/*
    * 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.persistence.jpa.dao;
  
  import java.time.OffsetDateTime;
  import java.util.List;
  import javax.persistence.Query;
  import javax.persistence.TypedQuery;
  import org.apache.syncope.core.persistence.api.dao.ReportExecDAO;
  import org.apache.syncope.core.persistence.api.dao.search.OrderByClause;
  import org.apache.syncope.core.persistence.api.entity.Report;
  import org.apache.syncope.core.persistence.api.entity.ReportExec;
  import org.apache.syncope.core.persistence.jpa.entity.JPAReportExec;
  import org.springframework.transaction.annotation.Transactional;
  import org.springframework.util.ReflectionUtils;
  
  public class JPAReportExecDAO extends AbstractDAO<ReportExec> implements ReportExecDAO {
  
      @Override
      public ReportExec find(final String key) {
          return entityManager().find(JPAReportExec.class, key);
      }
  
      @Override
      public List<ReportExec> findRecent(final int max) {
          TypedQuery<ReportExec> query = entityManager().createQuery(
                  "SELECT e FROM " + JPAReportExec.class.getSimpleName() + " e "
                  + "WHERE e.end IS NOT NULL ORDER BY e.end DESC", ReportExec.class);
          query.setMaxResults(max);
  
          return query.getResultList();
      }
  
      protected ReportExec findLatest(final Report report, final String field) {
          TypedQuery<ReportExec> query = entityManager().createQuery(
                  "SELECT e FROM " + JPAReportExec.class.getSimpleName() + " e "
                  + "WHERE e.report=:report ORDER BY e." + field + " DESC", ReportExec.class);
          query.setParameter("report", report);
          query.setMaxResults(1);
  
          List<ReportExec> result = query.getResultList();
          return result == null || result.isEmpty()
                  ? null
                  : result.iterator().next();
      }
  
      @Override
      public ReportExec findLatestStarted(final Report report) {
          return findLatest(report, "start");
      }
  
      @Override
      public ReportExec findLatestEnded(final Report report) {
          return findLatest(report, "end");
      }
  
      protected StringBuilder query(
              final StringBuilder select,
              final OffsetDateTime before,
              final OffsetDateTime after) {
  
          StringBuilder query = select.
                  append(JPAReportExec.class.getSimpleName()).
                  append(" e WHERE e.report=:report ");
          if (before != null) {
              query.append("AND e.start <= :before ");
          }
          if (after != null) {
              query.append("AND e.start >= :after ");
          }
          return query;
      }
  
      @Override
      public int count(
              final Report report,
              final OffsetDateTime before,
              final OffsetDateTime after) {
  
          StringBuilder queryString = query(new StringBuilder("SELECT COUNT(e) FROM "), before, after);
  
          Query query = entityManager().createQuery(queryString.toString());
          query.setParameter("report", report);
         if (before != null) {
             query.setParameter("before", before);
         }
         if (after != null) {
             query.setParameter("after", after);
         }
 
         return ((Number) query.getSingleResult()).intValue();
     }
 
     protected String toOrderByStatement(final List<OrderByClause> orderByClauses) {
         StringBuilder statement = new StringBuilder();
 
         for (OrderByClause clause : orderByClauses) {
             String field = clause.getField().trim();
             if (ReflectionUtils.findField(JPAReportExec.class, field) != null) {
                 statement.append("e.").append(field).append(' ').append(clause.getDirection().name());
             }
         }
 
         if (statement.length() == 0) {
             statement.append(" ORDER BY e.id DESC");
         } else {
             statement.insert(0, " ORDER BY ");
         }
         return statement.toString();
     }
 
     @Override
     public List<ReportExec> findAll(
             final Report report,
             final OffsetDateTime before,
             final OffsetDateTime after,
             final int page,
             final int itemsPerPage,
             final List<OrderByClause> orderByClauses) {
 
         StringBuilder queryString = query(new StringBuilder("SELECT e FROM "), before, after).
                 append(toOrderByStatement(orderByClauses));
 
         TypedQuery<ReportExec> query = entityManager().createQuery(queryString.toString(), ReportExec.class);
         query.setParameter("report", report);
         if (before != null) {
             query.setParameter("before", before);
         }
         if (after != null) {
             query.setParameter("after", after);
         }
 
         // page starts from 1, while setFirtResult() starts from 0
         query.setFirstResult(itemsPerPage * (page <= 0 ? 0 : page - 1));
 
         if (itemsPerPage >= 0) {
             query.setMaxResults(itemsPerPage);
         }
 
         return query.getResultList();
     }
 
     @Transactional(rollbackFor = Throwable.class)
     @Override
     public ReportExec save(final ReportExec execution) {
         return entityManager().merge(execution);
     }
 
     @Override
     public void delete(final String key) {
         ReportExec execution = find(key);
         if (execution == null) {
             return;
         }
 
         delete(execution);
     }
 
     @Override
     public void delete(final ReportExec execution) {
         if (execution.getReport() != null) {
             execution.getReport().getExecs().remove(execution);
         }
 
         entityManager().remove(execution);
     }
 }