/*
    *    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;
  
  import java.lang.reflect.InvocationTargetException;
  import java.util.Arrays;
  import java.util.Collection;
  import java.util.HashSet;
  import java.util.Locale;
  import java.util.Map;
  import java.util.Optional;
  import java.util.Properties;
  import java.util.Set;
  import java.util.function.BiFunction;
  
  import org.apache.ibatis.builder.SqlSourceBuilder;
  import org.apache.ibatis.mapping.BoundSql;
  import org.apache.ibatis.mapping.SqlSource;
  import org.apache.ibatis.reflection.MetaClass;
  import org.apache.ibatis.scripting.xmltags.DynamicContext;
  import org.apache.ibatis.session.Configuration;
  import org.thymeleaf.context.IContext;
  
  /**
   * The {@code SqlSource} for integrating with Thymeleaf.
   *
   * @author Kazuki Shimizu
   *
   * @version 1.0.0
   *
   * @see ThymeleafLanguageDriver
   */
  class ThymeleafSqlSource implements SqlSource {
  
    private static class TemporaryTakeoverKeys {
      private static final String CONFIGURATION = "__configuration__";
      private static final String DYNAMIC_CONTEXT = "__dynamicContext__";
      private static final String PROCESSING_PARAMETER_TYPE = "__processingParameterType__";
    }
  
    private final Configuration configuration;
    private final SqlGenerator sqlGenerator;
    private final SqlSourceBuilder sqlSourceBuilder;
    private final String sqlTemplate;
    private final Class<?> parameterType;
  
    /**
     * Constructor for for integrating with template engine provide by Thymeleaf.
     *
     * @param configuration
     *          A configuration instance of MyBatis
     * @param sqlGenerator
     *          A sql generator using the Thymeleaf feature
     * @param sqlTemplate
     *          A template string of SQL (inline SQL or template file path)
     * @param parameterType
     *          A parameter type that specified at mapper method argument or xml element
     */
    ThymeleafSqlSource(Configuration configuration, SqlGenerator sqlGenerator, String sqlTemplate,
        Class<?> parameterType) {
      this.configuration = configuration;
      this.sqlGenerator = sqlGenerator;
      this.sqlTemplate = sqlTemplate;
      this.parameterType = parameterType;
      this.sqlSourceBuilder = new SqlSourceBuilder(configuration);
    }
  
    /**
     * {@inheritDoc}
     */
    @Override
    public BoundSql getBoundSql(Object parameterObject) {
      Class<?> processingParameterType;
      if (parameterType == null) {
        processingParameterType = parameterObject == null ? Object.class : parameterObject.getClass();
      } else {
        processingParameterType = parameterType;
      }
  
      DynamicContext dynamicContext = new DynamicContext(configuration, parameterObject);
      Map<String, Object> customVariables = dynamicContext.getBindings();
      customVariables.put(TemporaryTakeoverKeys.CONFIGURATION, configuration);
      customVariables.put(TemporaryTakeoverKeys.DYNAMIC_CONTEXT, dynamicContext);
      customVariables.put(TemporaryTakeoverKeys.PROCESSING_PARAMETER_TYPE, processingParameterType);
      String sql = sqlGenerator.generate(sqlTemplate, parameterObject, dynamicContext::bind, customVariables);
  
     SqlSource sqlSource = sqlSourceBuilder.parse(sql, processingParameterType, dynamicContext.getBindings());
     BoundSql boundSql = sqlSource.getBoundSql(parameterObject);
     dynamicContext.getBindings().forEach(boundSql::setAdditionalParameter);
 
