#include "TriggeredTask.h"

FTriggeredTask::FTriggeredTask() {
	Client = nullptr;
	Thread = nullptr;
	ThreadStopRequested = false;
	CallEvent = nullptr;
	ReturnEvent = nullptr;
}

uint32 FTriggeredTask::Run() {
	while (true)
	{
		CallEvent->Wait();
		if (ThreadStopRequested) {
			break;
		}
		// The payload.
		Client->Run();
		ReturnEvent->Trigger();
	}
	return 0;
}

void FTriggeredTask::Startup(FRunnable *client) {
	FScopeLock lock(&Mutex);
	if (Thread == nullptr) {
		Client = client;
		CallEvent = FPlatformProcess::GetSynchEventFromPool(true);
		ReturnEvent = FPlatformProcess::GetSynchEventFromPool(false);
		ReturnEvent->Trigger();
		Thread = FRunnableThread::Create(this, TEXT("Worker Thread"));
	}
}

void FTriggeredTask::Shutdown() {
	FScopeLock lock(&Mutex);
	if (Thread != nullptr) {
		ReturnEvent->Wait();
		ThreadStopRequested = true;
		CallEvent->Trigger();
		delete Thread; // This waits for the thread to complete.
		Thread = nullptr;
		FPlatformProcess::ReturnSynchEventToPool(CallEvent);
		FPlatformProcess::ReturnSynchEventToPool(ReturnEvent);
		CallEvent = nullptr;
		ReturnEvent = nullptr;
	}
	ThreadStopRequested = false;
}

void FTriggeredTask::Trigger() {
	FScopeLock lock(&Mutex);
	if (Thread != nullptr) {
		ReturnEvent->Reset();
		CallEvent->Trigger();
	}
}

void FTriggeredTask::Wait() {
	FScopeLock lock(&Mutex);
	if (Thread != nullptr) {
		ReturnEvent->Wait();
	}
}

bool FTriggeredTask::IsRunning() {
	FScopeLock lock(&Mutex);
	return (Thread != nullptr);
}