refactor action buttons (#29416)

* refactor action buttons

* fix cult spell charge overlay

* lewc review

* update for a/mhelp buttons and xenobio organs

* update for minebot

* properly create button each time

* directly add/remove unavail overlay for reasons

* lewc review

code/datums/components/action_item_overlay.dm

@@ -0,0 +1,81 @@
+/**
+ * Apply to an action to allow it to take an item
+ * and apply it as an overlay of the action button
+ */
+/datum/component/action_item_overlay
+	/// UID of the item the component uses to apply as an overlay.
+	var/item_uid
+	/// Callback that dictates what item the component uses to apply as an overlay.
+	var/datum/callback/item_callback
+
+	/// The appearance of the item we've applied
+	var/mutable_appearance/item_appearance
+
+/datum/component/action_item_overlay/Initialize(atom/movable/item, datum/callback/item_callback)
+	if(!istype(parent, /datum/action))
+		return COMPONENT_INCOMPATIBLE
+
+	if(item && !istype(item))
+		stack_trace("[type] created with a non-null, non-movable item; item must be null or movable")
+		return COMPONENT_INCOMPATIBLE
+
+	if(!item && !item_callback)
+		stack_trace("[type] created without a reference item or an item callback - one or the other is required.")
+		return COMPONENT_INCOMPATIBLE
+
+	src.item_uid = item.UID()
+	src.item_callback = item_callback
+
+/datum/component/action_item_overlay/Destroy(force)
+	item_uid = null
+	item_callback = null
+	item_appearance = null
+	return ..()
+
+/datum/component/action_item_overlay/RegisterWithParent()
+	RegisterSignal(parent, COMSIG_ACTION_OVERLAY_APPLY, PROC_REF(on_overlays_applied))
+
+	var/datum/action/parent_action = parent
+	parent_action.build_all_button_icons(UPDATE_BUTTON_OVERLAY)
+
+/datum/component/action_item_overlay/UnregisterFromParent()
+	UnregisterSignal(parent, COMSIG_ACTION_OVERLAY_APPLY)
+
+	// If we're being unregistered / deleted but our parent is sticking around,
+	// force an overlay update to get rid of our item appearance
+	if(!QDELING(parent))
+		var/datum/action/parent_action = parent
+		parent_action.build_all_button_icons(UPDATE_BUTTON_OVERLAY)
+
+/// Signal proc for [COMSIG_ACTION_OVERLAY_APPLY], applies the item appearance if possible.
+/datum/component/action_item_overlay/proc/on_overlays_applied(datum/action/source, atom/movable/screen/movable/action_button/current_button, force)
+	SIGNAL_HANDLER
+
+	// We're in the middle of being removed / deleted, remove our associated overlay
+	if(QDELING(src))
+		if(item_appearance)
+			current_button.cut_overlay(item_appearance)
+			item_appearance = null
+		return
+
+	var/atom/movable/muse = item_callback?.Invoke() || locateUID(item_uid)
+	if(!istype(muse))
+		if(item_appearance) // New item does not exist but we have an old appearance
+			current_button.cut_overlay(item_appearance)
+			item_appearance = null
+		return
+
+	if(item_appearance)
+		// For caching purposes, we will try not to update if we don't need to
+		if(!force && item_appearance.icon == muse.icon && item_appearance.icon_state == muse.icon_state)
+			return
+		current_button.cut_overlay(item_appearance)
+
+	var/mutable_appearance/muse_appearance = new(muse.appearance)
+	muse_appearance.plane = FLOAT_PLANE
+	muse_appearance.layer = FLOAT_LAYER
+	muse_appearance.pixel_x = 0
+	muse_appearance.pixel_y = 0
+
+	current_button.add_overlay(muse_appearance)
+	item_appearance = muse_appearance

code/datums/components/scope.dm

@@ -276,4 +276,4 @@
 /datum/action/zoom
 	name = "Toggle Scope"
 	check_flags = AB_CHECK_CONSCIOUS|AB_CHECK_RESTRAINED|AB_CHECK_STUNNED|AB_CHECK_LYING
-	button_overlay_icon_state = "sniper_zoom"
+	button_icon_state = "sniper_zoom"