using System;
using System.Collections;

namespace Unosquare.Swan.Networking.Ldap {
  /// <summary>
  /// Represents an Ldap Search request.
  /// </summary>
  /// <seealso cref="LdapMessage" />
  internal sealed class LdapSearchRequest : LdapMessage {
    /// <summary>
    /// Initializes a new instance of the <see cref="LdapSearchRequest"/> class.
    /// </summary>
    /// <param name="ldapBase">The base distinguished name to search from.</param>
    /// <param name="scope">The scope of the entries to search. The following
    /// are the valid options:.
    /// <ul><li>SCOPE_BASE - searches only the base DN</li><li>SCOPE_ONE - searches only entries under the base DN</li><li>
    /// SCOPE_SUB - searches the base DN and all entries
    /// within its subtree
    /// </li></ul></param>
    /// <param name="filter">The search filter specifying the search criteria.</param>
    /// <param name="attrs">The names of attributes to retrieve.
    /// operation exceeds the time limit.</param>
    /// <param name="dereference">Specifies when aliases should be dereferenced.
    /// Must be one of the constants defined in
    /// LdapConstraints, which are DEREF_NEVER,
    /// DEREF_FINDING, DEREF_SEARCHING, or DEREF_ALWAYS.</param>
    /// <param name="maxResults">The maximum number of search results to return
    /// for a search request.
    /// The search operation will be terminated by the server
    /// with an LdapException.SIZE_LIMIT_EXCEEDED if the
    /// number of results exceed the maximum.</param>
    /// <param name="serverTimeLimit">The maximum time in seconds that the server
    /// should spend returning search results. This is a
    /// server-enforced limit.  A value of 0 means
    /// no time limit.</param>
    /// <param name="typesOnly">If true, returns the names but not the values of
    /// the attributes found.  If false, returns the
    /// names and values for attributes found.</param>
    /// <param name="cont">Any controls that apply to the search request.
    /// or null if none.</param>
    /// <seealso cref="LdapConnection.Search"></seealso>
    public LdapSearchRequest(
        String ldapBase,
        LdapScope scope,
        String filter,
        String[] attrs,
        Int32 dereference,
        Int32 maxResults,
        Int32 serverTimeLimit,
        Boolean typesOnly,
        LdapControl[] cont)
        : base(
            LdapOperation.SearchRequest,
            new RfcSearchRequest(ldapBase, scope, dereference, maxResults, serverTimeLimit, typesOnly, filter, attrs),
            cont) {
    }

    /// <summary>
    /// Retrieves an Iterator object representing the parsed filter for
    /// this search request.
    /// The first object returned from the Iterator is an Integer indicating
    /// the type of filter component. One or more values follow the component
    /// type as subsequent items in the Iterator. The pattern of Integer
    /// component type followed by values continues until the end of the
    /// filter.
    /// Values returned as a byte array may represent UTF-8 characters or may
    /// be binary values. The possible Integer components of a search filter
    /// and the associated values that follow are:.
    /// <ul><li>AND - followed by an Iterator value</li><li>OR - followed by an Iterator value</li><li>NOT - followed by an Iterator value</li><li>
    /// EQUALITY_MATCH - followed by the attribute name represented as a
    /// String, and by the attribute value represented as a byte array
    /// </li><li>
    /// GREATER_OR_EQUAL - followed by the attribute name represented as a
    /// String, and by the attribute value represented as a byte array
    /// </li><li>
    /// LESS_OR_EQUAL - followed by the attribute name represented as a
    /// String, and by the attribute value represented as a byte array
    /// </li><li>
    /// APPROX_MATCH - followed by the attribute name represented as a
    /// String, and by the attribute value represented as a byte array
    /// </li><li>PRESENT - followed by a attribute name respresented as a String</li><li>
    /// EXTENSIBLE_MATCH - followed by the name of the matching rule
    /// represented as a String, by the attribute name represented
    /// as a String, and by the attribute value represented as a
    /// byte array.
    /// </li><li>
    /// SUBSTRINGS - followed by the attribute name represented as a
    /// String, by one or more SUBSTRING components (INITIAL, ANY,
    /// or FINAL) followed by the SUBSTRING value.
    /// </li></ul>
    /// </summary>
    /// <value>
    /// The search filter.
    /// </value>
    public IEnumerator SearchFilter => this.RfcFilter.GetFilterIterator();

    /// <summary>
    ///     Retrieves the Base DN for a search request.
    /// </summary>
    /// <returns>
    ///     the base DN for a search request.
    /// </returns>
    public String DN => this.Asn1Object.RequestDn;

    /// <summary>
    /// Retrieves the scope of a search request.
    /// </summary>
    /// <value>
    /// The scope.
    /// </value>
    public Int32 Scope => ((Asn1Enumerated)((RfcSearchRequest)this.Asn1Object.Get(1)).Get(1)).IntValue();

    /// <summary>
    /// Retrieves the behaviour of dereferencing aliases on a search request.
    /// </summary>
    /// <value>
    /// The dereference.
    /// </value>
    public Int32 Dereference => ((Asn1Enumerated)((RfcSearchRequest)this.Asn1Object.Get(1)).Get(2)).IntValue();

    /// <summary>
    /// Retrieves the maximum number of entries to be returned on a search.
    /// </summary>
    /// <value>
    /// The maximum results.
    /// </value>
    public Int32 MaxResults => ((Asn1Integer)((RfcSearchRequest)this.Asn1Object.Get(1)).Get(3)).IntValue();

    /// <summary>
    /// Retrieves the server time limit for a search request.
    /// </summary>
    /// <value>
    /// The server time limit.
    /// </value>
    public Int32 ServerTimeLimit => ((Asn1Integer)((RfcSearchRequest)this.Asn1Object.Get(1)).Get(4)).IntValue();

    /// <summary>
    /// Retrieves whether attribute values or only attribute types(names) should
    /// be returned in a search request.
    /// </summary>
    /// <value>
    ///   <c>true</c> if [types only]; otherwise, <c>false</c>.
    /// </value>
    public Boolean TypesOnly => ((Asn1Boolean)((RfcSearchRequest)this.Asn1Object.Get(1)).Get(5)).BooleanValue();

    /// <summary>
    /// Retrieves an array of attribute names to request for in a search.
    /// </summary>
    /// <value>
    /// The attributes.
    /// </value>
    public String[] Attributes {
      get {
        RfcAttributeDescriptionList attrs = (RfcAttributeDescriptionList)((RfcSearchRequest)this.Asn1Object.Get(1)).Get(7);
        String[] values = new String[attrs.Size()];
        for(Int32 i = 0; i < values.Length; i++) {
          values[i] = ((Asn1OctetString)attrs.Get(i)).StringValue();
        }

        return values;
      }
    }

    /// <summary>
    /// Creates a string representation of the filter in this search request.
    /// </summary>
    /// <value>
    /// The string filter.
    /// </value>
    public String StringFilter => this.RfcFilter.FilterToString();

    /// <summary>
    /// Retrieves an SearchFilter object representing a filter for a search request.
    /// </summary>
    /// <value>
    /// The RFC filter.
    /// </value>
    private RfcFilter RfcFilter => (RfcFilter)((RfcSearchRequest)this.Asn1Object.Get(1)).Get(6);
  }
}