fix: derive calendar days in the app timezone, not UTC

app/[locale]/(auth)/reports/AdHocReportTab.tsx

@@ -9,6 +9,10 @@ import { formatCurrency as formatCurrencyLib } from "@/lib/currency";
 import { showSuccessToast, showErrorToast } from "@/lib/toast";
 import { resolveDocumentLocale, type DocumentLanguage } from "@/lib/document-language";
 import { useDocumentMessages } from "@/lib/document-messages";
+// NOT `new Date(y, m, 1).toISOString()` — that builds LOCAL midnight of the 1st and
+// then serializes it as UTC, so in Israel (UTC+2/+3) the "first day of this month"
+// preset resolved to the LAST day of the previous month, every single time.
+import { appDateBoundaries, appToday } from "@/lib/dates";
 import { printPdfContent } from "./printStyles";
 import { PdfReportContent } from "./PdfReportContent";
 import {
@@ -207,10 +211,8 @@ export default function AdHocReportTab() {
   const [filters, setFilters] = useState({
     clientId: "",
     projectId: "",
-    startDate: new Date(new Date().getFullYear(), new Date().getMonth(), 1)
-      .toISOString()
-      .split("T")[0], // First day of current month
-    endDate: new Date().toISOString().split("T")[0], // Today
+    startDate: appDateBoundaries().startOfMonth, // First day of current month
+    endDate: appToday(), // Today
     includeFixedCharges: true,
   });
   const [error, setError] = useState("");
@@ -298,10 +300,8 @@ export default function AdHocReportTab() {
       setFilters({
         clientId: clientId || "",
         projectId: projectId || "",
-        startDate: startDate || new Date(new Date().getFullYear(), new Date().getMonth(), 1)
-          .toISOString()
-          .split("T")[0],
-        endDate: endDate || new Date().toISOString().split("T")[0],
+        startDate: startDate || appDateBoundaries().startOfMonth,
+        endDate: endDate || appToday(),
         includeFixedCharges: includeFixedCharges !== "0",
       });
 
@@ -392,10 +392,8 @@ export default function AdHocReportTab() {
     setFilters({
       clientId: preset.clientId || "",
       projectId: preset.projectId || "",
-      startDate: preset.startDate || new Date(new Date().getFullYear(), new Date().getMonth(), 1)
-        .toISOString()
-        .split("T")[0],
-      endDate: preset.endDate || new Date().toISOString().split("T")[0],
+      startDate: preset.startDate || appDateBoundaries().startOfMonth,
+      endDate: preset.endDate || appToday(),
       includeFixedCharges: true,
     });
     setShowLoadPresetDialog(false);
@@ -510,7 +508,7 @@ export default function AdHocReportTab() {
 
       // Extract filename from Content-Disposition header or use default
       const contentDisposition = response.headers.get("Content-Disposition");
-      let filename = `report_${new Date().toISOString().split("T")[0]}.xlsx`;
+      let filename = `report_${appToday()}.xlsx`;
       if (contentDisposition) {
         const filenameMatch = contentDisposition.match(/filename="?(.+)"?/i);
         if (filenameMatch && filenameMatch[1]) {
@@ -701,14 +699,8 @@ export default function AdHocReportTab() {
                     setFilters({
                       clientId: "",
                       projectId: "",
-                      startDate: new Date(
-                        new Date().getFullYear(),
-                        new Date().getMonth(),
-                        1
-                      )
-                        .toISOString()
-                        .split("T")[0],
-                      endDate: new Date().toISOString().split("T")[0],
+                      startDate: appDateBoundaries().startOfMonth,
+                      endDate: appToday(),
                       includeFixedCharges: true,
                     })
                   }

app/[locale]/(auth)/reports/ChargePaymentsPanel.tsx

@@ -9,6 +9,7 @@ import {
   type PaymentMethod,
 } from "@/lib/charge-documents";
 import { showSuccessToast, showErrorToast } from "@/lib/toast";
+import { appToday } from "@/lib/dates";
 import { Input } from "@/components/ui/input";
 import { Label } from "@/components/ui/label";
 import { SimpleSelect } from "@/components/ui/simple-select";
@@ -55,7 +56,9 @@ export function ChargePaymentsPanel({
   const [editingId, setEditingId] = useState<string | null>(null);
 
