/*
 * Copyright 2018-2020 Ping Identity Corporation
 * All Rights Reserved.
 */
/*
 * Copyright 2018-2020 Ping Identity Corporation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * Copyright (C) 2018-2020 Ping Identity Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License (GPLv2 only)
 * or the terms of the GNU Lesser General Public License (LGPLv2.1 only)
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses>.
 */
package com.unboundid.ldap.sdk;



import java.io.Serializable;
import java.util.Comparator;

import com.unboundid.asn1.ASN1OctetString;
import com.unboundid.ldap.matchingrules.MatchingRule;
import com.unboundid.ldap.sdk.schema.AttributeTypeDefinition;
import com.unboundid.ldap.sdk.schema.Schema;
import com.unboundid.util.Debug;
import com.unboundid.util.NotMutable;
import com.unboundid.util.NotNull;
import com.unboundid.util.Nullable;
import com.unboundid.util.StaticUtils;
import com.unboundid.util.ThreadSafety;
import com.unboundid.util.ThreadSafetyLevel;



/**
 * This class provides a data structure that represents a single name-value pair
 * that may appear in a relative distinguished name.
 */
@NotMutable()
@ThreadSafety(level=ThreadSafetyLevel.COMPLETELY_THREADSAFE)
public final class RDNNameValuePair
       implements Comparable<RDNNameValuePair>, Comparator<RDNNameValuePair>,
                  Serializable
{
  /**
   * The serial version UID for this serializable class.
   */
  private static final long serialVersionUID = -8780852504883527870L;



  // The attribute value for this name-value pair.
  @NotNull private final ASN1OctetString attributeValue;

  // The schema to use to generate the normalized string representation of this
  // name-value pair, if any.
  @Nullable private final Schema schema;

  // The attribute name for this name-value pair.
  @NotNull private final String attributeName;

  // The all-lowercase representation of the attribute name for this name-value
  // pair.
  @Nullable private volatile String normalizedAttributeName;

  // The normalized string representation for this RDN name-value pair.
  @Nullable private volatile String normalizedString;

  // The string representation for this RDN name-value pair.
  @Nullable private volatile String stringRepresentation;



  /**
   * Creates a new RDN name-value pair with the provided information.
   *
   * @param  attributeName  The attribute name for this name-value pair.  It
   *                        must not be {@code null}.
   * @param  attributeValue The attribute value for this name-value pair.  It
   *                        must not be {@code null}.
   * @param  schema         The schema to use to generate the normalized string
   *                        representation of this name-value pair, if any.  It
   *                        may be {@code null} if no schema is available.
   */
  RDNNameValuePair(@NotNull final String attributeName,
                   @NotNull final ASN1OctetString attributeValue,
                   @Nullable final Schema schema)
  {
    this.attributeName = attributeName;
    this.attributeValue = attributeValue;
    this.schema = schema;

    normalizedAttributeName = null;
    normalizedString = null;
    stringRepresentation = null;
  }



  /**
   * Retrieves the attribute name for this name-value pair.
   *
   * @return  The attribute name for this name-value pair.
   */
  @NotNull()
  public String getAttributeName()
  {
    return attributeName;
  }



  /**
   * Retrieves a normalized representation of the attribute name.
   *
   * @return  A normalized representation of the attribute name.
   */
  @NotNull()
  public String getNormalizedAttributeName()
  {
    if (normalizedAttributeName == null)
    {
      if (schema != null)
      {
        final AttributeTypeDefinition attributeType =
             schema.getAttributeType(attributeName);
        if (attributeType != null)
        {
          normalizedAttributeName =
               StaticUtils.toLowerCase(attributeType.getNameOrOID());
        }
      }

      if (normalizedAttributeName == null)
      {
        normalizedAttributeName = StaticUtils.toLowerCase(attributeName);
      }
    }

    return normalizedAttributeName;
  }



  /**
   * Indicates whether this RDN name-value pair has the provided attribute name
   * (or a name that is logically equivalent to it).
   *
   * @param  name  The name for which to make the determination.
   *
   * @return  {@code true} if this name-value pair has the provided attribute
   *          name (or a name that is logically equivalent to it), or
   *          {@code false} if not.
   */
  public boolean hasAttributeName(@NotNull final String name)
  {
    if (attributeName.equalsIgnoreCase(name))
    {
      return true;
    }

    if (schema != null)
    {
      final AttributeTypeDefinition attributeType =
           schema.getAttributeType(attributeName);
      return ((attributeType != null) && attributeType.hasNameOrOID(name));
    }

    return false;
  }



  /**
   * Retrieves the string representation of the attribute value for this
   * name-value pair.
   *
   * @return  The string representation of the attribute value for this
   *          name-value pair.
   */
  @NotNull()
  public String getAttributeValue()
  {
    return attributeValue.stringValue();
  }



