#include "World/WorldMapSubsystem.h"

#include "Core/TelemetrySubsystem.h"
#include "Engine/AssetManager.h"
#include "Engine/Engine.h"
#include "Engine/GameInstance.h"
#include "Engine/World.h"
#include "GameFramework/Pawn.h"
#include "GameFramework/PlayerController.h"
#include "Salty.h"
#include "Telemetry/TelemetryEvent.h"
#include "Telemetry/TelemetryEvents.h"
#include "World/WorldMapDefinition.h"

bool UWorldMapSubsystem::ShouldCreateSubsystem(UObject* Outer) const
{
	if (!Super::ShouldCreateSubsystem(Outer))
	{
		return false;
	}
	// Game and PIE worlds only. An editor preview world or a thumbnail scene has no map and no one to show it to.
	const UWorld* World = Cast<UWorld>(Outer);
	return World && (World->IsGameWorld());
}

void UWorldMapSubsystem::Deinitialize()
{
	Markers.Reset();
	OnMarkersChanged.Clear();
	Definition = nullptr;
	bResolved = false;
	Super::Deinitialize();
}

void UWorldMapSubsystem::ResolveDefinition() const
{
	bResolved = true;
	Definition = nullptr;

	const UWorld* World = GetWorld();
	if (!World)
	{
		return;
	}

	// PIE renames the level package (/Game/Maps/UEDPIE_0_L_World), so the definition's own path would never
	// match what the world says it is. Strip it, or the map works in a cooked build and not in the editor.
	const FString LevelPackage = UWorld::RemovePIEPrefix(World->GetOutermost()->GetName());

	// IsInitialized, not IsValid: the manager is always constructed now and IsValid is deprecated for saying
	// so. The guard stays because this can be reached before UEngine::InitializeObjectReferences has run.
	if (!UAssetManager::IsInitialized())
	{
		return;
	}
	UAssetManager& Manager = UAssetManager::Get();

	TArray<FPrimaryAssetId> Ids;
	Manager.GetPrimaryAssetIdList(UWorldMapDefinition::AssetType, Ids);
	if (Ids.Num() == 0)
	{
		UE_LOG(LogSalty, Verbose,
			TEXT("World map: no %s assets are registered. Add a PrimaryAssetTypesToScan entry in DefaultGame.ini "
			     "and run Scripts/Authoring/build_world_map.sh."),
			*UWorldMapDefinition::AssetType.ToString());
		return;
	}

	for (const FPrimaryAssetId& Id : Ids)
	{
		const FSoftObjectPath Path = Manager.GetPrimaryAssetPath(Id);
		// Synchronous, because this happens once when a map is first opened and an asynchronous load would
		// mean a frame of blank map for no gain.
		const UWorldMapDefinition* Candidate = Cast<UWorldMapDefinition>(Path.TryLoad());
		if (Candidate && Candidate->Level.GetLongPackageName() == LevelPackage)
		{
			Definition = Candidate;
			UE_LOG(LogSalty, Log, TEXT("World map: %s covers %s - %s"),
				*Id.ToString(), *LevelPackage, *Candidate->Projection.ToString());
			return;
		}
	}

	// Deliberately not "fall back to the only one there is". L_Gym showing L_World's map would be a map that
	// lies about where you are, which is worse than no map.
	UE_LOG(LogSalty, Verbose, TEXT("World map: none of the %d definitions is a map of %s."), Ids.Num(), *LevelPackage);
}

const UWorldMapDefinition* UWorldMapSubsystem::GetDefinition() const
{
	if (!bResolved)
	{
		ResolveDefinition();
	}
	return Definition;
}

FGuid UWorldMapSubsystem::AddMarker(const FWorldMapMarker& Marker)
{
	const FGuid Handle = FGuid::NewGuid();
	Markers.Add(Handle, Marker);
	OnMarkersChanged.Broadcast();
	return Handle;
}

bool UWorldMapSubsystem::UpdateMarker(const FGuid& Handle, const FWorldMapMarker& Marker)
{
	if (FWorldMapMarker* Existing = Markers.Find(Handle))
	{
		*Existing = Marker;
		OnMarkersChanged.Broadcast();
		return true;
	}
	return false;
}

bool UWorldMapSubsystem::RemoveMarker(const FGuid& Handle)
{
	if (Markers.Remove(Handle) > 0)
	{
		OnMarkersChanged.Broadcast();
		return true;
	}
	return false;
}

void UWorldMapSubsystem::NoteMapOpened(FName LayerId, float MetresPerPixel, const FString& OpenedBy)
{
	const UWorld* World = GetWorld();
	const UGameInstance* GameInstance = World ? World->GetGameInstance() : nullptr;
	UTelemetrySubsystem* Telemetry = GameInstance ? GameInstance->GetSubsystem<UTelemetrySubsystem>() : nullptr;
	if (!Telemetry)
	{
		return;
	}
	Telemetry->Emit(TelemetryEvents::WorldMapOpened, FTelemetryPayload()
		.Set(TEXT("layer"), LayerId)
		.Set(TEXT("metres_per_pixel"), MetresPerPixel)
		.Set(TEXT("opened_by"), OpenedBy));
}

bool UWorldMapSubsystem::GetLocalPlayerMarker(FWorldMapMarker& OutMarker) const
{
	const UWorld* World = GetWorld();
	const APlayerController* Controller = World ? World->GetFirstPlayerController() : nullptr;
	if (!Controller)
	{
		return false;
	}

	// The spectator counts: someone flying the level with no pawn is still somewhere, and that is exactly when
	// a map is most useful.
	const AActor* Body = Controller->GetPawnOrSpectator();
	if (!Body)
	{
		Body = Controller->GetViewTarget();
	}
	if (!Body)
	{
		return false;
	}

	OutMarker = FWorldMapMarker();
	OutMarker.WorldLocation = Body->GetActorLocation();
	OutMarker.Shape = EWorldMapMarkerShape::Arrow;
	OutMarker.Colour = FLinearColor(1.f, 0.95f, 0.35f);
	OutMarker.SizePx = 13.f;
	OutMarker.HeadingDegrees = static_cast<float>(Controller->GetControlRotation().Yaw);
	return true;
}