/*
    *    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.render;
  
  import java.util.Objects;
  
  import org.mybatis.dynamic.sql.render.RenderedParameterInfo;
  import org.mybatis.dynamic.sql.render.RenderingContext;
  import org.mybatis.dynamic.sql.select.PagingModel;
  import org.mybatis.dynamic.sql.util.FragmentAndParameters;
  
  public class LimitAndOffsetPagingModelRenderer {
      private final RenderingContext renderingContext;
      private final Long limit;
      private final PagingModel pagingModel;
  
      public LimitAndOffsetPagingModelRenderer(RenderingContext renderingContext,
                                               Long limit, PagingModel pagingModel) {
          this.renderingContext = renderingContext;
          this.limit = Objects.requireNonNull(limit);
          this.pagingModel = pagingModel;
      }
  
      public FragmentAndParameters render() {
          return pagingModel.offset().map(this::renderLimitAndOffset)
                  .orElseGet(this::renderLimitOnly);
      }
  
      private FragmentAndParameters renderLimitOnly() {
          RenderedParameterInfo limitParameterInfo = renderingContext.calculateLimitParameterInfo();
          return FragmentAndParameters.withFragment("limit " + limitParameterInfo.renderedPlaceHolder()) //$NON-NLS-1$
                  .withParameter(limitParameterInfo.parameterMapKey(), limit)
                  .build();
      }
  
      private FragmentAndParameters renderLimitAndOffset(Long offset) {
          RenderedParameterInfo limitParameterInfo = renderingContext.calculateLimitParameterInfo();
          RenderedParameterInfo offsetParameterInfo = renderingContext.calculateOffsetParameterInfo();
          return FragmentAndParameters.withFragment("limit " + limitParameterInfo.renderedPlaceHolder() //$NON-NLS-1$
                      + " offset " + offsetParameterInfo.renderedPlaceHolder()) //$NON-NLS-1$
                  .withParameter(limitParameterInfo.parameterMapKey(), limit)
                  .withParameter(offsetParameterInfo.parameterMapKey(), offset)
                  .build();
      }
  }