using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;

namespace Nuclex.Networking.Gallery3.Requests {

  /// <summary>Creates requests that use HTTP authentication</summary>
  public class AuthenticatingRequestFactory : RequestFactory {

    /// <summary>Initializs a new simple request factory</summary>
    /// <param name="galleryUrl">URL of the gallery installation</param>
    /// <remarks>
    ///   If the URL doesn't end with 'index.php', it will automatically
    ///   be appended to the URL. For gallery installations where index.php
    ///   is not required in the path, use the second constructor overload.
    /// </remarks>
    public AuthenticatingRequestFactory(string galleryUrl) :
      base(galleryUrl) { }

    /// <summary>Initializs a new simple request factory</summary>
    /// <param name="galleryUrl">URL of the gallery installation</param>
    /// <param name="asIs">
    ///   Whether to take to URL as it is or to append 'index.php' if it is missing
    /// </param>
    /// <remarks>
    ///   By default, gallery 3 installations require 'index.php' to be specified
    ///   in the URL with any REST request. If you have modified your gallery 3
    ///   installation, renamed index.php or do not want this for any other reason,
    ///   specifying true for the <paramref name="asIs" /> parameter makes
    ///   the request factory use the URL exactly as it is specified.
    /// </remarks>
    public AuthenticatingRequestFactory(string galleryUrl, bool asIs) :
      base(galleryUrl, asIs) { }

    /// <summary>User name with which to log in at the server</summary>
    public string User { get; set; }

    /// <summary>Password to use for logging in at the server</summary>
    public string Password { get; set; }

    /// <summary>Authentication type to use</summary>
    /// <remarks>
    ///   Normally either "Basic" or "Digest" depending on the server's
    ///   authentication scheme.
    /// </remarks>
    public string AuthType { get; set; }


    /// <summary>Called when a new WebRequest is created</summary>
    /// <param name="request">The new WebRequest</param>
    /// <remarks>
    ///   This method can be overridden in derived classes to modify new requests
    ///   created by the factory, for example in order to add authentication options.
    /// </remarks>
    protected override void OnRequestCreated(System.Net.WebRequest request) {
      updateCredentialCache();

      request.Credentials = this.credentialCache;
    }

    /// <summary>Ensures that the credential cache is up-to-date</summary>
    private void updateCredentialCache() {
      bool changed =
        (cachedUser != User) ||
        (cachedPassword != Password);

      this.credentialCache = new CredentialCache();
      this.credentialCache.Add(
        GalleryUri, "Basic", new NetworkCredential(User, Password)
      );

      this.cachedUser = User;
      this.cachedPassword = Password;
    }

    /// <summary>Stores the credentials used to log in</summary>
    private CredentialCache credentialCache;
    /// <summary>User that is currently stored in the credential cache</summary>
    private string cachedUser;
    /// <summary>Password that is currently stored in the credential cache</summary>
    private string cachedPassword;

  }

} // namespace Nuclex.Networking.Gallery3.Requests