stopwatch.hpp

#pragma once

#include <format>
#include <sstream>

#include "Mountain/core.hpp"
#include "Mountain/utils/time_span.hpp"

namespace Mountain
{
    class MOUNTAIN_API Stopwatch
    {
    public:
        [[nodiscard]]
        static Stopwatch StartNew();

        [[nodiscard]]
        static int64_t GetFrequency();
        [[nodiscard]]
        static int64_t GetTimestamp();
        [[nodiscard]]
        static TimeSpan GetElapsedTime(int64_t startingTimestamp);
        [[nodiscard]]
        static TimeSpan GetElapsedTime(int64_t startingTimestamp, int64_t endingTimestamp);

        void Start();
        void Stop();
        void Reset();
        void Restart();

        GETTER(bool_t, IsRunning, m_IsRunning)

        [[nodiscard]]
        TimeSpan GetElapsed() const;
        [[nodiscard]]
        int64_t GetElapsedTicks() const;
        [[nodiscard]]
        double_t GetElapsedMilliseconds() const;
        [[nodiscard]]
        double_t GetElapsedSeconds() const;

        friend std::ostream& operator<<(std::ostream& out, const Stopwatch& stopwatch);

    private:
        static constexpr int64_t TicksPerMillisecond = 10000;
        static constexpr int64_t TicksPerSecond = TicksPerMillisecond * 1000;

        static const double_t TickFrequency;

        int64_t m_StartTimestamp = 0;
        int64_t m_Elapsed = 0;
        bool_t m_IsRunning = false;

        [[nodiscard]]
        int64_t GetRawElapsedTicks() const;
        [[nodiscard]]
        int64_t GetElapsedDateTimeTicks() const;
    };
}

template <>
struct std::formatter<Mountain::Stopwatch>
{
    template <class ParseContext>
    constexpr typename ParseContext::iterator parse(ParseContext& ctx)
    {
        auto it = ctx.begin();
        if (it == ctx.end())
            return it;

        if (*it != '}')
            throw std::format_error("Invalid format args for Mountain::Stopwatch");

        return it;
    }

    // ReSharper disable once CppMemberFunctionMayBeStatic
    template <class FormatContext>
    typename FormatContext::iterator format(const Mountain::Stopwatch& stopwatch, FormatContext& ctx) const
    {
        std::ostringstream out;

        out << stopwatch.GetElapsed();

        return std::ranges::copy(std::move(out).str(), ctx.out()).out;
    }
};