#pragma once

#include "Common/Pure.hpp"
#include "Common/Sizes.hpp"

namespace MC {

class Time {
public:
    // TODO: Document exact units of types.
    using Timestamp = U64;
    using Tick = U64;
    // TODO: Create `Time::Duration` type.

    Time() = default;

    void start_frame();
    void end_frame();

    // The total number of frames that have been rendered.
    // Starts at 1, with 0 being reserved as the empty value.
    PURE U64 total_frames() const;
    // The current frame number.
    // Starts at 1, with 0 being reserved as the empty value.
    // This is the same as total_frames(), but is more descriptive, sometimes.
    // :)
    PURE Tick tick() const;
    // The time in seconds that has passed since the last frame.
    // This is always a value between `0.001` and `0.1`.
    PURE Real delta() const;
    // The time in seconds that has passed since the last frame.
    // Unlike `delta()`, this value is not clamped, and can be any positive value.
    PURE Real delta_raw() const;

    PURE Timestamp frame_start() const;

    static Timestamp now();

private:
    static constexpr Real delta_max = 1.0 / 10.0;
    static constexpr Real delta_min = 1.0 / 1000.0;

    U64 m_total_frames = 1;

    Timestamp m_current_frame_start = 0;
    Real m_delta = 0;
};

}