feat: add versioned simulation state records

simulation/state/ResourceStateRecord.gd

@@ -0,0 +1,42 @@
+class_name ResourceStateRecord
+extends RefCounted
+
+const SCHEMA_VERSION := 1
+
+var data: Dictionary
+
+func _init(record_data: Dictionary = {}) -> void:
+	data = record_data.duplicate(true)
+
+static func capture(node: ResourceNode) -> ResourceStateRecord:
+	return ResourceStateRecord.new({
+		"schema_version": SCHEMA_VERSION,
+		"node_id": String(node.node_id),
+		"amount_remaining": node.amount_remaining,
+		"reserved_by": node.reserved_by,
+		"enabled": node.enabled
+	})
+
+static func from_dictionary(record_data: Dictionary) -> ResourceStateRecord:
+	if int(record_data.get("schema_version", -1)) != SCHEMA_VERSION:
+		return null
+	if not record_data.has_all([
+		"node_id", "amount_remaining", "reserved_by", "enabled"
+	]):
+		return null
+	if String(record_data["node_id"]).is_empty():
+		return null
+	return ResourceStateRecord.new(record_data)
+
+func restore(node: ResourceNode) -> bool:
+	if node == null or node.node_id != StringName(data["node_id"]):
+		return false
+	node.restore_persistent_state(
+		float(data["amount_remaining"]),
+		int(data["reserved_by"]),
+		bool(data["enabled"])
+	)
+	return true
+
+func to_dictionary() -> Dictionary:
+	return data.duplicate(true)