using System;
using Unosquare.Swan.Networking.Ldap;

namespace Unosquare.Swan.Exceptions {
  /// <summary>
  /// Thrown to indicate that an Ldap exception has occurred. This is a general
  /// exception which includes a message and an Ldap result code.
  /// An LdapException can result from physical problems (such as
  /// network errors) as well as problems with Ldap operations detected
  /// by the server. For example, if an Ldap add operation fails because of a
  /// duplicate entry, the server returns a result code.
  /// </summary>
  /// <seealso cref="System.Exception" />
  public class LdapException
      : Exception {
    internal const String UnexpectedEnd = "Unexpected end of filter";
    internal const String MissingLeftParen = "Unmatched parentheses, left parenthesis missing";
    internal const String MissingRightParen = "Unmatched parentheses, right parenthesis missing";
    internal const String ExpectingRightParen = "Expecting right parenthesis, found \"{0}\"";
    internal const String ExpectingLeftParen = "Expecting left parenthesis, found \"{0}\"";

    private readonly String _serverMessage;

    /// <summary>
    /// Initializes a new instance of the <see cref="LdapException" /> class.
    /// Constructs an exception with a detailed message obtained from the
    /// specified <c>MessageOrKey</c> String.
    /// Additional parameters specify the result code, the message returned
    /// from the server, and a matchedDN returned from the server.
    /// The String is used either as a message key to obtain a localized
    /// message from ExceptionMessages, or if there is no key in the
    /// resource matching the text, it is used as the detailed message itself.
    /// </summary>
    /// <param name="message">The message.</param>
    /// <param name="resultCode">The result code returned.</param>
    /// <param name="serverMsg">Error message specifying additional information
    /// from the server.</param>
    /// <param name="matchedDN">The maximal subset of a specified DN which could
    /// be matched by the server on a search operation.</param>
    /// <param name="rootException">The root exception.</param>
    public LdapException(
        String message,
        LdapStatusCode resultCode,
        String serverMsg = null,
        String matchedDN = null,
        Exception rootException = null)
        : base(message) {
      this.ResultCode = resultCode;
      this.Cause = rootException;
      this.MatchedDN = matchedDN;
      this._serverMessage = serverMsg;
    }

    /// <summary>
    ///     Returns the error message from the Ldap server, if this message is
    ///     available (that is, if this message was set). If the message was not set,
    ///     this method returns null.
    /// </summary>
    /// <returns>
    ///     The error message or null if the message was not set.
    /// </returns>
    public String LdapErrorMessage =>
        this._serverMessage != null && this._serverMessage.Length == 0 ? null : this._serverMessage;

    /// <summary>
    /// Returns the lower level Exception which caused the failure, if any.
    /// For example, an IOException with additional information may be returned
    /// on a CONNECT_ERROR failure.
    /// </summary>
    /// <value>
    /// The cause.
    /// </value>
    public Exception Cause {
      get;
    }

    /// <summary>
    /// Returns the result code from the exception.
    /// The codes are defined as <c>public final static int</c> members
    /// of the Ldap Exception class. If the exception is a
    /// result of error information returned from a directory operation, the
    /// code will be one of those defined for the class. Otherwise, a local error
    /// code is returned.
    /// </summary>
    /// <value>
    /// The result code.
    /// </value>
    public LdapStatusCode ResultCode {
      get;
    }

    /// <summary>
    /// Returns the part of a submitted distinguished name which could be
    /// matched by the server.
    /// If the exception was caused by a local error, such as no server
    /// available, the return value is null. If the exception resulted from
    /// an operation being executed on a server, the value is an empty string
    /// except when the result of the operation was one of the following:.
    /// <ul><li>NO_SUCH_OBJECT</li><li>ALIAS_PROBLEM</li><li>INVALID_DN_SYNTAX</li><li>ALIAS_DEREFERENCING_PROBLEM</li></ul>
    /// </summary>
    /// <value>
    /// The matched dn.
    /// </value>
    public String MatchedDN {
      get;
    }

    /// <inheritdoc />
    public override String Message => this.ResultCode.ToString().Humanize();

    /// <inheritdoc />
    public override String ToString() {
      // Craft a string from the resource file
      String msg = $"{nameof(LdapException)}: {base.Message} ({this.ResultCode}) {this.ResultCode.ToString().Humanize()}";

      // Add server message
      if(!String.IsNullOrEmpty(this._serverMessage)) {
        msg += $"\r\nServer Message: {this._serverMessage}";
      }

      // Add Matched DN message
      if(this.MatchedDN != null) {
        msg += $"\r\nMatched DN: {this.MatchedDN}";
      }

      if(this.Cause != null) {
        msg += $"\r\n{this.Cause}";
      }

      return msg;
    }
  }
}