content: /*
   *  Licensed to the Apache Software Foundation (ASF) under one
   *  or more contributor license agreements.  See the NOTICE file
   *  distributed with this work for additional information
   *  regarding copyright ownership.  The ASF licenses this file
   *  to you 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.apache.causeway.security.simple.realm;
  
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.Optional;
  import java.util.function.Function;
  import java.util.stream.Collectors;
  
  import org.jspecify.annotations.Nullable;
  
  import org.springframework.stereotype.Component;
  
  import org.apache.causeway.applib.Identifier;
  import org.apache.causeway.commons.internal.base._Strings;
  
  @Component
  public class SimpleRealm {
  
      public enum Grant {
          NONE,
          READ,
          CHANGE;
          public boolean grantsRead() {
              return this==READ
                      || this==CHANGE;
          }
          public boolean grantsChange() {
              return this==CHANGE;
          }
          public static Grant valueOf(final @Nullable Grant grant) {
              return grant!=null
                      ? grant
                      : Grant.NONE;
          }
      }
  
      public record Role(
              String name,
              Function<Identifier, Grant> grants) {
      }
  
      public record User(
              String name,
              String encryptedPass,
              List<Role> roles) {
      }
  
      final Map<String, Role> roles = new HashMap<>();
      final Map<String, User> users = new HashMap<>();
  
      public SimpleRealm addRole(final String name, final Function<Identifier, Grant> grants) {
          roles.put(name, new Role(name, grants));
          return this;
      }
      public SimpleRealm addUser(final String name, final String pass, final List<String> roleNames) {
          users.put(name, new User(name, pass, roleNames.stream().map(roles::get).collect(Collectors.toList())));
          return this;
      }
  
      public final Optional<Role> lookupRoleByName(final @Nullable String roleName) {
          return _Strings.isNullOrEmpty(roleName)
                  ? Optional.empty()
                  : Optional.ofNullable(roles.get(roleName));
      }
  
      public final Optional<User> lookupUserByName(final @Nullable String userName) {
          return _Strings.isNullOrEmpty(userName)
                  ? Optional.empty()
                  : Optional.ofNullable(users.get(userName));
      }
  
  }
  