/*
    *    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;
  
  import java.util.Objects;
  import java.util.Optional;
  
  import org.jspecify.annotations.Nullable;
  import org.mybatis.dynamic.sql.TableExpression;
  import org.mybatis.dynamic.sql.TableExpressionVisitor;
  
  public class SubQuery implements TableExpression {
      private final SelectModel selectModel;
      private final @Nullable String alias;
  
      private SubQuery(Builder builder) {
          selectModel = Objects.requireNonNull(builder.selectModel);
          alias = builder.alias;
      }
  
      public SelectModel selectModel() {
          return selectModel;
      }
  
      public Optional<String> alias() {
          return Optional.ofNullable(alias);
      }
  
      @Override
      public boolean isSubQuery() {
          return true;
      }
  
      @Override
      public <R> R accept(TableExpressionVisitor<R> visitor) {
          return visitor.visit(this);
      }
  
      public static class Builder {
          private @Nullable SelectModel selectModel;
          private @Nullable String alias;
  
          public Builder withSelectModel(SelectModel selectModel) {
              this.selectModel = selectModel;
              return this;
          }
  
          public Builder withAlias(@Nullable String alias) {
              this.alias = alias;
              return this;
          }
  
          public SubQuery build() {
              return new SubQuery(this);
          }
      }
  }