Add the ERPNext settings UI, History and detail controls, and voiced.invoice.v1 export (Phase F3)

- Settings gets an Integrations tab: connection fields with a write-only API secret, a CA PEM option, Test connection with versions and warnings, live mapping lists loaded after a test, naming mode, toggles and its own Save.
- Pushing for a GST-registered vendor is refused until a connection test result is stored. The UI shows the reason and disables Send.
- History shows an ERPNext status column from one bulk call, a row Send and Open in ERPNext, and a bulk Send selected with a draft-or-submit confirm step and per-row results that never abort the batch. The detail view gets an ERPNext panel and per-payment send. All of it is hidden or disabled when the integration is not configured.
- Optional auto-push after issue runs in the background and never blocks or fails the issue.
- Generic export: a deterministic voiced.invoice.v1 JSON (and CSV line items) for selected invoices, documented in docs/voiced-invoice-v1.md with a golden test. Money is integer paise plus a decimal string.

The new screens have not been run in a webview yet. The ERPNext Payment Entry deduction fields still need a live check.

docs/voiced-invoice-v1.md

@@ -0,0 +1,51 @@
+# voiced.invoice.v1
+
+A neutral export of issued invoices for software Voiced has no direct integration with. Choose invoices in the
+History list (checkboxes) or open one, then use "Export selected (voiced.invoice.v1 JSON)" or "(line items CSV)".
+The code is `src/lib/invoiceExportV1.ts`; `src/lib/__golden__/invoice-v1.golden.json` is a full example.
+
+## Rules
+
+- **Money is exact.** Every amount appears twice: `<name>_paise` (an integer) and `<name>` (a decimal string with two
+  places, e.g. `"7310.10"`). Nothing is a float. Rates (percent) are decimal strings such as `"9"` or `"6.25"`.
+- **Deterministic.** The same invoices give the same bytes: fixed key order, no timestamps, input order kept.
+- **JSON file** is an array with one object per invoice; each object carries `"schema": "voiced.invoice.v1"`.
+- Cancelled invoices are included with `"cancelled": true` (their figures are kept; filter them out of sums).
+- An unregistered supplier's plain "Invoice" has `document_type: "invoice"`, all tax heads zero and no supplier GSTIN.
+
+## Invoice object
+
+| Key | Meaning |
+| --- | --- |
+| `schema`, `number`, `issue_date`, `due_date` | `YYYY-MM-DD` dates; `due_date` is null when unset |
+| `document_type` | `tax_invoice` or `invoice` |
+| `status`, `cancelled`, `cancelled_at`, `cancel_reason` | `status` is `issued` or `cancelled` |
+| `currency`, `po_number` | always `INR` |
+| `supplier` | `name`, `address`, `gstin` (null if none), `pan`, `gst_registration`, `state {code, name}`; frozen at issue |
+| `client` | `name`, `gstin`, `gst_category`, `address {text, line1, line2, city, pincode, state}`, `place_of_supply {code, name}` |
+| `items[]` | `line`, `description`, `hsn_sac`, `quantity` (decimal string), `unit`, `rate`, `taxable_value` (each with `_paise`) |
+| `tax` | `cgst`, `sgst`, `utgst`, `igst`, each `{rate, amount_paise, amount}`; heads that do not apply are zero |
+| `totals` | `subtotal`, `discount`, `taxable_value`, `tax`, `total` (each with `_paise`), `amount_in_words` |
+| `reverse_charge`, `notes` | |
+| `payments[]` | `date`, `amount` (cash), `tds`, `mode`, `reference` (amounts with `_paise`) |
+
+Notes on the fields:
+
+- **Items.** `taxable_value` of a line is the line amount before the invoice-level discount. `totals.taxable_value` is
+  `subtotal - discount`, the base the tax is charged on. A fixed-amount line has `quantity "1"` and `unit null`.
+- **UTGST.** When the supplier is in a union territory without a legislature (state codes 04, 26, 31, 35, 38) the second
+  head is reported under `utgst` and `sgst` is zero.
+- **Client details.** The name, GSTIN, printed address and place of supply are frozen on the invoice. The structured
+  address parts and `gst_category` come from the client's saved record at export time (null or derived from the GSTIN
+  when the invoice has no saved client).
+- **Supplier snapshot.** Only name, address, GSTIN, PAN, registration and state are exported; logo paths, e-mail and
+  phone are not.
+
+## Line-items CSV
+
+One row per line item, UTF-8 with a byte order mark and CRLF line ends; text cells that a spreadsheet would read as a
+formula get a leading apostrophe. Columns: `invoice_number, issue_date, due_date, document_type, status, cancelled,
+currency, supplier_name, supplier_gstin, client_name, client_gstin, client_gst_category, place_of_supply_code,
+place_of_supply, reverse_charge, line, description, hsn_sac, quantity, unit, rate, taxable_value, invoice_discount,
+invoice_cgst, invoice_sgst, invoice_utgst, invoice_igst, invoice_total`. The `invoice_*` amounts are filled on the first
+row of each invoice only, so summing a column never counts an invoice twice.

src-tauri/src/commands/payments.rs

@@ -30,6 +30,9 @@ pub struct Payment {
     pub reference: String,
     pub notes: String,
     pub created_at: String,
+    /// Name of the Payment Entry on ERPNext once this payment was sent; `None` until then.
+    #[serde(default)]
+    pub erpnext_payment_entry: Option<String>,
 }
 
 #[derive(Debug, Clone, Deserialize)]
@@ -127,10 +130,11 @@ fn map_payment(r: &rusqlite::Row) -> rusqlite::Result<Payment> {
         reference: r.get(6)?,
         notes: r.get(7)?,
         created_at: r.get(8)?,
+        erpnext_payment_entry: r.get::<_, Option<String>>(9)?.filter(|e| !e.trim().is_empty()),
     })
 }
 
-const COLS: &str = "id, invoice_id, paid_on, amount_paise, tds_paise, mode, reference, notes, created_at";
+const COLS: &str = "id, invoice_id, paid_on, amount_paise, tds_paise, mode, reference, notes, created_at, erpnext_payment_entry";
 
 pub fn record_payment_impl(conn: &mut Connection, input: PaymentInput) -> Result<Payment, String> {
     let db = |e: rusqlite::Error| e.to_string();

src-tauri/src/integrations/erpnext/push.rs

@@ -323,6 +323,14 @@ fn load_item_codes(conn: &Connection, inv: &Invoice) -> Result<Vec<Option<String
     Ok(inv.items.iter().map(|i| by_desc.get(&i.description.trim().to_lowercase()).cloned()).collect())
 }
 
+/// True when a connection test result is stored (blank, `null` and `{}` count as none).
+fn has_detect_result(raw: &str) -> bool {
+    match serde_json::from_str::<Value>(raw) {
+        Ok(Value::Object(m)) => !m.is_empty(),
+        _ => false,
+    }
+}
+
 fn load_for_push(db: &Db, local_dir: &Path, invoice_id: i64) -> Result<Loaded, (String, ErpError)> {
     let conn = db
         .lock()
@@ -346,6 +354,11 @@ fn load_for_push(db: &Db, local_dir: &Path, invoice_id: i64) -> Result<Loaded, (
     let cfg = config::load(&conn).map_err(|e| fail(pre(e)))?;
     let vendor = Vendor::from_snapshot(&invoice.vendor_snapshot)
         .ok_or_else(|| fail(pre(format!("Invoice {number} has no supplier details recorded, so it cannot be sent."))))?;
+    // A registered vendor's invoices go out with India Compliance fields, and those depend on what the
+    // connection test detected, so refuse until the test has run once.
+    if vendor.registered && !has_detect_result(&cfg.last_detect_result) {
+        return Err(fail(pre("Run Test connection first (Settings, Integrations): Voiced has not yet checked this ERPNext site.")));
+    }
     let client = load_client(&conn, &invoice).map_err(|e| fail(pre(e)))?;
     let item_codes = load_item_codes(&conn, &invoice).map_err(|e| fail(pre(e)))?;
     let sync = load_sync(&conn, invoice_id).map_err(|e| fail(pre(e)))?;

src-tauri/src/integrations/erpnext/push/tests.rs

@@ -518,6 +518,45 @@ async fn cancelled_and_draft_invoices_are_refused_before_any_request() {
     assert!(fx.sync_row(inv.id).is_none() && fx.sync_row(draft_id).is_none());
 }
 
+#[tokio::test]
+async fn a_registered_vendor_must_run_the_connection_test_before_pushing() {
+    let fx = Fx::new(|c| c.last_detect_result = String::new());
+    let inv = fx.issue("Client Ltd");
+    let mut routes = master_routes();
+    routes.push(mirror_create(&inv.number, 0, inv.total));
+    let m = mock(routes).await;
+
+    let r = fx.push(&m, inv.id, Some(false)).await;
+    assert!(!r.ok && r.status == "refused" && r.error_kind == Some(ErrorKind::Precondition), "{r:?}");
+    assert!(r.error.as_deref().unwrap().contains("Run Test connection first"), "{r:?}");
+    assert!(m.requests.lock().unwrap().is_empty());
+    assert!(fx.sync_row(inv.id).is_none());
+
+    // `{}` and `null` are as good as nothing; a stored result unlocks the push.
+    assert!(!has_detect_result("") && !has_detect_result("{}") && !has_detect_result("null"));
+    fx.db.lock().unwrap().execute("UPDATE erpnext_config SET last_detect_result = '{\"indiaCompliance\":false}'", []).unwrap();
+    let r = fx.push(&m, inv.id, Some(false)).await;
+    assert!(r.ok, "{r:?}");
+}
+
+#[tokio::test]
+async fn an_unregistered_vendor_needs_no_connection_test() {
+    let fx = Fx::new(|c| c.last_detect_result = String::new());
+    let inv = fx.issue("Other Co");
+    // Only the frozen supplier snapshot decides whether the invoice counts as a registered vendor's.
+    fx.db
+        .lock()
+        .unwrap()
+        .execute("UPDATE invoices SET vendor_snapshot = replace(vendor_snapshot, '\"gstRegistration\":\"regular\"', '\"gstRegistration\":\"unregistered\"')", [])
+        .unwrap();
+    assert!(!Vendor::from_snapshot(&get_invoice_impl(&fx.db.lock().unwrap(), inv.id).unwrap().vendor_snapshot).unwrap().registered);
+    let mut routes = master_routes();
+    routes.push(mirror_create(&inv.number, 0, inv.total));
+    let m = mock(routes).await;
+    let r = fx.push(&m, inv.id, Some(false)).await;
+    assert!(r.status != "refused", "{r:?}");
+}
+
 #[tokio::test]
 async fn an_unarchived_invoice_is_pushed_without_a_pdf_and_attached_by_a_later_push() {
     let fx = Fx::new(|_| {});

src/App.tsx

@@ -10,6 +10,7 @@ import InvoiceDetail from "./views/InvoiceDetail";
 import Clients from "./views/Clients";
 import { ToastProvider, useToast } from "./components/ToastProvider";
 import AppSettings from "./views/AppSettings";
+import { requestSettingsTab } from "./lib/settingsTab";
 
 export default function App() {
   return (
@@ -89,6 +90,11 @@ function AppInner() {
     );
   }
 
