package com.finance.common.utils;

import java.util.HashMap;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.apache.commons.jexl3.JexlBuilder;
import org.apache.commons.jexl3.JexlContext;
import org.apache.commons.jexl3.JexlEngine;
import org.apache.commons.jexl3.JexlExpression;
import org.apache.commons.jexl3.MapContext;

/**
 * @author mitao
 * @date 2024/3/27
 */
public class CalculateUtil {

    public static Map<String, Integer> getFieldsAndValue(String rule) {
        // 正则表达式模式，匹配形如 "fieldName:value" 的字符串
        Pattern pattern = Pattern.compile("\\b(\\w+)_(\\d+)\\b");
        Matcher matcher = pattern.matcher(rule);
        Map<String, Integer> map = new HashMap<>();
        // 循环匹配并输出字段名和值
        while (matcher.find()) {
            String fieldName = matcher.group(1);
            int value = Integer.parseInt(matcher.group(2));
            map.put(fieldName + "_" + value, value);
        }
        return map;
    }

    public static double calculate(String expression, Map<String, Object> value) {
        
        expression = formatExpression(expression);
        // 创建 JEXL 引擎
        JexlEngine jexl = new JexlBuilder().create();

        // 创建表达式对象
        JexlExpression exp = jexl.createExpression(expression);
        // 创建上下文
        JexlContext context = new MapContext();
        for (Map.Entry<String, Object> stringObjectEntry : value.entrySet()) {
            context.set(stringObjectEntry.getKey(), stringObjectEntry.getValue());
        }
        // 执行计算
        Object result = exp.evaluate(context);

        // 输出结果
        System.out.println("Result: " + result);
        return Double.parseDouble(result.toString());
    }

    public static double calculate(String expression) {
        // 创建 JEXL 引擎
        JexlEngine jexl = new JexlBuilder().create();

        // 创建表达式对象
        JexlExpression exp = jexl.createExpression(expression);
        // 创建上下文
        JexlContext context = new MapContext();
        // 执行计算
        Object result = exp.evaluate(context);

        // 输出结果
        System.out.println("Result: " + result);
        return Double.parseDouble(result.toString());
    }

    public static String formatExpression(String expression) {
        return expression
                .replaceAll("×", "*")
                .replaceAll("÷", "/")
                .replaceAll("（", "(")
                .replaceAll("）", ")")
                .replaceAll("＋", "+")
                .replaceAll("－", "-");
    }

    public static void main(String[] args) {
        String string = "field_3 * field_2";
        System.out.println(getFieldsAndValue(string));
    }
}