package com.xzx.gc.batch;

import org.apache.ibatis.mapping.MappedStatement;
import tk.mybatis.mapper.entity.EntityColumn;
import tk.mybatis.mapper.mapperhelper.EntityHelper;
import tk.mybatis.mapper.mapperhelper.MapperHelper;
import tk.mybatis.mapper.mapperhelper.SqlHelper;
import tk.mybatis.mapper.provider.ExampleProvider;

import java.util.Set;

/**
 * 批量更新的SqlProvider
 * @author sunchangtan
 */

public class BatchInsertExampleProvider extends ExampleProvider {

    public BatchInsertExampleProvider(Class<?> mapperClass, MapperHelper mapperHelper) {
        super(mapperClass, mapperHelper);
    }


    /**
     * 拼update sql, 使用case when方式，id为主键
     *
     * @param ms
     * @return
     */
    public String insertBatchByPrimaryKeySelective(MappedStatement ms) {
        final Class<?> entityClass = getEntityClass(ms);
        //开始拼sql
        StringBuilder sql = new StringBuilder();
        sql.append(SqlHelper.insertIntoTable(entityClass, tableName(entityClass), "list[0]"));
        sql.append(SqlHelper.insertColumns(entityClass, false, false, false));
        sql.append(" VALUES ");
        sql.append("<foreach collection=\"list\" item=\"record\" separator=\",\" >");
        sql.append("<trim prefix=\"(\" suffix=\")\" suffixOverrides=\",\">");
        //获取全部列
        Set<EntityColumn> columnList = EntityHelper.getColumns(entityClass);
        //当某个列有主键策略时，不需要考虑他的属性是否为空，因为如果为空，一定会根据主键策略给他生成一个值
        for (EntityColumn column : columnList) {
                sql.append(column.getColumnHolder("record") + ",");
        }
        sql.append("</trim>");
        sql.append("</foreach>");

        return sql.toString();
    }


}