Add invoice drafts, read-only issued state and keyboard shortcuts

Views stay mounted so switching tabs no longer loses a half-typed invoice.
The form autosaves a draft after 1 s, drafts can be resumed or deleted,
and after issuing the form is read-only with Export again, Duplicate and
New invoice actions. A failed export keeps the issued invoice and offers a
retry instead of issuing again. Adds Ctrl+N/S/Enter/L and a shortcut sheet;
F5 and Ctrl+R are blocked in production builds.

src/App.tsx

@@ -88,9 +88,19 @@ export default function App() {
   return (
     <Theme theme={theme}>
       <AppShell view={view} onNavigate={setView} theme={settings.theme} onToggleTheme={toggleTheme}>
-        {view === "new" && <NewInvoice settings={settings} onSettingsChange={refreshSettings} />}
+        {/* Main views stay mounted so a half-typed invoice survives switching tabs. */}
-        {view === "invoices" && <InvoiceHistory settings={settings} />}
+        <NewInvoice
-        {view === "series" && <SeriesSettings />}
+          settings={settings}
+          onSettingsChange={refreshSettings}
+          active={view === "new"}
+          onActivate={() => setView("new")}
+        />
+        <div hidden={view !== "invoices"}>
+          <InvoiceHistory settings={settings} active={view === "invoices"} />
+        </div>
+        <div hidden={view !== "series"}>
+          <SeriesSettings active={view === "series"} />
+        </div>
         {view === "settings" && <AppSettings settings={settings} onSaved={refreshSettings} />}
       </AppShell>
     </Theme>

src/hooks/useShortcuts.ts

@@ -0,0 +1,62 @@
+import { useEffect, useRef } from "react";
+
+export interface ShortcutHandlers {
+  onNew?: () => void;
+  onSaveDraft?: () => void;
+  onIssue?: () => void;
+  onAddLine?: () => void;
+  onHelp?: () => void;
+}
+
+const isTyping = (target: EventTarget | null) => {
+  const el = target as HTMLElement | null;
+  if (!el) return false;
+  return el.tagName === "INPUT" || el.tagName === "TEXTAREA" || el.tagName === "SELECT" || el.isContentEditable;
+};
+
+/**
+ * Global keyboard shortcuts. Ctrl combinations work everywhere; the bare `?` is ignored
+ * while typing. F5 / Ctrl+R are blocked in production builds because a webview reload
+ * would discard in-memory state.
+ */
+export function useShortcuts(handlers: ShortcutHandlers) {
+  const ref = useRef(handlers);
+  ref.current = handlers;
+
+  useEffect(() => {
+    const onKey = (event: KeyboardEvent) => {
+      const ctrl = event.ctrlKey || event.metaKey;
+      const key = event.key.toLowerCase();
+
+      if (import.meta.env.PROD && (event.key === "F5" || (ctrl && key === "r"))) {
+        event.preventDefault();
+        return;
+      }
+
+      const run = (fn?: () => void) => {
+        event.preventDefault();
+        fn?.();
+      };
+
+      if (ctrl && !event.shiftKey && !event.altKey) {
+        if (key === "n") return run(ref.current.onNew);
+        if (key === "s") return run(ref.current.onSaveDraft);
+        if (key === "l") return run(ref.current.onAddLine);
+        if (key === "enter") return run(ref.current.onIssue);
+      }
+      if (!ctrl && !event.altKey && event.key === "?" && !isTyping(event.target)) {
+        run(ref.current.onHelp);
+      }
+    };
+    window.addEventListener("keydown", onKey);
+    return () => window.removeEventListener("keydown", onKey);
+  }, []);
+}
+
+export const SHORTCUT_LIST: { keys: string; action: string }[] = [
+  { keys: "Ctrl + N", action: "New invoice" },
+  { keys: "Ctrl + S", action: "Save draft" },
+  { keys: "Ctrl + Enter", action: "Issue and export PDF" },
+  { keys: "Ctrl + L", action: "Add line item" },
+  { keys: "?", action: "Show this list" },
+];

src/lib/draft.test.ts

@@ -0,0 +1,72 @@
+import { describe, expect, it } from "vitest";
+import { fromDraftPayload, toDraftPayload, type InvoiceFormState } from "./draft";
+import { EMPTY_ITEM } from "./types";
+
+const defaults: InvoiceFormState = {
+  invoiceDate: "2026-01-01",
+  dueDate: "2026-01-31",
+  clientId: null,
+  clientName: "",
+  clientAddress: "",
+  clientGstin: "",
+  poNumber: "",
+  placeOfSupply: "29",
+  saveClient: false,
+  items: [{ ...EMPTY_ITEM, hsnSac: "9983" }],
+  discount: 0,
+  taxRate: 18,
+  reverseCharge: false,
+  bankId: 2,
+  signaturePath: "/sig/default.png",
+  notes: "",
+};
+
+const filled: InvoiceFormState = {
+  invoiceDate: "2026-03-05",
+  dueDate: "2026-04-04",
+  clientId: 7,
+  clientName: "Acme Pvt Ltd",
+  clientAddress: "1 Main Rd\nKolkata",
+  clientGstin: "19AAAAA0000A1Z5",
+  poNumber: "PO-9",
+  placeOfSupply: "19",
+  saveClient: true,
+  items: [
+    { ...EMPTY_ITEM, description: "Design", mode: "rate", rate: 500, unit: "hour", quantity: 4, hsnSac: "9983" },
+    { ...EMPTY_ITEM, description: "Fee", amount: 1200, sortOrder: 1, hsnSac: "9983" },
+  ],
+  discount: 100,
+  taxRate: 12,
+  reverseCharge: true,
+  bankId: null,
+  signaturePath: null,
+  notes: "Thanks",
+};
+
+describe("draft payload", () => {
+  it("round-trips through JSON", () => {
+    const json = JSON.parse(JSON.stringify(toDraftPayload(filled)));
+    expect(fromDraftPayload(json, defaults)).toEqual(filled);
+  });
+
+  it("does not store derived totals", () => {
+    const keys = Object.keys(toDraftPayload(filled));
+    for (const k of ["total", "subtotal", "cgst", "sgst", "igst", "amountInWords"]) {
+      expect(keys).not.toContain(k);
+    }
+  });
+
+  it("falls back to defaults for missing fields", () => {
+    const out = fromDraftPayload({ clientName: "Only name" }, defaults);
+    expect(out).toEqual({ ...defaults, clientName: "Only name" });
+  });
+
+  it("tolerates garbage input and partial items", () => {
+    expect(fromDraftPayload(null, defaults)).toEqual(defaults);
+    expect(fromDraftPayload("x", defaults)).toEqual(defaults);
+    const out = fromDraftPayload({ items: [{ description: "A" }], discount: "oops" }, defaults);
+    expect(out.discount).toBe(0);
+    expect(out.items).toHaveLength(1);
+    expect(out.items[0]).toMatchObject({ description: "A", mode: "fixed", quantity: 1, hsnSac: "" });
+  });
+});

