Update CBS Mobile App codebase

src/modules/services/utils/chequeFate.ts

@@ -0,0 +1,118 @@
+/**
+ * Cheque status lookup.
+ *
+ * There is no CBS endpoint for this yet — `endpoints.ts` has cheque book
+ * requests and stop payments but nothing that answers "what happened to leaf
+ * 123456". Until there is, the answer is resolved locally, in the same way the
+ * dashboard, cards and loans resolve from fixtures today.
+ *
+ * The result is derived from the cheque number rather than drawn at random, so
+ * the same number always gives the same answer. A demo that changes its mind
+ * between two taps of the same button reads as a bug, and it makes the screen
+ * impossible to write a test against.
+ *
+ * To go live, replace the body of `lookupChequeFate` with the API call. The
+ * `ChequeFate` shape is what the screen renders, so it is the contract to map
+ * the response onto.
+ */
+
+export type ChequeFateStatus = 'paid' | 'in_clearing' | 'returned' | 'stopped' | 'not_found';
+
+export type ChequeFate = {
+  chequeNumber: string;
+  status: ChequeFateStatus;
+  /** Short human label for the status, shown as the result headline. */
+  label: string;
+  amount?: number;
+  presentedOn?: string;
+  clearedOn?: string;
+  payee?: string;
+  /** Why a cheque was returned or stopped. Absent for a clean outcome. */
+  reason?: string;
+  /** The caveat under the result — what the customer should do next. */
+  note: string;
+};
+
+const formatDay = (daysAgo: number) => {
+  const date = new Date();
+
+  date.setDate(date.getDate() - daysAgo);
+
+  return new Intl.DateTimeFormat('en-IN', {
+    day: '2-digit',
+    month: 'short',
+    year: 'numeric',
+  }).format(date);
+};
+
+export type ChequeFateQuery = {
+  accountNumber: string;
+  chequeNumber: string;
+};
+
+export const lookupChequeFate = async ({
+  accountNumber,
+  chequeNumber,
+}: ChequeFateQuery): Promise<ChequeFate> => {
+  // Stands in for the round trip, so the button's loading state is visible and
+  // the screen is exercised the way it will behave against the real API.
+  await new Promise((resolve) => setTimeout(resolve, 600));
+
+  const digits = Number.parseInt(chequeNumber, 10);
+  // Mixing the account in means the same leaf number on two accounts gives two
+  // answers, which is the behaviour the real ledger has.
+  const seed = (Number.isNaN(digits) ? 0 : digits) + Number(accountNumber.slice(-2) || 0);
+  const amount = 1500 + (seed % 220) * 125;
+
+  switch (seed % 5) {
+    case 0:
+      return {
+        chequeNumber,
+        status: 'paid',
+        label: 'Paid',
+        amount,
+        presentedOn: formatDay(6),
+        clearedOn: formatDay(4),
+        payee: 'Meghana Rao',
+        note: 'Funds have left your account. The clearing house record is final.',
+      };
+    case 1:
+      return {
+        chequeNumber,
+        status: 'in_clearing',
+        label: 'In clearing',
+        amount,
+        presentedOn: formatDay(1),
+        payee: 'Sunrise Traders',
+        note: 'Presented and awaiting settlement. Cheques normally clear within two working days.',
+      };
+    case 2:
+      return {
+        chequeNumber,
+        status: 'returned',
+        label: 'Returned unpaid',
+        amount,
+        presentedOn: formatDay(3),
+        payee: 'Vasan Electricals',
+        reason: 'Insufficient funds',
+        note: 'A return charge may apply. Contact your branch before re-presenting the cheque.',
+      };
+    case 3:
+      return {
+        chequeNumber,
+        status: 'stopped',
+        label: 'Stop payment in force',
+        amount,
+        presentedOn: formatDay(2),
+        reason: 'Stop payment requested by you',
+        note: 'This cheque will not be paid while the stop instruction stands.',
+      };
+    default:
+      return {
+        chequeNumber,
+        status: 'not_found',
+        label: 'No record found',
+        note: 'This cheque has not been presented on the selected account. Check the number and the account, then try again.',
+      };
+  }
+};