/*
    *    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.update.render;
  
  import java.util.Objects;
  import java.util.Optional;
  import java.util.stream.Collectors;
  
  import org.jspecify.annotations.Nullable;
  import org.mybatis.dynamic.sql.common.OrderByModel;
  import org.mybatis.dynamic.sql.common.OrderByRenderer;
  import org.mybatis.dynamic.sql.render.ExplicitTableAliasCalculator;
  import org.mybatis.dynamic.sql.render.RenderedParameterInfo;
  import org.mybatis.dynamic.sql.render.RenderingContext;
  import org.mybatis.dynamic.sql.render.RenderingStrategy;
  import org.mybatis.dynamic.sql.render.TableAliasCalculator;
  import org.mybatis.dynamic.sql.update.UpdateModel;
  import org.mybatis.dynamic.sql.util.FragmentAndParameters;
  import org.mybatis.dynamic.sql.util.FragmentCollector;
  import org.mybatis.dynamic.sql.util.Validator;
  import org.mybatis.dynamic.sql.where.EmbeddedWhereModel;
  
  public class UpdateRenderer {
      private final UpdateModel updateModel;
      private final RenderingContext renderingContext;
      private final SetPhraseVisitor visitor;
  
      private UpdateRenderer(Builder builder) {
          updateModel = Objects.requireNonNull(builder.updateModel);
          TableAliasCalculator tableAliasCalculator = builder.updateModel.tableAlias()
                  .map(a -> ExplicitTableAliasCalculator.of(updateModel.table(), a))
                  .orElseGet(TableAliasCalculator::empty);
          renderingContext = RenderingContext
                  .withRenderingStrategy(Objects.requireNonNull(builder.renderingStrategy))
                  .withTableAliasCalculator(tableAliasCalculator)
                  .withStatementConfiguration(updateModel.statementConfiguration())
                  .build();
          visitor = new SetPhraseVisitor(renderingContext);
      }
  
      public UpdateStatementProvider render() {
          FragmentCollector fragmentCollector = new FragmentCollector();
  
          fragmentCollector.add(calculateUpdateStatementStart());
          fragmentCollector.add(calculateSetPhrase());
          calculateWhereClause().ifPresent(fragmentCollector::add);
          calculateOrderByClause().ifPresent(fragmentCollector::add);
          calculateLimitClause().ifPresent(fragmentCollector::add);
  
          return toUpdateStatementProvider(fragmentCollector);
      }
  
      private UpdateStatementProvider toUpdateStatementProvider(FragmentCollector fragmentCollector) {
          return DefaultUpdateStatementProvider
                  .withUpdateStatement(fragmentCollector.collectFragments(Collectors.joining(" "))) //$NON-NLS-1$
                  .withParameters(fragmentCollector.parameters())
                  .build();
      }
  
      private FragmentAndParameters calculateUpdateStatementStart() {
          String aliasedTableName = renderingContext.aliasedTableName(updateModel.table());
          return FragmentAndParameters.fromFragment("update " + aliasedTableName); //$NON-NLS-1$
      }
  
      private FragmentAndParameters calculateSetPhrase() {
          FragmentCollector fragmentCollector = updateModel.columnMappings()
                  .map(m -> m.accept(visitor))
                  .flatMap(Optional::stream)
                  .collect(FragmentCollector.collect());
  
          Validator.assertFalse(fragmentCollector.isEmpty(), "ERROR.18"); //$NON-NLS-1$
  
          return fragmentCollector.toFragmentAndParameters(
                          Collectors.joining(", ", "set ", "")); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
      }
  
      private Optional<FragmentAndParameters> calculateWhereClause() {
          return updateModel.whereModel().flatMap(this::renderWhereClause);
      }
  
      private Optional<FragmentAndParameters> renderWhereClause(EmbeddedWhereModel whereModel) {
          return whereModel.render(renderingContext);
      }
  
      private Optional<FragmentAndParameters> calculateLimitClause() {
          return updateModel.limit().map(this::renderLimitClause);
     }
 
     private FragmentAndParameters renderLimitClause(Long limit) {
         RenderedParameterInfo parameterInfo = renderingContext.calculateLimitParameterInfo();
 
         return FragmentAndParameters.withFragment("limit " + parameterInfo.renderedPlaceHolder()) //$NON-NLS-1$
                 .withParameter(parameterInfo.parameterMapKey(), limit)
                 .build();
     }
 
     private Optional<FragmentAndParameters> calculateOrderByClause() {
         return updateModel.orderByModel().map(this::renderOrderByClause);
     }
 
     private FragmentAndParameters renderOrderByClause(OrderByModel orderByModel) {
         return new OrderByRenderer(renderingContext).render(orderByModel);
     }
 
     public static Builder withUpdateModel(UpdateModel updateModel) {
         return new Builder().withUpdateModel(updateModel);
     }
 
     public static class Builder {
         private @Nullable UpdateModel updateModel;
         private @Nullable RenderingStrategy renderingStrategy;
 
         public Builder withUpdateModel(UpdateModel updateModel) {
             this.updateModel = updateModel;
             return this;
         }
 
         public Builder withRenderingStrategy(RenderingStrategy renderingStrategy) {
             this.renderingStrategy = renderingStrategy;
             return this;
         }
 
         public UpdateRenderer build() {
             return new UpdateRenderer(this);
         }
     }
 }