/*
    * Licensed to The Apereo Foundation under one or more contributor license
    * agreements. See the NOTICE file distributed with this work for additional
    * information regarding copyright ownership.
    *
    *
    * The Apereo Foundation licenses this file to you under the Educational
    * Community 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://opensource.org/licenses/ecl2.txt
   *
   * 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.opencastproject.list.common.provider;
  
  import org.opencastproject.list.api.ResourceListProvider;
  import org.opencastproject.list.api.ResourceListQuery;
  import org.opencastproject.security.api.Role;
  import org.opencastproject.security.api.User;
  import org.opencastproject.security.api.UserDirectoryService;
  
  import org.apache.commons.lang3.StringUtils;
  import org.osgi.framework.BundleContext;
  import org.osgi.service.component.annotations.Activate;
  import org.osgi.service.component.annotations.Component;
  import org.osgi.service.component.annotations.Reference;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.Map;
  
  @Component(
      service = ResourceListProvider.class,
      property = {
          "service.description=Users list provider",
          "opencast.service.type=org.opencastproject.list.provider.UsersListProvider"
      }
  )
  public class UsersListProvider implements ResourceListProvider {
  
    private static final String PROVIDER_PREFIX = "USERS";
  
    public static final String NAME = PROVIDER_PREFIX + ".NAME"; // Username : Name
    public static final String NAME_AND_EMAIL = PROVIDER_PREFIX + ".NAME.AND.EMAIL"; // Username: Name <Email>
    public static final String NAME_AND_USERNAME = PROVIDER_PREFIX + ".NAME.AND.USERNAME"; // Username: Name (Username)
    public static final String USERNAME = PROVIDER_PREFIX + ".USERNAME"; // UserName: UserName
    public static final String EMAIL = PROVIDER_PREFIX + ".EMAIL"; // UserName: Email
  
    public static final String NAME_ONLY = PROVIDER_PREFIX + ".NAME.ONLY"; // Name : Name
    public static final String EMAIL_ONLY = PROVIDER_PREFIX + ".EMAIL.ONLY"; // Email: Email
    public static final String ROLE_ONLY = PROVIDER_PREFIX + ".ROLE.ONLY"; // Role: Role
    // UserDirectory: UserDirectory
    public static final String USERDIRECTORY_ONLY = PROVIDER_PREFIX + ".USERDIRECTORY.ONLY";
  
    protected static final String[] NAMES = { NAME, NAME_AND_EMAIL, NAME_AND_USERNAME, USERNAME, EMAIL, NAME_ONLY,
        EMAIL_ONLY, ROLE_ONLY, USERDIRECTORY_ONLY };
  
    private static final Logger logger = LoggerFactory.getLogger(UsersListProvider.class);
  
    private UserDirectoryService userDirectoryService;
  
    @Activate
    protected void activate(BundleContext bundleContext) {
      logger.info("Users list provider activated!");
    }
  
    /** OSGi callback for users services. */
    @Reference
    public void setUserDirectoryService(UserDirectoryService userDirectoryService) {
      this.userDirectoryService = userDirectoryService;
    }
  
    @Override
    public String[] getListNames() {
      return NAMES;
    }
  
    @Override
    public Map<String, String> getList(String listName, ResourceListQuery query) {
      Map<String, String> usersList = new HashMap<>();
      int offset = 0;
      int limit = 0;
  
      if (query != null) {
        if (query.getLimit().isPresent()) {
          limit = query.getLimit().get();
        }
  
        if (query.getOffset().isPresent()) {
         offset = query.getOffset().get();
       }
     }
 
     Iterator<User> users = userDirectoryService.findUsers("%", offset, limit);
 
     while (users.hasNext()) {
       User u = users.next();
       if (EMAIL.equals(listName) && StringUtils.isNotBlank(u.getEmail())) {
         usersList.put(u.getUsername(), u.getEmail());
       } else if (USERNAME.equals(listName) && StringUtils.isNotBlank(u.getUsername())) {
         usersList.put(u.getUsername(), u.getUsername());
       } else if (NAME.equals(listName) && StringUtils.isNotBlank(u.getName())) {
         usersList.put(u.getUsername(), u.getName());
       } else if (NAME.equals(listName)
               || NAME_AND_EMAIL.equals(listName)
               || NAME_AND_USERNAME.equals(listName)) {
         usersList.put(u.getUsername(), createDisplayName(u, listName));
       } else if (NAME_ONLY.equals(listName) && StringUtils.isNotBlank(u.getName())) {
         usersList.put(u.getName(), u.getName());
       } else if (EMAIL_ONLY.equals(listName) && StringUtils.isNotBlank(u.getEmail())) {
         usersList.put(u.getEmail(), u.getEmail());
       } else if (USERDIRECTORY_ONLY.equals(listName) && StringUtils.isNotBlank(u.getProvider())) {
         usersList.put(u.getProvider(), u.getProvider());
       } else if (ROLE_ONLY.equals(listName) && u.getRoles().size() > 0) {
         for (Role role : u.getRoles()) {
           usersList.put(role.getName(), role.getName());
         }
       }
     }
     return usersList;
   }
 
   /**
    * Returns the name of the user as to be displayed in user interfaces.
    *
    * @param user
    *          the user a displayable name should be generated for
    * @param listName
    *          the list name displayable names should be generated for
    * @return name
    *          a non-null string containing the name of the user to be displayed in user interfaces
    */
   private String createDisplayName(User user, String listName) {
     assert ((user != null) && (user.getUsername() != null));
     String name = StringUtils.isNotBlank(user.getName()) ? user.getName() : user.getUsername();
     if (StringUtils.isNotBlank(user.getEmail()) && NAME_AND_EMAIL.equals(listName)) {
       name = name + " <" + user.getEmail() + ">";
     } else if (NAME_AND_USERNAME.equals(listName)) {
       name = name + " (" + user.getUsername() + ")";
     }
     assert (name != null);
     return name;
   }
 
   @Override
   public boolean isTranslatable(String listName) {
     return false;
   }
 
   @Override
   public String getDefault() {
     return null;
   }
 }