/*
    * Copyright 2013–2023 Michael Osipov
    *
    * 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 net.sf.michaelo.tomcat.realm;
  
  import java.security.Principal;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.Enumeration;
  import java.util.List;
  import java.util.Map;
  
  import org.apache.catalina.TomcatPrincipal;
  import org.ietf.jgss.GSSCredential;
  import org.ietf.jgss.GSSName;
  
  /**
   * Represents a principal from Active Directory with a list of roles.
   * <p>
   * An Active Directory principal is comprised of the following items:
   * <ul>
   * <li>the GSS name,</li>
   * <li>the security identifier (SID),</li>
   * <li>an optional GSS credential for credential delegation (impersonation),</li>
   * <li>an array of security groups the user has been assigned to, stored according to the
   * role format configured in the realm,</li>
   * <li>and a map with additional attributes which are either a {@code String}, {@code byte[]} or a
   * {@code List} of either one.</li>
   * </ul>
   */
  public class ActiveDirectoryPrincipal implements TomcatPrincipal {
  
  	private final GSSName gssName;
  	private final Sid sid;
  	private final transient GSSCredential gssCredential;
  	private final String[] roles;
  	private final Map<String, Object> additionalAttributes;
  
  	/**
  	 * Constructs a new principal for the given parameters.
  	 */
  	public ActiveDirectoryPrincipal(GSSName gssName, Sid sid, GSSCredential gssCredential) {
  		this(gssName, sid, null, gssCredential, null);
  	}
  
  	/**
  	 * Constructs a new principal for the given parameters.
  	 */
  	public ActiveDirectoryPrincipal(GSSName gssName, Sid sid, List<String> roles,
  			GSSCredential gssCredential, Map<String, Object> additionalAttributes) {
  		this.gssName = gssName;
  		this.sid = sid;
  		if (roles == null || roles.isEmpty())
  			this.roles = new String[0];
  		else {
  			this.roles = roles.toArray(new String[0]);
  			Arrays.sort(this.roles);
  		}
  		this.gssCredential = gssCredential;
  		if (additionalAttributes == null || additionalAttributes.isEmpty())
  			this.additionalAttributes = Collections.emptyMap();
  		else
  			this.additionalAttributes = Collections.unmodifiableMap(additionalAttributes);
  	}
  
  	@Override
  	public Principal getUserPrincipal() {
  		return this;
  	}
  
  	@Override
  	public String getName() {
  		return gssName.toString();
  	}
  
  	/**
  	 * Returns the underlying GSS name.
  	 *
  	 * @return the underlying GSS name
  	 */
  	public GSSName getGssName() {
  		return gssName;
  	}
  
  	/**
  	 * Returns the security identifier (SID) of the principal.
  	 *
 	 * @return the security identifier
 	 */
 	public Sid getSid() {
 		return sid;
 	}
 
 	@Override
 	public GSSCredential getGssCredential() {
 		return gssCredential;
 	}
 
 	/**
 	 * Grants access if supplied role is associated with this principal.
 	 *
 	 * @param role
 	 *            the role to check
 	 * @return true if principal is associated with the role, else false
 	 */
 	public boolean hasRole(String role) {
 		if ("*".equals(role)) // Special 2.4 role meaning everyone
 			return true;
 		if (role == null)
 			return false;
 		return Arrays.binarySearch(roles, role) >= 0;
 	}
 
 	/**
 	 * Returns the sorted roles of the given principal.
 	 *
 	 * @return a sorted read-only view of the roles
 	 */
 	public String[] getRoles() {
 		return Arrays.copyOf(roles, roles.length);
 	}
 
 	@Override
 	public Object getAttribute(String name) {
 		return additionalAttributes.get(name);
 	}
 
 	@Override
 	public Enumeration<String> getAttributeNames() {
 		return Collections.enumeration(additionalAttributes.keySet());
 	}
 
 	/**
 	 * Holds additional attributes for a given principal which may be stored in Active Directory.
 	 *
 	 * @return a read-only view of the additional attributes
 	 */
 	public Map<String, Object> getAdditionalAttributes() {
 		return additionalAttributes;
 	}
 
 	@Override
 	public boolean equals(Object obj) {
 		if (obj == null)
 			return false;
 
 		if (!(obj instanceof ActiveDirectoryPrincipal))
 			return false;
 
 		ActiveDirectoryPrincipal other = (ActiveDirectoryPrincipal) obj;
 
 		return gssName.equals((Object) other.gssName);
 	}
 
 	@Override
 	public int hashCode() {
 		return gssName.hashCode();
 	}
 
 	@Override
 	public String toString() {
 		return gssName.toString();
 	}
 
 	@Override
 	public void logout() throws Exception {
 		if (gssCredential != null) {
 			gssCredential.dispose();
 		}
 	}
 
 }