+  const openIntegrations = () => {
+    requestSettingsTab("integrations");
+    setView("settings");
+  };
+
   const toggleTheme = async () => {
     const next: Settings = { ...settings, theme: settings.theme === "g100" ? "g10" : "g100" };
     setSettings(next);
@@ -115,6 +121,7 @@ function AppInner() {
           <InvoiceHistory
             settings={settings}
             active={view === "invoices"}
+            onOpenSettings={openIntegrations}
             onOpen={(id) => {
               setDetailId(id);
               setView("invoice");
@@ -127,6 +134,7 @@ function AppInner() {
             invoiceId={detailId}
             settings={settings}
             onBack={() => setView("invoices")}
+            onOpenSettings={openIntegrations}
             onDuplicated={(draftId) => {
               setOpenDraftId(draftId);
               setView("new");

src/components/ErpnextSettingsPanel.tsx

@@ -0,0 +1,591 @@
+import { useCallback, useEffect, useMemo, useState } from "react";
+import {
+  Button,
+  ComboBox,
+  FileUploaderButton,
+  InlineLoading,
+  InlineNotification,
+  PasswordInput,
+  RadioButton,
+  RadioButtonGroup,
+  TextArea,
+  TextInput,
+  Tag,
+  Tile,
+  Toggle,
+} from "@carbon/react";
+import { Save } from "@carbon/icons-react";
+import { api } from "../lib/api";
+import type { ErpnextConfig, ErpnextConfigInput, ErpnextConnectionTest, ErpnextOptionItem, ErpnextOptions } from "../lib/erpnext";
+import {
+  OPTION_LIST_LABELS,
+  UOM_UNITS,
+  connectionProblems,
+  emptyOptions,
+  hasProblems,
+  mirrorSupported,
+  optionErrors,
+  optionText,
+  sortWarnings,
+  toInput,
+  validateConfigForm,
+  versionsLine,
+  warningSeverity,
+  withStoredValue,
+  type FormProblems,
+} from "../lib/erpnextUi";
+import { useToast } from "./ToastProvider";
+
+const SEVERITY_TITLE = { error: "Needs fixing", warning: "Warning", info: "Note" } as const;
+
+interface PickProps {
+  id: string;
+  label: string;
+  value: string;
+  onChange: (value: string) => void;
+  /** The loaded list; an empty list means "not loaded", and the field takes typed text instead. */
+  items: ErpnextOptionItem[];
+  /** Why this list is empty although the lists were loaded (a load error for this list). */
+  error?: string;
+  /** The control is switched off, with the reason shown under it. */
+  disabledReason?: string;
+  helper?: string;
+}
+
+/** A searchable dropdown over a live list, or a text box while the list has not been loaded. */
+function PickField({ id, label, value, onChange, items, error, disabledReason, helper }: PickProps) {
+  const options = useMemo(() => withStoredValue(items, value), [items, value]);
+  const note = disabledReason ?? error ?? helper;
+  if (items.length === 0 || disabledReason) {
+    return (
+      <TextInput
+        id={id}
+        labelText={label}
+        value={value}
+        disabled={Boolean(disabledReason)}
+        invalid={Boolean(error) && !disabledReason}
+        invalidText={error}
+        helperText={error ? undefined : note}
+        onChange={(e) => onChange(e.target.value)}
+      />
+    );
+  }
+  return (
+    <ComboBox
+      id={id}
+      titleText={label}
+      items={options}
+      itemToString={(i: ErpnextOptionItem | null) => (i ? optionText(i) : "")}
+      selectedItem={options.find((o) => o.name === value) ?? null}
+      onChange={({ selectedItem }: { selectedItem?: ErpnextOptionItem | null }) => onChange(selectedItem?.name ?? "")}
+      shouldFilterItem={({ item, inputValue }: { item: ErpnextOptionItem; inputValue: string | null }) =>
+        !inputValue || optionText(item).toLowerCase().includes(inputValue.toLowerCase())
+      }
+      helperText={helper}
+      placeholder="Search or choose"
+    />
+  );
+}
+
+function Section({ title, children, note }: { title: string; children: React.ReactNode; note?: string }) {
+  return (
+    <section className="voiced-erp__section" aria-label={title}>
+      <h3>{title}</h3>
+      {note ? <p className="voiced-muted">{note}</p> : null}
+      <div className="voiced-erp__fields">{children}</div>
+    </section>
+  );
+}
+
+/** Settings, Integrations, ERPNext. It has its own Save: the page-level Save settings button does not cover it. */
+export default function ErpnextSettingsPanel({ active }: { active: boolean }) {
+  const toast = useToast();
+  const [saved, setSaved] = useState<ErpnextConfig | null>(null);
+  const [form, setForm] = useState<ErpnextConfigInput | null>(null);
+  const [loadError, setLoadError] = useState<string | null>(null);
+  const [replacing, setReplacing] = useState(false);
+  const [test, setTest] = useState<ErpnextConnectionTest | null>(null);
+  /** A test result from this session that is not saved yet. */
+  const [testUnsaved, setTestUnsaved] = useState(false);
+  const [testError, setTestError] = useState<string | null>(null);
+  const [testing, setTesting] = useState(false);
+  const [options, setOptions] = useState<ErpnextOptions | null>(null);
+  const [loadingOptions, setLoadingOptions] = useState(false);
+  const [saving, setSaving] = useState(false);
+  const [showProblems, setShowProblems] = useState(false);
+  const [saveError, setSaveError] = useState<string | null>(null);
+
+  const load = useCallback(async () => {
+    try {
+      const cfg = await api.erpnextGetConfig();
+      setSaved(cfg);
+      setForm(toInput(cfg));
+      setTest(cfg.lastDetectResult);
+      setTestUnsaved(false);
+      setLoadError(null);
+    } catch (e) {
+      setLoadError(String(e));
+    }
+  }, []);
+
+  useEffect(() => {
+    if (active && form === null) void load();
+    // Reload only on first show; edits must survive switching tabs.
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [active]);
+
+  if (loadError) {
+    return <InlineNotification kind="error" lowContrast hideCloseButton title="Could not load the ERPNext settings" subtitle={loadError} />;
+  }
+  if (!form || !saved) return <InlineLoading description="Loading ERPNext settings" />;
+
+  const set = <K extends keyof ErpnextConfigInput>(key: K, value: ErpnextConfigInput[K]) => setForm((f) => (f ? { ...f, [key]: value } : f));
+  const secretStored = saved.apiSecretSet;
+  const secretShown = secretStored && !replacing && !form.clearSecret;
+  const problems: FormProblems = showProblems ? validateConfigForm(form, secretStored, test) : {};
+  const connProblems = connectionProblems(form, secretStored);
+  const canConnect = !hasProblems(connProblems);
+  const optErrors = optionErrors(options);
+  const opts = options ?? emptyOptions();
+  const noCompany = !form.company.trim();
+  const companyReason = noCompany ? "Pick a company first." : undefined;
+  const seriesMode = form.namingMode === "series";
+  const mirrorOk = mirrorSupported(test);
+
+  const loadOptions = async (values: ErpnextConfigInput) => {
+    setLoadingOptions(true);
+    try {
+      setOptions(await api.erpnextLoadOptions(values));
+    } catch (e) {
+      setOptions(null);
+      toast.error("Could not load the ERPNext lists", String(e));
+    } finally {
+      setLoadingOptions(false);
+    }
+  };
+
+  const runTest = async () => {
+    setShowProblems(true);
+    if (!canConnect) return;
+    setTesting(true);
+    setTestError(null);
+    try {
+      const result = await api.erpnextTestConnection(form);
+      setTest(result);
+      setTestUnsaved(true);
+      let next = form;
+      // A site that keeps no posted name cannot mirror the Voiced number.
+      if (!result.features.v2Naming && form.namingMode === "mirror") {
+        next = { ...form, namingMode: "series" };
+        setForm(next);
+      }
+      await loadOptions(next);
+    } catch (e) {
+      setTestError(String(e));
+    } finally {
+      setTesting(false);
+    }
+  };
+
+  const changeCompany = (company: string) => {
+    const next = { ...form, company };
+    setForm(next);
+    // Accounts, addresses and cost centers belong to the company, so the lists are reloaded for it.
+    if (options && canConnect) void loadOptions(next);
+  };
+
+  const save = async () => {
+    setShowProblems(true);
+    setSaveError(null);
+    if (hasProblems(validateConfigForm(form, secretStored, test))) return;
+    setSaving(true);
+    try {
+      const cfg = await api.erpnextSaveConfig({ ...form, ...(testUnsaved && test ? { lastDetectResult: test } : {}) });
+      setSaved(cfg);
+      setForm(toInput(cfg));
+      setReplacing(false);
+      setTest(cfg.lastDetectResult ?? test);
+      setTestUnsaved(false);
+      setShowProblems(false);
+      toast.success("ERPNext settings saved");
+    } catch (e) {
+      const text = String(e);
+      setSaveError(text);
+      toast.error("Could not save the ERPNext settings", text);
+    } finally {
+      setSaving(false);
+    }
+  };
+
+  const readPem = async (file: File | undefined) => {
+    if (!file) return;
+    try {
+      set("extraCaPem", (await file.text()).trim());
+    } catch (e) {
+      toast.error("Could not read the certificate file", String(e));
+    }
+  };
+
+  const secretInvalid = problems.apiSecret ?? (saveError && /secret again/i.test(saveError) ? saveError : undefined);
+
+  return (
+    <div className="voiced-stack voiced-erp">
+      <div>
+        <h2 className="voiced-detail__h2">ERPNext</h2>
+        <p>
+          Send issued invoices and payments to your ERPNext site as Sales Invoices. Everything is sent from this computer; ERPNext is never
+          needed to issue an invoice.
+        </p>
+        <p className="voiced-muted">
+          Create a dedicated ERPNext user for Voiced with only these permissions: create and submit Sales Invoice, read on the master data
+          (Customer, Item, Address, Account, Company), and write on File. Use that user&rsquo;s API key and secret below. An address must be
+          https://; plain http is only allowed for localhost, 127.0.0.1, *.localhost and *.test hosts.
+        </p>
+      </div>
+
+      <Section title="Connection">
+        <TextInput
+          id="erp-baseUrl"
+          labelText="Site address"
+          placeholder="https://erp.example.com"
+          value={form.baseUrl}
+          invalid={Boolean(problems.baseUrl)}
+          invalidText={problems.baseUrl}
+          onChange={(e) => set("baseUrl", e.target.value)}
+        />
+        <TextInput
+          id="erp-apiKey"
+          labelText="API key"
+          autoComplete="off"
+          value={form.apiKey}
+          invalid={Boolean(problems.apiKey)}
+          invalidText={problems.apiKey}
+          onChange={(e) => set("apiKey", e.target.value)}
+        />
+        {secretShown ? (
+          <div className="voiced-erp__secret">
+            <p className="voiced-erp__label" id="erp-secret-label">
+              API secret
+            </p>
+            <p aria-labelledby="erp-secret-label">
+              <Tag type="green" size="sm">
+                set
+              </Tag>{" "}
+              <span className="voiced-muted">The secret is stored on this computer and is never shown again.</span>
+            </p>
+            <div className="voiced-header-action">
+              <Button kind="tertiary" size="sm" onClick={() => setReplacing(true)}>
+                Replace
+              </Button>
+              <Button kind="ghost" size="sm" onClick={() => set("clearSecret", true)}>
+                Clear
+              </Button>
+            </div>
+          </div>
+        ) : (
+          <div>
+            <PasswordInput
+              id="erp-apiSecret"
+              labelText="API secret"
+              autoComplete="new-password"
+              value={form.apiSecret}
+              invalid={Boolean(secretInvalid)}
+              invalidText={secretInvalid}
+              helperText={form.clearSecret ? "The stored secret is removed when you save, unless you type a new one." : undefined}
+              onChange={(e) => set("apiSecret", e.target.value)}
+            />
+            {secretStored ? (
+              <Button
+                kind="ghost"
+                size="sm"
+                onClick={() => {
+                  setReplacing(false);
+                  setForm((f) => (f ? { ...f, apiSecret: "", clearSecret: false } : f));
+                }}
+              >
+                Keep the stored secret
+              </Button>
+            ) : null}
+          </div>
+        )}
+        <div>
+          <TextArea
+            id="erp-extraCa"
+            labelText="Extra CA certificate (optional, PEM)"
+            helperText="Only for a self-hosted site whose certificate is not trusted by this computer."
+            rows={3}
+            value={form.extraCaPem}
+            onChange={(e) => set("extraCaPem", e.target.value)}
+          />
+          <FileUploaderButton
+            labelText="Load from file…"
+            buttonKind="ghost"
+            size="sm"
+            accept={[".pem", ".crt", ".cer"]}
+            disableLabelChanges
+            onChange={(e: React.ChangeEvent<HTMLInputElement>) => {
+              const file = e.target.files?.[0];
+              e.target.value = "";
+              void readPem(file);
+            }}
+          />
+        </div>
+        <div className="voiced-header-action">
+          <Button kind="secondary" size="md" onClick={() => void runTest()} disabled={testing || loadingOptions}>
+            {testing ? "Testing…" : "Test connection"}
+          </Button>
+          {testing || loadingOptions ? <InlineLoading description={testing ? "Contacting ERPNext" : "Loading lists"} /> : null}
+          {!canConnect && showProblems ? <span className="voiced-muted">Fix the address, key and secret first.</span> : null}
+        </div>
+        {testError ? <InlineNotification kind="error" lowContrast hideCloseButton title="Connection failed" subtitle={testError} /> : null}
+        {test ? (
+          <Tile className="voiced-erp__result" aria-label="Connection test result">
+            <p>
+              <strong>Connected as {test.user || "an unknown user"}</strong>{" "}
+              <Tag type={test.indiaCompliance ? "green" : "warm-gray"} size="sm">
+                {test.indiaCompliance ? "India Compliance detected" : "India Compliance not detected"}
+              </Tag>
+            </p>
+            <p className="voiced-muted">{versionsLine(test)}</p>
+            {testUnsaved ? (
+              <InlineNotification
+                kind="info"
+                lowContrast
+                hideCloseButton
+                title="Save to keep this result"
+                subtitle="Sending invoices needs a saved connection test."
+              />
+            ) : (
+              <p className="voiced-muted">Last saved test result.</p>
+            )}
+            {sortWarnings(test.warnings).map((w, i) => {
+              const severity = warningSeverity(w.code);
+              return (
+                <InlineNotification
+                  key={`${w.code}-${i}`}
+                  kind={severity}
+                  lowContrast
+                  hideCloseButton
+                  title={SEVERITY_TITLE[severity]}
+                  subtitle={w.message}
+                />
+              );
+            })}
+            {test.warnings.length === 0 ? <p className="voiced-muted">No problems found with the current settings.</p> : null}
+            <p className="voiced-muted">Test again after changing the mappings below to refresh these warnings.</p>
+          </Tile>
+        ) : null}
+      </Section>
+
+      <Section
+        title="Company and accounts"
+        note={options ? "Choose from what your ERPNext site has." : "Run Test connection to choose from your site's lists; until then, type the exact names."}
+      >
+        {options && options.errors.length > 0 ? (
+          <InlineNotification
+            kind="warning"
+            lowContrast
+            hideCloseButton
+            title="Some lists could not be loaded"
+            subtitle={options.errors.map((e) => `${OPTION_LIST_LABELS[e.list] ?? e.list}: ${e.message}`).join(" ")}
+          />
+        ) : null}
+        <PickField
+          id="erp-company"
+          label="Company"
+          value={form.company}
+          onChange={changeCompany}
+          items={opts.companies}
+          error={optErrors.get("companies")}
+        />
+        <PickField
+          id="erp-companyAddress"
+          label="Company address"
+          value={form.companyAddress}
+          onChange={(v) => set("companyAddress", v)}
+          items={opts.companyAddresses}
+          error={optErrors.get("companyAddresses")}
+          disabledReason={companyReason}
+          helper="Required by India Compliance on every invoice."
+        />
+        <PickField
+          id="erp-incomeAccount"
+          label="Income account"
+          value={form.incomeAccount}
+          onChange={(v) => set("incomeAccount", v)}
+          items={opts.incomeAccounts}
+          error={optErrors.get("incomeAccounts")}
+          disabledReason={companyReason}
+        />
+        <PickField
+          id="erp-costCenter"
+          label="Cost center"
+          value={form.costCenter}
+          onChange={(v) => set("costCenter", v)}
+          items={opts.costCenters}
+          error={optErrors.get("costCenters")}
+          disabledReason={companyReason}
+        />
+        {(
+          [
+            ["cgstAccount", "CGST account"],
+            ["sgstAccount", "SGST account"],
+            ["utgstAccount", "UTGST account"],
+            ["igstAccount", "IGST account"],
+          ] as const
+        ).map(([key, label]) => (
+          <PickField
+            key={key}
+            id={`erp-${key}`}
+            label={label}
+            value={form[key]}
+            onChange={(v) => set(key, v)}
+            items={opts.taxAccounts}
+            error={optErrors.get("taxAccounts")}
+            disabledReason={companyReason}
+            helper={key === "utgstAccount" ? "Only needed when the supplier is in a union territory without a legislature." : "Must be the account set in GST Settings."}
+          />
+        ))}
+        <TextInput
+          id="erp-paymentBank"
+          labelText="Payment bank account"
+          helperText="The bank or cash account that receives payments, e.g. HDFC Bank - AC. Needed to send payments."
+          value={form.paymentBankAccount}
+          onChange={(e) => set("paymentBankAccount", e.target.value)}
+        />
+        <TextInput
+          id="erp-tdsAccount"
+          labelText="TDS account"
+          helperText="The account that holds tax deducted by clients. Needed only for payments with TDS."
+          value={form.tdsAccount}
+          onChange={(e) => set("tdsAccount", e.target.value)}
+        />
+      </Section>
+
+      <Section title="Customers and items">
+        <TextInput
+          id="erp-defaultItem"
+          labelText="Default item code (optional)"
+          helperText="Used for invoice lines without an item code of their own; a line with none is sent as a description-only row."
+          value={form.defaultItemCode}
+          onChange={(e) => set("defaultItemCode", e.target.value)}
+        />
+        <PickField
+          id="erp-customerGroup"
+          label="Customer group for new customers"
+          value={form.customerGroup}
+          onChange={(v) => set("customerGroup", v)}
+          items={opts.customerGroups}
+          error={optErrors.get("customerGroups")}
+        />
+        <PickField
+          id="erp-territory"
+          label="Territory for new customers"
+          value={form.territory}
+          onChange={(v) => set("territory", v)}
+          items={opts.territories}
+          error={optErrors.get("territories")}
+        />
+        <PickField
+          id="erp-priceList"
+          label="Selling price list"
+          value={form.sellingPriceList}
+          onChange={(v) => set("sellingPriceList", v)}
+          items={opts.priceLists}
+          error={optErrors.get("priceLists")}
+        />
+        <fieldset className="voiced-erp__uoms">
+          <legend>Units of measure</legend>
+          <p className="voiced-muted">The ERPNext unit used for each Voiced unit. Whole-number units such as Nos reject fractional quantities.</p>
+          {UOM_UNITS.map((unit) => (
+            <PickField
+              key={unit}
+              id={`erp-uom-${unit}`}
+              label={`Voiced ${unit}`}
+              value={form.uomMap[unit] ?? ""}
+              onChange={(v) => setForm((f) => (f ? { ...f, uomMap: { ...f.uomMap, [unit]: v } } : f))}
+              items={opts.uoms}
+              error={optErrors.get("uoms")}
+            />
+          ))}
+        </fieldset>
+      </Section>
+
+      <Section title="Invoice numbers">
+        <RadioButtonGroup
+          legendText="Numbering in ERPNext"
+          name="erp-namingMode"
+          orientation="vertical"
+          valueSelected={form.namingMode}
+          onChange={(value) => set("namingMode", value === "series" ? "series" : "mirror")}
+        >
+          <RadioButton
+            id="erp-nm-mirror"
+            value="mirror"
+            labelText="Mirror the Voiced number (recommended)"
+            disabled={!mirrorOk}
+          />
+          <RadioButton id="erp-nm-series" value="series" labelText="Use an ERPNext naming series" />
+        </RadioButtonGroup>
+        <p className="voiced-muted">
+          {mirrorOk
+            ? "Mirror keeps the number printed on the PDF as the ERPNext invoice name, so GST returns match. Needs Frappe 15.73 or later."
+            : "Mirror is unavailable: this ERPNext version replaces a posted invoice number. The Voiced number is stored in the remarks instead."}
+        </p>
+        {problems.namingMode ? <p className="voiced-erp__error">{problems.namingMode}</p> : null}
+        <PickField
+          id="erp-namingSeries"
+          label="Naming series"
+          value={form.namingSeries}
+          onChange={(v) => set("namingSeries", v)}
+          items={opts.namingSeries}
+          error={problems.namingSeries ?? optErrors.get("namingSeries")}
+          disabledReason={seriesMode ? undefined : "Only used with an ERPNext naming series."}
+        />
+      </Section>
+
+      <Section title="Sending">
+        <Toggle
+          id="erp-submit"
+          labelText="Submit invoices when sending"
+          labelA="Off: drafts for review"
+          labelB="On: submitted"
+          toggled={form.submitOnPush}
+          onToggle={(v) => set("submitOnPush", v)}
+        />
+        <Toggle
+          id="erp-attach"
+          labelText="Attach the PDF"
+          labelA="Off"
+          labelB="On"
+          toggled={form.attachPdf}
+          onToggle={(v) => set("attachPdf", v)}
+        />
+        <Toggle
+          id="erp-auto"
+          labelText="Send automatically when an invoice is issued"
+          labelA="Off"
+          labelB="On"
+          toggled={form.autoPushOnIssue}
+          onToggle={(v) => set("autoPushOnIssue", v)}
+        />
+        <Toggle
+          id="erp-customers"
+          labelText="Create customers that are missing in ERPNext"
+          labelA="Off"
+          labelB="On"
+          toggled={form.createMissingCustomers}
+          onToggle={(v) => set("createMissingCustomers", v)}
+        />
+      </Section>
+
+      {saveError && !secretInvalid ? <InlineNotification kind="error" lowContrast hideCloseButton title="Not saved" subtitle={saveError} /> : null}
+      <div>
+        <Button renderIcon={Save} onClick={() => void save()} disabled={saving}>
+          {saving ? "Saving…" : "Save ERPNext settings"}
+        </Button>
+        <p className="voiced-muted">This tab has its own Save button; Save settings at the bottom of the page does not cover it.</p>
+      </div>
+    </div>
+  );
+}

