using System;
namespace Unosquare.Swan.Networking.Ldap {
  /// <summary>
  /// The base class for Ldap request and response messages.
  /// Subclassed by response messages used in asynchronous operations.
  /// </summary>
  public class LdapMessage {
    internal RfcLdapMessage Message;

    private Int32 _imsgNum = -1; // This instance LdapMessage number

    private LdapOperation _messageType = LdapOperation.Unknown;

    private String _stringTag;

    internal LdapMessage() {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref="LdapMessage"/> class.
    /// Creates an LdapMessage when sending a protocol operation and sends
    /// some optional controls with the message.
    /// </summary>
    /// <param name="type">The type.</param>
    /// <param name="op">The operation type of message.</param>
    /// <param name="controls">The controls to use with the operation.</param>
    /// <seealso cref="Type"></seealso>
    internal LdapMessage(LdapOperation type, IRfcRequest op, LdapControl[] controls = null) {
      // Get a unique number for this request message
      this._messageType = type;
      RfcControls asn1Ctrls = null;

      if(controls != null) {
        // Move LdapControls into an RFC 2251 Controls object.
        asn1Ctrls = new RfcControls();

        foreach(LdapControl t in controls) {
          asn1Ctrls.Add(t.Asn1Object);
        }
      }

      // create RFC 2251 LdapMessage
      this.Message = new RfcLdapMessage(op, asn1Ctrls);
    }

    /// <summary>
    /// Initializes a new instance of the <see cref="LdapMessage"/> class.
    /// Creates an Rfc 2251 LdapMessage when the libraries receive a response
    /// from a command.
    /// </summary>
    /// <param name="message">A response message.</param>
    internal LdapMessage(RfcLdapMessage message) => this.Message = message;

    /// <summary>
    /// Returns the message ID.  The message ID is an integer value
    /// identifying the Ldap request and its response.
    /// </summary>
    /// <value>
    /// The message identifier.
    /// </value>
    public virtual Int32 MessageId {
      get {
        if(this._imsgNum == -1) {
          this._imsgNum = this.Message.MessageId;
        }

        return this._imsgNum;
      }
    }

    /// <summary>
    /// Indicates whether the message is a request or a response.
    /// </summary>
    /// <value>
    ///   <c>true</c> if request; otherwise, <c>false</c>.
    /// </value>
    public virtual Boolean Request => this.Message.IsRequest();

    internal LdapOperation Type {
      get {
        if(this._messageType == LdapOperation.Unknown) {
          this._messageType = this.Message.Type;
        }

        return this._messageType;
      }
    }

    internal virtual RfcLdapMessage Asn1Object => this.Message;

    internal virtual LdapMessage RequestingMessage => this.Message.RequestingMessage;

    /// <summary>
    /// Retrieves the identifier tag for this message.
    /// An identifier can be associated with a message with the
    /// <c>setTag</c> method.
    /// Tags are set by the application and not by the API or the server.
    /// If a server response <c>isRequest() == false</c> has no tag,
    /// the tag associated with the corresponding server request is used.
    /// </summary>
    /// <value>
    /// The tag.
    /// </value>
    public virtual String Tag {
      get => this._stringTag ?? (this.Request ? null : this.RequestingMessage?._stringTag);

      set => this._stringTag = value;
    }

    private String Name => this.Type.ToString();

    /// <summary>
    /// Returns a <see cref="System.String" /> that represents this instance.
    /// </summary>
    /// <returns>
    /// A <see cref="System.String" /> that represents this instance.
    /// </returns>
    public override String ToString() => $"{this.Name}({this.MessageId}): {this.Message}";
  }
}