package com.micro.bench;

import javassist.ClassPool;
import javassist.CtClass;
import javassist.CtNewMethod;

interface Evaluator {
    public double eval(double x);
}

abstract class Fight {

    private int steps;
    private int loops;

    public Fight(int loops, int steps) {
        this.loops = loops;
        this.steps = steps;
    }

    public abstract Object step(Timer timer);

    public void loop(Timer timer) {
        for (int j = 0; j < steps; ++j) {
            step(timer);
        }
    }

    public void fight() {
        Timer statistics = new Timer();
        for (int i = 0; i < loops; i++) {
            loop(statistics);
            statistics.flush();
            System.out.println(statistics);
        }
    }
}

public class Evaluation extends Fight {

    private static final int MAX = 1000000;

    private Evaluator runtime;
    private Evaluator compileTime;

    public Evaluation(int loops, int steps) {
        super(loops, steps);
        init();
    }

    public void init() {

        try {

            ClassPool pool = ClassPool.getDefault();

            CtClass evalClass = pool.makeClass("Formula");
            evalClass.setInterfaces(
                    new CtClass[]{
                            pool.makeClass("com.micro.bench.Evaluator")
                    });

            String expession = "x * x + x / 2";

            evalClass.addMethod(
                    CtNewMethod.make(
                            "public double eval (double x) { return (" + expession + ") ; }",
                            evalClass));

            Class clazz = evalClass.toClass();
            runtime = (Evaluator) clazz.newInstance();
        } catch (Exception e) {
            e.printStackTrace();
        }

        compileTime = new Evaluator() {
            public double eval(double x) {
                return x * x + x / 2;
            }
        };
    }

    public Object step(Timer timer) {

        timer.start("runtime calc");
        double result = 0;
        for (int i1 = 0; i1 < MAX; i1++) {
            result += runtime.eval(i1);
        }
        timer.stop();

        double i = result;

        timer.start("compile-time calc");
        double result11 = 0;
        for (int i1 = 0; i1 < MAX; i1++) {
            result11 += compileTime.eval(i1);
        }
        timer.stop();

        return i + result11;
    }

    public static void main(String[] args) throws Exception {
        new Evaluation(20, 100).fight();
    }
}