src/components/SendToErpnextModal.tsx

@@ -0,0 +1,140 @@
+import { useEffect, useRef, useState } from "react";
+import { Button, InlineLoading, Modal, RadioButton, RadioButtonGroup, Tag } from "@carbon/react";
+import { api } from "../lib/api";
+import type { ErpnextPushResult } from "../lib/erpnext";
+import { describePush, failedPush, summarizeBatch } from "../lib/erpnextUi";
+import { useReturnFocus } from "../hooks/useReturnFocus";
+
+export interface SendTarget {
+  id: number;
+  number: string;
+}
+
+interface Props {
+  open: boolean;
+  invoices: SendTarget[];
+  /** Cancelled or draft invoices that were left out of the selection. */
+  skipped?: number;
+  /** The "submit on push" setting; the user still chooses explicitly. */
+  defaultSubmit: boolean;
+  onClose: () => void;
+  /** Called once when a send has finished, so the list can refresh its statuses. */
+  onFinished: (results: ErpnextPushResult[]) => void;
+}
+
+type Phase = "confirm" | "running" | "done";
+
+const TAG = { success: "green", info: "blue", warning: "warm-gray", error: "red" } as const;
+
+/** Confirm step (draft or submit), then a sequential send with progress, then per-invoice results. A failure never stops the rest. */
+export default function SendToErpnextModal({ open, invoices, skipped = 0, defaultSubmit, onClose, onFinished }: Props) {
+  const [submit, setSubmit] = useState(defaultSubmit);
+  const [phase, setPhase] = useState<Phase>("confirm");
+  const [results, setResults] = useState<ErpnextPushResult[]>([]);
+  const alive = useRef(true);
+  useReturnFocus(open);
+
+  useEffect(() => {
+    alive.current = true;
+    return () => {
+      alive.current = false;
+    };
+  }, []);
+
+  useEffect(() => {
+    if (!open) return;
+    setSubmit(defaultSubmit);
+    setPhase("confirm");
+    setResults([]);
+  }, [open, defaultSubmit]);
+
+  const run = async () => {
+    setPhase("running");
+    const out: ErpnextPushResult[] = [];
+    for (const inv of invoices) {
+      let result: ErpnextPushResult;
+      try {
+        result = await api.erpnextPushInvoice(inv.id, submit);
+      } catch (e) {
+        // Not set up, or the command itself failed: this row fails, the others still go.
+        result = failedPush(inv.id, inv.number, e);
+      }
+      out.push(result);
+      if (alive.current) setResults([...out]);
+    }
+    if (alive.current) setPhase("done");
+    onFinished(out);
+  };
+
+  const count = invoices.length;
+  const noun = count === 1 ? "invoice" : "invoices";
+
+  if (phase === "confirm") {
+    return (
+      <Modal
+        open={open}
+        modalHeading={count === 1 ? `Send ${invoices[0]?.number} to ERPNext` : `Send ${count} invoices to ERPNext`}
+        primaryButtonText={`Send ${count} ${noun}`}
+        secondaryButtonText="Cancel"
+        primaryButtonDisabled={count === 0}
+        onRequestClose={onClose}
+        onRequestSubmit={() => void run()}
+      >
+        <div className="voiced-stack">
+          <RadioButtonGroup legendText="What should ERPNext do with it?" name="erp-send-mode" orientation="vertical" valueSelected={submit ? "submit" : "draft"} onChange={(v) => setSubmit(v === "submit")}>
+            <RadioButton id="erp-send-draft" value="draft" labelText="Save as a draft for review" />
+            <RadioButton id="erp-send-submit" value="submit" labelText="Submit it (posts to the books)" />
+          </RadioButtonGroup>
+          <p className="voiced-muted">
+            An invoice that is already in ERPNext is never overwritten or created twice.
+            {skipped > 0 ? ` ${skipped} cancelled ${skipped === 1 ? "invoice is" : "invoices are"} left out: cancelled invoices are never sent.` : ""}
+          </p>
+        </div>
+      </Modal>
+    );
+  }
+
+  const summary = phase === "done" ? summarizeBatch(results) : null;
+  return (
+    <Modal
+      open={open}
+      passiveModal
+      modalHeading={phase === "running" ? "Sending to ERPNext" : "Send finished"}
+      preventCloseOnClickOutside
+      onRequestClose={() => {
+        if (phase === "done") onClose();
+      }}
+    >
+      <div className="voiced-stack">
+        {phase === "running" ? (
+          <InlineLoading description={`Sent ${results.length} of ${count}…`} />
+        ) : (
+          <p role="status">
+            <strong>{summary?.title}</strong>
+          </p>
+        )}
+        <ul className="voiced-erp__results" aria-label="Results">
+          {results.map((r) => {
+            const note = describePush(r);
+            return (
+              <li key={r.invoiceId}>
+                <Tag type={TAG[note.kind]} size="sm">
+                  {r.ok ? (r.noOp ? "Up to date" : r.remoteDocstatus === 1 ? "Submitted" : "Draft") : r.status === "conflict" ? "Conflict" : r.status === "refused" ? "Not sent" : "Error"}
+                </Tag>{" "}
+                <strong>{r.number || `#${r.invoiceId}`}</strong>
+                {r.remoteName && r.ok ? <span className="voiced-muted"> {r.remoteName}</span> : null}
+                {!r.ok && r.error ? <div className="voiced-muted">{r.error}</div> : null}
+                {r.ok && r.warnings.length > 0 ? <div className="voiced-muted">{r.warnings.join(" ")}</div> : null}
+              </li>
+            );
+          })}
+        </ul>
+        {phase === "done" ? (
+          <Button kind="primary" size="md" onClick={onClose}>
+            Close
+          </Button>
+        ) : null}
+      </div>
+    </Modal>
+  );
+}

