// Copyright Epic Games, Inc. All Rights Reserved.

#include "LuprexGameModeBase.h"
#include "lpx-drvutil.hpp"
#include "lpx-paths.hpp"
#include "ConsoleOutput.h"
#include "Tangible.h"
#include "TangibleManager.h"
#include "LuaCall.h"
#include "Blueprint/UserWidget.h"
#include "Blueprint/WidgetBlueprintLibrary.h"
#include "Kismet/GameplayStatics.h"

#include "CommonTypes.h"
#include "AnimQueue.h"
#include <string>
#include <string_view>

using namespace CommonTypes;

DEFINE_LOG_CATEGORY(LogLuprex);
DEFINE_LOG_CATEGORY(LogLuprexIntegration);

ALuprexGameModeBase::ALuprexGameModeBase()
{
	TangibleManager = nullptr;
	AssetLookup = nullptr;
	PlayerId = 0;
	EngineSeconds = 0.0;
	MustCallLookAtChanged = false;
	//PrimaryActorTick.bCanEverTick = true; // Probably wrong
	//PrimaryActorTick.bTickEvenWhenPaused = true; // Probably wrong
	//PrimaryActorTick.TickGroup = TG_PrePhysics; // Probably wrong
	SetActorTickEnabled(true);
	SetActorTickInterval(0.0f);
	ResetToInitialState();
	OnWorldPreActorTickHandle = FWorldDelegates::OnWorldPreActorTick.AddUObject(this, &ALuprexGameModeBase::OnWorldPreActorTick);
	OnWorldPostActorTickHandle = FWorldDelegates::OnWorldPostActorTick.AddUObject(this, &ALuprexGameModeBase::OnWorldPostActorTick);
}

ALuprexGameModeBase::~ALuprexGameModeBase()
{
	ResetToInitialState();
	FWorldDelegates::OnWorldPreActorTick.Remove(OnWorldPreActorTickHandle);
	FWorldDelegates::OnWorldPostActorTick.Remove(OnWorldPostActorTickHandle);
}

// This method runs in the background thread,
// at the moment we trigger it.
//
uint32 ALuprexGameModeBase::Run() {
	FlxLockedWrapper lockedwrap(LockableWrapper);
	Sockets->Update(lockedwrap);
	lockedwrap->play_update(lockedwrap.Get(), EngineSeconds);
	Sockets->Update(lockedwrap);
	return 0;
}

void ALuprexGameModeBase::ResetToInitialState()
{
	Playing = false;

	if (TangibleManager != nullptr) {
		TangibleManager->ConditionalBeginDestroy();
		TangibleManager = nullptr;
	}

	if (AssetLookup != nullptr) {
		AssetLookup->ConditionalBeginDestroy();
		AssetLookup = nullptr;
	}

	// Shut down the thread
	LuprexUpdateTask.Shutdown();

	// Now that the thread's gone, we should be able to
	// just claim and hold the lock on the wrapper.
	FlxLockedWrapper w(LockableWrapper);

	// Release and close all sockets.
	if (Sockets != nullptr)
	{
		Sockets->ForceCloseEverything(w);
		Sockets.Reset();
	}

	// Delete the engine.
	if (w->release != nullptr)
	{
		w->release(w.Get());
	}

	// Stop trapping log errors to the debugger.
	BreakToDebuggerLogVerbosityDevice.Reset();

	// Clear the lua call assembly buffer.
	LuaCallBuffer.clear();

	// Clear the PlayerID
	PlayerId = 0;

	// Clear the look-at state;
	CurrentLookAt.Init();
	MustCallLookAtChanged = false;
	
	// Reset the clocks.
	EngineSeconds = 0.0;
	NextRotateCube = 1.0;
}


void ALuprexGameModeBase::UpdateConsoleOutput() {
	// Copy Luprex Stdout into the console.
	FlxLockedWrapper lockedwrap(LockableWrapper);
	if (Playing) {
		ConsoleOutput.Append(lockedwrap.FetchStdout());
	}

	// If the Console text has changed, update the widget.
	if (ConsoleOutput.IsDirty()) {
		ConsoleSetOutput(ConsoleOutput.Get());
		ConsoleOutput.ClearDirty();
	}
}

