Scheduler.cpp

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#include <VoltMod/Core/Time/Durations.hpp>
#include <VoltMod/Core/Time/Scheduler.hpp>
#include <utility>
 
namespace VoltMod
{
 
int64_t Scheduler::GetCurrentTimeMs() const
{
    return Time::MonotonicMs();
}
 
Subscription Scheduler::AddTimer(int64_t nextFireTime, int64_t interval, std::function<void()> callback)
{
    const uint64_t id = _timers.Add({nextFireTime, interval, std::move(callback), 0});
    _timers.Find(id)->Id = id;
    return Subscription([this, id] { _timers.Remove(id); });
}
 
Subscription Scheduler::Delay(int64_t delayMs, std::function<void()> callback)
{
    return AddTimer(GetCurrentTimeMs() + delayMs, 0, std::move(callback));
}
 
Subscription Scheduler::Repeat(int64_t intervalMs, std::function<void()> callback)
{
    return AddTimer(GetCurrentTimeMs() + intervalMs, intervalMs, std::move(callback));
}
 
Subscription Scheduler::NextTick(std::function<void()> callback)
{
    return Delay(0, std::move(callback));
}
 
Subscription Scheduler::EveryFrame(std::function<void()> callback)
{
    // -1 repeats every frame, 0 is one-shot, and positive values wait between calls.
    return AddTimer(0, -1, std::move(callback));
}
 
void Scheduler::OnGameFrame()
{
    const int64_t now = GetCurrentTimeMs();
 
    // Timers added by a callback start next frame.
    _timers.DispatchIf([now](const Timer& timer) { return now >= timer.NextFireTime; },
                       [this, now](Timer& timer) {
                           if (timer.Callback)
                           {
                               timer.Callback();
                           }
 
                           // The callback may have cancelled this timer.
                           if (!_timers.Find(timer.Id))
                           {
                               return;
                           }
 
                           if (timer.Interval > 0)
                           {
                               timer.NextFireTime = now + timer.Interval;
                           }
                           else if (timer.Interval < 0)
                           {
                               timer.NextFireTime = now;  // repeat on the next frame
                           }
                           else
                           {
                               _timers.Remove(timer.Id);
                           }
                       });
}
 
}  // namespace VoltMod