// Fill out your copyright notice in the Description page of Project Settings.


#include "AsyncTraceActor.h"



// Sets default values
AAsyncTraceActor::AAsyncTraceActor()
{
 	// Set this actor to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
	PrimaryActorTick.bCanEverTick = true;

}

// Called when the game starts or when spawned
void AAsyncTraceActor::BeginPlay()
{
 Super::BeginPlay();   TraceDelegate.BindUObject(this,&AAsyncTraceActor::OnTraceCompleted);
}

// Called every frame

void AAsyncTraceActor::OnTraceCompleted(const FTraceHandle& Handle, FTraceDatum& Data)
{
    ensure(Handle == LastTraceHandle);
    DoWorkWithTraceResults(Data);
    LastTraceHandle._Data.FrameNumber = 0; // reset it
}

void AAsyncTraceActor::DoWorkWithTraceResults(const FTraceDatum& TraceData)
{
    // do things here
    ReceiveOnTraceCompleted(TraceData.OutHits);
}

FTraceHandle AAsyncTraceActor::RequestTrace()
{
    UWorld* World = GetWorld();
    if (World == nullptr)
        return FTraceHandle();

    auto Channel = UEngineTypes::ConvertToCollisionChannel(MyTraceType);
    FCollisionObjectQueryParams ObjectQueryParams(Channel);

    bool bTraceComplex = false;
    bool bIgnoreSelf = true;
    TArray<AActor*> ActorsToIgnore;
    
    auto Params = UKismetSystemLibrary::ConfigureCollisionParams(NAME_AsyncRequestTrace, bTraceComplex, ActorsToIgnore, bIgnoreSelf, this);
    auto Start = FVector::ZeroVector;
    auto End = FVector(1000.f);
    return World->AsyncLineTraceByChannel(EAsyncTraceType::Single, 
        Start, End, 
        Channel, 
        Params,
        FCollisionResponseParams::DefaultResponseParam, 
        &TraceDelegate);
}

void AAsyncTraceActor::SetWantsTrace()
{
    // don't allow overlapping traces here.
    if (!GetWorld()->IsTraceHandleValid(LastTraceHandle,false))
    {
        bWantsTrace = true;
    }
}

void AAsyncTraceActor::Tick(float DeltaTime)
{
    Super::Tick(DeltaTime);
    if (LastTraceHandle._Data.FrameNumber != 0)
    {
        FTraceDatum OutData;
        if (GetWorld()->QueryTraceData(LastTraceHandle, OutData))
        {
            // Clear out handle so next tick we don't enter
            LastTraceHandle._Data.FrameNumber = 0;
            // trace is finished, do stuff with results
            DoWorkWithTraceResults(OutData);
        }
    }

    if (bWantsTrace)
    {
        LastTraceHandle = RequestTrace();
        bWantsTrace = false;
    }
}