src/lib/draft.ts

@@ -0,0 +1,92 @@
+import { EMPTY_ITEM } from "./types";
+import type { InvoiceItem, LineMode, LineUnit } from "./types";
+
+/** Everything that defines an invoice on the New invoice form. Derived totals are not part of it. */
+export interface InvoiceFormState {
+  invoiceDate: string;
+  dueDate: string;
+  clientId: number | null;
+  clientName: string;
+  clientAddress: string;
+  clientGstin: string;
+  poNumber: string;
+  placeOfSupply: string;
+  saveClient: boolean;
+  items: InvoiceItem[];
+  discount: number;
+  taxRate: number;
+  reverseCharge: boolean;
+  bankId: number | null;
+  signaturePath: string | null;
+  notes: string;
+}
+
+const str = (v: unknown, fallback: string) => (typeof v === "string" ? v : fallback);
+const num = (v: unknown, fallback: number) =>
+  typeof v === "number" && Number.isFinite(v) ? v : fallback;
+const bool = (v: unknown, fallback: boolean) => (typeof v === "boolean" ? v : fallback);
+const nullableNum = (v: unknown, fallback: number | null) =>
+  v === null ? null : typeof v === "number" && Number.isFinite(v) ? v : fallback;
+
+function itemFromJson(raw: unknown, index: number): InvoiceItem {
+  const r = (raw && typeof raw === "object" ? raw : {}) as Record<string, unknown>;
+  return {
+    description: str(r.description, ""),
+    mode: (r.mode === "rate" ? "rate" : "fixed") as LineMode,
+    rate: num(r.rate, EMPTY_ITEM.rate),
+    unit: str(r.unit, EMPTY_ITEM.unit) as LineUnit,
+    quantity: num(r.quantity, EMPTY_ITEM.quantity),
+    amount: num(r.amount, EMPTY_ITEM.amount),
+    sortOrder: index,
+    hsnSac: str(r.hsnSac, ""),
+  };
+}
+
+export function toDraftPayload(state: InvoiceFormState): Record<string, unknown> {
+  return {
+    version: 1,
+    invoiceDate: state.invoiceDate,
+    dueDate: state.dueDate,
+    clientId: state.clientId,
+    clientName: state.clientName,
+    clientAddress: state.clientAddress,
+    clientGstin: state.clientGstin,
+    poNumber: state.poNumber,
+    placeOfSupply: state.placeOfSupply,
+    saveClient: state.saveClient,
+    items: state.items.map((item, index) => ({ ...item, sortOrder: index })),
+    discount: state.discount,
+    taxRate: state.taxRate,
+    reverseCharge: state.reverseCharge,
+    bankId: state.bankId,
+    signaturePath: state.signaturePath,
+    notes: state.notes,
+  };
+}
+
+/** Tolerant: any missing or wrongly typed field falls back to `defaults`. */
+export function fromDraftPayload(json: unknown, defaults: InvoiceFormState): InvoiceFormState {
+  const r = (json && typeof json === "object" ? json : {}) as Record<string, unknown>;
+  const items = Array.isArray(r.items) && r.items.length > 0 ? r.items.map(itemFromJson) : defaults.items;
+  return {
+    invoiceDate: str(r.invoiceDate, defaults.invoiceDate),
+    dueDate: str(r.dueDate, defaults.dueDate),
+    clientId: nullableNum(r.clientId, defaults.clientId),
+    clientName: str(r.clientName, defaults.clientName),
+    clientAddress: str(r.clientAddress, defaults.clientAddress),
+    clientGstin: str(r.clientGstin, defaults.clientGstin),
+    poNumber: str(r.poNumber, defaults.poNumber),
+    placeOfSupply: str(r.placeOfSupply, defaults.placeOfSupply),
+    saveClient: bool(r.saveClient, defaults.saveClient),
+    items,
+    discount: num(r.discount, defaults.discount),
+    taxRate: num(r.taxRate, defaults.taxRate),
+    reverseCharge: bool(r.reverseCharge, defaults.reverseCharge),
+    bankId: nullableNum(r.bankId, defaults.bankId),
+    signaturePath:
+      r.signaturePath === null || typeof r.signaturePath === "string"
+        ? r.signaturePath
+        : defaults.signaturePath,
+    notes: str(r.notes, defaults.notes),
+  };
+}

src/styles/carbon.scss

@@ -143,6 +143,11 @@ body {
   gap: 0.5rem;
 }
 
+// Views stay mounted while hidden so their state survives navigation.
+[hidden] {
+  display: none !important;
+}
+
 .voiced-page {
   padding: 2rem;
   max-width: 1600px;

src/views/InvoiceHistory.tsx

@@ -20,7 +20,7 @@ import { formatAmount, formatDate } from "../lib/format";
 import { exportInvoicePdf } from "../lib/pdf";
 import type { InvoiceSummary, Settings } from "../lib/types";
 