   // Form fields shared between add and edit modes
-  const today = new Date().toISOString().slice(0, 10);
+  // App-timezone day — this becomes the stored `paid_at`, so the UTC day would
+  // book a late-night payment on the day before.
+  const today = appToday();
   const [amount, setAmount] = useState("");
   const [paidAt, setPaidAt] = useState(today);
   const [method, setMethod] = useState<PaymentMethod | "">("");

app/[locale]/entries/import/page.tsx

@@ -19,6 +19,7 @@ import {
   type CsvImportRow,
   type ImportProject,
 } from "@/lib/csv-entry-import";
+import { appToday } from "@/lib/dates";
 
 const EMPTY_PROJECTS: ImportProject[] = [];
 
@@ -49,7 +50,8 @@ export default function CsvEntryImportPage() {
     [rows, selectedRows]
   );
   const templateHref = useMemo(() => {
-    const today = new Date().toISOString().slice(0, 10);
+    // The sample row is often imported as-is, so this date can become real data.
+    const today = appToday();
     const csv = locale === "he"
       ? `\uFEFFתאריך,לקוח,פרויקט,תיאור,משך_בדקות,הערות,לחיוב,תעריף\n${today},שם לקוח,שם פרויקט,פגישת עבודה,60,,כן,250`
       : `date,client,project,description,duration_minutes,notes,billable,rate\n${today},Client name,Project name,Work session,60,,yes,250`;

app/[locale]/entries/page.tsx

@@ -15,6 +15,7 @@ import { showSuccessToast, showErrorToast } from "@/lib/toast";
 import { messageForError } from "@/lib/api-error";
 import { readRecentWorkContext, writeRecentWorkContext } from "@/lib/recent-work-context";
 import { validateRequired, validateDate, validateNumber } from "@/lib/validation";
+import { appToday } from "@/lib/dates";
 import { useValidationMessage } from "@/lib/validation-messages";
 import { pickDefaultHourlyRate, type ClientRate } from "@/lib/schemas/rates";
 import { applyPercentDiscount, calcHourlyAmount, calcItemAmount } from "@/lib/money";
@@ -146,10 +147,13 @@ export default function EntriesPage() {
   // Two-step form selection: with several clients, pick the client first and
   // see only its projects (mirrors the timer start modal).
   const [formClientId, setFormClientId] = useState("");
+  // `appToday()` — NOT toISOString(), which is the UTC day and pre-fills yesterday
+  // between local midnight and 03:00. Hardcoding the app timezone (rather than the
+  // browser's) keeps this default aligned with the server's month/week boundaries.
   const [formData, setFormData] = useState({
     projectId: "",
     taskId: "",
-    date: new Date().toISOString().split("T")[0],
+    date: appToday(),
     duration: "",
     description: "",
     notes: "",
@@ -554,7 +558,7 @@ export default function EntriesPage() {
         setFormData({
           projectId: "",
           taskId: "",
-          date: new Date().toISOString().split("T")[0],
+          date: appToday(),
           duration: "",
           description: "",
           notes: "",
@@ -625,7 +629,7 @@ export default function EntriesPage() {
     setFormData({
       projectId: "",
       taskId: "",
-      date: new Date().toISOString().split("T")[0],
+      date: appToday(),
       duration: "",
       description: "",
       notes: "",
@@ -653,7 +657,7 @@ export default function EntriesPage() {
     setFormData({
       projectId: recentProject?.id ?? "",
       taskId: "",
-      date: new Date().toISOString().split("T")[0],
+      date: appToday(),
       duration: "",
       description: "",
       notes: "",

