/*
    *    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;
  
  import static org.mybatis.dynamic.sql.util.StringUtilities.spaceBefore;
  
  import java.util.function.Function;
  import java.util.function.Predicate;
  import java.util.function.Supplier;
  
  import org.jspecify.annotations.NonNull;
  import org.mybatis.dynamic.sql.render.RenderedParameterInfo;
  import org.mybatis.dynamic.sql.render.RenderingContext;
  import org.mybatis.dynamic.sql.util.FragmentAndParameters;
  
  public abstract class AbstractSingleValueCondition<T> implements RenderableCondition<T> {
      protected final T value;
  
      protected AbstractSingleValueCondition(T value) {
          this.value = value;
      }
  
      public T value() {
          return value;
      }
  
      protected <S extends AbstractSingleValueCondition<T>> S filterSupport(Predicate<? super T> predicate,
              Supplier<S> emptySupplier, S self) {
          if (isEmpty()) {
              return self;
          } else {
              return predicate.test(value) ? self : emptySupplier.get();
          }
      }
  
      protected <R, S extends AbstractSingleValueCondition<R>> S mapSupport(Function<? super T, ? extends R> mapper,
              Function<R, S> constructor, Supplier<S> emptySupplier) {
          if (isEmpty()) {
              return emptySupplier.get();
          } else {
              return constructor.apply(mapper.apply(value));
          }
      }
  
      public abstract String operator();
  
      @Override
      public FragmentAndParameters renderCondition(RenderingContext renderingContext, BindableColumn<T> leftColumn) {
          RenderedParameterInfo parameterInfo = renderingContext.calculateParameterInfo(leftColumn);
          String finalFragment = operator() + spaceBefore(parameterInfo.renderedPlaceHolder());
  
          return FragmentAndParameters.withFragment(finalFragment)
                  .withParameter(parameterInfo.parameterMapKey(), leftColumn.convertParameterType(value()))
                  .build();
      }
  
      /**
       * Conditions may implement Filterable to add optionality to rendering.
       *
       * <p>If a condition is Filterable, then a user may add a filter to the usage of the condition that makes a decision
       * whether to render the condition at runtime. Conditions that fail the filter will be dropped from the
       * rendered SQL.
       *
       * <p>Implementations of Filterable may call
       * {@link AbstractSingleValueCondition#filterSupport(Predicate, Supplier, AbstractSingleValueCondition)} as
       * a common implementation of the filtering algorithm.
       *
       * @param <T> the Java type related to the database column type
       */
      public interface Filterable<T> {
          /**
           * If renderable and the value matches the predicate, returns this condition. Else returns a condition
           *     that will not render.
           *
           * @param predicate predicate applied to the value, if renderable
           * @return this condition if renderable and the value matches the predicate, otherwise a condition
           *     that will not render.
           */
          AbstractSingleValueCondition<T> filter(Predicate<? super @NonNull T> predicate);
      }
  
      /**
       * Conditions may implement Mappable to alter condition values or types during rendering.
       *
       * <p>If a condition is Mappable, then a user may add a mapper to the usage of the condition that can alter the
       * values of a condition, or change that datatype.
      *
      * <p>Implementations of Mappable may call
      * {@link AbstractSingleValueCondition#mapSupport(Function, Function, Supplier)} as
      * a common implementation of the mapping algorithm.
      *
      * @param <T> the Java type related to the database column type
      */
     public interface Mappable<T> {
         /**
          * If renderable, apply the mapping to the value and return a new condition with the new value. Else return a
          * condition that will not render (this).
          *
          * @param mapper a mapping function to apply to the value, if renderable
          * @param <R> type of the new condition
          * @return a new condition with the result of applying the mapper to the value of this condition,
          *     if renderable, otherwise a condition that will not render.
          */
         <R> AbstractSingleValueCondition<R> map(Function<? super @NonNull T, ? extends R> mapper);
     }
 }