using System;
using System.IO;

namespace Unosquare.Swan.Networking.Ldap {
  /// <summary>
  /// Encapsulates a single search result that is in response to an asynchronous
  /// search operation.
  /// </summary>
  /// <seealso cref="Unosquare.Swan.Networking.Ldap.LdapMessage" />
  internal class LdapSearchResult : LdapMessage {
    private LdapEntry _entry;

    internal LdapSearchResult(RfcLdapMessage message)
        : base(message) {
    }

    public LdapEntry Entry {
      get {
        if(this._entry != null) {
          return this._entry;
        }

        LdapAttributeSet attrs = new LdapAttributeSet();
        RfcSearchResultEntry entry = (RfcSearchResultEntry)this.Message.Response;

        foreach(Asn1Object o in entry.Attributes.ToArray()) {
          Asn1Sequence seq = (Asn1Sequence)o;
          LdapAttribute attr = new LdapAttribute(((Asn1OctetString)seq.Get(0)).StringValue());
          Asn1Set set = (Asn1Set)seq.Get(1);

          foreach(Asn1Object t in set.ToArray()) {
            attr.AddValue(((Asn1OctetString)t).ByteValue());
          }

          _ = attrs.Add(attr);
        }

        this._entry = new LdapEntry(entry.ObjectName, attrs);

        return this._entry;
      }
    }

    public override String ToString() => this._entry?.ToString() ?? base.ToString();
  }

  /// <summary>
  /// Represents an Ldap Search Result Reference.
  /// <pre>
  /// SearchResultReference ::= [APPLICATION 19] SEQUENCE OF LdapURL
  /// </pre>
  /// </summary>
  /// <seealso cref="Unosquare.Swan.Networking.Ldap.Asn1SequenceOf" />
  internal class RfcSearchResultReference : Asn1SequenceOf {
    /// <summary>
    /// Initializes a new instance of the <see cref="RfcSearchResultReference"/> class.
    /// The only time a client will create a SearchResultReference is when it is
    /// decoding it from an Stream.
    /// </summary>
    /// <param name="stream">The streab.</param>
    /// <param name="len">The length.</param>
    public RfcSearchResultReference(Stream stream, Int32 len)
        : base(stream, len) {
    }

    public override Asn1Identifier GetIdentifier() => new Asn1Identifier(LdapOperation.SearchResultReference);
  }

  /// <summary>
  /// Represents an Ldap Extended Response.
  /// <pre>
  /// ExtendedResponse ::= [APPLICATION 24] SEQUENCE {
  /// COMPONENTS OF LdapResult,
  /// responseName     [10] LdapOID OPTIONAL,
  /// response         [11] OCTET STRING OPTIONAL }
  /// </pre>
  /// </summary>
  /// <seealso cref="Unosquare.Swan.Networking.Ldap.Asn1Sequence" />
  /// <seealso cref="Unosquare.Swan.Networking.Ldap.IRfcResponse" />
  internal class RfcExtendedResponse : Asn1Sequence, IRfcResponse {
    public const Int32 ResponseNameCode = 10;

    public const Int32 ResponseCode = 11;

    private readonly Int32 _referralIndex;
    private readonly Int32 _responseNameIndex;
    private readonly Int32 _responseIndex;

    /// <summary>
    /// Initializes a new instance of the <see cref="RfcExtendedResponse"/> class.
    /// The only time a client will create a ExtendedResponse is when it is
    /// decoding it from an stream.
    /// </summary>
    /// <param name="stream">The stream.</param>
    /// <param name="len">The length.</param>
    public RfcExtendedResponse(Stream stream, Int32 len)
        : base(stream, len) {
      if(this.Size() <= 3) {
        return;
      }

      for(Int32 i = 3; i < this.Size(); i++) {
        Asn1Tagged obj = (Asn1Tagged)this.Get(i);
        Asn1Identifier id = obj.GetIdentifier();

        switch(id.Tag) {
          case RfcLdapResult.Referral:
            SByte[] content = ((Asn1OctetString)obj.TaggedValue).ByteValue();

            using(MemoryStream bais = new MemoryStream(content.ToByteArray())) {
              this.Set(i, new Asn1SequenceOf(bais, content.Length));
            }

            this._referralIndex = i;
            break;
          case ResponseNameCode:
            this.Set(i, new Asn1OctetString(((Asn1OctetString)obj.TaggedValue).ByteValue()));
            this._responseNameIndex = i;
            break;
          case ResponseCode:
            this.Set(i, obj.TaggedValue);
            this._responseIndex = i;
            break;
        }
      }
    }

    public Asn1OctetString ResponseName => this._responseNameIndex != 0 ? (Asn1OctetString)this.Get(this._responseNameIndex) : null;

    public Asn1OctetString Response => this._responseIndex != 0 ? (Asn1OctetString)this.Get(this._responseIndex) : null;

    public Asn1Enumerated GetResultCode() => (Asn1Enumerated)this.Get(0);

    public Asn1OctetString GetMatchedDN() => new Asn1OctetString(((Asn1OctetString)this.Get(1)).ByteValue());

    public Asn1OctetString GetErrorMessage() => new Asn1OctetString(((Asn1OctetString)this.Get(2)).ByteValue());

    public Asn1SequenceOf GetReferral()
        => this._referralIndex != 0 ? (Asn1SequenceOf)this.Get(this._referralIndex) : null;

    public override Asn1Identifier GetIdentifier() => new Asn1Identifier(LdapOperation.ExtendedResponse);
  }

