// Copyright Epic Games, Inc. All Rights Reserved.

#pragma once

#include "CoreMinimal.h"
#include "HAL/PlatformTime.h"

// Simple stopwatch.
struct FStopwatch
{
    uint64 AccumulatedTime = 0;
    uint64 StartTime       = 0;
    bool bIsStarted        = false;

    void Start()
    {
        if (!bIsStarted)
        {
            bIsStarted = true;
            StartTime  = FPlatformTime::Cycles64();
        }
    }

    void Stop()
    {
        if (bIsStarted)
        {
            bIsStarted = false;
            AccumulatedTime += FPlatformTime::Cycles64() - StartTime;
        }
    }

    void Update()
    {
        if (bIsStarted)
        {
            uint64 CrtTime = FPlatformTime::Cycles64();
            AccumulatedTime += CrtTime - StartTime;
            StartTime = CrtTime;
        }
    }

    void Restart()
    {
        AccumulatedTime = 0;
        bIsStarted      = true;
        StartTime       = FPlatformTime::Cycles64();
    }

    void Reset()
    {
        AccumulatedTime = 0;
        StartTime       = 0;
        bIsStarted      = false;
    }

    double GetAccumulatedTime() const
    {
        return FStopwatch::Cycles64ToSeconds(AccumulatedTime);
    }

    uint64 GetAccumulatedTimeMs() const
    {
        return FStopwatch::Cycles64ToMilliseconds(AccumulatedTime);
    }

    static double Cycles64ToSeconds(const uint64 Cycles64)
    {
        return static_cast<double>(Cycles64) * FPlatformTime::GetSecondsPerCycle64();
    }

    static uint64 Cycles64ToMilliseconds(const uint64 Cycles64)
    {
        const double Milliseconds = FMath::RoundToDouble(static_cast<double>(Cycles64 * 1000) * FPlatformTime::GetSecondsPerCycle64());
        return static_cast<uint64>(Milliseconds);
    }
};