/*
    *    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.util;
  
  import java.util.Objects;
  import java.util.Optional;
  import java.util.function.Supplier;
  
  import org.jspecify.annotations.Nullable;
  import org.mybatis.dynamic.sql.SqlColumn;
  
  public class ValueWhenPresentMapping<T> extends AbstractColumnMapping {
  
      private final Supplier<@Nullable T> valueSupplier;
      // keep a reference to the column so we don't lose the type
      private final SqlColumn<T> localColumn;
  
      private ValueWhenPresentMapping(SqlColumn<T> column, Supplier<@Nullable T> valueSupplier) {
          super(column);
          this.valueSupplier = Objects.requireNonNull(valueSupplier);
          localColumn = Objects.requireNonNull(column);
      }
  
      public Optional<Object> value() {
          return Optional.ofNullable(valueSupplier.get()).flatMap(this::convert);
      }
  
      private Optional<Object> convert(T value) {
          return Optional.ofNullable(localColumn.convertParameterType(value));
      }
  
      @Override
      public <R> R accept(ColumnMappingVisitor<R> visitor) {
          return visitor.visit(this);
      }
  
      public static <T> ValueWhenPresentMapping<T> of(SqlColumn<T> column, Supplier<@Nullable T> valueSupplier) {
          return new ValueWhenPresentMapping<>(column, valueSupplier);
      }
  }