  /// <summary>
  /// Represents and Ldap Bind Response.
  /// <pre>
  /// BindResponse ::= [APPLICATION 1] SEQUENCE {
  /// COMPONENTS OF LdapResult,
  /// serverSaslCreds    [7] OCTET STRING OPTIONAL }
  /// </pre>
  /// </summary>
  /// <seealso cref="Unosquare.Swan.Networking.Ldap.Asn1Sequence" />
  /// <seealso cref="Unosquare.Swan.Networking.Ldap.IRfcResponse" />
  internal class RfcBindResponse : Asn1Sequence, IRfcResponse {
    /// <summary>
    /// Initializes a new instance of the <see cref="RfcBindResponse"/> class.
    /// The only time a client will create a BindResponse is when it is
    /// decoding it from an InputStream
    /// Note: If serverSaslCreds is included in the BindResponse, it does not
    /// need to be decoded since it is already an OCTET STRING.
    /// </summary>
    /// <param name="stream">The in renamed.</param>
    /// <param name="len">The length.</param>
    public RfcBindResponse(Stream stream, Int32 len)
        : base(stream, len) {
      // Decode optional referral from Asn1OctetString to Referral.
      if(this.Size() <= 3) {
        return;
      }

      Asn1Tagged obj = (Asn1Tagged)this.Get(3);

      if(obj.GetIdentifier().Tag != RfcLdapResult.Referral) {
        return;
      }

      SByte[] content = ((Asn1OctetString)obj.TaggedValue).ByteValue();

      using(MemoryStream bais = new MemoryStream(content.ToByteArray())) {
        this.Set(3, new Asn1SequenceOf(bais, content.Length));
      }
    }

    public Asn1Enumerated GetResultCode() => (Asn1Enumerated)this.Get(0);

    public Asn1OctetString GetMatchedDN() => new Asn1OctetString(((Asn1OctetString)this.Get(1)).ByteValue());

    public Asn1OctetString GetErrorMessage() => new Asn1OctetString(((Asn1OctetString)this.Get(2)).ByteValue());

    public Asn1SequenceOf GetReferral() => this.Size() > 3 && this.Get(3) is Asn1SequenceOf ? (Asn1SequenceOf)this.Get(3) : null;

    public override Asn1Identifier GetIdentifier() => new Asn1Identifier(LdapOperation.BindResponse);
  }

  /// <summary>
  /// Represents an LDAP Intermediate Response.
  /// IntermediateResponse ::= [APPLICATION 25] SEQUENCE {
  /// COMPONENTS OF LDAPResult, note: only present on incorrectly
  /// encoded response from pre Falcon-sp1 server
  /// responseName     [10] LDAPOID OPTIONAL,
  /// responseValue    [11] OCTET STRING OPTIONAL }.
  /// </summary>
  /// <seealso cref="Unosquare.Swan.Networking.Ldap.Asn1Sequence" />
  /// <seealso cref="Unosquare.Swan.Networking.Ldap.IRfcResponse" />
  internal class RfcIntermediateResponse : Asn1Sequence, IRfcResponse {
    public const Int32 TagResponseName = 0;
    public const Int32 TagResponse = 1;

    public RfcIntermediateResponse(Stream stream, Int32 len)
        : base(stream, len) {
      Int32 i = this.Size() >= 3 ? 3 : 0;

      for(; i < this.Size(); i++) {
        Asn1Tagged obj = (Asn1Tagged)this.Get(i);

        switch(obj.GetIdentifier().Tag) {
          case TagResponseName:
            this.Set(i, new Asn1OctetString(((Asn1OctetString)obj.TaggedValue).ByteValue()));
            break;
          case TagResponse:
            this.Set(i, obj.TaggedValue);
            break;
        }
      }
    }

    public Asn1Enumerated GetResultCode() => this.Size() > 3 ? (Asn1Enumerated)this.Get(0) : null;

    public Asn1OctetString GetMatchedDN() => this.Size() > 3 ? new Asn1OctetString(((Asn1OctetString)this.Get(1)).ByteValue()) : null;

    public Asn1OctetString GetErrorMessage() =>
        this.Size() > 3 ? new Asn1OctetString(((Asn1OctetString)this.Get(2)).ByteValue()) : null;

    public Asn1SequenceOf GetReferral() => this.Size() > 3 ? (Asn1SequenceOf)this.Get(3) : null;

    public override Asn1Identifier GetIdentifier() => new Asn1Identifier(LdapOperation.IntermediateResponse);
  }
}