses will be decoded
    /// </param>
    /// <param name="webRequest">Web request that will be used by the instance</param>
    public Request(JavaScriptSerializer jsonSerializer, WebRequest webRequest) {
      this.jsonSerializer = jsonSerializer;
      this.webRequest = webRequest;
    }

    /// <summary>HTTP request method</summary>
    /// <remarks>
    ///   Can be "GET", "POST", "PUT" or "DELETE". Not all server support
    ///   the "PUT" and "DELETE" methods, so these methods are passed to
    ///   Gallery 3 as a "POST" request with a custom header:
    ///   "X-Gallery-Request-Method".
    /// </remarks>
    public string Method {
      get { return this.webRequest.Method; }
      set { this.webRequest.Method = value; }
    }

    /// <summary>The type/format of the content in a "POST" request</summary>
    /// <remarks>
    ///   Should be "application/x-www-form-urlencoded" for any request.
    /// </remarks>
    public string ContentType {
      get { return this.webRequest.ContentType; }
      set { this.webRequest.ContentType = value; }
    }

    /// <summary>Adds a custom header field to the request</summary>
    /// <param name="name">Name of the header that will be added</param>
    /// <param name="value">Value that will be assigned to the header field</param>
    public void AddHeader(string name, string value) {
      this.webRequest.Headers.Add(name, value);
    }

    /// <summary>Attaches content to a POST request</summary>
    /// <param name="data">Data that will be attached to the request as content</param>
    public void AttachContent(byte[] data) {
      this.webRequest.ContentLength = data.Length;
      using (Stream requestStream = this.webRequest.GetRequestStream()) {
        requestStream.Write(data, 0, data.Length);
      }
    }

    /// <summary>Sends the request to the server and returns the response</summary>
    /// <returns>A JSON reader through which the response can be read</returns>
    public ResponseType GetJsonResponse<ResponseType>() {
      string json;

      using (WebResponse response = this.webRequest.GetResponse()) {
        using (Stream contentStream = response.GetResponseStream()) {
          StreamReader reader = new StreamReader(contentStream);
          json = reader.ReadToEnd();
        }
      }

      return this.jsonSerializer.Deserialize<ResponseType>(json);
    }

    /// <summary>Actual WebRequest being wrapped by this class</summary>
    private WebRequest webRequest;
    /// <summary>JSON serializer being used to decode the response</summary>
    private JavaScriptSerializer jsonSerializer;

  }

} // namespace Nuclex.Networking.Gallery3.Requests