  /**
   * Retrieves the bytes that comprise the attribute value for this name-value
   * pair.
   *
   * @return  The bytes that comprise the attribute value for this name-value
   *          pair.
   */
  @NotNull()
  public byte[] getAttributeValueBytes()
  {
    return attributeValue.getValue();
  }



  /**
   * Retrieves the raw attribute value for this name-value pair.
   *
   * @return  The raw attribute value for this name-value pair.
   */
  @NotNull()
  public ASN1OctetString getRawAttributeValue()
  {
    return attributeValue;
  }



  /**
   * Indicates whether this RDN name-value pair has the provided attribute value
   * (or a value that is logically equivalent to it).
   *
   * @param  value  The value for which to make the determination.
   *
   * @return  {@code true} if this RDN name-value pair has the provided
   *          attribute value (or a value that is logically equivalent to it),
   *          or {@code false} if not.
   */
  public boolean hasAttributeValue(@NotNull final String value)
  {
    try
    {
      final MatchingRule matchingRule =
           MatchingRule.selectEqualityMatchingRule(attributeName, schema);
      return matchingRule.valuesMatch(new ASN1OctetString(value),
           attributeValue);
    }
    catch (final Exception e)
    {
      Debug.debugException(e);
      return false;
    }
  }



  /**
   * Indicates whether this RDN name-value pair has the provided attribute value
   * (or a value that is logically equivalent to it).
   *
   * @param  value  The value for which to make the determination.
   *
   * @return  {@code true} if this RDN name-value pair has the provided
   *          attribute value (or a value that is logically equivalent to it),
   *          or {@code false} if not.
   */
  public boolean hasAttributeValue(@NotNull final byte[] value)
  {
    try
    {
      final MatchingRule matchingRule =
           MatchingRule.selectEqualityMatchingRule(attributeName, schema);
      return matchingRule.valuesMatch(new ASN1OctetString(value),
           attributeValue);
    }
    catch (final Exception e)
    {
      Debug.debugException(e);
      return false;
    }
  }



  /**
   * Retrieves an integer value that represents the order in which this RDN
   * name-value pair should be placed in relation to the provided RDN name-value
   * pair in a sorted list.
   *
   * @param  p  The RDN name-value pair to be ordered relative to this RDN
   *            name-value pair.  It must not be {@code null}.
   *
   * @return  A negative integer if this RDN name-value pair should be ordered
   *          before the provided RDN name-value pair, a positive integer if
   *          this RDN name-value pair should be ordered after the provided RDN
   *          name-value pair, or zero if this RDN name-value pair is logically
   *          equivalent to the provided RDN name-value pair.
   */
  @Override()
  public int compareTo(@NotNull final RDNNameValuePair p)
  {
    final String thisNormalizedName = getNormalizedAttributeName();
    final String thatNormalizedName = p.getNormalizedAttributeName();
    final int nameComparison =
         thisNormalizedName.compareTo(thatNormalizedName);
    if (nameComparison != 0)
    {
      return nameComparison;
    }

    try
    {
      final MatchingRule matchingRule =
           MatchingRule.selectOrderingMatchingRule(attributeName, schema);
      return matchingRule.compareValues(attributeValue, p.attributeValue);
    }
    catch (final Exception e)
    {
      Debug.debugException(e);

      final String thisNormalizedString = toNormalizedString();
      final String thatNormalizedString = p.toNormalizedString();
      return thisNormalizedString.compareTo(thatNormalizedString);
    }
  }



