Fuzzing for dates

In addition to fuzzing amounts, this shifts all dates to the past by a
random number of days (between 7 and 14).

generate-stats.ts

@@ -100,6 +100,16 @@ function getFuzzFactor(amount) {
   return normalized * 0.02 - 0.01; // -1% to +1% for larger amounts
 }
 
+// Randomly choose a date shift between 7 and 14 days
+const dateShiftDays = Math.floor(Math.random() * 8) + 7;
+
+// Shift date to the past by a number of days
+function shiftDate(date, days) {
+  const shifted = new Date(date);
+  shifted.setDate(date.getDate() - days); // Subtract days to shift to past
+  return shifted.toISOString().split("T")[0]; // YYYY-MM-DD
+}
+
 // Process a single user and return CSV rows
 async function processUser(userId, client) {
   // Check the number of settled invoices for the user
@@ -131,10 +141,10 @@ async function processUser(userId, client) {
 
   // Aggregate daily statistics using BigInt
   const dailyData = {};
-  let runningBalance = BigInt(0); // Initialize as BigInt
+  let runningBalance = BigInt(0);
 
   for (const invoice of invoices) {
-    const day = invoice.settled_at.toISOString().split("T")[0]; // YYYY-MM-DD
+    const day = shiftDate(invoice.settled_at, dateShiftDays);
 
     // Get fuzzing factor for this invoice
     const fuzzFactor = getFuzzFactor(Number(invoice.amount));