src/hooks/useGenericExport.ts

@@ -0,0 +1,39 @@
+import { useCallback, useState } from "react";
+import { save } from "@tauri-apps/plugin-dialog";
+import { api } from "../lib/api";
+import { exportInvoicesV1, type InvoiceExportFormat } from "../lib/invoiceExportV1";
+import { useToast } from "../components/ToastProvider";
+
+/** "Export as voiced.invoice.v1": JSON or line-item CSV of the given invoices, through the save dialog. */
+export function useGenericExport(): { busy: boolean; run: (ids: number[], format: InvoiceExportFormat) => Promise<void> } {
+  const toast = useToast();
+  const [busy, setBusy] = useState(false);
+  const run = useCallback(
+    async (ids: number[], format: InvoiceExportFormat) => {
+      setBusy(true);
+      try {
+        const done = await exportInvoicesV1(
+          {
+            getInvoice: api.getInvoice,
+            listPayments: api.listPayments,
+            listClients: api.listClients,
+            getLastExportDir: api.getLastExportDir,
+            save: ({ defaultPath, format: fmt }) =>
+              save({ defaultPath, filters: [fmt === "csv" ? { name: "CSV (line items)", extensions: ["csv"] } : { name: "JSON (voiced.invoice.v1)", extensions: ["json"] }] }),
+            writeExportFile: api.writeExportFile,
+            now: () => new Date(),
+          },
+          ids,
+          format,
+        );
+        if (done) toast.success(`Exported ${done.count} ${done.count === 1 ? "invoice" : "invoices"}`, done.path);
+      } catch (e) {
+        toast.error("Could not export the invoices", String(e));
+      } finally {
+        setBusy(false);
+      }
+    },
+    [toast],
+  );
+  return { busy, run };
+}

src/lib/__golden__/invoice-v1.golden.json

@@ -0,0 +1,118 @@
+[
+  {
+    "schema": "voiced.invoice.v1",
+    "number": "INV/2026-001",
+    "issue_date": "2026-04-01",
+    "due_date": "2026-05-01",
+    "document_type": "tax_invoice",
+    "status": "issued",
+    "cancelled": false,
+    "cancelled_at": null,
+    "cancel_reason": null,
+    "currency": "INR",
+    "po_number": "PO-9",
+    "supplier": {
+      "name": "Test Vendor",
+      "address": "1 Main Rd\nPune",
+      "gstin": "27AAPFU0939F1ZV",
+      "pan": "AAPFU0939F",
+      "gst_registration": "regular",
+      "state": {
+        "code": "27",
+        "name": "Maharashtra"
+      }
+    },
+    "client": {
+      "name": "Client Ltd",
+      "gstin": "29AABCU9603R1ZJ",
+      "gst_category": "registered_regular",
+      "address": {
+        "text": "12 MG Road\nBengaluru 560001",
+        "line1": "12 MG Road",
+        "line2": null,
+        "city": "Bengaluru",
+        "pincode": "560001",
+        "state": {
+          "code": "29",
+          "name": "Karnataka"
+        }
+      },
+      "place_of_supply": {
+        "code": "29",
+        "name": "Karnataka"
+      }
+    },
+    "items": [
+      {
+        "line": 1,
+        "description": "Design",
+        "hsn_sac": "998391",
+        "quantity": "1",
+        "unit": null,
+        "rate_paise": 500010,
+        "rate": "5000.10",
+        "taxable_value_paise": 500010,
+        "taxable_value": "5000.10"
+      },
+      {
+        "line": 2,
+        "description": "Consulting",
+        "hsn_sac": null,
+        "quantity": "2",
+        "unit": "hour",
+        "rate_paise": 115505,
+        "rate": "1155.05",
+        "taxable_value_paise": 231000,
+        "taxable_value": "2310.00"
+      }
+    ],
+    "tax": {
+      "cgst": {
+        "rate": "0",
+        "amount_paise": 0,
+        "amount": "0.00"
+      },
+      "sgst": {
+        "rate": "0",
+        "amount_paise": 0,
+        "amount": "0.00"
+      },
+      "utgst": {
+        "rate": "0",
+        "amount_paise": 0,
+        "amount": "0.00"
+      },
+      "igst": {
+        "rate": "18",
+        "amount_paise": 131400,
+        "amount": "1314.00"
+      }
+    },
+    "totals": {
+      "subtotal_paise": 731010,
+      "subtotal": "7310.10",
+      "discount_paise": 1010,
+      "discount": "10.10",
+      "taxable_value_paise": 730000,
+      "taxable_value": "7300.00",
+      "tax_paise": 131400,
+      "tax": "1314.00",
+      "total_paise": 861400,
+      "total": "8614.00",
+      "amount_in_words": "Rupees Eight Thousand Six Hundred Fourteen Only"
+    },
+    "reverse_charge": false,
+    "notes": "Thank you",
+    "payments": [
+      {
+        "date": "2026-04-10",
+        "amount_paise": 700000,
+        "amount": "7000.00",
+        "tds_paise": 70000,
+        "tds": "700.00",
+        "mode": "bank_transfer",
+        "reference": "UTR123"
+      }
+    ]
+  }
+]

src/lib/erpnext.ts

@@ -1,4 +1,4 @@
-/** Types for the ERPNext commands (see src-tauri/src/commands/erpnext.rs). Types only: no UI yet. */
+/** Types for the ERPNext commands (see src-tauri/src/commands/erpnext.rs); the UI helpers live in erpnextUi.ts. */
 
 export type ErpnextNamingMode = "mirror" | "series";
 

src/lib/erpnextActions.ts

@@ -0,0 +1,7 @@
+import { openUrl } from "@tauri-apps/plugin-opener";
+import { api } from "./api";
+
+/** Opens the invoice's ERPNext page in the system browser (`<base>/app/sales-invoice/<name>`); rejects if it was never sent. */
+export async function openInErpnext(invoiceId: number): Promise<void> {
+  await openUrl(await api.erpnextOpenUrl(invoiceId));
+}