-export default function InvoiceHistory({ settings }: { settings: Settings }) {
+export default function InvoiceHistory({ settings, active }: { settings: Settings; active: boolean }) {
   const [rows, setRows] = useState<InvoiceSummary[]>([]);
   const [loading, setLoading] = useState(true);
   const [error, setError] = useState<string | null>(null);
@@ -39,9 +39,10 @@ export default function InvoiceHistory({ settings }: { settings: Settings }) {
     }
   };
 
+  // The view stays mounted, so refetch every time it is shown again.
   useEffect(() => {
-    void load();
+    if (active) void load();
-  }, []);
+  }, [active]);
 
   const onExport = async (id: number) => {
     setBusyId(id);

src/views/NewInvoice.tsx

@@ -1,23 +1,45 @@
-import { useEffect, useMemo, useState } from "react";
+import { useCallback, useEffect, useMemo, useRef, useState } from "react";
 import {
+  ActionableNotification,
   Button,
   Column,
   Dropdown,
   Grid,
+  InlineLoading,
   InlineNotification,
+  Modal,
   NumberInput,
   Select,
   SelectItem,
+  Table,
+  TableBody,
+  TableCell,
+  TableHead,
+  TableHeader,
+  TableRow,
+  Tag,
   TextArea,
   TextInput,
   Toggle,
 } from "@carbon/react";
-import { Add, Save, TrashCan } from "@carbon/icons-react";
+import {
+  Add,
+  Copy,
+  DocumentAdd,
+  Download,
+  Keyboard,
+  Renew,
+  Save,
+  TrashCan,
+} from "@carbon/icons-react";
+import { confirm } from "@tauri-apps/plugin-dialog";
 import { api } from "../lib/api";
 import { EMPTY_ITEM, INDIAN_STATES, UNIT_LABELS } from "../lib/types";
 import type {
   BankAccount,
   Client,
+  DraftSummary,
+  Invoice,
   InvoiceInput,
   InvoiceItem,
   LineMode,
@@ -30,6 +52,8 @@ import { amountInWords } from "../lib/numberToWords";
 import { gstinFullError } from "../lib/validators";
 import { addDays, formatAmount, todayIso } from "../lib/format";
 import { buildPdfProps, exportPdfFromProps } from "../lib/pdf";
+import { fromDraftPayload, toDraftPayload, type InvoiceFormState } from "../lib/draft";
+import { SHORTCUT_LIST, useShortcuts } from "../hooks/useShortcuts";
 import { InvoicePreview } from "../components/InvoicePreview";
 import { ImagePicker } from "../components/ImagePicker";
 import type { InvoicePdfProps } from "../pdf/InvoiceDocument";
@@ -37,10 +61,43 @@ import type { InvoicePdfProps } from "../pdf/InvoiceDocument";
 interface NewInvoiceProps {
   settings: Settings;
   onSettingsChange: () => void;
+  /** Whether this view is the one on screen. It stays mounted while hidden. */
+  active: boolean;
+  /** Ask the shell to show this view (used by Ctrl+N from another tab). */
+  onActivate: () => void;
 }
 
-export default function NewInvoice({ settings }: NewInvoiceProps) {
+const AUTOSAVE_MS = 1000;
+
+const formatTime = (d: Date) => d.toLocaleTimeString("en-GB", { hour: "2-digit", minute: "2-digit" });
+const formatStamp = (iso: string) => {
+  const d = new Date(iso);
+  return Number.isNaN(d.getTime()) ? iso : `${d.toLocaleDateString("en-GB")} ${formatTime(d)}`;
+};
+
+export default function NewInvoice({ settings, active, onActivate }: NewInvoiceProps) {
   const newItem = (): InvoiceItem => ({ ...EMPTY_ITEM, hsnSac: settings.defaultHsnSac });
+  const blankState = (): InvoiceFormState => {
+    const t = todayIso();
+    return {
+      invoiceDate: t,
+      dueDate: addDays(t, settings.paymentTermsDays),
+      clientId: null,
+      clientName: "",
+      clientAddress: "",
+      clientGstin: "",
+      poNumber: "",
+      placeOfSupply: settings.vendorStateCode,
+      saveClient: false,
+      items: [newItem()],
+      discount: 0,
+      taxRate: settings.defaultTaxRate,
+      reverseCharge: false,
+      bankId: settings.defaultBankId,
+      signaturePath: settings.signaturePath,
+      notes: "",
+    };
+  };
   const today = todayIso();
   const [invoiceDate, setInvoiceDate] = useState(today);
   const [dueDate, setDueDate] = useState(addDays(today, settings.paymentTermsDays));
@@ -72,21 +129,43 @@ export default function NewInvoice({ settings }: NewInvoiceProps) {
 
   const [saving, setSaving] = useState(false);
   const [error, setError] = useState<string | null>(null);
-  const [saved, setSaved] = useState<string | null>(null);
+
+  // Issued invoice shown read-only after a successful issue. Its number is consumed, so the
+  // form never issues again until the user starts a new one.
+  const [issued, setIssued] = useState<Invoice | null>(null);
+  const [exporting, setExporting] = useState(false);
+  const [exportedPath, setExportedPath] = useState<string | null>(null);
+  const [exportError, setExportError] = useState<string | null>(null);
+  const locked = issued !== null;
+
+  // Drafts.
+  const [draftId, setDraftId] = useState<number | null>(null);
+  const [baseline, setBaseline] = useState<string | null>(null);
+  const [savedSnapshot, setSavedSnapshot] = useState<string | null>(null);
+  const [savedAt, setSavedAt] = useState<Date | null>(null);
+  const [draftSaving, setDraftSaving] = useState(false);
+  const [draftError, setDraftError] = useState<string | null>(null);
+  const [drafts, setDrafts] = useState<DraftSummary[]>([]);
+  const [noticeOpen, setNoticeOpen] = useState(false);
+  const [draftsOpen, setDraftsOpen] = useState(false);
+  const [helpOpen, setHelpOpen] = useState(false);
 
   useEffect(() => {
     let active = true;
     (async () => {
       try {
-        const [next, clientList, bankList] = await Promise.all([
+        const [next, clientList, bankList, draftList] = await Promise.all([
           api.peekNextInvoiceNumber(),
           api.listClients(),
           api.listBanks(),
+          api.listDrafts(),
         ]);
         if (!active) return;
         setNumber(next);
         setClients(clientList);
         setBanks(bankList);
+        setDrafts(draftList);
+        setNoticeOpen(draftList.length > 0);
       } catch (e) {
         if (active) setError(String(e));
       }
@@ -135,12 +214,128 @@ export default function NewInvoice({ settings }: NewInvoiceProps) {
   const words = useMemo(() => amountInWords(totals.total), [totals.total]);
   const bank = useMemo(() => banks.find((b) => b.id === bankId) ?? null, [banks, bankId]);
 
