#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2012 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
 *
 * This file is part of HeuristicLab.
 *
 * HeuristicLab is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * HeuristicLab is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
 */
#endregion

using System;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Net;
using System.Security;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using System.Text;
using System.Xml.Linq;

namespace HeuristicLab.Clients.Hive.CloudManager.Azure {
  public class ServiceWebRequest {
    private string thumbprint;
    private string versionId;

    #region Constructors

    public ServiceWebRequest(string thumbprint)
      : this(thumbprint, Constants.APIVersionDefault) {

    }

    public ServiceWebRequest(string thumbprint, string versionId) {
      this.thumbprint = thumbprint;
      this.versionId = versionId;
    }

    #endregion

    #region Public Methods

    public XDocument Invoke(string uri) {
      XDocument responsePayload = null; ;
      Uri operationUri = new Uri(uri);
      HttpWebRequest httpWebRequest = CreateHttpWebRequest(operationUri, Constants.HttpMethodGET);
      try {
        using (HttpWebResponse response = (HttpWebResponse)httpWebRequest.GetResponse()) {
          Stream responseStream = response.GetResponseStream();
          responsePayload = XDocument.Load(responseStream);
        }
      }
      catch (WebException ex) {
        Debug.WriteLine("Response status code: " + ex.Status);
        string response = ParseResponse(ex.Response);
        WriteRespone(response);
        string errorMsg = GetErrorMessageFromWebExceptionResponse(response);
        throw new SystemException(errorMsg);
      }
      return responsePayload;
    }

    public string Invoke(string uri, XDocument payload) {
      string requestId = Invoke(uri, Constants.HttpMethodPOST, payload);
      return requestId;
    }

    public string Invoke(string uri, string httpWebRequestMethod) {
      Uri operationUri = new Uri(uri);
      HttpWebRequest httpWebRequest = CreateHttpWebRequest(operationUri, httpWebRequestMethod);
      String requestId = String.Empty;
      try {
        using (HttpWebResponse response = (HttpWebResponse)httpWebRequest.GetResponse()) {
          requestId = response.Headers[Constants.HeaderRequestId];
        }
      }
      catch (WebException ex) {
        Debug.WriteLine("Response status code: " + ex.Status);
        string response = ParseResponse(ex.Response);
        WriteRespone(response);
        string errorMsg = GetErrorMessageFromWebExceptionResponse(response);
        throw new SystemException(errorMsg);
      }
      return requestId;
    }

    public string Invoke(string uri, string httpWebRequestMethod, XDocument payload) {
      Uri operationUri = new Uri(uri);
      HttpWebRequest httpWebRequest = CreateHttpWebRequest(operationUri, httpWebRequestMethod);
      using (Stream requestStream = httpWebRequest.GetRequestStream()) {
        using (StreamWriter streamWriter = new StreamWriter(requestStream, UTF8Encoding.UTF8)) {
          payload.Save(streamWriter, SaveOptions.DisableFormatting);
        }
      }
      string requestId = String.Empty;
      try {
        using (HttpWebResponse response = (HttpWebResponse)httpWebRequest.GetResponse()) {
          requestId = response.Headers[Constants.HeaderRequestId];
        }
      }
      catch (WebException ex) {
        Debug.WriteLine("Response status code: " + ex.Status);
        string response = ParseResponse(ex.Response);
        WriteRespone(response);
        string errorMsg = GetErrorMessageFromWebExceptionResponse(response);
        throw new SystemException(errorMsg);
      }
      return requestId;
    }

    #endregion

    #region Private Methods

    private string ParseResponse(WebResponse webResponse) {
      string response = string.Empty;
      using (Stream responseStream = webResponse.GetResponseStream()) {
        if (responseStream == null) return response;

        using (StreamReader reader = new StreamReader(responseStream)) {
          response = reader.ReadToEnd();
        }
      }
      return response;
    }

    private void WriteRespone(string response) {
      Debug.WriteLine("Response output:");
      Debug.WriteLine(response);
    }


    private string GetErrorMessageFromWebExceptionResponse(string response) {
      XNamespace wa = Constants.NSWindowsAzure;
      XDocument doc = XDocument.Parse(response);
      string errorCode = doc.Descendants(wa + "Code").Single().Value;
      string errorMessage = doc.Descendants(wa + "Message").Single().Value;
      return errorCode + ": " + errorMessage;
    }


    private X509Certificate2 GetCertificate(string certThumbprint) {
      X509Store certStore = new X509Store(StoreName.My, StoreLocation.CurrentUser);
      X509Certificate2 cert = null;

      try {
        certStore.Open(OpenFlags.ReadOnly);
        X509Certificate2Collection certCollection = certStore.Certificates.Find(X509FindType.FindByThumbprint, certThumbprint, false);
        if (certCollection.Count == 0) {
          throw new Exception("Error: No certificate found containing thumbprint" + certThumbprint);
        }
        cert = certCollection[0];
      }
      catch (Exception e) {
        if (e is CryptographicException)
          throw new SystemException("Error: The certificate store is unreadable.");
        else if (e is SecurityException)
          throw new SystemException("Error: You don't have the required permission.");
        else if (e is ArgumentException)
          throw new SystemException("Error: Invalid values in the certificate store.");
        else
          throw new SystemException(e.Message, e);
      }
      finally {
        certStore.Close();
      }

      return cert;
    }

    private HttpWebRequest CreateHttpWebRequest(Uri uri, string httpWebRequestMethod) {
      HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(uri);
      request.Headers.Add(Constants.HeaderVersionName, versionId);
      request.Method = httpWebRequestMethod;
      request.ContentType = Constants.ContentTypeAppXml;
      X509Certificate2 cert = GetCertificate(thumbprint);
      request.ClientCertificates.Add(cert);

      return request;
    }

    #endregion
  }
}