src/lib/erpnextUi.test.ts

@@ -0,0 +1,286 @@
+import { describe, expect, it, vi } from "vitest";
+import type { ErpnextConfig, ErpnextConnectionTest, ErpnextPushResult, ErpnextSyncStatus } from "./erpnext";
+import {
+  autoPushIssued,
+  baseUrlProblem,
+  connectionProblems,
+  describePaymentPush,
+  describePush,
+  failedPush,
+  hasDetectResult,
+  isConfigured,
+  paymentPushDisabledReason,
+  pushDisabledReason,
+  summarizeBatch,
+  syncTag,
+  toInput,
+  validateConfigForm,
+  warningSeverity,
+  withDefaultUoms,
+  withStoredValue,
+  sortWarnings,
+  sendableSelection,
+  formatSyncedAt,
+} from "./erpnextUi";
+
+const test: ErpnextConnectionTest = {
+  user: "api@example.com",
+  versions: { frappe: "15.80.0", erpnext: "15.70.0", indiaCompliance: "15.30.0" },
+  features: { v2Naming: true, indiaCompliance: true },
+  indiaCompliance: true,
+  warnings: [],
+};
+
+const config = (patch: Partial<ErpnextConfig> = {}): ErpnextConfig => ({
+  baseUrl: "https://erp.example.com",
+  apiKey: "key",
+  apiSecretSet: true,
+  extraCaPem: "",
+  company: "Test Co",
+  companyAddress: "",
+  namingMode: "mirror",
+  namingSeries: "",
+  incomeAccount: "",
+  costCenter: "",
+  cgstAccount: "",
+  sgstAccount: "",
+  utgstAccount: "",
+  igstAccount: "",
+  taxTemplateIntra: "",
+  taxTemplateInter: "",
+  paymentBankAccount: "",
+  tdsAccount: "",
+  defaultItemCode: "",
+  uomMap: {},
+  customerGroup: "",
+  territory: "",
+  sellingPriceList: "",
+  submitOnPush: false,
+  attachPdf: true,
+  autoPushOnIssue: false,
+  createMissingCustomers: true,
+  lastDetectResult: test,
+  ...patch,
+});
+
+const sync = (patch: Partial<ErpnextSyncStatus>): ErpnextSyncStatus => ({
+  invoiceId: 1,
+  status: "synced",
+  remoteName: "INV/2026-001",
+  remoteDocstatus: 0,
+  lastError: "",
+  syncedAt: null,
+  attached: false,
+  ...patch,
+});
+
+const push = (patch: Partial<ErpnextPushResult> = {}): ErpnextPushResult => ({
+  invoiceId: 1,
+  number: "INV/2026-001",
+  ok: true,
+  status: "synced",
+  remoteName: "INV/2026-001",
+  remoteDocstatus: 0,
+  created: true,
+  noOp: false,
+  attached: true,
+  error: null,
+  errorKind: null,
+  warnings: [],
+  ...patch,
+});
+
+describe("status tags", () => {
+  it("maps every sync state", () => {
+    expect(syncTag(undefined)).toMatchObject({ label: "Not sent", type: "gray" });
+    expect(syncTag(sync({ status: "none" })).label).toBe("Not sent");
+    expect(syncTag(sync({ remoteDocstatus: 0 }))).toMatchObject({ label: "Draft in ERPNext", type: "blue" });
+    expect(syncTag(sync({ remoteDocstatus: 1 }))).toMatchObject({ label: "Submitted", type: "green" });
+    expect(syncTag(sync({ status: "error", lastError: "Item missing" }))).toMatchObject({ label: "Error", type: "red", tooltip: "Item missing" });
+    expect(syncTag(sync({ status: "conflict", lastError: "" }))).toMatchObject({ label: "Conflict", type: "purple" });
+    expect(syncTag(sync({ status: "error", lastError: "" })).tooltip).toBeTruthy();
+  });
+});
+
+describe("configured and disabled reasons", () => {
+  it("needs an address, a key and a stored secret", () => {
+    expect(isConfigured(config())).toBe(true);
+    expect(isConfigured(config({ baseUrl: " " }))).toBe(false);
+    expect(isConfigured(config({ apiKey: "" }))).toBe(false);
+    expect(isConfigured(config({ apiSecretSet: false }))).toBe(false);
+    expect(isConfigured(null)).toBe(false);
+  });
+
+  it("asks for a connection test only when the vendor is registered", () => {
+    const untested = config({ lastDetectResult: null });
+    expect(pushDisabledReason({ cfg: untested, vendorRegistered: true })).toMatch(/Run Test connection first/);
+    expect(pushDisabledReason({ cfg: untested, vendorRegistered: false })).toBeNull();
+    expect(pushDisabledReason({ cfg: config(), vendorRegistered: true })).toBeNull();
+    expect(hasDetectResult(null)).toBe(false);
+    expect(hasDetectResult({} as ErpnextConnectionTest)).toBe(false);
+    expect(pushDisabledReason({ cfg: null, vendorRegistered: false })).toMatch(/not set up/);
+    expect(pushDisabledReason({ cfg: config(), vendorRegistered: false, invoiceStatus: "cancelled" })).toMatch(/Cancelled/);
+    expect(pushDisabledReason({ cfg: config(), vendorRegistered: false, invoiceStatus: "issued" })).toBeNull();
+  });
+
+  it("allows a payment only against a submitted invoice, once", () => {
+    const cfg = config();
+    expect(paymentPushDisabledReason({ cfg, sync: undefined, entry: null })).toMatch(/Send the invoice/);
+    expect(paymentPushDisabledReason({ cfg, sync: sync({ remoteDocstatus: 0 }), entry: null })).toMatch(/Submit the invoice in ERPNext first/);
+    expect(paymentPushDisabledReason({ cfg, sync: sync({ remoteDocstatus: 1 }), entry: null })).toBeNull();
+    expect(paymentPushDisabledReason({ cfg, sync: sync({ remoteDocstatus: 1 }), entry: "ACC-PAY-1" })).toMatch(/ACC-PAY-1/);
+  });
+});
+
+describe("push results", () => {
+  it("describes outcomes", () => {
+    expect(describePush(push())).toMatchObject({ kind: "success", subtitle: "INV/2026-001 (draft)" });
+    expect(describePush(push({ remoteDocstatus: 1 })).subtitle).toContain("submitted");
+    expect(describePush(push({ noOp: true })).kind).toBe("info");
+    const warned = describePush(push({ warnings: ["The PDF was not attached: no permission"] }));
+    expect(warned.kind).toBe("warning");
+    expect(warned.subtitle).toContain("no permission");
+    expect(describePush(push({ ok: false, status: "refused", error: "Run Test connection first", errorKind: "precondition" })).kind).toBe("warning");
+    expect(describePush(push({ ok: false, status: "conflict", error: "different total" })).title).toMatch(/conflicts/);
+    expect(describePush(push({ ok: false, status: "error", error: "417", errorKind: "validation" })).kind).toBe("error");
+    expect(describePaymentPush({ paymentId: 1, invoiceId: 1, ok: true, entryName: "PE-1", alreadySynced: false, error: null, errorKind: null }).kind).toBe("success");
+    expect(describePaymentPush({ paymentId: 1, invoiceId: 1, ok: false, entryName: null, alreadySynced: false, error: "nope", errorKind: "other" }).kind).toBe("error");
+  });
+
+  it("turns a rejected call into a failed row", () => {
+    const r = failedPush(3, "INV/3", "ERPNext is not set up yet");
+    expect(r).toMatchObject({ ok: false, invoiceId: 3, number: "INV/3", error: "ERPNext is not set up yet" });
+    expect(failedPush(3, "INV/3", new Error("boom")).error).toBe("boom");
+  });
+
+  it("summarises a batch", () => {
+    const s = summarizeBatch([push(), push({ noOp: true }), push({ ok: false, status: "error", error: "x" })]);
+    expect(s).toMatchObject({ total: 3, sent: 1, upToDate: 1, failed: 1, kind: "warning" });
+    expect(s.title).toBe("1 sent, 1 already up to date, 1 failed");
+    expect(summarizeBatch([push(), push()]).kind).toBe("success");
+    expect(summarizeBatch([push({ ok: false })]).kind).toBe("error");
+    expect(summarizeBatch([push({ warnings: ["w"] })]).kind).toBe("warning");
+  });
+});
+
+describe("auto push on issue", () => {
+  const invoice = { id: 7, number: "INV/2026-007" };
+
+  it("does nothing when it is off or ERPNext is not set up", async () => {
+    const pushFn = vi.fn();
+    expect(await autoPushIssued({ getConfig: async () => config(), push: pushFn }, invoice, true)).toBeNull();
+    expect(await autoPushIssued({ getConfig: async () => config({ autoPushOnIssue: true, apiSecretSet: false }), push: pushFn }, invoice, true)).toBeNull();
+    expect(await autoPushIssued({ getConfig: async () => Promise.reject(new Error("db")), push: pushFn }, invoice, true)).toBeNull();
+    expect(pushFn).not.toHaveBeenCalled();
+  });
+
+  it("pushes with the configured submit setting and reports the result", async () => {
+    const pushFn = vi.fn(async () => push({ number: invoice.number }));
+    const notice = await autoPushIssued({ getConfig: async () => config({ autoPushOnIssue: true }), push: pushFn }, invoice, true);
+    expect(pushFn).toHaveBeenCalledWith(7);
+    expect(notice?.kind).toBe("success");
+  });
+
+  it("never throws: a rejected push becomes an error notice", async () => {
+    const notice = await autoPushIssued(
+      { getConfig: async () => config({ autoPushOnIssue: true }), push: async () => Promise.reject("ERPNext is not set up yet") },
+      invoice,
+      false,
+    );
+    expect(notice).toMatchObject({ kind: "error" });
+    expect(notice?.subtitle).toContain("not set up");
+  });
+
+  it("explains a missing connection test instead of pushing", async () => {
+    const pushFn = vi.fn();
+    const notice = await autoPushIssued({ getConfig: async () => config({ autoPushOnIssue: true, lastDetectResult: null }), push: pushFn }, invoice, true);
+    expect(pushFn).not.toHaveBeenCalled();
+    expect(notice?.subtitle).toMatch(/Run Test connection first/);
+  });
+});
+
+describe("warnings", () => {
+  it("ranks errors before warnings before notes", () => {
+    expect(warningSeverity("gst_accounts_not_configured")).toBe("error");
+    expect(warningSeverity("ic_not_detected")).toBe("warning");
+    expect(warningSeverity("versions_unknown")).toBe("info");
+    const sorted = sortWarnings([
+      { code: "versions_unknown", message: "a" },
+      { code: "company_missing", message: "b" },
+      { code: "ic_not_detected", message: "c" },
+    ]);
+    expect(sorted.map((w) => w.code)).toEqual(["company_missing", "ic_not_detected", "versions_unknown"]);
+  });
+});
+
+describe("settings form", () => {
+  it("validates the address like the backend", () => {
+    expect(baseUrlProblem("")).toMatch(/Enter/);
+    expect(baseUrlProblem("https://erp.example.com")).toBeNull();
+    expect(baseUrlProblem("erp.example.com")).toBeNull();
+    expect(baseUrlProblem("http://erp.example.com")).toMatch(/https/);
+    expect(baseUrlProblem("http://localhost:8000")).toBeNull();
+    expect(baseUrlProblem("localhost:8000")).toBeNull();
+    expect(baseUrlProblem("http://site.test")).toBeNull();
+    expect(baseUrlProblem("http://127.0.0.1:8000")).toBeNull();
+    expect(baseUrlProblem("https://user:pw@erp.example.com")).toMatch(/credentials/);
+    expect(baseUrlProblem("ftp://erp.example.com")).toMatch(/https/);
+  });
+
+  it("builds the input without write-only fields and fills the UOM defaults", () => {
+    const input = toInput(config({ uomMap: { hour: "Hr" } }));
+    expect(input).not.toHaveProperty("apiSecretSet");
+    expect(input).not.toHaveProperty("lastDetectResult");
+    expect(input.apiSecret).toBe("");
+    expect(input.uomMap).toEqual({ second: "Second", minute: "Minute", hour: "Hr", session: "Nos", unit: "Nos" });
+    expect(withDefaultUoms({ hour: " " }).hour).toBe("Hour");
+  });
+
+  it("needs a secret only when none is stored or it is being cleared", () => {
+    const form = toInput(config());
+    expect(connectionProblems(form, true)).toEqual({});
+    expect(connectionProblems(form, false).apiSecret).toBeTruthy();
+    expect(connectionProblems({ ...form, clearSecret: true }, true).apiSecret).toBeTruthy();
+    expect(connectionProblems({ ...form, clearSecret: true, apiSecret: "new" }, true)).toEqual({});
+    expect(connectionProblems({ ...form, apiKey: " " }, true).apiKey).toBeTruthy();
+  });
+
+  it("validates a save: untouched is fine, series mode needs a series, mirror needs v2 naming", () => {
+    const empty = toInput(config({ baseUrl: "", apiKey: "", apiSecretSet: false }));
+    expect(validateConfigForm(empty, false, null)).toEqual({});
+    const form = toInput(config());
+    expect(validateConfigForm(form, true, test)).toEqual({});
+    expect(validateConfigForm({ ...form, namingMode: "series", namingSeries: "" }, true, test).namingSeries).toBeTruthy();
+    expect(validateConfigForm({ ...form, namingMode: "series", namingSeries: "SINV-.YY.-" }, true, test)).toEqual({});
+    const old = { ...test, features: { v2Naming: false, indiaCompliance: true } };
+    expect(validateConfigForm(form, true, old).namingMode).toBeTruthy();
+    expect(validateConfigForm(form, true, null).namingMode).toBeUndefined();
+  });
+
+  it("keeps a saved value visible when the loaded list lacks it", () => {
+    const items = [{ name: "A", label: "A", detail: "" }];
+    expect(withStoredValue(items, "A")).toBe(items);
+    expect(withStoredValue(items, "")).toBe(items);
+    const out = withStoredValue(items, "Sales - AC");
+    expect(out[0]).toMatchObject({ name: "Sales - AC" });
+    expect(out).toHaveLength(2);
+  });
+});
+
+describe("selection and dates", () => {
+  it("leaves cancelled invoices out of a send", () => {
+    const rows = [
+      { id: 1, status: "issued" },
+      { id: 2, status: "cancelled" },
+      { id: 3, status: "issued" },
+    ];
+    expect(sendableSelection(rows)).toEqual({ send: [rows[0], rows[2]], skipped: 1 });
+    expect(sendableSelection([])).toEqual({ send: [], skipped: 0 });
+  });
+
+  it("formats the sync time defensively", () => {
+    expect(formatSyncedAt(null)).toBe("");
+    expect(formatSyncedAt("not a date")).toBe("not a date");
+    expect(formatSyncedAt("2026-04-01T10:30:00+00:00")).toMatch(/2026/);
+  });
+});

