/**
 *  Copyright 2003-2007 Greg Luck
 *
 *  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.exoplatform.services.security.pam;

import java.util.Collection;
import java.util.HashSet;

import javax.security.auth.login.LoginException;

import org.exoplatform.services.log.Log;

import org.exoplatform.container.xml.InitParams;
import org.exoplatform.container.xml.PropertiesParam;
import org.exoplatform.services.log.ExoLogger;
import org.exoplatform.services.security.Authenticator;
import org.exoplatform.services.security.Credential;
import org.exoplatform.services.security.Identity;
import org.exoplatform.services.security.MembershipEntry;
import org.exoplatform.services.security.PasswordCredential;
import org.exoplatform.services.security.UsernameCredential;

public class JPamAuthenticator implements Authenticator {

  private static final Log    log                  = ExoLogger.getLogger("core.JPamAuthenticator");

  private static final String DEFAULT_SERVICE_NAME = "exo-jpam";

  private String              serviceName;

  public JPamAuthenticator(InitParams params) {
    PropertiesParam pparams = params.getPropertiesParam("jpam-configuration");
    if (pparams == null || pparams.getProperty("service-name") == null)
      log.warn("Properties param were not found in configuration.xml. " + "Service name unknown, "
          + DEFAULT_SERVICE_NAME + " will be used.");
    else
      serviceName = pparams.getProperty("service-name");
  }

  public JPamAuthenticator(String serviceName) {
    this.serviceName = serviceName;
  }

  public JPamAuthenticator() {
    log.warn("Properties param were not found in configuration.xml. " + "Service name unknown, "
        + DEFAULT_SERVICE_NAME + " will be used.");
    this.serviceName = DEFAULT_SERVICE_NAME;
  }

  /*
   * (non-Javadoc)
   * @see
   * org.exoplatform.services.security.Authenticator#createIdentity(java.lang
   * .String)
   */
  public Identity createIdentity(String userId) throws Exception {
    Collection<MembershipEntry> entries = new HashSet<MembershipEntry>();
    Pam pam = new Pam(serviceName);
    for (String g : pam.getGroups())
      entries.add(new MembershipEntry(g));

    return new Identity(userId, entries);
  }

  /*
   * (non-Javadoc)
   * @see
   * org.exoplatform.services.security.Authenticator#validateUser(org.exoplatform
   * .services.security.Credential[])
   */
  public String validateUser(Credential[] credentials) throws LoginException, Exception {
    String user = null;
    String pass = null;
    for (Credential cred : credentials) {
      if (cred instanceof UsernameCredential)
        user = ((UsernameCredential) cred).getUsername();
      if (cred instanceof PasswordCredential)
        pass = ((PasswordCredential) cred).getPassword();
    }
    Pam pam = new Pam(serviceName);

    PamReturnValue res = null;
    if (!(res = pam.authenticate(user, pass)).equals(PamReturnValue.PAM_SUCCESS)) {
      throw new LoginException("Authentication failed. Status : " + res.toString());
    }

    if (log.isDebugEnabled()) {
      log.debug("Authentication for user '" + user + "' success.");
    }

    Collection<MembershipEntry> entries = new HashSet<MembershipEntry>();
    for (String g : pam.getGroups())
      entries.add(new MembershipEntry(g));
    return user;
  }

}