/*
    *    Copyright 2018-2022 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.scripting.thymeleaf.processor;
  
  import java.util.List;
  import java.util.Objects;
  
  import org.mybatis.scripting.thymeleaf.MyBatisBindingContext;
  import org.thymeleaf.context.ITemplateContext;
  import org.thymeleaf.engine.AttributeName;
  import org.thymeleaf.exceptions.TemplateProcessingException;
  import org.thymeleaf.model.IProcessableElementTag;
  import org.thymeleaf.processor.element.AbstractAttributeTagProcessor;
  import org.thymeleaf.processor.element.IElementTagStructureHandler;
  import org.thymeleaf.standard.expression.Assignation;
  import org.thymeleaf.standard.expression.AssignationSequence;
  import org.thymeleaf.standard.expression.AssignationUtils;
  import org.thymeleaf.standard.expression.IStandardExpression;
  import org.thymeleaf.templatemode.TemplateMode;
  import org.thymeleaf.util.StringUtils;
  
  /**
   * The processor class for handling the {@code mybatis:bind} tag. <br>
   * This processor register an any value to the MyBatis’s bind variables (similar to that of the {@code <bind>} provided
   * by MyBatis core module) This class's implementation was inspired with the {@code StandardWithTagProcessor} provide by
   * Thymeleaf.
   *
   * @author Kazuki Shimizu
   *
   * @version 1.0.0
   *
   * @see org.thymeleaf.standard.processor.StandardWithTagProcessor
   */
  public class MyBatisBindTagProcessor extends AbstractAttributeTagProcessor {
  
    private static final int PRECEDENCE = 600;
    private static final String ATTR_NAME = "bind";
  
    /**
     * Constructor that can be specified the template mode and dialect prefix.
     *
     * @param templateMode
     *          A target template mode
     * @param prefix
     *          A target dialect prefix
     */
    public MyBatisBindTagProcessor(final TemplateMode templateMode, final String prefix) {
      super(templateMode, prefix, null, false, ATTR_NAME, true, PRECEDENCE, true);
    }
  
    /**
     * {@inheritDoc}
     */
    @Override
    protected void doProcess(ITemplateContext context, IProcessableElementTag tag, AttributeName attributeName,
        String attributeValue, IElementTagStructureHandler structureHandler) {
      AssignationSequence assignations = AssignationUtils.parseAssignationSequence(context, attributeValue, false);
  
      List<Assignation> assignationValues = assignations.getAssignations();
      assignationValues.forEach(assignation -> {
        IStandardExpression nameExp = assignation.getLeft();
        Object name = nameExp.execute(context);
        IStandardExpression valueExp = assignation.getRight();
        Object value = valueExp.execute(context);
  
        if (Objects.isNull(name) || StringUtils.isEmpty(name.toString())) {
          throw new TemplateProcessingException(
              "Variable name expression evaluated as null or empty: \"" + nameExp + "\"");
        }
  
        MyBatisBindingContext bindingContext = MyBatisBindingContext.load(context);
        bindingContext.setCustomBindVariable(name.toString(), value);
      });
    }
  
  }