package com.changhong.epc.config.tool;

import com.iemsoft.framework.cloud.core.tools.ObjectUtil;

import java.util.HashSet;
import java.util.Set;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * 权限过滤工具类
 */
public class PowerFilterTool {

    /**
     * 查询表名正则
     */
    public static final Pattern FORM_TABLE_REGEX    = Pattern.compile("((?i)from)\\s+\\S+");

    /**
     * form 关键字 正则
     */
    public static final Pattern FORM_REGEX          = Pattern.compile("((?i)from)\\s+");

    /**
     * 是不是查询语句
     * @param sql
     * @return
     */
    public static boolean isSelect(String sql){
        if(ObjectUtil.empty(sql)){
            return Boolean.FALSE;
        }
        sql = sql.trim();
        return sql.matches("^((?i)select).+");
    }

    /**
     * 查询select的所以表
     * @param sql
     * @return
     */
    public static Set<String> getSelectTables(String sql){
        Matcher matcher = FORM_TABLE_REGEX.matcher(sql);
        Set<String> talbes = new HashSet<>();
        String tableName;
        while (matcher.find()){
            tableName = FORM_REGEX.matcher(matcher.group()).replaceAll("");
            tableName = tableName.replace(")", "");
            // 子表单不控制
            if(tableName.split("_").length != 4) {
                talbes.add(tableName);
            }
        }
        return talbes;
    }

}