// Author:   Tong Qin               qintonguav@gmail.com
// 	         Shaozu Cao 		    saozu.cao@connect.ust.hk

#pragma once

#include <ctime>
#include <iostream>
#include <string>
#include <cstdlib>
#include <chrono>

class TicToc
{
public:
    TicToc()
    {
        tic();
    }

    TicToc( bool _disp )
    {
        disp_ = _disp;
        tic();
    }

    void tic()
    {
        start = std::chrono::system_clock::now();
    }

    void toc( std::string _about_task )
    {
        end = std::chrono::system_clock::now();
        std::chrono::duration<double> elapsed_seconds = end - start;
        double elapsed_ms = elapsed_seconds.count() * 1000;

        if( disp_ )
        {
          std::cout.precision(3); // 10 for sec, 3 for ms 
          std::cout << _about_task << ": " << elapsed_ms << " msec." << std::endl;
        }
    }

private:  
    std::chrono::time_point<std::chrono::system_clock> start, end;
    bool disp_ = false;
};