src/lib/erpnextUi.ts

@@ -0,0 +1,390 @@
+/** Pure helpers behind the ERPNext screens (Settings, History, invoice detail, auto-push). No UI, no Tauri. */
+import type {
+  ErpnextConfig,
+  ErpnextConfigInput,
+  ErpnextConnectionTest,
+  ErpnextOptionItem,
+  ErpnextOptions,
+  ErpnextPaymentPushResult,
+  ErpnextPushResult,
+  ErpnextSyncStatus,
+  ErpnextWarning,
+} from "./erpnext";
+
+export type TagColor = "red" | "green" | "blue" | "gray" | "purple" | "cool-gray" | "warm-gray";
+export type NoticeKind = "success" | "info" | "warning" | "error";
+
+export const SETTINGS_LINK_TEXT = "Settings, Integrations";
+
+// ---- configuration state ----
+
+/** Enough saved to try a push: address, key and a stored secret. */
+export function isConfigured(cfg: Pick<ErpnextConfig, "baseUrl" | "apiKey" | "apiSecretSet"> | null | undefined): boolean {
+  return Boolean(cfg && cfg.baseUrl.trim() && cfg.apiKey.trim() && cfg.apiSecretSet);
+}
+
+/** True when a connection test result is stored (the backend refuses a registered vendor's push without one). */
+export function hasDetectResult(result: ErpnextConnectionTest | null | undefined): boolean {
+  return Boolean(result && typeof result === "object" && Object.keys(result).length > 0);
+}
+
+export const NOT_CONFIGURED_REASON = "ERPNext is not set up. Enter the address, API key and secret in Settings, Integrations.";
+export const RUN_TEST_REASON = "Run Test connection first (Settings, Integrations).";
+
+/**
+ * Why an invoice cannot be sent right now, or null. The backend applies the same registered-vendor rule using the
+ * supplier snapshot frozen on the invoice; the current GST registration setting is the proxy here.
+ */
+export function pushDisabledReason(opts: {
+  cfg: ErpnextConfig | null;
+  vendorRegistered: boolean;
+  invoiceStatus?: string;
+}): string | null {
+  if (!isConfigured(opts.cfg)) return NOT_CONFIGURED_REASON;
+  if (opts.invoiceStatus !== undefined && opts.invoiceStatus !== "issued") {
+    return opts.invoiceStatus === "cancelled"
+      ? "Cancelled invoices are never sent to ERPNext."
+      : "Only issued invoices are sent to ERPNext.";
+  }
+  if (opts.vendorRegistered && !hasDetectResult(opts.cfg?.lastDetectResult)) return RUN_TEST_REASON;
+  return null;
+}
+
+/** A payment can be posted only against a submitted invoice, once. */
+export function paymentPushDisabledReason(opts: {
+  cfg: ErpnextConfig | null;
+  sync: ErpnextSyncStatus | undefined;
+  entry: string | null | undefined;
+}): string | null {
+  if (!isConfigured(opts.cfg)) return NOT_CONFIGURED_REASON;
+  if (opts.entry) return `Already sent as ${opts.entry}.`;
+  if (!opts.sync || opts.sync.status !== "synced") return "Send the invoice to ERPNext first.";
+  if (opts.sync.remoteDocstatus !== 1) return "Submit the invoice in ERPNext first.";
+  return null;
+}
+
+// ---- sync status ----
+
+export interface SyncTag {
+  label: string;
+  type: TagColor;
+  /** Hover text: the stored error for a failure. */
+  tooltip?: string;
+}
+
+export function syncTag(s: ErpnextSyncStatus | undefined): SyncTag {
+  if (!s || s.status === "none") return { label: "Not sent", type: "gray" };
+  switch (s.status) {
+    case "synced":
+      return s.remoteDocstatus === 1
+        ? { label: "Submitted", type: "green", tooltip: s.remoteName || undefined }
+        : { label: "Draft in ERPNext", type: "blue", tooltip: s.remoteName || undefined };
+    case "error":
+      return { label: "Error", type: "red", tooltip: s.lastError || "The last send failed." };
+    case "conflict":
+      return { label: "Conflict", type: "purple", tooltip: s.lastError || "ERPNext already has a different document with this name." };
+    case "pending":
+      return { label: "Sending", type: "warm-gray" };
+    default:
+      return { label: "Not sent", type: "gray" };
+  }
+}
+
+export function indexSyncStatuses(list: ErpnextSyncStatus[]): Map<number, ErpnextSyncStatus> {
+  return new Map(list.map((s) => [s.invoiceId, s]));
+}
+
+/** Rows that have an ERPNext document to open. */
+export const canOpenInErpnext = (s: ErpnextSyncStatus | undefined): boolean => Boolean(s && s.remoteName);
+
+/** Stored sync time (RFC 3339) for display; the raw text if it cannot be parsed, blank if there is none. */
+export function formatSyncedAt(iso: string | null | undefined): string {
+  if (!iso) return "";
+  const d = new Date(iso);
+  return Number.isNaN(d.getTime()) ? iso : d.toLocaleString("en-GB", { day: "2-digit", month: "short", year: "numeric", hour: "2-digit", minute: "2-digit" });
+}
+
+/** From a selection: the issued invoices that can be sent, and how many were left out (cancelled or draft). */
+export function sendableSelection<T extends { status: string }>(rows: T[]): { send: T[]; skipped: number } {
+  const send = rows.filter((r) => r.status === "issued");
+  return { send, skipped: rows.length - send.length };
+}
+
+// ---- push results ----
+
+export interface Notice {
+  kind: NoticeKind;
+  title: string;
+  subtitle?: string;
+}
+
+const docState = (docstatus: number) => (docstatus === 1 ? "submitted" : "draft");
+
+/** One push outcome as a toast. Warnings turn a success into a warning toast so they are read. */
+export function describePush(r: ErpnextPushResult): Notice {
+  if (r.ok) {
+    const where = `${r.remoteName} (${docState(r.remoteDocstatus)})`;
+    if (r.warnings.length > 0) {
+      return { kind: "warning", title: `Invoice ${r.number} sent to ERPNext with notes`, subtitle: [where, ...r.warnings].join(" ") };
+    }
+    if (r.noOp) return { kind: "info", title: `Invoice ${r.number} is already up to date in ERPNext`, subtitle: where };
+    return { kind: "success", title: `Invoice ${r.number} sent to ERPNext`, subtitle: where };
+  }
+  if (r.status === "refused" || r.errorKind === "precondition" || r.errorKind === "config") {
+    return { kind: "warning", title: `Invoice ${r.number || r.invoiceId} was not sent`, subtitle: r.error ?? undefined };
+  }
+  if (r.status === "conflict") {
+    return { kind: "error", title: `Invoice ${r.number} conflicts with ERPNext`, subtitle: r.error ?? undefined };
+  }
+  return { kind: "error", title: `Could not send invoice ${r.number || r.invoiceId}`, subtitle: r.error ?? undefined };
+}
+
+export function describePaymentPush(r: ErpnextPaymentPushResult): Notice {
+  if (r.ok) {
+    return r.alreadySynced
+      ? { kind: "info", title: "Payment was already sent", subtitle: r.entryName ?? undefined }
+      : { kind: "success", title: "Payment sent to ERPNext", subtitle: r.entryName ?? undefined };
+  }
+  return { kind: "error", title: "Could not send the payment", subtitle: r.error ?? undefined };
+}
+
+/** A rejected invoke (for example "ERPNext is not set up yet") turned into a result row, so a batch carries on. */
+export function failedPush(invoiceId: number, number: string, error: unknown): ErpnextPushResult {
+  return {
+    invoiceId,
+    number,
+    ok: false,
+    status: "error",
+    remoteName: "",
+    remoteDocstatus: 0,
+    created: false,
+    noOp: false,
+    attached: false,
+    error: error instanceof Error ? error.message : String(error),
+    errorKind: "other",
+    warnings: [],
+  };
+}
+
+export interface BatchSummary {
+  total: number;
+  sent: number;
+  upToDate: number;
+  failed: number;
+  withNotes: number;
+  kind: NoticeKind;
+  title: string;
+}
+
+export function summarizeBatch(results: ErpnextPushResult[]): BatchSummary {
+  const failed = results.filter((r) => !r.ok).length;
+  const upToDate = results.filter((r) => r.ok && r.noOp && r.warnings.length === 0).length;
+  const sent = results.filter((r) => r.ok).length - upToDate;
+  const withNotes = results.filter((r) => r.ok && r.warnings.length > 0).length;
+  const kind: NoticeKind = failed > 0 ? (failed === results.length ? "error" : "warning") : withNotes > 0 ? "warning" : "success";
+  const parts = [`${sent} sent`];
+  if (upToDate > 0) parts.push(`${upToDate} already up to date`);
+  if (failed > 0) parts.push(`${failed} failed`);
+  return { total: results.length, sent, upToDate, failed, withNotes, kind, title: parts.join(", ") };
+}
+
+// ---- auto-push after issue ----
+
+export interface AutoPushDeps {
+  getConfig(): Promise<ErpnextConfig>;
+  push(id: number, submit?: boolean): Promise<ErpnextPushResult>;
+}
+
+/**
+ * Pushes a just-issued invoice when "send on issue" is on. Never throws and never blocks the issue: anything that
+ * goes wrong comes back as a notice. Returns null when nothing was attempted (off, or not set up).
+ */
+export async function autoPushIssued(
+  deps: AutoPushDeps,
+  invoice: { id: number; number: string },
+  vendorRegistered: boolean,
+): Promise<Notice | null> {
+  let cfg: ErpnextConfig;
+  try {
+    cfg = await deps.getConfig();
+  } catch {
+    return null;
+  }
+  if (!cfg.autoPushOnIssue || !isConfigured(cfg)) return null;
+  const blocked = pushDisabledReason({ cfg, vendorRegistered });
+  if (blocked) return { kind: "warning", title: `Invoice ${invoice.number} was not sent to ERPNext`, subtitle: blocked };
+  try {
+    return describePush(await deps.push(invoice.id));
+  } catch (e) {
+    return describePush(failedPush(invoice.id, invoice.number, e));
+  }
+}
+
+// ---- connection test display ----
+
+const ERROR_CODES = new Set([
+  "company_missing",
+  "company_address_missing",
+  "income_account_missing",
+  "tax_accounts_missing",
+  "naming_series_missing",
+  "naming_series_too_long",
+  "number_invalid",
+  "mirror_unsupported",
+  "gst_accounts_not_configured",
+]);
+const INFO_CODES = new Set(["versions_unknown", "gst_settings_unreadable"]);
+
+/** How loudly a test warning is shown: the ones that would make invoices land wrong are errors. */
+export function warningSeverity(code: string): "error" | "warning" | "info" {
+  if (ERROR_CODES.has(code)) return "error";
+  if (INFO_CODES.has(code)) return "info";
+  return "warning";
+}
+
+export function sortWarnings(list: ErpnextWarning[]): ErpnextWarning[] {
+  const rank = { error: 0, warning: 1, info: 2 } as const;
+  return [...list].sort((a, b) => rank[warningSeverity(a.code)] - rank[warningSeverity(b.code)]);
+}
+
+export function versionsLine(test: ErpnextConnectionTest): string {
+  const v = test.versions;
+  const parts = [
+    `Frappe ${v.frappe ?? "unknown"}`,
+    `ERPNext ${v.erpnext ?? "unknown"}`,
+    test.indiaCompliance ? `India Compliance ${v.indiaCompliance ?? "installed"}` : "India Compliance not detected",
+  ];
+  return parts.join(" · ");
+}
+
+// ---- settings form ----
+
+export const UOM_UNITS = ["second", "minute", "hour", "session", "unit"] as const;
+export const DEFAULT_UOM_MAP: Record<string, string> = {
+  second: "Second",
+  minute: "Minute",
+  hour: "Hour",
+  session: "Nos",
+  unit: "Nos",
+};
+
+export function withDefaultUoms(map: Record<string, string> | undefined): Record<string, string> {
+  const out: Record<string, string> = { ...DEFAULT_UOM_MAP };
+  for (const [k, v] of Object.entries(map ?? {})) if (v.trim()) out[k] = v;
+  return out;
+}
+
+/** What the form edits: the saved config minus the write-only fields, plus the secret being typed. */
+export function toInput(cfg: ErpnextConfig): ErpnextConfigInput {
+  const { apiSecretSet: _set, lastDetectResult: _last, ...rest } = cfg;
+  void _set;
+  void _last;
+  return { ...rest, uomMap: withDefaultUoms(rest.uomMap), apiSecret: "", clearSecret: false };
+}
+
+/** Mirror mode needs a Frappe that keeps a posted name; an untested site defaults to it (the backend default). */
+export function mirrorSupported(test: ErpnextConnectionTest | null): boolean {
+  return test ? test.features.v2Naming : true;
+}
+
+export function isLocalDevHost(host: string): boolean {
+  const h = host.replace(/\.$/, "").toLowerCase();
+  return h === "localhost" || h === "127.0.0.1" || h.endsWith(".localhost") || h.endsWith(".test");
+}
+
+/** Same rules as the backend's address check, so a bad address is caught before the round trip. */
+export function baseUrlProblem(raw: string): string | null {
+  const text = raw.trim();
+  if (!text) return "Enter the address of your ERPNext site.";
+  const withScheme = text.includes("://") ? text : `${isLocalDevHost(text.split(/[/:]/)[0] ?? "") ? "http" : "https"}://${text}`;
+  let url: URL;
+  try {
+    url = new URL(withScheme);
+  } catch {
+    return "This is not a valid address, e.g. https://erp.example.com";
+  }
+  if (url.protocol !== "https:" && url.protocol !== "http:") return "Use an https:// address.";
+  if (url.protocol === "http:" && !isLocalDevHost(url.hostname)) {
+    return "Use an https:// address. Plain http is only allowed for localhost, 127.0.0.1, *.localhost and *.test.";
+  }
+  if (url.username || url.password) return "Do not put credentials in the address; use the API key and secret fields.";
+  return null;
+}
+
+export interface FormProblems {
+  baseUrl?: string;
+  apiKey?: string;
+  apiSecret?: string;
+  company?: string;
+  namingSeries?: string;
+  namingMode?: string;
+}
+
+/** Problems that stop a Test connection (address, key, secret). */
+export function connectionProblems(form: ErpnextConfigInput, secretStored: boolean): FormProblems {
+  const p: FormProblems = {};
+  const url = baseUrlProblem(form.baseUrl);
+  if (url) p.baseUrl = url;
+  if (!form.apiKey.trim()) p.apiKey = "Enter the API key.";
+  if (!form.apiSecret.trim() && (form.clearSecret || !secretStored)) p.apiSecret = "Enter the API secret.";
+  return p;
+}
+
+/** Problems that stop a Save. An empty form (nothing set up) saves fine; a half-filled one does not. */
+export function validateConfigForm(form: ErpnextConfigInput, secretStored: boolean, test: ErpnextConnectionTest | null): FormProblems {
+  const touched = form.baseUrl.trim() || form.apiKey.trim() || form.apiSecret.trim() || secretStored;
+  if (!touched) return {};
+  const p = connectionProblems(form, secretStored);
+  if (form.namingMode === "series" && !form.namingSeries.trim()) p.namingSeries = "Choose or enter the naming series.";
+  if (form.namingMode === "mirror" && !mirrorSupported(test)) {
+    p.namingMode = "This ERPNext version does not keep a posted invoice number. Use ERPNext series.";
+  }
+  return p;
+}
+
+export const hasProblems = (p: FormProblems): boolean => Object.keys(p).length > 0;
+
+/** Options for a dropdown, with the saved value kept visible when the loaded list does not contain it. */
+export function withStoredValue(items: ErpnextOptionItem[], stored: string): ErpnextOptionItem[] {
+  const value = stored.trim();
+  if (!value || items.some((i) => i.name === value)) return items;
+  return [{ name: value, label: value, detail: "saved value, not in the loaded list" }, ...items];
+}
+
+export const optionText = (i: ErpnextOptionItem): string => (i.detail ? `${i.label} (${i.detail})` : i.label);
+
+export const OPTION_LIST_LABELS: Record<string, string> = {
+  companies: "Companies",
+  companyAddresses: "Company addresses",
+  incomeAccounts: "Income accounts",
+  taxAccounts: "Tax accounts",
+  taxTemplates: "Tax templates",
+  namingSeries: "Naming series",
+  itemGroups: "Item groups",
+  uoms: "Units of measure",
+  costCenters: "Cost centers",
+  priceLists: "Price lists",
+  customerGroups: "Customer groups",
+  territories: "Territories",
+};
+
+/** Per-list load errors keyed by list name; the other lists stay usable. */
+export function optionErrors(options: ErpnextOptions | null): Map<string, string> {
+  return new Map((options?.errors ?? []).map((e) => [e.list, e.message]));
+}
+
+export const emptyOptions = (): ErpnextOptions => ({
+  companies: [],
+  companyAddresses: [],
+  incomeAccounts: [],
+  taxAccounts: [],
+  taxTemplates: [],
+  namingSeries: [],
+  itemGroups: [],
+  uoms: [],
+  costCenters: [],
+  priceLists: [],
+  customerGroups: [],
+  territories: [],
+  errors: [],
+});

