package org.yeshi.utils;

import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.core.DefaultParameterNameDiscoverer;
import org.springframework.expression.EvaluationContext;
import org.springframework.expression.Expression;
import org.springframework.expression.ExpressionParser;
import org.springframework.expression.spel.standard.SpelExpressionParser;
import org.springframework.expression.spel.support.StandardEvaluationContext;

public class SPELExpressionUtil {
    private static ExpressionParser parser = new SpelExpressionParser();

    public static String generateKeyBySpEL(String spELString, ProceedingJoinPoint joinPoint) {
        DefaultParameterNameDiscoverer nameDiscoverer = new DefaultParameterNameDiscoverer();
        MethodSignature methodSignature = (MethodSignature) joinPoint.getSignature();
        String[] paramNames = nameDiscoverer.getParameterNames(methodSignature.getMethod());
        Expression expression = parser.parseExpression(spELString);
        EvaluationContext context = new StandardEvaluationContext();
        Object[] args = joinPoint.getArgs();
        for (int i = 0; i < args.length; i++) {
            context.setVariable(paramNames[i], args[i]);
        }
        return expression.getValue(context).toString();
    }

}