/*
    *    Copyright 2016-2025 the original author or authors.
    *
    *    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
    *
    *       https://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.mybatis.dynamic.sql.select.aggregate;
  
  import java.util.Objects;
  
  import org.mybatis.dynamic.sql.BasicColumn;
  import org.mybatis.dynamic.sql.render.RenderingContext;
  import org.mybatis.dynamic.sql.util.FragmentAndParameters;
  
  public class CountDistinct extends AbstractCount {
  
      private final BasicColumn column;
  
      private CountDistinct(BasicColumn column) {
          this.column = Objects.requireNonNull(column);
      }
  
      private CountDistinct(BasicColumn column, String alias) {
          super(alias);
          this.column = Objects.requireNonNull(column);
      }
  
      @Override
      public FragmentAndParameters render(RenderingContext renderingContext) {
          return column.render(renderingContext)
                  .mapFragment(s -> "count(distinct " + s + ")"); //$NON-NLS-1$ //$NON-NLS-2$)
      }
  
      @Override
      public CountDistinct as(String alias) {
          return new CountDistinct(column, alias);
      }
  
      public static CountDistinct of(BasicColumn column) {
          return new CountDistinct(column);
      }
  }