#pragma optimize("", off)
void ALuprexGameModeBase::UpdateTangibles() {
	double radius = 1000.0; // Hardwired for now.
	using TanArray = UlxTangibleManager::TanArray;
	if (!Playing) return;
	TanArray alltans;
	{
		FlxLockedWrapper w(LockableWrapper);
		PlayerId = w.GetActor();
		IdView nearids = w.GetNear(PlayerId, radius, radius, radius);
		TangibleManager->UpdateNearAccordingToLuprex(nearids);
		alltans = TangibleManager->GetAllTangibles();
		IdArray allids = TangibleManager->GetIds(alltans);
		StringViewVec allqueues = w.GetAnimationQueues(allids);
		for (int i = 0; i < alltans.Num(); i++) {
			alltans[i]->UpdateAnimationQueue(allqueues[i]);
		}
	}
	// This is where we run the blueprint code that updates animation
	// states.  Be aware that the blueprint code could call back
	// into the gamemode, which could in turn access the FlxLockedWrapper.
	// This is why we've released the FlxLockedWrapper before doing this.
	for (int i = 0; i < alltans.Num(); i++) {
		alltans[i]->MaybeExecuteAnimStateChanged();
	}
	TangibleManager->RecalcNearAccordingToUnreal(PlayerId, radius);
	TangibleManager->DeleteFarawayTangibles();
}

void ALuprexGameModeBase::UpdatePossessedTangible() {
	UlxTangible *ptan = TangibleManager->GetPossessedTangible();
	UlxTangible *tan = TangibleManager->GetTangible(PlayerId);
	APlayerController *ctrl = GetWorld()->GetFirstPlayerController();
	APawn *pawn = nullptr;
	if (tan != nullptr) pawn = Cast<APawn>(tan->GetActor());
	if (pawn == nullptr) {
		if (ptan != nullptr) {
			TangibleManager->SetPossessedTangible(nullptr);
			ctrl->Possess(nullptr);
		}
	} else {
		if (ptan != tan) {
			TangibleManager->SetPossessedTangible(tan);
			ctrl->Possess(pawn);
		}
	}	
}

UlxLuaValues *ALuprexGameModeBase::LuaCallEnd(InvocationKind kind, int64 place_id) {
	std::string_view datapk = LuaCallBuffer.view();
	FlxLockedWrapper w(LockableWrapper);
	if (place_id == 0) place_id = w.GetActor();
	uint32_t retpklen;
	const char *retpk;
	w->play_call_function(w.Get(), kind, place_id, datapk.size(), datapk.data(), &retpklen, &retpk);
	if (kind == InvocationKind::LUA_PROBE)
	{
		UlxLuaValues *Result = NewObject<UlxLuaValues>(this);
		Result->Initialize(std::string_view(retpk, retpklen));
		return Result;
	}
	else return nullptr;
}

UlxLuaValues *ALuprexGameModeBase::LuaCallEnd(InvocationKind kind) {
	return LuaCallEnd(kind, int64(0));
}

UlxLuaValues *ALuprexGameModeBase::LuaCallEnd(InvocationKind kind, AActor *place) {
	if (place == nullptr) {
		return LuaCallEnd(kind, int64(0));
	} else {
		UlxTangible *tan = UlxTangible::GetActorTangibleOrLog(place);
		if (tan == nullptr) {
			return NewObject<UlxLuaValues>(this);
		} else {
			return LuaCallEnd(kind, tan->TangibleId);
		}
	}
}

void ALuprexGameModeBase::ExecuteDebuggingCommand(FlxLockedWrapper &w, const FString &fs) {
	// Nothing here right now.
}

void ALuprexGameModeBase::ConsoleSendInput(const FString& fs)
{
	if (fs.IsEmpty()) {
		return;
	}

	FlxLockedWrapper w(LockableWrapper);
	if (w->engine != nullptr)
	{
		ConsoleOutput.AppendLine(FString("> ") + fs);
		// This is a bad way to do this.  The problem is that if some
		// lua code contains '\\', we'll catch it instead of passing it
		// through.  There's no simple solution, though.
		if (fs[0] == '\\') {
			ExecuteDebuggingCommand(w, fs);
		} else {
			FTCHARToUTF8 utf8fs(fs);
			std::string ufs(utf8fs.Get(), utf8fs.Length());
			ufs = ufs + "\n";
			w->play_recv_incoming(w.Get(), 0, ufs.size(), ufs.c_str());
		}
	}
}

void ALuprexGameModeBase::OnWorldPreActorTick(UWorld* InWorld, ELevelTick InLevelTick, float deltaseconds)
{
	if(Playing && (GetWorld() == InWorld) && (InLevelTick == LEVELTICK_All))
	{
		LuprexUpdateTask.Wait();
		EngineSeconds += deltaseconds;
		UpdateConsoleOutput();
		UpdateTangibles();
		UpdatePossessedTangible();
		UpdateLookAt();
	}
}

void ALuprexGameModeBase::OnWorldPostActorTick(UWorld* InWorld, ELevelTick InLevelTick, float deltaseconds)
{
	if(Playing && (GetWorld() == InWorld) && (InLevelTick == LEVELTICK_All))
	{
		LuprexUpdateTask.Trigger();
	}
}


void ALuprexGameModeBase::Tick(float deltaseconds)
{
	Super::Tick(deltaseconds);
}

void ALuprexGameModeBase::BeginPlay()
{
	ResetToInitialState();
	InitializeGlobalState();
	Super::BeginPlay();
}

void ALuprexGameModeBase::InitializeGlobalState()
{
	FlxLockedWrapper w(LockableWrapper);