     return boundSql;
   }
 
   /**
    * The factory class for Thymeleaf's context.
    *
    * @since 1.0.2
    */
   static class ContextFactory implements BiFunction<Object, Map<String, Object>, IContext> {
     /**
      * {@inheritDoc}
      */
     @Override
     public IContext apply(Object parameter, Map<String, Object> customVariable) {
       Configuration configuration = (Configuration) customVariable.remove(TemporaryTakeoverKeys.CONFIGURATION);
       DynamicContext dynamicContext = (DynamicContext) customVariable.remove(TemporaryTakeoverKeys.DYNAMIC_CONTEXT);
       Class<?> processingParameterType = (Class<?>) customVariable
           .remove(TemporaryTakeoverKeys.PROCESSING_PARAMETER_TYPE);
       MyBatisBindingContext bindingContext = new MyBatisBindingContext(
           parameter != null && configuration.getTypeHandlerRegistry().hasTypeHandler(processingParameterType));
       dynamicContext.bind(MyBatisBindingContext.CONTEXT_VARIABLE_NAME, bindingContext);
       IContext context;
       if (parameter instanceof Map) {
         @SuppressWarnings(value = "unchecked")
         Map<String, Object> map = (Map<String, Object>) parameter;
         context = new MapBasedContext(map, dynamicContext, configuration.getVariables());
       } else {
         MetaClass metaClass = MetaClass.forClass(processingParameterType, configuration.getReflectorFactory());
         context = new MetaClassBasedContext(parameter, metaClass, processingParameterType, dynamicContext,
             configuration.getVariables());
       }
       return context;
     }
   }
 
   private abstract static class AbstractContext implements IContext {
 
     private final DynamicContext dynamicContext;
     private final Properties configurationProperties;
     private final Set<String> variableNames;
 
     private AbstractContext(DynamicContext dynamicContext, Properties configurationProperties) {
       this.dynamicContext = dynamicContext;
       this.configurationProperties = configurationProperties;
       this.variableNames = new HashSet<>();
       addVariableNames(dynamicContext.getBindings().keySet());
       Optional.ofNullable(configurationProperties).ifPresent(v -> addVariableNames(v.stringPropertyNames()));
     }
 
     void addVariableNames(Collection<String> names) {
       variableNames.addAll(names);
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public Locale getLocale() {
       return Locale.getDefault();
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public boolean containsVariable(String name) {
       return variableNames.contains(name);
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public Set<String> getVariableNames() {
       return variableNames;
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public Object getVariable(String name) {
       if (dynamicContext.getBindings().containsKey(name)) {
         return dynamicContext.getBindings().get(name);
       }
       if (configurationProperties != null && configurationProperties.containsKey(name)) {
         return configurationProperties.getProperty(name);
       }
       return getParameterValue(name);
     }
 
     abstract Object getParameterValue(String name);
 
   }
 
   private static class MapBasedContext extends AbstractContext {
 
     private final Map<String, Object> variables;
 
     private MapBasedContext(Map<String, Object> parameterMap, DynamicContext dynamicContext,
         Properties configurationProperties) {
       super(dynamicContext, configurationProperties);
       this.variables = parameterMap;
       addVariableNames(parameterMap.keySet());
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public Object getParameterValue(String name) {
       return variables.get(name);
     }
 
   }
 
   private static class MetaClassBasedContext extends AbstractContext {
 
     private final Object parameterObject;
     private final MetaClass parameterMetaClass;
     private final Class<?> parameterType;
 
     private MetaClassBasedContext(Object parameterObject, MetaClass parameterMetaClass, Class<?> parameterType,
         DynamicContext dynamicContext, Properties configurationProperties) {
       super(dynamicContext, configurationProperties);
       this.parameterObject = parameterObject;
       this.parameterMetaClass = parameterMetaClass;
       this.parameterType = parameterType;
       addVariableNames(Arrays.asList(parameterMetaClass.getGetterNames()));
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public Object getParameterValue(String name) {
       try {
         return parameterMetaClass.getGetInvoker(name).invoke(parameterObject, null);
       } catch (IllegalAccessException | InvocationTargetException e) {
         throw new IllegalStateException(
             String.format("Cannot get a value for property named '%s' in '%s'", name, parameterType), e);
       }
     }
 
   }
 
 }