DB: add parseLoyaltyCard utility function

Co-Authored-By: Jannis R <[email protected]>

p/db/loyalty-cards.js

@@ -1,3 +1,5 @@
+import {deepStrictEqual as eql} from 'node:assert';
+
 // todo: generate from https://reiseauskunft.bahn.de/addons/fachkonfig-utf8.cfg ?
 const c = {
 	NONE: Symbol('no loyalty card'),
@@ -45,7 +47,37 @@ const formatLoyaltyCard = (data) => {
 	return 0;
 };
 
+const parseLoyaltyCard = (cardId) => {
+	switch (cardId) {
+		case 1:
+		case 2: return {type: c.BAHNCARD, discount: 25, class: cardId === 1 ? 1 : 2};
+		case 3:
+		case 4: return {type: c.BAHNCARD, discount: 50, class: cardId === 3 ? 1 : 2};
+		case 9: return {type: c.VORTEILSCARD};
+		case 10:
+		case 11: return {type: c.HALBTAXABO, railplus: cardId === 10};
+		case 12:
+		case 13: return {type: c.VOORDEELURENABO, railplus: cardId === 12};
+		case 14: return {type: c.SHCARD};
+		case 15: return {type: c.GENERALABONNEMENT};
+		default: return {type: c.NONE};
+	}
+};
+
+const bcFirst50 = {
+	type: c.BAHNCARD,
+	class: 1,
+	discount: 50,
+};
+eql(parseLoyaltyCard(formatLoyaltyCard(bcFirst50)), bcFirst50);
+const halbtaxRailplus = {
+	type: c.HALBTAXABO,
+	railplus: true,
+};
+eql(parseLoyaltyCard(formatLoyaltyCard(halbtaxRailplus)), halbtaxRailplus);
+
 export {
 	c as data,
 	formatLoyaltyCard,
+	parseLoyaltyCard,
 };