//MyClasses/Stopwatch.hpp
//Matthew Ellison
// Created: 10-30-18
//Modified: 07-09-20
//This file defines a class that can be used as a simple timer for programs
/*
	Copyright (C) 2020  Matthew Ellison

	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU Lesser General Public License as published by
	the Free Software Foundation, either version 3 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU Lesser General Public License for more details.

	You should have received a copy of the GNU Lesser General Public License
	along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/


#ifndef STOPWATCH_HPP
#define STOPWATCH_HPP


#include <chrono>
#include <sstream>
#include <iomanip>

namespace mee{
class Stopwatch{
public:
	//Create an error class
	class stopBeforeStart{};	//Used in stop() to check if you are trying to stop the stopwatch before starting it
	class timeBeforeStart{};	//Used in getTime() to check if you are trying to get a time before you start it
	class invalidTimeResolution{};	//Used to detect invalid time resolution in the getStr function
private:
	std::chrono::high_resolution_clock::time_point startTime;	//The time the start function was called
	std::chrono::high_resolution_clock::time_point endTime;		//The time the stop function was called
	bool hasStarted;	//A flag to show that start() has been called
	bool hasStopped;		//A flag to show that stop() has been called
	enum TIME_RESOLUTION {NANOSECOND, MICROSECOND, MILLISECOND, SECOND, MINUTE, HOUR, DEFAULT};
	//Return the duration in the default time period for the high_resolution_clock
	double getTime(TIME_RESOLUTION timeResolution){
		double timePassed = 0;	//Holds the amount of time that has passed
		//If the timer hasn't been stopped then record the time right now. This will simulate looping at the stopwatch while it is still running
		//I put this at the beginning to get the timestamp at close to the calling of the function as possible
		if(!hasStopped){
			endTime = std::chrono::high_resolution_clock::now();
		}
		//If the timer hasn't been started throw an exception
		if(!hasStarted){
			throw timeBeforeStart();
		}
		//Decide what resolution to make the duration
		if(timeResolution == HOUR){
			std::chrono::duration<double, std::ratio<3600LL>> dur = (endTime - startTime);
			timePassed = dur.count();
		}
		else if(timeResolution == MINUTE){
			std::chrono::duration<double, std::ratio<60LL>> dur = (endTime - startTime);
			timePassed = dur.count();
		}
		else if(timeResolution == SECOND){
			std::chrono::duration<double> dur = (endTime - startTime);
			timePassed = dur.count();
		}
		else if(timeResolution == MILLISECOND){
			std::chrono::duration<double, std::milli> dur = (endTime - startTime);
			timePassed = dur.count();
		}
		else if(timeResolution == MICROSECOND){
			std::chrono::duration<double, std::micro> dur = (endTime - startTime);
			timePassed = dur.count();
		}
		else if(timeResolution == NANOSECOND){
			std::chrono::duration<double, std::nano> dur = (endTime - startTime);
			timePassed = dur.count();
		}
		else if(timeResolution == DEFAULT){
			std::chrono::high_resolution_clock::duration dur = (endTime - startTime);
			timePassed = dur.count();
		}

		return timePassed;
	}
public:
	Stopwatch(){
		//Make sure the flags are set to false to show nothing has been called yet
		hasStarted = hasStopped = false;
		startTime = endTime = std::chrono::high_resolution_clock::time_point();	//Set the times with a blank time
	}
	~Stopwatch(){

	}
	//Set the start time and flag and make sure the stop flag is unset
	void start(){
		hasStarted = true;	//Show that the stopwatch has been started
		hasStopped = false;	//Show that the stopwatch is still running. Security in case the Stopwatch is used in multiple places
		//Put this last to ensure that the time recorded is as close to the return time as possible
		startTime = std::chrono::high_resolution_clock::now();
	}
	//Set the stop time and flag
	void stop(){
		//Put this first to ensure the time recorded is as close to the call time as possible
		std::chrono::high_resolution_clock::time_point tempTime = std::chrono::high_resolution_clock::now();
		//Make sure the stopwatch has started before you say it has stopped
		if(hasStarted){
			endTime = tempTime;	//Set the end time appropriately
			hasStopped = true;	//Show that the stop function has been called
		}
		//If the stopwatch hadn't been started throw an exception
		else{
			throw stopBeforeStart();
		}
	}
	//Return the duration in nanoseconds
	double getNano(){
		return getTime(NANOSECOND);
	}
	//Return the duration in microseconds
	double getMicro(){
		return getTime(MICROSECOND);
	}
	//Return the duration in milliseconds
	double getMilli(){
		return getTime(MILLISECOND);
	}
	//Return the duration in seconds
	double getSeconds(){
		return getTime(SECOND);
	}
	//Return the duration in minutes
	double getMinutes(){
		return getTime(MINUTE);
	}
	//Return the duration in hours
	double getHours(){
		return getTime(HOUR);
	}
	//Return the duration in the default resolution of high_resolution_clock
	double getTime(){
		return getTime(DEFAULT);
	}
	//Returns a string with the time at best resolution
	std::string getStr(){
		//Setup the variables
		return getStr(getTime(NANOSECOND));	//Holds the time that we are manipulating
	}
	//This function resets all the variables so that it can be run again
	void reset(){
		hasStarted = hasStopped = false;	//Set the flags as though nothing has happened
		endTime = startTime = std::chrono::high_resolution_clock::time_point();	//Set the times with a blank time
	}
	friend std::ostream& operator<<(std::ostream& out, Stopwatch& timer);

	static std::string getStr(double nanoseconds){
		//Setup the variables
		double tempTime = nanoseconds;	//Holds the time that we are manipulating
		std::stringstream timeStr;

		//Decide what time resolution would be best. Looking for the format of XXX.XXX
		int timeRes = NANOSECOND;
		for(timeRes = NANOSECOND;(timeRes < SECOND) && (tempTime >= 1000);++timeRes){
			tempTime /= 1000;
		}

		//Check if the resolution is seconds and if there are more than 120 seconds
		if((timeRes == SECOND) && (tempTime >= 120)){
			++timeRes;
			tempTime /= 60;
		}
		//Check if the resolution is minutes and if there are more than 120 minutes
		if((timeRes == MINUTE) && (tempTime >= 120)){
			++timeRes;
			tempTime /= 60;
		}

		//Put the number in the string
		timeStr << std::fixed << std::setprecision(3) << tempTime << ' ';

		//From the timeRes variable decide what word should go on the end of the string
		switch(timeRes){
			case HOUR: timeStr << "hours"; break;
			case MINUTE: timeStr << "minutes"; break;
			case SECOND: timeStr << "seconds"; break;
			case MILLISECOND: timeStr << "milliseconds"; break;
			case MICROSECOND: timeStr << "microseconds"; break;
			case NANOSECOND: timeStr << "nanoseconds"; break;
			case DEFAULT: timeStr << "time"; break;
			default: throw invalidTimeResolution();	//This should never be hit with this code, but it's good to have all the bases covered
		}

		//Return the string
		return timeStr.str();
	}
};	//end class Stopwatch
std::ostream& operator<<(std::ostream& out, Stopwatch& timer){
	out << timer.getStr();
	bool num = timer.hasStopped;
	return out;
}
}	//end namespace mee

#endif //end STOPWATCH_HPP