+  const payload = useMemo(
+    () =>
+      toDraftPayload({
+        invoiceDate,
+        dueDate,
+        clientId,
+        clientName,
+        clientAddress,
+        clientGstin,
+        poNumber,
+        placeOfSupply,
+        saveClient,
+        items,
+        discount,
+        taxRate,
+        reverseCharge,
+        bankId,
+        signaturePath,
+        notes,
+      }),
+    [
+      invoiceDate,
+      dueDate,
+      clientId,
+      clientName,
+      clientAddress,
+      clientGstin,
+      poNumber,
+      placeOfSupply,
+      saveClient,
+      items,
+      discount,
+      taxRate,
+      reverseCharge,
+      bankId,
+      signaturePath,
+      notes,
+    ],
+  );
+  const snapshot = useMemo(() => JSON.stringify(payload), [payload]);
+
+  // The untouched form is the baseline; anything else is dirty. A pristine form is never saved.
+  useEffect(() => {
+    setBaseline((current) => current ?? snapshot);
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, []);
+  const dirty = baseline !== null && snapshot !== baseline;
+  const unsaved = !locked && dirty && snapshot !== savedSnapshot;
+
+  const latest = useRef({ snapshot, payload });
+  latest.current = { snapshot, payload };
+  const draftIdRef = useRef<number | null>(null);
+  const savedRef = useRef<string | null>(null);
+  const issuedRef = useRef(false);
+  const chain = useRef<Promise<void>>(Promise.resolve());
+
+  const refreshDrafts = useCallback(async () => {
+    try {
+      setDrafts(await api.listDrafts());
+    } catch {
+      /* the list is a convenience; ignore */
+    }
+  }, []);
+
+  const refreshNumber = async () => {
+    try {
+      setNumber(await api.peekNextInvoiceNumber());
+    } catch {
+      /* ignore */
+    }
+  };
+
+  // Saves are serialised so a slow first save cannot race a second one into creating two drafts.
+  const persistDraft = useCallback((): Promise<void> => {
+    const run = async () => {
+      if (issuedRef.current) return;
+      const { snapshot: snap, payload: body } = latest.current;
+      if (snap === savedRef.current) return;
+      setDraftSaving(true);
+      try {
+        const id = await api.saveDraft(draftIdRef.current, body);
+        draftIdRef.current = id;
+        savedRef.current = snap;
+        setDraftId(id);
+        setSavedSnapshot(snap);
+        setSavedAt(new Date());
+        setDraftError(null);
+      } finally {
+        setDraftSaving(false);
+      }
+    };
+    const next = chain.current.then(run);
+    chain.current = next.catch(() => {});
+    return next;
+  }, []);
+
+  useEffect(() => {
+    if (!unsaved) return;
+    const timer = setTimeout(() => {
+      persistDraft()
+        .then(refreshDrafts)
+        .catch((e) => setDraftError(String(e)));
+    }, AUTOSAVE_MS);
+    return () => clearTimeout(timer);
+  }, [unsaved, snapshot, persistDraft, refreshDrafts]);
+
+  useEffect(() => {
+    if (!unsaved) return;
+    const onBeforeUnload = (event: BeforeUnloadEvent) => {
+      event.preventDefault();
+      event.returnValue = "";
+    };
+    window.addEventListener("beforeunload", onBeforeUnload);
+    return () => window.removeEventListener("beforeunload", onBeforeUnload);
+  }, [unsaved]);
+
   const previewProps: InvoicePdfProps = {
     vendor: settings,
     bank,
     logoDataUri: logoUri,
     signatureDataUri: signatureUri,
-    number: number || "DRAFT",
+    number: issued?.number ?? (number || "DRAFT"),
     invoiceDate,
     dueDate,
     clientName,
@@ -177,35 +372,182 @@ export default function NewInvoice({ settings }: NewInvoiceProps) {
     if (selected.stateCode) setPlaceOfSupply(selected.stateCode);
   };
 