app/api/dashboard/stats/route.ts

@@ -214,10 +214,13 @@ export async function GET(_request: NextRequest) {
          ) crd ON TRUE
          WHERE te.user_id = $1
            AND te.is_billable = TRUE
-           AND te.date >= DATE_TRUNC('month', CURRENT_DATE - INTERVAL '11 months')
+           AND te.date >= ($2::date - INTERVAL '11 months')
          GROUP BY TO_CHAR(te.date, 'YYYY-MM')
          ORDER BY month ASC`,
-        [userId]
+        // Window anchored to the app-timezone month start, not CURRENT_DATE — that
+        // reads the DB session clock (Neon = UTC) and would disagree with every
+        // other boundary in this handler on the 1st of the month before 03:00.
+        [userId, startOfMonthStr]
       ),
       // Hours by project this month (folded in from /api/dashboard/project-hours).
       query<{ project_id: string; project_name: string; total_minutes: string }>(

app/api/tasks/[id]/move/route.ts

@@ -3,6 +3,7 @@ import type { PoolClient } from "pg";
 import { getUser } from "@/lib/auth";
 import { parseBody } from "@/lib/api-validation";
 import { moveTaskSchema } from "@/lib/schemas/tasks";
+import { appToday } from "@/lib/dates";
 import { createLogger } from "@/lib/logger";
 
 const logger = createLogger("tasks:move");
@@ -65,7 +66,8 @@ export async function PATCH(
       if (running.rows.length > 0) return running.rows[0].id;
 
       const now = new Date();
-      const today = now.toISOString().split("T")[0];
+      // App-timezone day, not the UTC runtime's — see the note in /api/timer/start.
+      const today = appToday(now);
       const inserted = await client.query<{ id: string }>(
         `INSERT INTO time_entries
            (id, user_id, project_id, task_id, description, start_time, date, duration,

app/api/timer/start/route.ts

@@ -3,6 +3,7 @@ import { z } from "zod";
 import { withTransaction } from "@/lib/db";
 import { getUser } from "@/lib/auth";
 import { parseBody } from "@/lib/api-validation";
+import { appToday } from "@/lib/dates";
 import { createLogger } from "@/lib/logger";
 
 const logger = createLogger("timer:start");
@@ -38,7 +39,10 @@ export async function POST(request: NextRequest) {
     projectId = parsed.data.projectId;
 
     const now = new Date();
-    const today = now.toISOString().split("T")[0];
+    // The entry's calendar day must be the user's, not the runtime's. Vercel runs
+    // in UTC, so toISOString() would file a timer started at 01:00 in Israel under
+    // YESTERDAY — and /timer/stop never rewrites `date`, so it would stay wrong.
+    const today = appToday(now);
 
     const newEntry = await withTransaction(async (client) => {
       // Verify the project belongs to the user.

components/tasks/task-card.tsx

@@ -2,6 +2,7 @@
 
 import { useTranslations } from "next-intl";
 import { type TaskRecord } from "@/lib/tasks-types";
+import { appToday } from "@/lib/dates";
 
 interface TaskCardProps {
   task: TaskRecord;
@@ -32,8 +33,9 @@ const cardTone: Record<TaskRecord["priority"], string> = {
 
 function isOverdue(dueDate: string | null): boolean {
   if (!dueDate) return false;
-  const today = new Date().toISOString().slice(0, 10);
-  return dueDate < today;
+  // App-timezone day: the UTC day would flag a task due today as overdue
+  // between local midnight and 03:00.
+  return dueDate < appToday();
 }
 
