package com.java110.db;

import org.apache.commons.collections4.CollectionUtils;
import org.apache.ibatis.executor.statement.StatementHandler;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.plugin.*;
import org.apache.ibatis.reflection.MetaObject;
import org.apache.ibatis.reflection.SystemMetaObject;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;

import java.beans.Statement;
import java.lang.reflect.Proxy;
import java.util.*;

@Intercepts({
        @Signature(type = StatementHandler.class, method = "update", args = {Statement.class}),
        @Signature(type = StatementHandler.class, method = "query", args = {Statement.class}),
        @Signature(type = StatementHandler.class, method = "batch", args = {Statement.class})
})

public class Java110MybatisInterceptor implements Interceptor {
    private static Logger logger = LoggerFactory.getLogger(Java110MybatisInterceptor.class);

    @Override
    public Object intercept(Invocation invocation) throws Throwable {
        Statement statement;
        //获取方法参数
        Object firstArg = invocation.getArgs()[0];
        if (Proxy.isProxyClass(firstArg.getClass())) {
            statement = (Statement) SystemMetaObject.forObject(firstArg).getValue("h.statement");
        } else {
            statement = (Statement) firstArg;
        }
        MetaObject stmtMetaObj = SystemMetaObject.forObject(statement);
        //获取Statement对象（sql语法已经构建完毕）
        statement = (Statement) stmtMetaObj.getValue("stmt.statement");
        //获取sql语句
        String originalSql = statement.toString();

        //将原始sql中的空白字符（\s包括换行符，制表符，空格符）替换为" "
        originalSql = originalSql.replaceAll("[\\s]+", " ");

        //只获取sql的select/update/insert/delete开头的sql
        int index = indexOfSqlStart(originalSql);
        if (index > 0) {
            originalSql = originalSql.substring(index);
        }

        // 计算执行 SQL 耗时
        long start = System.currentTimeMillis();
        Object result = invocation.proceed();
        long timing = System.currentTimeMillis() - start;

        //获取MapperStatement对象，获取到sql的详细信息
        Object realTarget = realTarget(invocation.getTarget());
        //获取metaObject对象
        MetaObject metaObject = SystemMetaObject.forObject(realTarget);
        //获取MappedStatement对象
        MappedStatement ms = (MappedStatement) metaObject.getValue("delegate.mappedStatement");
        StringBuilder formatSql = new StringBuilder()
                .append(" Time：").append(timing)
                //获取Mapper信息和方法信息
                .append(" ms - ID：").append(ms.getId())
                .append("Execute SQL：")
                .append(originalSql);
        //打印sql信息
        logger.debug(formatSql.toString());
        return result;
    }

    @Override
    public Object plugin(Object target) {
        if (target instanceof StatementHandler) {

            return Plugin.wrap(target, this);
        }
        return target;
    }

    @Override
    public void setProperties(Properties properties) {

    }

    /**
     * 获取sql语句开头部分
     *
     * @param sql
     * @return
     */
    private int indexOfSqlStart(String sql) {
        String upperCaseSql = sql.toUpperCase();
        Set<Integer> set = new HashSet<>();
        set.add(upperCaseSql.indexOf("SELECT "));
        set.add(upperCaseSql.indexOf("UPDATE "));
        set.add(upperCaseSql.indexOf("INSERT "));
        set.add(upperCaseSql.indexOf("DELETE "));
        set.remove(-1);
        if (CollectionUtils.isEmpty(set)) {
            return -1;
        }
        List<Integer> list = new ArrayList<>(set);
        list.sort(Comparator.naturalOrder());
        return list.get(0);
    }

    /**
     * <p>
     * 获得真正的处理对象,可能多层代理.
     * </p>
     */
    @SuppressWarnings("unchecked")
    public static <T> T realTarget(Object target) {
        if (Proxy.isProxyClass(target.getClass())) {
            MetaObject metaObject = SystemMetaObject.forObject(target);
            return realTarget(metaObject.getValue("h.target"));
        }
        return (T) target;
    }
}