ProjectEleri/Source/ProjectEleriEditor/Public/NpcScheduleActionCustomization.h

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

#pragma once

#include "CoreMinimal.h"
#include "IPropertyTypeCustomization.h"
#include "Styling/SlateColor.h"

class AActor;
class IPropertyHandle;
class SWidget;

/**
 * Details panel layout for one FScheduledAction, the element type of
 * UNpcScheduleAsset::ScheduledActions.
 *
 * An action's anchor is stored as a PersistentId rather than as an actor pointer, so that a re-cook or
 * a re-save cannot leave a schedule dangling. The price of that is a value nobody can type in, so this
 * customization replaces the raw Guid row with one that names the actor the id currently resolves to,
 * offers the current selection and every anchor in the level in a menu, and has a button that clears
 * it. The id therefore always comes from the actor itself and can never drift away from it. A row for
 * an id that no actor in this level claims is left as it is, because that is a real state (furniture
 * that was deleted, or furniture sitting in a sublevel that is not loaded) and not something to hide.
 *
 * Every other member of the struct keeps the row the details panel would have given it.
 */
class FNpcScheduleActionCustomization : public IPropertyTypeCustomization
{
public:

	static TSharedRef<IPropertyTypeCustomization> MakeInstance();

	virtual void CustomizeHeader(TSharedRef<IPropertyHandle> PropertyHandle, FDetailWidgetRow& HeaderRow, IPropertyTypeCustomizationUtils& CustomizationUtils) override;
	virtual void CustomizeChildren(TSharedRef<IPropertyHandle> PropertyHandle, IDetailChildrenBuilder& ChildBuilder, IPropertyTypeCustomizationUtils& CustomizationUtils) override;

protected:

	/** The anchor row: the label, the name of the actor the id resolves to, the assign menu, and the
	 *  unassign button. Stands in for the raw Guid field, which is never shown. */
	void AddAnchorRow(IDetailChildrenBuilder& ChildBuilder, TSharedRef<IPropertyHandle> AnchorHandle) const;

	/** What the id points at: the actor's label, "None" when nothing is assigned, or the raw id when no
	 *  actor in this level claims it. */
	FText GetAnchorText(TSharedRef<IPropertyHandle> AnchorHandle) const;

	/** The id itself and what it means, so that an id can be read off the panel and matched against a
	 *  log or a save without the panel offering a text box to mistype it into. */
	FText GetAnchorTooltip(TSharedRef<IPropertyHandle> AnchorHandle) const;

	/** Subdues the row while nothing is assigned, so an action with no anchor reads differently at a
	 *  glance from one whose anchor the panel cannot name. */
	FSlateColor GetAnchorColor(TSharedRef<IPropertyHandle> AnchorHandle) const;

	bool CanClearAnchor(TSharedRef<IPropertyHandle> AnchorHandle) const;

	/** Writes one id into the action. An invalid id is what unassign does, so the button that clears
	 *  the anchor and the menu entries that set one both come through here. */
	void AssignAnchor(TSharedRef<IPropertyHandle> AnchorHandle, FGuid NewAnchorGuid) const;

	/** The assign menu: the current selection first, then every anchor in the level, with the one in
	 *  use radioed. */
	TSharedRef<SWidget> BuildAnchorMenu(TSharedRef<IPropertyHandle> AnchorHandle) const;

	/** The id a property handle currently holds, read as text so that it works whether the handle is
	 *  reached on its own, inside the array, or through a multi selection, which reports no single
	 *  value and so comes back as unassigned. */
	static FGuid ReadAnchorGuid(const TSharedRef<IPropertyHandle>& AnchorHandle);

	/** The first actor in the current selection that can be an anchor, or null when there is none. */
	static AActor* GetSelectedAnchorActor();

	/** The id of an actor, invalid when the actor cannot be an anchor. Implementing
	 *  IActorPersistentIdInterface is the whole of that rule, since the interface is what carries the id
	 *  a schedule stores. */
	static FGuid GetAnchorId(AActor* Actor);

	/** The actor a single id belongs to, or null when no actor in the current level claims it. */
	static AActor* FindActorWithGuid(const FGuid& Guid);

	/** How many actors in the current level claim an id. More than one is a real state - a pasted actor
	 *  carries its source's id - and everything that stores the id, this schedule included, resolves to
	 *  whichever of them a search reaches first, so the row says so rather than leaving it to be found
	 *  in game. Walked on the spot rather than indexed, because this is read while the panel is drawn
	 *  and an index would be stale the moment the author adds, deletes or pastes an anchor. */
	static int32 CountActorsWithGuid(const FGuid& Guid);

	/** Every actor in the current level that can be an anchor, sorted by label so that the menu does not
	 *  reshuffle itself between two openings. */
	static void CollectAnchorActors(TArray<AActor*>& OutAnchors);

	/** For the menu entries that only exist to explain themselves, such as "nothing is selected". */
	static bool NeverExecutable();

	/** Past this many anchors the menu stops listing actors and says how many it left out, because a
	 *  level can hold hundreds and a menu is not a browser. Assigning from the selection still works. */
	static constexpr int32 MaxListedAnchors = 40;
};