#include "UI/DescentHudSubsystem.h"
#include "Core/DescentSimSubsystem.h"
#include "Debug/DescentStateRegistry.h"
#include "TheDescent.h"

#include "Engine/World.h"

// ---------------------------------------------------------------------------------------------------------
// The model
// ---------------------------------------------------------------------------------------------------------

void FDescentHudModel::PushToast(const FString& Text, EDescentHudToastKind Kind, float Seconds)
{
	FDescentHudToast T;
	T.Text = Text;
	T.Kind = Kind;
	T.SecondsLeft = Seconds;
	Toasts.Add(MoveTemp(T));
	while (Toasts.Num() > MaxToasts)
	{
		Toasts.RemoveAt(0);
	}
}

void FDescentHudModel::SetRadio(const FString& Text, float Seconds)
{
	Radio = Text;
	RadioSecondsLeft = Seconds;
}

void FDescentHudModel::Advance(float DeltaSeconds)
{
	for (FDescentHudToast& T : Toasts)
	{
		T.SecondsLeft -= DeltaSeconds;
	}
	Toasts.RemoveAll([](const FDescentHudToast& T) { return T.SecondsLeft <= 0.f; });

	if (RadioSecondsLeft > 0.f)
	{
		RadioSecondsLeft -= DeltaSeconds;
		if (RadioSecondsLeft <= 0.f)
		{
			Radio.Reset();
			RadioSecondsLeft = 0.f;
		}
	}
}

FString FDescentHudModel::FormatThousands(double Value)
{
	const int64 Rounded = static_cast<int64>(FMath::RoundToDouble(Value));
	const bool bNegative = Rounded < 0;
	FString Digits = FString::Printf(TEXT("%lld"), bNegative ? -Rounded : Rounded);
	FString Out;
	for (int32 I = 0; I < Digits.Len(); ++I)
	{
		if (I > 0 && (Digits.Len() - I) % 3 == 0)
		{
			Out.AppendChar(TEXT(','));
		}
		Out.AppendChar(Digits[I]);
	}
	return bNegative ? TEXT("-") + Out : Out;
}

FString FDescentHudModel::FormatDepth(double DepthMetres)
{
	return FormatThousands(DepthMetres) + TEXT(" m");
}

FString FDescentHudModel::FormatTemperature(double Celsius, const FString& Label)
{
	return FString::Printf(TEXT("%s %.1f °C"), *Label, Celsius);
}

// ---------------------------------------------------------------------------------------------------------
// The subsystem
// ---------------------------------------------------------------------------------------------------------

UDescentHudSubsystem* UDescentHudSubsystem::Get(const UWorld* World)
{
	return World ? World->GetSubsystem<UDescentHudSubsystem>() : nullptr;
}

void UDescentHudSubsystem::Initialize(FSubsystemCollectionBase& Collection)
{
	Collection.InitializeDependency<UDescentSimSubsystem>();
	Super::Initialize(Collection);

	if (UDescentSimSubsystem* Sim = UDescentSimSubsystem::Get(GetWorld()))
	{
		// First in the HudModel entry (SubOrder very low), so the writers that run after it see counted-down toasts.
		FDescentSimRegisterOptions Options;
		Options.Owner = TEXT("HudModel");
		Options.SubOrder = -1000;
		StepHandle = Sim->RegisterLateStep(EDescentLateStep::HudModel, [this](const FDescentSimFrame& F)
		{
			HudModel.Advance(static_cast<float>(F.Dt));
			++Housekeeping;
		}, Options);
	}
}

void UDescentHudSubsystem::Deinitialize()
{
	if (UDescentSimSubsystem* Sim = UDescentSimSubsystem::Get(GetWorld()))
	{
		Sim->Unregister(StepHandle);
	}
	StepHandle.Reset();
	Super::Deinitialize();
}

// ---------------------------------------------------------------------------------------------------------
// State section "ui", part "hud" (section 9.4). The UI track adds the other parts ("widgets", "window",
// "cargo_display") with its own FDescentStatePartRegistrar.
// ---------------------------------------------------------------------------------------------------------

static FDescentStatePartRegistrar GHudPart(TEXT("ui"), TEXT("hud"), [](UWorld* World, FJsonObject& Out)
{
	const UDescentHudSubsystem* Sub = UDescentHudSubsystem::Get(World);
	Out.SetBoolField(TEXT("available"), Sub != nullptr);
	if (!Sub)
	{
		return;
	}
	const FDescentHudModel& M = Sub->Model();
	Out.SetStringField(TEXT("mode"), M.Mode.IsNone() ? FString() : M.Mode.ToString());
	Out.SetNumberField(TEXT("depth_m"), Descent::Json::Round(M.DepthM));
	Out.SetStringField(TEXT("depth_text"), M.DepthText);
	Out.SetStringField(TEXT("band"), M.Band);
	Out.SetStringField(TEXT("rating_text"), M.RatingText);
	Out.SetStringField(TEXT("prompt"), M.Prompt);
	Out.SetStringField(TEXT("radio"), M.Radio);
	Out.SetStringField(TEXT("objective"), M.Objective);
	Out.SetStringField(TEXT("temperature_text"), M.TemperatureText);
	Out.SetNumberField(TEXT("temperature_c"), Descent::Json::Round(M.TemperatureC));
	Out.SetBoolField(TEXT("shear_warning"), M.Warnings.bShear);
	Out.SetStringField(TEXT("warning_text"), M.Warnings.Text);

	TArray<TSharedPtr<FJsonValue>> Toasts;
	for (const FDescentHudToast& T : M.Toasts)
	{
		Toasts.Add(MakeShared<FJsonValueString>(T.Text));
	}
	Out.SetArrayField(TEXT("toasts"), Toasts);

	TSharedRef<FJsonObject> Vitals = MakeShared<FJsonObject>();
	Vitals->SetNumberField(TEXT("health"), Descent::Json::Round(M.Vitals.Health));
	Vitals->SetNumberField(TEXT("nutrition"), Descent::Json::Round(M.Vitals.Nutrition));
	Vitals->SetNumberField(TEXT("o2_s"), Descent::Json::Round(M.Vitals.O2Seconds));
	Vitals->SetNumberField(TEXT("bio_fu"), Descent::Json::Round(M.Vitals.BioReserveFu));
	Out.SetObjectField(TEXT("vitals"), Vitals);

	TSharedRef<FJsonObject> Vehicle = MakeShared<FJsonObject>();
	Vehicle->SetBoolField(TEXT("visible"), M.Vehicle.bVisible);
	Vehicle->SetNumberField(TEXT("hull_pct"), Descent::Json::Round(M.Vehicle.HullPct));
	Vehicle->SetNumberField(TEXT("power_pct"), Descent::Json::Round(M.Vehicle.PowerPct));
	Vehicle->SetNumberField(TEXT("speed_mps"), Descent::Json::Round(M.Vehicle.SpeedMps));
	Out.SetObjectField(TEXT("vehicle"), Vehicle);

	Out.SetNumberField(TEXT("markers"), M.Markers.Num());
	Out.SetNumberField(TEXT("late_housekeeping_count"), static_cast<double>(Sub->HousekeepingCount()));
});