/// <summary>
/// Gets an authorised Session Key for the API Key and Secret provided. You must Authorise first, see <see cref="GetAuthorisationUri"/>.
/// See http://www.last.fm/api/desktopauth for the full Authorisation process. Sets the Authentication Session for this instance at the same time
/// </summary>
/// <returns>The session key returned from Last.fm as string to be cached or stored by the client</returns>
/// <remarks>Session Keys are forever. Once a client has obtained a session key it should be cached or stored by the client, and the next time this
/// Scrobbler is instantiated, it should be passed in with the constructor arguments</remarks>
/// <exception cref="InvalidOperationException"/>
public Session GetSession()
{
//if (Authentication.Session != null && !string.IsNullOrEmpty(Authentication.Session.Key))
// throw new InvalidOperationException("This Scrobbler already has a Session Key");
// Get a token
GetAuthenticationToken();
// Request a Session
AuthApi.GetSession(Authentication, AuthenticationToken);
if (Authentication.Session == null)
{
throw new InvalidOperationException();
}
return(Authentication.Session);
}