/*
    * Copyright 2005-2008 the original author or authors.
    *
    * 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.
   */
  package org.springframework.ldap.core;
  
  import java.io.Serializable;
  import java.net.URI;
  import java.net.URISyntaxException;
  
  import org.apache.commons.lang.StringUtils;
  import org.apache.commons.lang.Validate;
  
  /**
   * Represents part of an LdapRdn. As specified in RFC2253 an LdapRdn may be
   * composed of several attributes, separated by "+". An
   * LdapRdnComponent represents one of these attributes.
   * 
   * @author Mattias Hellborg Arthursson
   * 
   */
  public class LdapRdnComponent implements Comparable, Serializable {
  	private static final long serialVersionUID = -3296747972616243038L;
  
  	public static final boolean DONT_DECODE_VALUE = false;
  
  	private String key;
  
  	private String value;
  
  	/**
  	 * Constructs an LdapRdnComponent without decoding the value.
  	 * 
  	 * @param key the Attribute name.
  	 * @param value the Attribute value.
  	 */
  	public LdapRdnComponent(String key, String value) {
  		this(key, value, DONT_DECODE_VALUE);
  	}
  
  	/**
  	 * Constructs an LdapRdnComponent, optionally decoding the value.
  	 * 
  	 * @param key the Atttribute name.
  	 * @param value the Attribute value.
  	 * @param decodeValue if <code>true</code> the value is decoded (typically
  	 * used when a DN is parsed from a String), otherwise the value is used as
  	 * specified.
  	 */
  	public LdapRdnComponent(String key, String value, boolean decodeValue) {
  		Validate.notEmpty(key, "Key must not be empty");
  		Validate.notEmpty(value, "Value must not be empty");
  
  		this.key = StringUtils.lowerCase(key);
  		if (decodeValue) {
  			this.value = LdapEncoder.nameDecode(value);
  		}
  		else {
  			this.value = value;
  		}
  	}
  
  	/**
  	 * Get the key (Attribute name) of this component.
  	 * 
  	 * @return the key.
  	 */
  	public String getKey() {
  		return key;
  	}
  
  	/**
  	 * Set the key (Attribute name) of this component.
  	 * 
  	 * @param key the key.
  	 * @deprecated Using this method changes the internal state of surrounding
  	 * DistinguishedName instance. This should be avoided.
  	 */
  	public void setKey(String key) {
  		this.key = key;
  	}
  
  	/**
  	 * Get the (Attribute) value of this component.
  	 * 
  	 * @return the value.
  	 */
  	public String getValue() {
 		return value;
 	}
 
 	/**
 	 * Set the (Attribute) value of this component.
 	 * 
 	 * @param value the value.
 	 * @deprecated Using this method changes the internal state of surrounding
 	 * DistinguishedName instance. This should be avoided.
 	 */
 	public void setValue(String value) {
 		this.value = value;
 	}
 
 	/**
 	 * Encode key and value to ldap.
 	 * 
 	 * @return Properly ldap escaped rdn.
 	 */
 	protected String encodeLdap() {
 		StringBuffer buff = new StringBuffer(key.length() + value.length() * 2);
 
 		buff.append(key);
 		buff.append('=');
 		buff.append(LdapEncoder.nameEncode(value));
 
 		return buff.toString();
 	}
 
 	/*
 	 * (non-Javadoc)
 	 * 
 	 * @see java.lang.Object#toString()
 	 */
 	public String toString() {
 		return getLdapEncoded();
 	}
 
 	/**
 	 * @return The LdapRdn as a string where the value is LDAP-encoded.
 	 */
 	public String getLdapEncoded() {
 		return encodeLdap();
 	}
 
 	/**
 	 * Get a String representation of this instance for use in URLs.
 	 * 
 	 * @return a properly URL encoded representation of this instancs.
 	 */
 	public String encodeUrl() {
 		// Use the URI class to properly URL encode the value.
 		try {
 			URI valueUri = new URI(null, null, value, null);
 			return key + "=" + valueUri.toString();
 		}
 		catch (URISyntaxException e) {
 			// This should really never happen...
 			return key + "=" + "value";
 		}
 	}
 
 	/*
 	 * (non-Javadoc)
 	 * 
 	 * @see java.lang.Object#hashCode()
 	 */
 	public int hashCode() {
 		return key.toUpperCase().hashCode() ^ value.toUpperCase().hashCode();
 	}
 
 	/*
 	 * (non-Javadoc)
 	 * 
 	 * @see java.lang.Object#equals(java.lang.Object)
 	 */
 	public boolean equals(Object obj) {
 		// Slightly more lenient equals comparison here to enable immutable
 		// instances to equal mutable ones.
 		if (obj != null && obj instanceof LdapRdnComponent) {
 			LdapRdnComponent that = (LdapRdnComponent) obj;
 			return StringUtils.equalsIgnoreCase(this.key, that.key)
 					&& StringUtils.equalsIgnoreCase(this.value, that.value);
 
 		}
 		else {
 			return false;
 		}
 	}
 
 	/**
 	 * Compare this instance to the supplied object.
 	 * 
 	 * @param obj the object to compare to.
 	 * @throws ClassCastException if the object is not possible to cast to an
 	 * LdapRdnComponent.
 	 */
 	public int compareTo(Object obj) {
 		LdapRdnComponent that = (LdapRdnComponent) obj;
 		return this.toString().compareTo(that.toString());
 	}
 
 	/**
 	 * Create an immutable copy of this instance. It will not be possible to
 	 * modify the key or the value of the returned instance.
 	 * 
 	 * @return an immutable copy of this instance.
 	 * @since 1.3
 	 */
 	public LdapRdnComponent immutableLdapRdnComponent() {
 		return new ImmutableLdapRdnComponent(key, value);
 	}
 
 	private static class ImmutableLdapRdnComponent extends LdapRdnComponent {
 		private static final long serialVersionUID = -7099970046426346567L;
 
 		public ImmutableLdapRdnComponent(String key, String value) {
 			super(key, value);
 		}
 
 		public void setKey(String key) {
 			throw new UnsupportedOperationException("SetValue not supported for this immutable LdapRdnComponent");
 		}
 
 		public void setValue(String value) {
 			throw new UnsupportedOperationException("SetKey not supported for this immutable LdapRdnComponent");
 		}
 	}
 }