-  const resetForNext = async () => {
+  const applyState = (s: InvoiceFormState) => {
-    setClientId(null);
+    setInvoiceDate(s.invoiceDate);
-    setClientName("");
+    setDueDate(s.dueDate);
-    setClientAddress("");
+    setClientId(s.clientId);
-    setClientGstin("");
+    setClientName(s.clientName);
-    setPoNumber("");
+    setClientAddress(s.clientAddress);
-    setSaveClient(false);
+    setClientGstin(s.clientGstin);
-    setItems([newItem()]);
+    setPoNumber(s.poNumber);
-    setDiscount(0);
+    setPlaceOfSupply(s.placeOfSupply);
-    setNotes("");
+    setSaveClient(s.saveClient);
-    setInvoiceDate(todayIso());
+    setItems(s.items);
-    setDueDate(addDays(todayIso(), settings.paymentTermsDays));
+    setDiscount(s.discount);
+    setTaxRate(s.taxRate);
+    setReverseCharge(s.reverseCharge);
+    setBankId(s.bankId);
+    setSignaturePath(s.signaturePath);
+    setNotes(s.notes);
+  };
+
+  const clearIssued = () => {
+    issuedRef.current = false;
+    setIssued(null);
+    setExportedPath(null);
+    setExportError(null);
+    setError(null);
+  };
+
+  const detachDraft = () => {
+    draftIdRef.current = null;
+    savedRef.current = null;
+    setDraftId(null);
+    setSavedSnapshot(null);
+    setSavedAt(null);
+    setDraftError(null);
+  };
+
+  const resetForm = () => {
+    const blank = blankState();
+    applyState(blank);
+    setBaseline(JSON.stringify(toDraftPayload(blank)));
+    clearIssued();
+    detachDraft();
+    void refreshNumber();
+    api.listClients().then(setClients).catch(() => {});
+    void refreshDrafts();
+  };
+
+  // Keeps the work in a draft before it is replaced. Returns false if that was not possible
+  // and the user chose to keep the current form.
+  const parkCurrentWork = async (): Promise<boolean> => {
+    if (locked || !unsaved) return true;
     try {
-      setNumber(await api.peekNextInvoiceNumber());
+      await persistDraft();
-      setClients(await api.listClients());
+      return true;
-    } catch {
+    } catch (e) {
-      /* ignore */
+      return confirm(`The current form could not be saved as a draft (${String(e)}). Discard it?`, {
+        title: "Unsaved changes",
+        kind: "warning",
+      });
+    }
+  };
+
+  const newInvoice = async () => {
+    onActivate();
+    if (!(await parkCurrentWork())) return;
+    resetForm();
+  };
+
+  const duplicateAsNew = () => {
+    const t = todayIso();
+    clearIssued();
+    detachDraft();
+    setInvoiceDate(t);
+    setDueDate(addDays(t, settings.paymentTermsDays));
+    setSaveClient(false);
+    void refreshNumber();
+  };
+
+  const saveDraftNow = async () => {
+    if (locked || !dirty) return;
+    try {
+      await persistDraft();
+      await refreshDrafts();
+    } catch (e) {
+      setDraftError(String(e));
+    }
+  };
+
+  const discardDraft = async () => {
+    const ok = await confirm(
+      draftId !== null
+        ? "Discard this draft and clear the form?"
+        : "Clear the form? Nothing has been saved as a draft.",
+      { title: "Discard draft", kind: "warning" },
+    );
+    if (!ok) return;
+    // Wait for any in-flight save so it cannot recreate the draft after the delete.
+    await chain.current;
+    const id = draftIdRef.current;
+    try {
+      if (id !== null) await api.deleteDraft(id);
+    } catch (e) {
+      setDraftError(String(e));
+      return;
+    }
+    resetForm();
+  };
+
+  const resumeDraft = async (id: number) => {
+    if (id === draftIdRef.current) {
+      setDraftsOpen(false);
+      return;
+    }
+    if (!(await parkCurrentWork())) return;
+    try {
+      const restored = fromDraftPayload(await api.getDraft(id), blankState());
+      if (restored.bankId !== null && !banks.some((b) => b.id === restored.bankId)) {
+        restored.bankId = null;
+      }
+      applyState(restored);
+      setBaseline(JSON.stringify(toDraftPayload(blankState())));
+      clearIssued();
+      const snap = JSON.stringify(toDraftPayload(restored));
+      draftIdRef.current = id;
+      savedRef.current = snap;
+      setDraftId(id);
+      setSavedSnapshot(snap);
+      setSavedAt(null);
+      setDraftError(null);
+      setNoticeOpen(false);
+      setDraftsOpen(false);
+      void refreshNumber();
+      void refreshDrafts();
+    } catch (e) {
+      setError(String(e));
+    }
+  };
+
+  const removeDraft = async (id: number) => {
+    try {
+      await api.deleteDraft(id);
+    } catch (e) {
+      setError(String(e));
+    }
+    await refreshDrafts();
+  };
+
+  const runExport = async (invoice: Invoice) => {
+    setExporting(true);
+    setExportError(null);
+    try {
+      const props = await buildPdfProps(invoice, settings, bank);
+      const path = await exportPdfFromProps(props, invoice.number);
+      setExportedPath(path ?? null);
+    } catch (e) {
+      setExportError(String(e));
+    } finally {
+      setExporting(false);
     }
   };
 
   const onSave = async () => {
+    if (locked || saving) return;
     if (clientGstinError) {
       setError(`Client GSTIN: ${clientGstinError}`);
       return;
     }
     setSaving(true);
     setError(null);
-    setSaved(null);
+    setExportedPath(null);
+    setExportError(null);
+    let invoice: Invoice;
     try {
+      // Let a pending autosave land first so the issue call knows which draft to delete.
+      await chain.current;
+      issuedRef.current = true;
       const input: InvoiceInput = {
         invoiceDate,
         dueDate,
@@ -223,52 +565,161 @@ export default function NewInvoice({ settings }: NewInvoiceProps) {
         signaturePath,
         notes,
         saveClient,
-        draftId: null,
+        draftId: draftIdRef.current,
         items: items.map((item, index) => ({ ...item, sortOrder: index })),
       };
-      const invoice = await api.issueInvoice(input, {});
+      invoice = await api.issueInvoice(input, {});
-      const props = await buildPdfProps(invoice, settings, bank);
-      const path = await exportPdfFromProps(props, invoice.number);
-      if (path) setSaved(path);
-      await resetForNext();
     } catch (e) {
+      issuedRef.current = false;
       setError(String(e));
-    } finally {
       setSaving(false);
+      return;
     }
+    // The number is consumed from here on. A failed export must never lead to a second issue.
+    setIssued(invoice);
+    detachDraft();
+    api.listClients().then(setClients).catch(() => {});
+    void refreshDrafts();
+    await runExport(invoice);
+    setSaving(false);
   };
 
