/*
    * 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.shardingsphere.authority.rule;
  
  import lombok.Getter;
  import org.apache.shardingsphere.authority.config.AuthorityRuleConfiguration;
  import org.apache.shardingsphere.authority.constant.AuthorityOrder;
  import org.apache.shardingsphere.authority.model.ShardingSpherePrivileges;
  import org.apache.shardingsphere.authority.spi.PrivilegeProvider;
  import org.apache.shardingsphere.infra.annotation.HighFrequencyInvocation;
  import org.apache.shardingsphere.infra.metadata.user.Grantee;
  import org.apache.shardingsphere.infra.metadata.user.ShardingSphereUser;
  import org.apache.shardingsphere.infra.rule.scope.GlobalRule;
  import org.apache.shardingsphere.infra.spi.type.typed.TypedSPILoader;
  
  import java.util.Collection;
  import java.util.LinkedHashMap;
  import java.util.Map;
  import java.util.Optional;
  import java.util.stream.Collectors;
  
  /**
   * Authority rule.
   */
  public final class AuthorityRule implements GlobalRule {
      
      @Getter
      private final AuthorityRuleConfiguration configuration;
      
      private final Map<ShardingSphereUser, ShardingSpherePrivileges> privileges;
      
      public AuthorityRule(final AuthorityRuleConfiguration ruleConfig) {
          configuration = ruleConfig;
          Collection<ShardingSphereUser> users = ruleConfig.getUsers().stream()
                  .map(each -> new ShardingSphereUser(each.getUsername(), each.getPassword(), each.getHostname(), each.getAuthenticationMethodName(), each.isAdmin())).collect(Collectors.toList());
          privileges = users.stream().collect(Collectors.toMap(each -> each,
                  each -> TypedSPILoader.getService(PrivilegeProvider.class, ruleConfig.getPrivilegeProvider().getType(), ruleConfig.getPrivilegeProvider().getProps())
                          .build(ruleConfig, each.getGrantee()),
                  (oldValue, currentValue) -> oldValue, LinkedHashMap::new));
      }
      
      /**
       * Get authenticator type.
       *
       * @param user user
       * @return authenticator type
       */
      public String getAuthenticatorType(final ShardingSphereUser user) {
          if (configuration.getAuthenticators().containsKey(user.getAuthenticationMethodName())) {
              return configuration.getAuthenticators().get(user.getAuthenticationMethodName()).getType();
          }
          if (configuration.getAuthenticators().containsKey(configuration.getDefaultAuthenticator())) {
              return configuration.getAuthenticators().get(configuration.getDefaultAuthenticator()).getType();
          }
          return "";
      }
      
      /**
       * Get grantees.
       *
       * @return grantees
       */
      public Collection<Grantee> getGrantees() {
          return privileges.keySet().stream().map(ShardingSphereUser::getGrantee).collect(Collectors.toList());
      }
      
      /**
       * Find user.
       *
       * @param grantee grantee user
       * @return found user
       */
      @HighFrequencyInvocation
      public Optional<ShardingSphereUser> findUser(final Grantee grantee) {
          for (ShardingSphereUser each : privileges.keySet()) {
              if (each.getGrantee().accept(grantee)) {
                  return Optional.of(each);
              }
          }
          return Optional.empty();
      }
      
      /**
       * Find privileges.
      *
      * @param grantee grantee
      * @return found privileges
      */
     @HighFrequencyInvocation
     public Optional<ShardingSpherePrivileges> findPrivileges(final Grantee grantee) {
         for (ShardingSphereUser each : privileges.keySet()) {
             if (each.getGrantee().accept(grantee)) {
                 return Optional.of(each).map(privileges::get);
             }
         }
         return Optional.empty();
     }
     
     @Override
     public int getOrder() {
         return AuthorityOrder.ORDER;
     }
 }