Add fishing shop and persistent upgrades

world/fishing_shop_interaction.gd

@@ -0,0 +1,47 @@
+class_name FishingShopInteraction
+extends Area3D
+
+signal local_player_range_changed(in_range: bool)
+
+var _local_player: Player
+var _local_player_in_range: bool = false
+
+
+func _ready() -> void:
+	body_entered.connect(_on_body_entered)
+	body_exited.connect(_on_body_exited)
+
+
+func setup_local_player(player: Player) -> void:
+	_local_player = player
+	_refresh_overlaps()
+
+
+func is_local_player_in_range() -> bool:
+	return _local_player_in_range
+
+
+func _refresh_overlaps() -> void:
+	var is_overlapping: bool = (
+		_local_player != null
+		and is_instance_valid(_local_player)
+		and _local_player in get_overlapping_bodies()
+	)
+	_set_local_player_in_range(is_overlapping)
+
+
+func _on_body_entered(body: Node3D) -> void:
+	if body == _local_player:
+		_set_local_player_in_range(true)
+
+
+func _on_body_exited(body: Node3D) -> void:
+	if body == _local_player:
+		_set_local_player_in_range(false)
+
+
+func _set_local_player_in_range(in_range: bool) -> void:
+	if _local_player_in_range == in_range:
+		return
+	_local_player_in_range = in_range
+	local_player_range_changed.emit(in_range)