 export function TaskCard({ task, isTimerRunning, onClick }: TaskCardProps) {

tests/unit/app-today.test.ts

@@ -0,0 +1,81 @@
+/**
+ * Guards the day boundary used by every WRITE path (timer start, task→in_progress,
+ * new-entry form default).
+ *
+ * The bug this locks down: those paths used `new Date().toISOString().split("T")[0]`
+ * — the UTC calendar day — while the dashboard computes today/week/month in
+ * Asia/Jerusalem. That left a nightly 2-3h window (00:00-03:00 local, DST-dependent)
+ * where a fresh entry landed on YESTERDAY. `timer/stop` never rewrites `date`, so it
+ * stayed wrong forever and "שעות היום" read 0:00 while the work sat on the day before.
+ */
+
+import { appToday, appDateBoundaries, addDays } from "../../lib/dates";
+
+function assert(condition: unknown, message: string): asserts condition {
+  if (!condition) throw new Error(message);
+}
+
+function eq(actual: string, expected: string, message: string): void {
+  assert(actual === expected, `${message}\n  expected: ${expected}\n  actual:   ${actual}`);
+}
+
+let passed = 0;
+function check(fn: () => void): void {
+  fn();
+  passed++;
+}
+
+function run(): void {
+  // --- The window that used to break -----------------------------------------
+  // 22:30 UTC on Jul 30 is 01:30 on Jul 31 in Israel (IDT, UTC+3).
+  // toISOString() would say "2026-07-30". The user's calendar says the 31st.
+  check(() => eq(appToday(new Date("2026-07-30T22:30:00Z")), "2026-07-31", "IDT: 01:30 local must be the NEXT day"));
+
+  // Winter (IST, UTC+2) — the window narrows to 2h but does not disappear.
+  check(() => eq(appToday(new Date("2026-01-15T22:30:00Z")), "2026-01-16", "IST: 00:30 local must be the NEXT day"));
+
+  // One minute before the local rollover the day must NOT advance yet.
+  check(() => eq(appToday(new Date("2026-07-30T20:59:00Z")), "2026-07-30", "23:59 local is still the same day"));
+
+  // Exactly local midnight.
+  check(() => eq(appToday(new Date("2026-07-30T21:00:00Z")), "2026-07-31", "local midnight rolls the day over"));
+
+  // --- Regression: the ordinary daytime case must be untouched ---------------
+  // A real prod row: created 2026-08-02 07:04:48Z = 10:04 in Israel.
+  check(() => eq(appToday(new Date("2026-08-02T07:04:48Z")), "2026-08-02", "daytime must be unchanged"));
+
+  // --- Month boundary, the case that decides which month revenue lands in ----
+  // 21:30 UTC on Jul 31 is 00:30 on Aug 1 local → a NEW month, not the old one.
+  const b = appDateBoundaries(new Date("2026-07-31T21:30:00Z"));
+  check(() => eq(b.today, "2026-08-01", "crossing midnight into the 1st must land in the new month"));
+  check(() => eq(b.startOfMonth, "2026-08-01", "startOfMonth must follow the local day, not UTC"));
+  check(() => eq(b.endOfMonth, "2026-08-31", "endOfMonth must be the last day of the LOCAL month"));
+
+  // February in a non-leap year — the classic off-by-one in hand-rolled month math.
+  check(() =>
+    eq(appDateBoundaries(new Date("2026-02-10T12:00:00Z")).endOfMonth, "2026-02-28", "Feb 2026 ends on the 28th")
+  );
+
+  // Week starts Sunday (Israeli convention). 2026-08-02 is a Sunday → it IS the start.
+  check(() =>
+    eq(appDateBoundaries(new Date("2026-08-02T07:00:00Z")).startOfWeek, "2026-08-02", "Sunday is its own week start")
+  );
+
+  // addDays must not drift across a DST change (Israel ends DST 2026-10-25).
+  check(() => eq(addDays("2026-10-24", 3), "2026-10-27", "addDays must survive the DST transition"));
+
+  // --- The report-preset bug: startOfMonth must ALWAYS be the 1st ------------
+  // The ad-hoc report built it as `new Date(y, m, 1).toISOString().split("T")[0]`
+  // — local midnight of the 1st, serialized as UTC. East of Greenwich that is the
+  // PREVIOUS month's last day, every single time, which silently pulled an extra
+  // day of the previous month into every "this month" report.
+  for (const iso of ["2026-08-02T07:00:00Z", "2026-01-01T00:30:00Z", "2026-03-15T23:00:00Z"]) {
+    const start = appDateBoundaries(new Date(iso)).startOfMonth;
+    check(() => assert(start.endsWith("-01"), `startOfMonth must be the 1st, got ${start} for ${iso}`));
+    check(() => eq(start.slice(0, 7), appToday(new Date(iso)).slice(0, 7), `startOfMonth must be in TODAY's month (${iso})`));
+  }
+
+  console.log(`app-today: ${passed} passed, 0 failed`);
+}
+
+run();