+  useShortcuts({
+    onNew: () => void newInvoice(),
+    onSaveDraft: () => active && void saveDraftNow(),
+    onIssue: () => active && !locked && void onSave(),
+    onAddLine: () => active && !locked && addItem(),
+    onHelp: () => active && setHelpOpen(true),
+  });
+
+  const otherDrafts = drafts.filter((d) => d.id !== draftId);
+  const busy = saving || exporting;
+
   return (
-    <div className="voiced-page">
+    <>
+    <div className="voiced-page" hidden={!active}>
       <Grid>
         <Column sm={4} md={8} lg={16}>
           <div style={{ display: "flex", justifyContent: "space-between", alignItems: "flex-end", gap: "1rem", flexWrap: "wrap" }}>
             <div>
-              <h1 className="voiced-page__title">New invoice</h1>
+              <h1 className="voiced-page__title">{locked ? `Invoice ${issued.number}` : "New invoice"}</h1>
               <p className="voiced-page__subtitle" style={{ marginBottom: 0 }}>
+                {locked ? (
+                  "Issued and read-only. Use the actions below to continue."
+                ) : (
+                  <>
                     Next number: <strong>{number || "—"}</strong>
+                  </>
+                )}
               </p>
             </div>
-            <div className="voiced-header-action">
+            {locked ? null : (
-              <Button kind="ghost" onClick={resetForNext} disabled={saving}>
+              <div className="voiced-header-action" style={{ flexWrap: "wrap" }}>
-                Clear
+                {draftSaving ? (
+                  <InlineLoading status="active" description="Saving draft…" />
+                ) : savedAt && !unsaved ? (
+                  <InlineLoading status="finished" description={`Draft saved ${formatTime(savedAt)}`} />
+                ) : unsaved ? (
+                  <Tag type="gray" size="sm">
+                    Unsaved changes
+                  </Tag>
+                ) : null}
+                {drafts.length > 0 ? (
+                  <Button kind="ghost" onClick={() => setDraftsOpen(true)} disabled={busy}>
+                    {`Drafts (${drafts.length})`}
                   </Button>
-              <Button renderIcon={Save} onClick={onSave} disabled={saving}>
+                ) : null}
+                <Button kind="ghost" renderIcon={Keyboard} hasIconOnly iconDescription="Keyboard shortcuts (?)" tooltipPosition="bottom" onClick={() => setHelpOpen(true)} />
+                {dirty || draftId !== null ? (
+                  <Button kind="ghost" onClick={discardDraft} disabled={busy}>
+                    Discard draft
+                  </Button>
+                ) : null}
+                <Button kind="tertiary" renderIcon={Save} onClick={saveDraftNow} disabled={busy || !dirty}>
+                  Save draft
+                </Button>
+                <Button renderIcon={Download} onClick={onSave} disabled={busy}>
                   {saving ? "Saving…" : "Save & export PDF"}
                 </Button>
               </div>
+            )}
           </div>
           {error ? (
-            <InlineNotification kind="error" lowContrast title="Could not save invoice" subtitle={error} />
+            <InlineNotification
+              kind="error"
+              lowContrast
+              title="Could not save invoice"
+              subtitle={error}
+              onCloseButtonClick={() => setError(null)}
+            />
           ) : null}
-          {saved ? (
+          {draftError ? (
+            <InlineNotification
+              kind="warning"
+              lowContrast
+              title="Draft not saved"
+              subtitle={draftError}
+              onCloseButtonClick={() => setDraftError(null)}
+            />
+          ) : null}
+          {!locked && noticeOpen && !dirty && otherDrafts.length > 0 ? (
+            <ActionableNotification
+              inline
+              kind="info"
+              lowContrast
+              title={`You have ${otherDrafts.length} unfinished draft${otherDrafts.length === 1 ? "" : "s"}`}
+              subtitle="Pick up where you left off."
+              actionButtonLabel="Resume latest"
+              onActionButtonClick={() => void resumeDraft(otherDrafts[0].id)}
+              onCloseButtonClick={() => setNoticeOpen(false)}
+            />
+          ) : null}
+          {locked ? (
+            <>
+              {exportError ? (
+                <InlineNotification
+                  kind="error"
+                  lowContrast
+                  hideCloseButton
+                  title={`Invoice ${issued.number} was issued, but the PDF export failed`}
+                  subtitle={`${exportError} The number is already used; retry the export, do not issue again.`}
+                />
+              ) : exportedPath ? (
                 <InlineNotification
                   kind="success"
                   lowContrast
-              title="Invoice saved"
+                  hideCloseButton
-              subtitle={saved}
+                  title={`Invoice ${issued.number} issued`}
-              onCloseButtonClick={() => setSaved(null)}
+                  subtitle={exportedPath}
                 />
+              ) : exporting ? (
+                <InlineLoading description="Exporting PDF…" />
+              ) : (
+                <InlineNotification
+                  kind="info"
+                  lowContrast
+                  hideCloseButton
+                  title={`Invoice ${issued.number} issued`}
+                  subtitle="The PDF was not saved. Use Export again to save it."
+                />
+              )}
+              <div className="voiced-header-action" style={{ flexWrap: "wrap", marginTop: "0.5rem" }}>
+                <Button
+                  kind={exportError ? "primary" : "tertiary"}
+                  renderIcon={exportError ? Renew : Download}
+                  onClick={() => void runExport(issued)}
+                  disabled={exporting}
+                >
+                  {exporting ? "Exporting…" : exportError ? "Retry export" : "Export again"}
+                </Button>
+                <Button kind="tertiary" renderIcon={Copy} onClick={duplicateAsNew} disabled={exporting}>
+                  Duplicate as new
+                </Button>
+                <Button kind="tertiary" renderIcon={DocumentAdd} onClick={() => void newInvoice()} disabled={exporting}>
+                  New invoice
+                </Button>
+              </div>
+            </>
           ) : null}
           <div style={{ marginTop: "1.5rem" }} />
         </Column>
@@ -278,6 +729,7 @@ export default function NewInvoice({ settings }: NewInvoiceProps) {
             <Column sm={4} md={4} lg={5}>
               <TextInput
                 id="invoiceDate"
+                disabled={locked}
                 type="date"
                 labelText="Invoice date"
                 value={invoiceDate}
@@ -290,6 +742,7 @@ export default function NewInvoice({ settings }: NewInvoiceProps) {
             <Column sm={4} md={4} lg={5}>
               <TextInput
                 id="dueDate"
+                disabled={locked}
                 type="date"
                 labelText={`Due date (net ${settings.paymentTermsDays} days)`}
                 value={dueDate}
@@ -297,22 +750,25 @@ export default function NewInvoice({ settings }: NewInvoiceProps) {
               />
             </Column>
             <Column sm={4} md={8} lg={6}>
-              <TextInput id="invoiceNumber" labelText="Invoice number" value={number} readOnly />
+              <TextInput id="invoiceNumber" labelText="Invoice number" value={issued?.number ?? number} readOnly />
             </Column>
 
