#pragma once

#include "CoreMinimal.h"
#include "InputCoreTypes.h"
#include "UI/DescentUiSubsystem.h"
#include "Widgets/DeclarativeSyntaxSupport.h"
#include "Widgets/SCompoundWidget.h"

class SDPIScaler;
class SBox;

namespace Descent::Ui
{
	/** The body of a window for its current tab, drawn from the subsystem's view-models. Called again whenever the window, the tab or a view-model changes. */
	TSharedRef<SWidget> BuildPage(UDescentUiSubsystem& Ui, EDescentWindow Window, FName Tab);

	/** Tabs of a window as (id, label). The PDA has four; the fabricator one per recipe category; the rest none. */
	/** Which keys close which window: Esc closes every window but the title card; Tab and M close the PDA; E closes a station (not the PDA, the pause window or the end card). */
	THEDESCENT_API bool KeyClosesWindow(EDescentWindow Window, const FKey& Key);

	void GetWindowTabs(const UDescentUiSubsystem& Ui, EDescentWindow Window, TArray<FName>& OutIds, TArray<FString>& OutLabels);
}

/**
 * Full-viewport host of the windows: a dark scrim (an opaque backdrop for the title card), the SNeuWindow frame centred and
 * scaled down uniformly when the viewport is smaller than the window's design size, and the keyboard (Esc, Tab, M, E close).
 * It follows the subsystem: when the open window, the tab or the revision changes, it rebuilds its page on the next tick.
 */
class THEDESCENT_API SDescentWindowHost : public SCompoundWidget
{
public:
	SLATE_BEGIN_ARGS(SDescentWindowHost) {}
		SLATE_ARGUMENT(TWeakObjectPtr<UDescentUiSubsystem>, Ui)
	SLATE_END_ARGS()

	void Construct(const FArguments& InArgs);
	virtual void Tick(const FGeometry& AllottedGeometry, const double InCurrentTime, const float InDeltaTime) override;
	virtual bool SupportsKeyboardFocus() const override { return true; }
	virtual FReply OnKeyDown(const FGeometry& MyGeometry, const FKeyEvent& InKeyEvent) override;

	/** Rebuilds the frame and page for what the subsystem has open now. */
	void Rebuild();

	/** Where the frame is, in the host's own layout units, as of the last tick. */
	Descent::Ui::FWindowFit GetFit() const { return Fit; }
	FVector2f GetLayoutSize() const { return LayoutSize; }

private:
	float GetFitScale() const { return Fit.Scale; }

	TWeakObjectPtr<UDescentUiSubsystem> Ui;
	TSharedPtr<SBox> FrameBox;
	TSharedPtr<SDPIScaler> Scaler;
	TSharedPtr<SWidget> Backdrop;
	EDescentWindow BuiltWindow = EDescentWindow::None;
	FName BuiltTab;
	int32 BuiltRevision = -1;
	FVector2f LayoutSize = FVector2f(1280.f, 720.f);
	Descent::Ui::FWindowFit Fit;
};