Initialize the API and add managed app banners.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/common/utils/check-rass.ts

@@ -0,0 +1,62 @@
+export type CheckRassInput = {
+  amount: number;
+  dueDate: Date | string;
+};
+
+export type CheckRassResult = {
+  checkCount: number;
+  totalAmount: number;
+  nearestDueDate: string | null;
+  farthestDueDate: string | null;
+  rassDays: number;
+  rassDate: string | null;
+};
+
+import {
+  addDays,
+  calendarDayOf,
+  diffInDays,
+  tehranCalendarDay,
+} from './tehran-time';
+
+export function calculateCheckRass(
+  checks: CheckRassInput[],
+  baseDate: Date = new Date(),
+): CheckRassResult {
+  if (checks.length === 0) {
+    return {
+      checkCount: 0,
+      totalAmount: 0,
+      nearestDueDate: null,
+      farthestDueDate: null,
+      rassDays: 0,
+      rassDate: null,
+    };
+  }
+
+  const base = tehranCalendarDay(baseDate);
+  let totalAmount = 0;
+  let weightedDays = 0;
+  const dueDates: Date[] = [];
+
+  for (const check of checks) {
+    const due = calendarDayOf(check.dueDate);
+    dueDates.push(due);
+    const days = Math.max(0, diffInDays(base, due));
+    totalAmount += check.amount;
+    weightedDays += check.amount * days;
+  }
+
+  const rassDays = totalAmount > 0 ? Math.round(weightedDays / totalAmount) : 0;
+  const rassDate = addDays(base, rassDays);
+  dueDates.sort((a, b) => a.getTime() - b.getTime());
+
+  return {
+    checkCount: checks.length,
+    totalAmount,
+    nearestDueDate: dueDates[0]?.toISOString() ?? null,
+    farthestDueDate: dueDates[dueDates.length - 1]?.toISOString() ?? null,
+    rassDays,
+    rassDate: rassDate.toISOString(),
+  };
+}