/*
    * Copyright 2012-2017 CodeLibs Project and the Others.
    *
    * Licensed 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.codelibs.fess.helper;
  
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Locale;
  import java.util.Map;
  
  import javax.annotation.PostConstruct;
  
  import org.codelibs.core.lang.StringUtil;
  import org.codelibs.fess.es.config.exbhv.RelatedQueryBhv;
  import org.codelibs.fess.es.config.exentity.RelatedQuery;
  import org.codelibs.fess.mylasta.direction.FessConfig;
  import org.codelibs.fess.util.ComponentUtil;
  
  public class RelatedQueryHelper {
  
      protected volatile Map<String, Map<String, String[]>> relatedQueryMap = Collections.emptyMap();
  
      @PostConstruct
      public void init() {
          reload();
      }
  
      public void update() {
          reload();
      }
  
      public List<RelatedQuery> getAvailableRelatedQueryList() {
  
          return ComponentUtil.getComponent(RelatedQueryBhv.class).selectList(cb -> {
              cb.query().matchAll();
              cb.query().addOrderBy_Term_Asc();
              cb.fetchFirst(ComponentUtil.getFessConfig().getPageRelatedqueryMaxFetchSizeAsInteger());
          });
      }
  
      protected void reload() {
          final Map<String, Map<String, String[]>> relatedQueryMap = new HashMap<>();
          getAvailableRelatedQueryList().stream().forEach(entity -> {
              final String key = getHostKey(entity);
              Map<String, String[]> map = relatedQueryMap.get(key);
              if (map == null) {
                  map = new HashMap<>();
                  relatedQueryMap.put(key, map);
              }
              map.put(toLowerCase(entity.getTerm()), entity.getQueries());
          });
          this.relatedQueryMap = relatedQueryMap;
      }
  
      protected String getHostKey(final RelatedQuery entity) {
          final String key = entity.getVirtualHost();
          return StringUtil.isBlank(key) ? StringUtil.EMPTY : key;
      }
  
      public String[] getRelatedQueries(final String query) {
          final FessConfig fessConfig = ComponentUtil.getFessConfig();
          final String key = fessConfig.getVirtualHostKey();
          final Map<String, String[]> map = relatedQueryMap.get(key);
          if (map != null) {
              final String[] queries = map.get(toLowerCase(query));
              if (queries != null) {
                  return queries;
              }
          }
          return StringUtil.EMPTY_STRINGS;
      }
  
      private String toLowerCase(final String term) {
          return term != null ? term.toLowerCase(Locale.ROOT) : term;
      }
  
  }