             <Column sm={4} md={8} lg={8}>
               <Dropdown
                 id="savedClient"
+                disabled={locked}
                 titleText="Saved client (optional)"
                 label="Select a saved client to autofill"
                 items={clients}
                 itemToString={(item) => (item ? item.name : "")}
+                selectedItem={clients.find((c) => c.id === clientId) ?? null}
                 onChange={({ selectedItem }) => selectedItem && applyClient(selectedItem)}
               />
             </Column>
             <Column sm={4} md={8} lg={8}>
               <TextInput
                 id="clientName"
+                disabled={locked}
                 labelText="Client name"
                 value={clientName}
                 onChange={(e) => {
@@ -324,6 +780,7 @@ export default function NewInvoice({ settings }: NewInvoiceProps) {
             <Column sm={4} md={8} lg={16}>
               <TextArea
                 id="clientAddress"
+                disabled={locked}
                 labelText="Client address"
                 rows={3}
                 value={clientAddress}
@@ -333,6 +790,7 @@ export default function NewInvoice({ settings }: NewInvoiceProps) {
             <Column sm={4} md={4} lg={5}>
               <TextInput
                 id="clientGstin"
+                disabled={locked}
                 labelText="Client GSTIN (optional)"
                 value={clientGstin}
                 onChange={(e) => setClientGstin(e.target.value.toUpperCase())}
@@ -343,6 +801,7 @@ export default function NewInvoice({ settings }: NewInvoiceProps) {
             <Column sm={4} md={4} lg={5}>
               <TextInput
                 id="poNumber"
+                disabled={locked}
                 labelText="PO number (optional)"
                 value={poNumber}
                 onChange={(e) => setPoNumber(e.target.value)}
@@ -351,6 +810,7 @@ export default function NewInvoice({ settings }: NewInvoiceProps) {
             <Column sm={4} md={8} lg={6}>
               <Select
                 id="placeOfSupply"
+                disabled={locked}
                 labelText="Place of supply"
                 value={placeOfSupply}
                 onChange={(e) => setPlaceOfSupply(e.target.value)}
@@ -363,6 +823,7 @@ export default function NewInvoice({ settings }: NewInvoiceProps) {
             <Column sm={4} md={8} lg={16}>
               <Toggle
                 id="saveClient"
+                disabled={locked}
                 labelText="Save this client for next time"
                 toggled={saveClient}
                 onToggle={setSaveClient}
@@ -388,6 +849,7 @@ export default function NewInvoice({ settings }: NewInvoiceProps) {
                 <div style={{ flex: "3 1 240px" }}>
                   <TextInput
                     id={`desc-${index}`}
+                    disabled={locked}
                     labelText="Particulars / description"
                     value={item.description}
                     onChange={(e) => updateItem(index, { description: e.target.value })}
@@ -397,6 +859,7 @@ export default function NewInvoice({ settings }: NewInvoiceProps) {
                   <div style={{ flex: "0 1 120px" }}>
                     <TextInput
                       id={`hsn-${index}`}
+                      disabled={locked}
                       labelText="HSN/SAC"
                       value={item.hsnSac ?? ""}
                       onChange={(e) => updateItem(index, { hsnSac: e.target.value })}
@@ -406,6 +869,7 @@ export default function NewInvoice({ settings }: NewInvoiceProps) {
                 <div style={{ flex: "0 1 150px" }}>
                   <Select
                     id={`mode-${index}`}
+                    disabled={locked}
                     labelText="Type"
                     value={item.mode}
                     onChange={(e) => updateItem(index, { mode: e.target.value as LineMode })}
@@ -419,6 +883,7 @@ export default function NewInvoice({ settings }: NewInvoiceProps) {
                     <div style={{ flex: "0 1 130px" }}>
                       <NumberInput
                         id={`rate-${index}`}
+                        disabled={locked}
                         label="Rate (₹)"
                         min={0}
                         step={1}
@@ -429,6 +894,7 @@ export default function NewInvoice({ settings }: NewInvoiceProps) {
                     <div style={{ flex: "0 1 140px" }}>
                       <Select
                         id={`unit-${index}`}
+                        disabled={locked}
                         labelText="Unit"
                         value={item.unit}
                         onChange={(e) => updateItem(index, { unit: e.target.value as LineUnit })}
@@ -441,6 +907,7 @@ export default function NewInvoice({ settings }: NewInvoiceProps) {
                     <div style={{ flex: "0 1 110px" }}>
                       <NumberInput
                         id={`qty-${index}`}
+                        disabled={locked}
                         label="Quantity"
                         min={0}
                         step={1}
@@ -453,6 +920,7 @@ export default function NewInvoice({ settings }: NewInvoiceProps) {
                   <div style={{ flex: "0 1 150px" }}>
                     <NumberInput
                       id={`amount-${index}`}
+                      disabled={locked}
                       label="Amount (₹)"
                       min={0}
                       step={1}
@@ -471,11 +939,11 @@ export default function NewInvoice({ settings }: NewInvoiceProps) {
                   renderIcon={TrashCan}
                   iconDescription="Remove line"
                   onClick={() => removeItem(index)}
-                  disabled={items.length === 1}
+                  disabled={locked || items.length === 1}
                 />
               </div>
             ))}
-            <Button kind="tertiary" size="sm" renderIcon={Add} onClick={addItem}>
+            <Button kind="tertiary" size="sm" renderIcon={Add} onClick={addItem} disabled={locked}>
               Add line
             </Button>
           </div>
@@ -484,6 +952,7 @@ export default function NewInvoice({ settings }: NewInvoiceProps) {
             <Column sm={4} md={4} lg={8}>
               <NumberInput
                 id="discount"
+                disabled={locked}
                 label="Discount (₹)"
                 min={0}
                 step={1}
@@ -503,6 +972,7 @@ export default function NewInvoice({ settings }: NewInvoiceProps) {
                 <Column sm={4} md={4} lg={8}>
                   <NumberInput
                     id="taxRate"
+                    disabled={locked}
                     label="Tax rate (%)"
                     min={0}
                     max={100}
@@ -514,6 +984,7 @@ export default function NewInvoice({ settings }: NewInvoiceProps) {
                 <Column sm={4} md={8} lg={16}>
                   <Toggle
                     id="reverseCharge"
+                    disabled={locked}
                     labelText="Tax payable on reverse charge"
                     toggled={reverseCharge}
                     onToggle={setReverseCharge}
@@ -525,6 +996,7 @@ export default function NewInvoice({ settings }: NewInvoiceProps) {
 
