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/*
 *    Copyright 2017-2022 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
 *
 *       http://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 com.alilitech.mybatis.jpa;

import com.alilitech.mybatis.jpa.anotation.NoMapperBean;
import com.alilitech.mybatis.jpa.definition.ColumnDefinition;
import com.alilitech.mybatis.jpa.definition.JoinStatementDefinition;
import com.alilitech.mybatis.jpa.definition.MapperDefinition;
import com.alilitech.mybatis.jpa.mapper.Mapper;
import com.alilitech.mybatis.jpa.meta.EntityMetaData;
import com.alilitech.mybatis.jpa.meta.JoinColumnMetaData;
import org.apache.ibatis.session.Configuration;

import java.util.*;
import java.util.stream.Collectors;


/**
 *  Mybatis Jpa initializer
 *
 * @author Zhou Xiaoxiang
 * @since 1.0
 */
public class JpaInitializer {

    private final Configuration configuration;

    protected final EntityMetaDataRegistry entityMetaDataRegistry = EntityMetaDataRegistry.getInstance();

    protected final MapperDefinitionRegistry mapperDefinitionRegistry = MapperDefinitionRegistry.getInstance();

    public JpaInitializer(Configuration configuration) {

        this.configuration = configuration;

        //register Boolean Handler
//        configuration.getTypeHandlerRegistry().register(Boolean.class, new BooleanTypeHandler());

        Collection> mapperClasses = configuration.getMapperRegistry().getMappers();

        for(Class mapperClass : mapperClasses) {
            // If mapper is not extend from Mapper, not register
            // if mapper has NoMapperBean, not register
            if(!Mapper.class.isAssignableFrom(mapperClass)
                || mapperClass.isAnnotationPresent(NoMapperBean.class)) {
                continue;
            }

            Class entityType = mapperDefinitionRegistry.register(mapperClass);
            entityMetaDataRegistry.register(entityType);
        }
    }

    public JpaInitializer buildJoinMetaDataAndRelationMethodDefinition() {
        //哪些需要关联的方法
//        List joinColumnList = new ArrayList<>();


        //遍历每个实体，找出对应的关联查询
        for(EntityMetaData entityMetaData : entityMetaDataRegistry.values()) {
            List joinColumnList = new JoinColumnMetaDataAssistant(entityMetaData).init().getJoinColumnList();

            MapperDefinition mapperDefinition = mapperDefinitionRegistry.getMapperDefinition(entityMetaData.getEntityType());

            // 用set去判断是否有重复的列，重复的列会导致结果拼接有问题
            Set columnDefinitions = new HashSet<>(covertToColumnDefinitions(entityMetaData));

            //将关联列转换成MethodDefinition，并添加至关联Mapper方法里
            for(JoinColumnMetaData joinColumnMetaData : joinColumnList) {

                // 构建ColumnDefinition
                EntityMetaData joinEntityMetaData = entityMetaDataRegistry.get(joinColumnMetaData.getJoinEntityType());
                Set joinColumnDefinitions = covertToColumnDefinitions(joinEntityMetaData);

                joinColumnDefinitions.forEach(columnDefinition -> {
                    int i = 0;
                    while(!columnDefinitions.add(columnDefinition)) {
                        columnDefinition.setColumnName(columnDefinition.getOriginalColumnName() + "_" + (++ i));
                    }
                });

                JoinStatementDefinition joinStatementDefinition = new MethodDefinitionAssistant(mapperDefinitionRegistry, joinColumnMetaData).addRelationMethodDefinition(joinColumnDefinitions);
                joinStatementDefinition.setColumnDefinitions(joinColumnDefinitions);
                // 所有关联的 定义都会保存在自己的MapperDefinition里
                mapperDefinition.addJoinStatementDefinition(joinStatementDefinition);
            }
        }

        return this;
    }

    private Set covertToColumnDefinitions(EntityMetaData entityMetaData) {
        return entityMetaData.getColumnMetaDataMap().values().stream().filter(columnMetaData -> !columnMetaData.isJoin()).map(ColumnDefinition::new).collect(Collectors.toCollection(LinkedHashSet::new));
    }

    public void invokeJpaMapperStatementBuilder() {
        for(MapperDefinition mapperDefinition : mapperDefinitionRegistry.values()) {
            JpaMapperStatementBuilder jpaMapperStatementBuilder = new JpaMapperStatementBuilder(configuration, mapperDefinition);
            jpaMapperStatementBuilder.build();
        }
    }

}