src/lib/historyExport.ts

@@ -154,7 +154,7 @@ export interface HistoryExportDeps {
   now(): Date;
 }
 
-function joinPath(dir: string, name: string): string {
+export function joinPath(dir: string, name: string): string {
   if (!dir) return name;
   if (/[\\/]$/.test(dir)) return `${dir}${name}`;
   return `${dir}${dir.includes("\\") && !dir.includes("/") ? "\\" : "/"}${name}`;

src/lib/invoiceExportV1.test.ts

@@ -0,0 +1,311 @@
+import { readFileSync, writeFileSync, existsSync } from "node:fs";
+import { describe, expect, it } from "vitest";
+import {
+  buildInvoiceDoc,
+  exportInvoicesV1,
+  invoiceExportName,
+  LINE_CSV_HEADERS,
+  loadInvoiceDocs,
+  rateString,
+  rupeesToPaise,
+  toInvoiceJson,
+  toLineItemsCsv,
+  type InvoiceExportDeps,
+} from "./invoiceExportV1";
+import type { Payment } from "./payments";
+import { blankClient, type Client, type Invoice } from "./types";
+
+const VENDOR = (patch: Record<string, unknown> = {}) =>
+  JSON.stringify({
+    vendorName: "Test Vendor",
+    vendorAddress: "1 Main Rd\nPune",
+    vendorEmail: "a@example.com",
+    vendorPhone: "999",
+    vendorPan: "AAPFU0939F",
+    vendorGstin: "27AAPFU0939F1ZV",
+    vendorStateCode: "27",
+    logoPath: "/secret/logo.png",
+    signaturePath: "/secret/sig.png",
+    gstRegistration: "regular",
+    signatoryName: "Sample",
+    ...patch,
+  });
+
+const invoice = (patch: Partial<Invoice> = {}): Invoice => ({
+  id: 1,
+  number: "INV/2026-001",
+  seriesId: 1,
+  invoiceDate: "2026-04-01",
+  dueDate: "2026-05-01",
+  clientId: 5,
+  clientName: "Client Ltd",
+  clientAddress: "12 MG Road\nBengaluru 560001",
+  clientGstin: "29AABCU9603R1ZJ",
+  poNumber: "PO-9",
+  placeOfSupplyStateCode: "29",
+  subtotal: 7310.1,
+  discount: 10.1,
+  taxType: "igst",
+  taxRate: 18,
+  cgstAmount: 0,
+  sgstAmount: 0,
+  igstAmount: 1314,
+  total: 8614,
+  amountInWords: "Rupees Eight Thousand Six Hundred Fourteen Only",
+  bankAccountId: null,
+  bankSnapshot: "",
+  signaturePath: null,
+  notes: "Thank you",
+  status: "issued",
+  createdAt: "2026-04-01T00:00:00Z",
+  updatedAt: "2026-04-01T00:00:00Z",
+  docType: "tax_invoice",
+  reverseCharge: false,
+  vendorSnapshot: VENDOR(),
+  snapshotOrigin: "issued",
+  cancelledAt: null,
+  cancelReason: "",
+  archivedPdfSha256: null,
+  renderPrefs: "",
+  items: [
+    { id: 1, description: "Design", mode: "fixed", rate: 0, unit: "unit", quantity: 1, amount: 5000.1, sortOrder: 0, hsnSac: "998391" },
+    { id: 2, description: "Consulting", mode: "rate", rate: 1155.05, unit: "hour", quantity: 2, amount: 2310, sortOrder: 1, hsnSac: "" },
+  ],
+  totalPaise: 861400,
+  ...patch,
+});
+
+const client: Client = {
+  ...blankClient(),
+  id: 5,
+  name: "Client Ltd",
+  stateCode: "29",
+  addressLine1: "12 MG Road",
+  addressLine2: "",
+  city: "Bengaluru",
+  pincode: "560001",
+  gstCategory: "registered_regular",
+};
+
+const payment = (patch: Partial<Payment> = {}): Payment => ({
+  id: 1,
+  invoiceId: 1,
+  paidOn: "2026-04-10",
+  amountPaise: 700000,
+  tdsPaise: 70000,
+  mode: "bank_transfer",
+  reference: "UTR123",
+  notes: "n",
+  createdAt: "x",
+  ...patch,
+});
+
+describe("voiced.invoice.v1 document", () => {
+  it("matches the golden file for a fixture invoice", () => {
+    const text = toInvoiceJson([buildInvoiceDoc(invoice(), [payment()], client)]);
+    const path = new URL("./__golden__/invoice-v1.golden.json", import.meta.url);
+    if (!existsSync(path)) writeFileSync(path, text);
+    expect(text).toBe(readFileSync(path, "utf8"));
+  });
+
+  it("is deterministic and keeps the key order", () => {
+    const a = toInvoiceJson([buildInvoiceDoc(invoice(), [payment()], client)]);
+    const b = toInvoiceJson([buildInvoiceDoc(invoice(), [payment()], client)]);
+    expect(a).toBe(b);
+    const doc = buildInvoiceDoc(invoice(), [], null);
+    expect(Object.keys(doc).slice(0, 4)).toEqual(["schema", "number", "issue_date", "due_date"]);
+    expect(doc.schema).toBe("voiced.invoice.v1");
+  });
+
+  it("carries every amount as exact paise and a matching decimal string", () => {
+    const doc = buildInvoiceDoc(invoice(), [payment()], client);
+    // Plain float multiplication is off (0.29 * 100 is 28.999999999999996); the paise must be exact integers.
+    expect(0.29 * 100).not.toBe(29);
+    expect(doc.totals.subtotal_paise).toBe(731010);
+    expect(doc.totals.subtotal).toBe("7310.10");
+    expect(doc.totals.discount).toBe("10.10");
+    expect(doc.totals.taxable_value_paise).toBe(730000);
+    expect(doc.totals.tax).toBe("1314.00");
+    expect(doc.totals.total_paise).toBe(861400);
+    expect(doc.totals.total).toBe("8614.00");
+    expect(doc.items[0]).toMatchObject({ quantity: "1", unit: null, rate: "5000.10", taxable_value_paise: 500010, hsn_sac: "998391" });
+    expect(doc.items[1]).toMatchObject({ quantity: "2", unit: "hour", rate: "1155.05", rate_paise: 115505, hsn_sac: null });
+    expect(doc.payments[0]).toMatchObject({ amount: "7000.00", tds: "700.00", tds_paise: 70000 });
+    // Every *_paise field is a safe integer and agrees with its decimal.
+    const walk = (o: unknown, path: string[] = []) => {
+      if (!o || typeof o !== "object") return;
+      const rec = o as Record<string, unknown>;
+      for (const [k, v] of Object.entries(rec)) {
+        if (k.endsWith("_paise")) {
+          expect(Number.isSafeInteger(v), path.concat(k).join(".")).toBe(true);
+          const dec = rec[k.slice(0, -6)];
+          expect(dec, path.concat(k).join(".")).toBe(`${Math.trunc((v as number) / 100)}.${String(Math.abs(v as number) % 100).padStart(2, "0")}`);
+        } else walk(v, path.concat(k));
+      }
+    };
+    walk(JSON.parse(toInvoiceJson([doc])));
+  });
+
+  it("reports the tax heads: CGST+SGST at half rate, IGST whole, none for an unregistered vendor", () => {
+    const intra = buildInvoiceDoc(invoice({ taxType: "cgst_sgst", taxRate: 12.5, cgstAmount: 100.25, sgstAmount: 100.25, igstAmount: 0 }), [], client);
+    expect(intra.tax.cgst).toEqual({ rate: "6.25", amount_paise: 10025, amount: "100.25" });
+    expect(intra.tax.sgst).toEqual({ rate: "6.25", amount_paise: 10025, amount: "100.25" });
+    expect(intra.tax.igst).toEqual({ rate: "0", amount_paise: 0, amount: "0.00" });
+    expect(intra.tax.utgst.amount_paise).toBe(0);
+    expect(intra.totals.tax_paise).toBe(20050);
+
+    const inter = buildInvoiceDoc(invoice(), [], client);
+    expect(inter.tax.igst).toEqual({ rate: "18", amount_paise: 131400, amount: "1314.00" });
+    expect(inter.tax.cgst.rate).toBe("0");
+  });
+
+  it("moves the second head to UTGST when the supplier is in a union territory", () => {
+    const doc = buildInvoiceDoc(
+      invoice({ taxType: "cgst_sgst", taxRate: 18, cgstAmount: 90, sgstAmount: 90, igstAmount: 0, vendorSnapshot: VENDOR({ vendorStateCode: "04" }) }),
+      [],
+      client,
+    );
+    expect(doc.tax.sgst.amount_paise).toBe(0);
+    expect(doc.tax.utgst).toEqual({ rate: "9", amount_paise: 9000, amount: "90.00" });
+    expect(doc.supplier.state).toEqual({ code: "04", name: "Chandigarh" });
+  });
+
+  it("flags a cancelled invoice and keeps its figures", () => {
+    const doc = buildInvoiceDoc(invoice({ status: "cancelled", cancelledAt: "2026-04-05T10:00:00Z", cancelReason: "wrong client" }), [], client);
+    expect(doc).toMatchObject({ status: "cancelled", cancelled: true, cancelled_at: "2026-04-05T10:00:00Z", cancel_reason: "wrong client" });
+    expect(doc.totals.total).toBe("8614.00");
+    const live = buildInvoiceDoc(invoice(), [], client);
+    expect(live).toMatchObject({ cancelled: false, cancelled_at: null, cancel_reason: null });
+  });
+
+  it("exports an unregistered vendor's plain invoice without tax or GSTIN", () => {
+    const doc = buildInvoiceDoc(
+      invoice({
+        docType: "invoice",
+        taxType: "none",
+        taxRate: 0,
+        igstAmount: 0,
+        subtotal: 7300,
+        discount: 0,
+        total: 7300,
+        totalPaise: 730000,
+        clientGstin: "",
+        vendorSnapshot: VENDOR({ gstRegistration: "unregistered", vendorGstin: "" }),
+      }),
+      [],
+      null,
+    );
+    expect(doc.document_type).toBe("invoice");
+    expect(doc.supplier).toMatchObject({ gstin: null, gst_registration: "unregistered" });
+    expect(doc.totals.tax_paise).toBe(0);
+    expect(doc.tax.igst.rate).toBe("0");
+    expect(doc.client.gstin).toBeNull();
+    expect(doc.client.gst_category).toBe("unregistered");
+    expect(doc.client.address).toMatchObject({ line1: null, city: null, state: null });
+  });
+
+  it("does not leak local file paths from the supplier snapshot", () => {
+    const text = toInvoiceJson([buildInvoiceDoc(invoice(), [], client)]);
+    expect(text).not.toContain("/secret/");
+    expect(text).not.toContain("a@example.com");
+  });
+
+  it("survives a missing or broken supplier snapshot", () => {
+    for (const vendorSnapshot of ["", "not json", "null"]) {
+      const doc = buildInvoiceDoc(invoice({ vendorSnapshot }), [], client);
+      expect(doc.supplier).toMatchObject({ name: "", gstin: null, state: { code: "", name: "" } });
+    }
+  });
+
+  it("converts rupees and rates without noise", () => {
+    expect(rupeesToPaise(0.29)).toBe(29);
+    expect(rupeesToPaise(-0.001)).toBe(0);
+    expect(() => rupeesToPaise(Number.NaN)).toThrow();
+    expect(rateString(9)).toBe("9");
+    expect(rateString(2.5)).toBe("2.5");
+    expect(rateString(0.1 + 0.2)).toBe("0.3");
+  });
+});
+
+describe("line-items CSV", () => {
+  it("writes a BOM, CRLF, a header and one row per line with invoice amounts on the first row only", () => {
+    const csv = toLineItemsCsv([buildInvoiceDoc(invoice(), [], client)]);
+    expect(csv.startsWith("")).toBe(true);
+    const lines = csv.slice(1).split("\r\n");
+    expect(lines[0]).toBe(LINE_CSV_HEADERS.join(","));
+    expect(lines).toHaveLength(4); // header, 2 lines, trailing empty
+    const first = lines[1].split(",");
+    const second = lines[2].split(",");
+    const col = (name: string) => LINE_CSV_HEADERS.indexOf(name);
+    expect(first[col("invoice_total")]).toBe("8614.00");
+    expect(second[col("invoice_total")]).toBe("");
+    expect(first[col("invoice_igst")]).toBe("1314.00");
+    expect(second[col("taxable_value")]).toBe("2310.00");
+    expect(first[col("invoice_number")]).toBe("INV/2026-001");
+  });
+
+  it("quotes commas and quotes, and guards formulas", () => {
+    const doc = buildInvoiceDoc(invoice({ items: [{ id: 1, description: '=SUM(A1), "x"', mode: "fixed", rate: 0, unit: "unit", quantity: 1, amount: 10, sortOrder: 0 }] }), [], client);
+    const csv = toLineItemsCsv([doc]);
+    expect(csv).toContain(`"'=SUM(A1), ""x"""`);
+  });
+
+  it("keeps an invoice with no items as one row", () => {
+    const csv = toLineItemsCsv([buildInvoiceDoc(invoice({ items: [] }), [], client)]);
+    expect(csv.slice(1).split("\r\n")).toHaveLength(3);
+  });
+});
+
+describe("saving", () => {
+  const deps = (over: Partial<InvoiceExportDeps> = {}): InvoiceExportDeps & { written: { path: string; text: string }[] } => {
+    const written: { path: string; text: string }[] = [];
+    return {
+      written,
+      getInvoice: async (id) => invoice({ id, number: `INV/2026-00${id}` }),
+      listPayments: async () => [payment()],
+      listClients: async () => [client],
+      getLastExportDir: async () => "/home/a/exports",
+      save: async ({ defaultPath }) => defaultPath,
+      writeExportFile: async (path, bytes) => {
+        written.push({ path, text: new TextDecoder().decode(bytes) });
+        return path;
+      },
+      now: () => new Date("2026-06-01T10:00:00Z"),
+      ...over,
+    };
+  };
+
+  it("names the file after the invoice or the count", () => {
+    const one = [buildInvoiceDoc(invoice(), [], null)];
+    const now = new Date("2026-06-01T10:00:00Z");
+    expect(invoiceExportName(one, "json", now)).toBe("voiced-invoice-INV-2026-001.json");
+    expect(invoiceExportName(one, "csv", now)).toBe("voiced-invoice-INV-2026-001-lines.csv");
+    expect(invoiceExportName([...one, ...one], "json", now)).toBe("voiced-invoices-2-2026-06-01.json");
+  });
+
+  it("writes the chosen invoices in order, once each", async () => {
+    const d = deps();
+    const done = await exportInvoicesV1(d, [2, 1, 2], "json");
+    expect(done).toEqual({ path: "/home/a/exports/voiced-invoices-2-2026-06-01.json", count: 2 });
+    const docs = JSON.parse(d.written[0].text) as { number: string }[];
+    expect(docs.map((x) => x.number)).toEqual(["INV/2026-002", "INV/2026-001"]);
+  });
+
+  it("returns null when the dialog is cancelled and writes nothing", async () => {
+    const d = deps({ save: async () => null });
+    expect(await exportInvoicesV1(d, [1], "csv")).toBeNull();
+    expect(d.written).toHaveLength(0);
+  });
+
+  it("still exports when the client list cannot be read", async () => {
+    const docs = await loadInvoiceDocs(deps({ listClients: async () => Promise.reject(new Error("db")) }), [1]);
+    expect(docs).toHaveLength(1);
+    expect(docs[0].client.address.line1).toBeNull();
+  });
+
+  it("works without a remembered folder", async () => {
+    const d = deps({ getLastExportDir: async () => Promise.reject(new Error("none")) });
+    const done = await exportInvoicesV1(d, [1], "json");
+    expect(done?.path).toBe("voiced-invoice-INV-2026-001.json");
+  });
+});