           <Select
             id="bankAccount"
+            disabled={locked}
             labelText="Bank account (Pay To)"
             value={bankId ?? ""}
             onChange={(e) => setBankId(e.target.value ? Number(e.target.value) : null)}
@@ -544,10 +1016,12 @@ export default function NewInvoice({ settings }: NewInvoiceProps) {
             label="Signature for this invoice (optional)"
             value={signaturePath}
             onChange={setSignaturePath}
+            disabled={locked}
           />
 
           <TextArea
             id="notes"
+            disabled={locked}
             labelText="Notes (optional)"
             rows={2}
             value={notes}
@@ -563,5 +1037,81 @@ export default function NewInvoice({ settings }: NewInvoiceProps) {
         </Column>
       </Grid>
     </div>
+
+    <Modal
+      open={draftsOpen}
+      passiveModal
+      size="md"
+      modalHeading="Unfinished drafts"
+      onRequestClose={() => setDraftsOpen(false)}
+    >
+      <Table size="md" aria-label="Drafts">
+        <TableHead>
+          <TableRow>
+            <TableHeader>Client</TableHeader>
+            <TableHeader>Last edited</TableHeader>
+            <TableHeader>Actions</TableHeader>
+          </TableRow>
+        </TableHead>
+        <TableBody>
+          {drafts.map((d) => (
+            <TableRow key={d.id}>
+              <TableCell>{d.clientName || "—"}</TableCell>
+              <TableCell>{formatStamp(d.updatedAt)}</TableCell>
+              <TableCell>
+                {d.id === draftId ? (
+                  <Tag type="blue" size="sm">
+                    Open now
+                  </Tag>
+                ) : (
+                  <div className="voiced-header-action">
+                    <Button kind="ghost" size="sm" onClick={() => void resumeDraft(d.id)}>
+                      Resume
+                    </Button>
+                    <Button
+                      kind="ghost"
+                      size="sm"
+                      hasIconOnly
+                      renderIcon={TrashCan}
+                      iconDescription="Delete draft"
+                      onClick={() => void removeDraft(d.id)}
+                    />
+                  </div>
+                )}
+              </TableCell>
+            </TableRow>
+          ))}
+        </TableBody>
+      </Table>
+      {drafts.length === 0 ? <p style={{ marginTop: "1rem" }}>No drafts.</p> : null}
+    </Modal>
+
+    <Modal
+      open={helpOpen}
+      passiveModal
+      size="sm"
+      modalHeading="Keyboard shortcuts"
+      onRequestClose={() => setHelpOpen(false)}
+    >
+      <Table size="md" aria-label="Keyboard shortcuts">
+        <TableHead>
+          <TableRow>
+            <TableHeader>Keys</TableHeader>
+            <TableHeader>Action</TableHeader>
+          </TableRow>
+        </TableHead>
+        <TableBody>
+          {SHORTCUT_LIST.map((row) => (
+            <TableRow key={row.keys}>
+              <TableCell>
+                <strong>{row.keys}</strong>
+              </TableCell>
+              <TableCell>{row.action}</TableCell>
+            </TableRow>
+          ))}
+        </TableBody>
+      </Table>
+    </Modal>
+    </>
   );
 }

src/views/SeriesSettings.tsx

@@ -1,4 +1,4 @@
-import { useEffect, useState } from "react";
+import { useEffect, useRef, useState } from "react";
 import {
   Button,
   Column,
@@ -20,7 +20,7 @@ import { confirm } from "@tauri-apps/plugin-dialog";
 import { api } from "../lib/api";
 import type { InvoiceSeries } from "../lib/types";
 
-export default function SeriesSettings() {
+export default function SeriesSettings({ active: visible }: { active: boolean }) {
   const [active, setActive] = useState<InvoiceSeries | null>(null);
   const [all, setAll] = useState<InvoiceSeries[]>([]);
   const [loading, setLoading] = useState(true);
@@ -31,14 +31,18 @@ export default function SeriesSettings() {
   const [error, setError] = useState<string | null>(null);
   const [notice, setNotice] = useState<string | null>(null);
 
+  const seeded = useRef(false);
+
   const load = async () => {
     try {
       const [current, list] = await Promise.all([api.getActiveSeries(), api.listSeries()]);
       setActive(current);
       setAll(list);
-      if (current) {
+      // Only seed the form once, so a refetch on re-entry does not overwrite what was typed.
+      if (current && !seeded.current) {
         setPrefix(current.prefix);
         setPadding(current.padding);
+        seeded.current = true;
       }
       setError(null);
     } catch (e) {
@@ -48,9 +52,10 @@ export default function SeriesSettings() {
     }
   };
 
+  // The view stays mounted, so refetch every time it is shown again.
   useEffect(() => {
-    void load();
+    if (visible) void load();
-  }, []);
+  }, [visible]);
 
   const startNew = async () => {
     const ok = await confirm(