/*
    * Licensed to The Apereo Foundation under one or more contributor license
    * agreements. See the NOTICE file distributed with this work for additional
    * information regarding copyright ownership.
    *
    *
    * The Apereo Foundation licenses this file to you under the Educational
    * Community 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://opensource.org/licenses/ecl2.txt
   *
   * 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.opencastproject.list.api;
  
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.Optional;
  
  public class DefaultResourceListQuery implements ResourceListQuery {
  
    protected final List<ResourceListFilter<?>> availableFilters = new ArrayList<>();
    private final Map<String, ResourceListFilter<?>> filters = new HashMap<>();
    private Optional<Integer> limit;
    private Optional<Integer> offset;
    protected Optional<String> sortBy;
  
    public DefaultResourceListQuery() {
      limit = Optional.empty();
      offset = Optional.empty();
      sortBy = Optional.empty();
    }
  
    public void addFilter(ResourceListFilter<?> filter) {
      this.filters.put(filter.getName(), filter);
    }
  
    public void removeFilter(ResourceListFilter<?> filter) {
      this.filters.remove(filter.getName());
    }
  
    public void setLimit(Integer limit) {
      this.limit = Optional.ofNullable(limit);
    }
  
    public void setOffset(Integer offset) {
      this.offset = Optional.ofNullable(offset);
    }
  
    @Override
    public List<ResourceListFilter<?>> getFilters() {
      return new ArrayList<>(filters.values());
    }
  
    @Override
    public ResourceListFilter<?> getFilter(String name) {
      return filters.get(name);
    }
  
    @Override
    public Optional<Integer> getLimit() {
      return limit;
    }
  
    @Override
    public Optional<Integer> getOffset() {
      return offset;
    }
  
    @Override
    public Optional<String> getSortBy() {
      return sortBy;
    }
  
    @Override
    public Boolean hasFilter(String name) {
      return filters.containsKey(name);
    }
  
    @Override
    public List<ResourceListFilter<?>> getAvailableFilters() {
      return availableFilters;
    }
  
    /**
     * Returns the filter value wrapped in an {@link Optional} or none if the filter is not existing or has no value.
     *
     * @param name
     *          the filter name
    * @return an {@link Optional} wrapping the value or none.
    */
   public <A> Optional<A> getFilterValue(String name) {
     if (this.hasFilter(name)) {
       return (Optional<A>) this.getFilter(name).getValue();
     }
 
     return Optional.empty();
   }
 
 }