	// Sanity checks.  Make sure everything is clean.
	checkf(!LuprexUpdateTask.IsRunning(), TEXT("There should be no thread here."));
	checkf(w->engine == nullptr, TEXT("There should be no engine here."));

	// Try to initialize the wrapper.
	w.InitWrapper();

	// If we failed to initialize the wrapper, print an error message.
	if (w->play_initialize == nullptr)
	{
		UE_LOG(LogLuprexIntegration, Error, TEXT("Luprex wrapper initialization failed"));
	}

	// If wrapper is initialized, try to initialize the luprex engine.
	if (w->play_initialize != nullptr)
	{
		drvutil::ostringstream srcpak;
		std::string srcpakerr = drvutil::package_lua_source(LUPREX_ROOT_PATH, &srcpak);
		if (!srcpakerr.empty())
		{
			FString FMessage((const UTF8CHAR *)(srcpakerr.c_str()));
			UE_LOG(LogLuprexIntegration, Error, TEXT("Trying to read Lua source: %s"), *FMessage);
		}
		else
		{
			std::string_view srcpakv = srcpak.view();
			char* argv[1];
			argv[0] = const_cast<char*>("lpxclient");
			w->play_initialize(w.Get(), 1, argv, srcpakv.size(), srcpakv.data(), "");
			if (w->error[0])
			{
				FString FMessage((const UTF8CHAR *)w->error);
				UE_LOG(LogLuprexIntegration, Error, TEXT("Calling Luprex play_initialize: %s"), *FMessage);
			}
			if (w->engine != nullptr) {
				UE_LOG(LogLuprexIntegration, Verbose, TEXT("Luprex initialization success."));
				Playing = true;
			}
		}
	}

	// If we successfully created a luprex engine, create a socket system and a worker thread.
	if (Playing) {
		Sockets.Reset(FlxSockets::Create(w));
		std::string error = Sockets->GetError();
		check(error.empty());
		LuprexUpdateTask.Startup(this);
	}

	// Initialize the asset lookup table.
	AssetLookup = NewObject<UlxAssetLookup>(this);
	AssetLookup->RebuildIndex();

	// Initialize the tangible manager.
	TangibleManager = NewObject<UlxTangibleManager>(this);
	TangibleManager->Init(this);

	// If somebody generates a log message that's severe enough, break to debugger.
	BreakToDebuggerLogVerbosityDevice.Reset(
		new FlxDebugBlueprintErrorsOutputDevice(BreakToDebuggerLogVerbosity));
}

void ALuprexGameModeBase::EndPlay(const EEndPlayReason::Type EndPlayReason)
{
	ResetToInitialState();
}

int64 ALuprexGameModeBase::GetPlayerId() {
	return PlayerId;
}

ALuprexGameModeBase *ALuprexGameModeBase::FromContext(const UObject *context) {
	ALuprexGameModeBase *result = context->GetWorld()->GetAuthGameMode<ALuprexGameModeBase>();
	if (result == nullptr) {
		UE_LOG(LogBlueprint, Fatal, TEXT("Not currently using a Luprex Game Mode."));
	}
	return result;
}


void ALuprexGameModeBase::SetLookAt(const UObject *Context, const FHitResult &HitResult)
{
	ALuprexGameModeBase *Mode = FromContext(Context);
	if (Mode->CurrentLookAt.HitObjectHandle != HitResult.HitObjectHandle)
	{
		Mode->MustCallLookAtChanged = true;
	}
	Mode->CurrentLookAt = HitResult;
}

void ALuprexGameModeBase::SetLookAtChanged(const UObject *Context)
{
	ALuprexGameModeBase *Mode = FromContext(Context);
	Mode->MustCallLookAtChanged = true;
}

FVector2D ALuprexGameModeBase::GetLookAtPixel(const UObject *Context)
{
	ALuprexGameModeBase *Mode = FromContext(Context);
    APlayerController *pc = Context->GetWorld()->GetFirstPlayerController();
    if (pc == nullptr) return FVector2D();
	FVector2D ScreenPosition;
	if (!UGameplayStatics::ProjectWorldToScreen(pc, Mode->CurrentLookAt.Location, ScreenPosition, false))
	{
		return FVector2D();
	}
	return ScreenPosition;
}

void ALuprexGameModeBase::UpdateLookAt() {
	// Make sure the world is fully configured before we attempt to cast rays.
    UlxTangible *possessed = TangibleManager->GetPossessedTangible();
 	if (possessed == nullptr) return;
    APlayerController *pc = GetWorld()->GetFirstPlayerController();
    if (pc == nullptr) return;
    APawn *pawn = pc->GetPawn();
    if (pawn == nullptr) return;
	if (possessed->GetActor() != pawn) return;
 	APlayerCameraManager *cam = pc->PlayerCameraManager;
    if (cam == nullptr) return;

	CalculateLookAt(pc);

	if (MustCallLookAtChanged) {
		MustCallLookAtChanged = false;
		LookAtChanged();
	}
}