  /**
   * Retrieves an integer value that represents the order in which the provided
   * RDN name-value pairs should be placed in a sorted list.
   *
   * @param  p1  The first RDN name-value pair to compare.  It must not be
   *             {@code null}.
   * @param  p2  The second RDN name-value pair to compare.  It must not be
   *             {@code null}.
   *
   * @return  A negative integer if the first RDN name-value pair should be
   *          ordered before the second RDN name-value pair, a positive integer
   *          if the first RDN name-value pair should be ordered after the
   *          second RDN name-value pair, or zero if the provided RDN name-value
   *          pairs are logically equivalent.
   */
  @Override()
  public int compare(@NotNull final RDNNameValuePair p1,
                     @NotNull final RDNNameValuePair p2)
  {
    return p1.compareTo(p2);
  }



  /**
   * Retrieves a hash code for this RDN name-value pair.
   *
   * @return  A hash code for this RDN name-value pair.
   */
  @Override()
  public int hashCode()
  {
    return toNormalizedString().hashCode();
  }



  /**
   * Indicates whether the provided object is considered logically equivalent to
   * this RDN name-value pair.
   *
   * @param  o  The object for which to make the determination.
   *
   * @return  {@code true} if the provided object is an RDN name-value pair that
   *          is logically equivalent to this RDN name-value pair, or
   *          {@code false} if not.
   */
  public boolean equals(@Nullable final Object o)
  {
    if (o == null)
    {
      return false;
    }

    if (o == this)
    {
      return true;
    }

    if (! (o instanceof RDNNameValuePair))
    {
      return false;
    }

    final RDNNameValuePair p = (RDNNameValuePair) o;
    return toNormalizedString().equals(p.toNormalizedString());
  }



  /**
   * Retrieves a string representation of this RDN name-value pair.
   *
   * @return  A string representation of this RDN name-value pair.
   */
  @Override()
  @NotNull()
  public String toString()
  {
    if (stringRepresentation == null)
    {
      final StringBuilder buffer = new StringBuilder();
      toString(buffer, false);
      stringRepresentation = buffer.toString();
    }

    return stringRepresentation;
  }



  /**
   * Retrieves a string representation of this RDN name-value pair with minimal
   * encoding for special characters.  Only those characters specified in RFC
   * 4514 section 2.4 will be escaped.  No escaping will be used for non-ASCII
   * characters or non-printable ASCII characters.
   *
   * @return  A string representation of this RDN name-value pair with minimal
   *          encoding for special characters.
   */
  @NotNull()
  public String toMinimallyEncodedString()
  {
    final StringBuilder buffer = new StringBuilder();
    toString(buffer, true);
    return buffer.toString();
  }



  /**
   * Appends a string representation of this RDN name-value pair to the provided
   * buffer.
   *
   * @param  buffer            The buffer to which the string representation is
   *                           to be appended.
   * @param  minimizeEncoding  Indicates whether to restrict the encoding of
   *                           special characters to the bare minimum required
   *                           by LDAP (as per RFC 4514 section 2.4).  If this
   *                           is {@code true}, then only leading and trailing
   *                           spaces, double quotes, plus signs, commas,
   *                           semicolons, greater-than, less-than, and
   *                           backslash characters will be encoded.
   */
  public void toString(@NotNull final StringBuilder buffer,
                       final boolean minimizeEncoding)
  {
    if ((stringRepresentation != null) && (! minimizeEncoding))
    {
      buffer.append(stringRepresentation);
      return;
    }

    final boolean bufferWasEmpty = (buffer.length() == 0);

    buffer.append(attributeName);
    buffer.append('=');
    RDN.appendValue(buffer, attributeValue, minimizeEncoding);

    if (bufferWasEmpty && (! minimizeEncoding))
    {
      stringRepresentation = buffer.toString();
    }
  }



  /**
   * Retrieves a normalized string representation of this RDN name-value pair.
   *
   * @return  A normalized string representation of this RDN name-value pair.
   */
  @NotNull()
  public String toNormalizedString()
  {
    if (normalizedString == null)
    {
      final StringBuilder buffer = new StringBuilder();
      toNormalizedString(buffer);
      normalizedString = buffer.toString();
    }

    return normalizedString;
  }



  /**
   * Appends a normalized string representation of this RDN name-value pair to
   * the provided buffer.
   *
   * @param  buffer  The buffer to which the normalized string representation
   *                 should be appended.  It must not be {@code null}.
   */
  public void toNormalizedString(@NotNull final StringBuilder buffer)
  {
    buffer.append(getNormalizedAttributeName());
    buffer.append('=');
    RDN.appendNormalizedValue(buffer, attributeName, attributeValue, schema);
  }
}