/*
    * 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.syncope.core.spring.policy;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.List;
  import java.util.Map;
  import java.util.Optional;
  import java.util.concurrent.ConcurrentHashMap;
  import org.apache.syncope.core.persistence.api.dao.RealmDAO;
  import org.apache.syncope.core.persistence.api.entity.ExternalResource;
  import org.apache.syncope.core.persistence.api.entity.Implementation;
  import org.apache.syncope.core.persistence.api.entity.Realm;
  import org.apache.syncope.core.persistence.api.entity.policy.AccountPolicy;
  import org.apache.syncope.core.persistence.api.entity.policy.PasswordPolicy;
  import org.apache.syncope.core.provisioning.api.rules.AccountRule;
  import org.apache.syncope.core.provisioning.api.rules.PasswordRule;
  import org.apache.syncope.core.provisioning.api.rules.RuleEnforcer;
  import org.apache.syncope.core.spring.implementation.ImplementationManager;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.springframework.transaction.annotation.Transactional;
  
  public class DefaultRuleEnforcer implements RuleEnforcer {
  
      protected static final Logger LOG = LoggerFactory.getLogger(RuleEnforcer.class);
  
      protected final RealmDAO realmDAO;
  
      protected final Map<String, AccountRule> perContextAccountRules = new ConcurrentHashMap<>();
  
      protected final Map<String, PasswordRule> perContextPasswordRules = new ConcurrentHashMap<>();
  
      public DefaultRuleEnforcer(final RealmDAO realmDAO) {
          this.realmDAO = realmDAO;
      }
  
      @Transactional(readOnly = true)
      @Override
      public List<AccountPolicy> getAccountPolicies(final Realm realm, final Collection<ExternalResource> resources) {
          List<AccountPolicy> policies = new ArrayList<>();
  
          // add resource policies
          resources.forEach(resource -> Optional.ofNullable(resource.getAccountPolicy()).
                  filter(p -> !policies.contains(p)).
                  ifPresent(policies::add));
  
          // add realm policies
          if (realm != null) {
              realmDAO.findAncestors(realm).
                      forEach(r -> Optional.ofNullable(r.getAccountPolicy()).
                      filter(p -> !policies.contains(p)).
                      ifPresent(policies::add));
          }
  
          return policies;
      }
  
      @Transactional(readOnly = true)
      @Override
      public List<AccountRule> getAccountRules(final AccountPolicy policy) {
          List<AccountRule> result = new ArrayList<>();
  
          for (Implementation impl : policy.getRules()) {
              try {
                  ImplementationManager.buildAccountRule(
                          impl,
                          () -> perContextAccountRules.get(impl.getKey()),
                          instance -> perContextAccountRules.put(impl.getKey(), instance)).
                          ifPresent(result::add);
              } catch (Exception e) {
                  LOG.warn("While building {}", impl, e);
              }
          }
  
          return result;
      }
  
      @Transactional(readOnly = true)
      @Override
      public List<PasswordPolicy> getPasswordPolicies(final Realm realm, final Collection<ExternalResource> resources) {
          List<PasswordPolicy> policies = new ArrayList<>();
 
         // add resource policies
         resources.forEach(resource -> Optional.ofNullable(resource.getPasswordPolicy()).
                 filter(p -> !policies.contains(p)).
                 ifPresent(policies::add));
 
         // add realm policies
         if (realm != null) {
             realmDAO.findAncestors(realm).
                     forEach(r -> Optional.ofNullable(r.getPasswordPolicy()).
                     filter(p -> !policies.contains(p)).
                     ifPresent(policies::add));
         }
 
         return policies;
     }
 
     @Transactional(readOnly = true)
     @Override
     public List<PasswordRule> getPasswordRules(final PasswordPolicy policy) {
         List<PasswordRule> result = new ArrayList<>();
 
         for (Implementation impl : policy.getRules()) {
             try {
                 ImplementationManager.buildPasswordRule(
                         impl,
                         () -> perContextPasswordRules.get(impl.getKey()),
                         instance -> perContextPasswordRules.put(impl.getKey(), instance)).
                         ifPresent(result::add);
             } catch (Exception e) {
                 LOG.warn("While building {}", impl, e);
             }
         }
 
         return result;
     }
 }