src/lib/invoiceExportV1.ts

@@ -0,0 +1,364 @@
+/**
+ * The generic `voiced.invoice.v1` export: a canonical, deterministic JSON document per invoice (and a CSV of line
+ * items) for software that Voiced has no direct integration with. Pure: it formats data it is handed, using integer
+ * paise for every amount, and never touches Tauri. The format is described in docs/voiced-invoice-v1.md.
+ */
+import { csvField, guardFormula, joinPath, paiseToDecimal } from "./historyExport";
+import type { Payment } from "./payments";
+import { INDIAN_STATES, type Client, type Invoice } from "./types";
+
+export const INVOICE_SCHEMA = "voiced.invoice.v1";
+
+/** Union territories without a legislature (mirror of `is_ut_without_legislature` in gst.rs): their second head is UTGST. */
+const UT_WITHOUT_LEGISLATURE = new Set(["04", "26", "31", "35", "38"]);
+
+export interface TaxHeadV1 {
+  /** Percent, e.g. "9" or "2.5"; "0" when the head does not apply to the invoice. */
+  rate: string;
+  amount_paise: number;
+  amount: string;
+}
+
+export interface InvoiceDocV1 {
+  schema: typeof INVOICE_SCHEMA;
+  number: string;
+  issue_date: string;
+  due_date: string | null;
+  document_type: "tax_invoice" | "invoice";
+  status: string;
+  cancelled: boolean;
+  cancelled_at: string | null;
+  cancel_reason: string | null;
+  currency: "INR";
+  po_number: string | null;
+  supplier: {
+    name: string;
+    address: string;
+    gstin: string | null;
+    pan: string | null;
+    gst_registration: string;
+    state: { code: string; name: string };
+  };
+  client: {
+    name: string;
+    gstin: string | null;
+    gst_category: string;
+    address: {
+      text: string;
+      line1: string | null;
+      line2: string | null;
+      city: string | null;
+      pincode: string | null;
+      state: { code: string; name: string } | null;
+    };
+    place_of_supply: { code: string; name: string };
+  };
+  items: {
+    line: number;
+    description: string;
+    hsn_sac: string | null;
+    quantity: string;
+    unit: string | null;
+    rate_paise: number;
+    rate: string;
+    taxable_value_paise: number;
+    taxable_value: string;
+  }[];
+  tax: { cgst: TaxHeadV1; sgst: TaxHeadV1; utgst: TaxHeadV1; igst: TaxHeadV1 };
+  totals: {
+    subtotal_paise: number;
+    subtotal: string;
+    discount_paise: number;
+    discount: string;
+    taxable_value_paise: number;
+    taxable_value: string;
+    tax_paise: number;
+    tax: string;
+    total_paise: number;
+    total: string;
+    amount_in_words: string | null;
+  };
+  reverse_charge: boolean;
+  notes: string | null;
+  payments: {
+    date: string;
+    amount_paise: number;
+    amount: string;
+    tds_paise: number;
+    tds: string;
+    mode: string;
+    reference: string | null;
+  }[];
+}
+
+/** Rupees as stored (a REAL with two decimals) to integer paise, rounded exactly as the backend does. */
+export function rupeesToPaise(rupees: number): number {
+  const paise = Math.round(rupees * 100);
+  if (!Number.isSafeInteger(paise)) throw new Error(`Not an amount: ${rupees}`);
+  return paise === 0 ? 0 : paise; // no negative zero
+}
+
+const blank = (s: string | null | undefined): string | null => {
+  const t = (s ?? "").trim();
+  return t === "" ? null : t;
+};
+
+const gstinOf = (s: string | null | undefined): string | null => {
+  const t = blank(s);
+  return t === null || t.toUpperCase() === "NA" ? null : t;
+};
+
+const stateOf = (code: string): { code: string; name: string } => ({
+  code,
+  name: INDIAN_STATES.find((s) => s.code === code)?.name ?? "",
+});
+
+/** A percentage as the shortest decimal string (9, 6.25), without binary noise. */
+export function rateString(rate: number): string {
+  return String(Number(rate.toFixed(4)));
+}
+
+interface Snapshot {
+  vendorName?: string;
+  vendorAddress?: string;
+  vendorGstin?: string;
+  vendorPan?: string;
+  vendorStateCode?: string;
+  gstRegistration?: string;
+}
+
+function parseSnapshot(text: string): Snapshot {
+  try {
+    const v: unknown = text ? JSON.parse(text) : {};
+    return v && typeof v === "object" ? (v as Snapshot) : {};
+  } catch {
+    return {};
+  }
+}
+
+const head = (rate: number, rupees: number): TaxHeadV1 => {
+  const paise = rupeesToPaise(rupees);
+  return { rate: rateString(rate), amount_paise: paise, amount: paiseToDecimal(paise) };
+};
+
+/**
+ * One invoice as `voiced.invoice.v1`. The supplier comes from the snapshot frozen at issue. The client's name, GSTIN
+ * and place of supply are frozen on the invoice too; the structured address and GST category are read from the saved
+ * client record (`client`, optional) because the invoice only froze the printed text.
+ */
+export function buildInvoiceDoc(invoice: Invoice, payments: Payment[], client?: Client | null): InvoiceDocV1 {
+  const snap = parseSnapshot(invoice.vendorSnapshot);
+  const supplierState = snap.vendorStateCode ?? "";
+  const isUt = UT_WITHOUT_LEGISLATURE.has(supplierState);
+  const half = invoice.taxType === "cgst_sgst" ? invoice.taxRate / 2 : 0;
+  const igstRate = invoice.taxType === "igst" ? invoice.taxRate : 0;
+
+  const zero = (): TaxHeadV1 => head(0, 0);
+  const secondHead = head(half, invoice.sgstAmount);
+  const tax = {
+    cgst: head(half, invoice.cgstAmount),
+    sgst: isUt ? zero() : secondHead,
+    utgst: isUt ? secondHead : zero(),
+    igst: head(igstRate, invoice.igstAmount),
+  };
+
+  const subtotal = rupeesToPaise(invoice.subtotal);
+  const discount = rupeesToPaise(invoice.discount);
+  const totalTax = tax.cgst.amount_paise + tax.sgst.amount_paise + tax.utgst.amount_paise + tax.igst.amount_paise;
+  const total = invoice.totalPaise ?? rupeesToPaise(invoice.total);
+
+  const gstin = gstinOf(invoice.clientGstin);
+  const pos = invoice.placeOfSupplyStateCode;
+  const clientState = client && client.stateCode ? stateOf(client.stateCode) : null;
+
+  return {
+    schema: INVOICE_SCHEMA,
+    number: invoice.number,
+    issue_date: invoice.invoiceDate,
+    due_date: blank(invoice.dueDate),
+    document_type: invoice.docType,
+    status: invoice.status,
+    cancelled: invoice.status === "cancelled",
+    cancelled_at: invoice.status === "cancelled" ? blank(invoice.cancelledAt) : null,
+    cancel_reason: invoice.status === "cancelled" ? blank(invoice.cancelReason) : null,
+    currency: "INR",
+    po_number: blank(invoice.poNumber),
+    supplier: {
+      name: snap.vendorName ?? "",
+      address: snap.vendorAddress ?? "",
+      gstin: gstinOf(snap.vendorGstin),
+      pan: blank(snap.vendorPan),
+      gst_registration: snap.gstRegistration ?? "",
+      state: stateOf(supplierState),
+    },
+    client: {
+      name: invoice.clientName,
+      gstin,
+      gst_category: client?.gstCategory ?? (gstin ? "registered_regular" : "unregistered"),
+      address: {
+        text: invoice.clientAddress,
+        line1: blank(client?.addressLine1),
+        line2: blank(client?.addressLine2),
+        city: blank(client?.city),
+        pincode: blank(client?.pincode),
+        state: clientState,
+      },
+      place_of_supply: stateOf(pos),
+    },
+    items: invoice.items.map((item, index) => {
+      const fixed = item.mode === "fixed";
+      const amount = rupeesToPaise(item.amount);
+      const rate = fixed ? amount : rupeesToPaise(item.rate);
+      return {
+        line: index + 1,
+        description: item.description,
+        hsn_sac: blank(item.hsnSac),
+        quantity: fixed ? "1" : String(item.quantity),
+        unit: fixed ? null : item.unit,
+        rate_paise: rate,
+        rate: paiseToDecimal(rate),
+        taxable_value_paise: amount,
+        taxable_value: paiseToDecimal(amount),
+      };
+    }),
+    tax,
+    totals: {
+      subtotal_paise: subtotal,
+      subtotal: paiseToDecimal(subtotal),
+      discount_paise: discount,
+      discount: paiseToDecimal(discount),
+      taxable_value_paise: subtotal - discount,
+      taxable_value: paiseToDecimal(subtotal - discount),
+      tax_paise: totalTax,
+      tax: paiseToDecimal(totalTax),
+      total_paise: total,
+      total: paiseToDecimal(total),
+      amount_in_words: blank(invoice.amountInWords),
+    },
+    reverse_charge: invoice.reverseCharge,
+    notes: blank(invoice.notes),
+    payments: payments.map((p) => ({
+      date: p.paidOn,
+      amount_paise: p.amountPaise,
+      amount: paiseToDecimal(p.amountPaise),
+      tds_paise: p.tdsPaise,
+      tds: paiseToDecimal(p.tdsPaise),
+      mode: p.mode,
+      reference: blank(p.reference),
+    })),
+  };
+}
+
+/** The JSON file: an array of invoice documents in the given order. Same input, same bytes. */
+export function toInvoiceJson(docs: InvoiceDocV1[]): string {
+  return `${JSON.stringify(docs, null, 2)}\n`;
+}
+
+// ---- CSV: one row per line item ----
+
+type Kind = "text" | "amount";
+
+const LINE_COLUMNS: readonly { header: string; kind: Kind; value: (d: InvoiceDocV1, line: number) => string }[] = [
+  { header: "invoice_number", kind: "text", value: (d) => d.number },
+  { header: "issue_date", kind: "text", value: (d) => d.issue_date },
+  { header: "due_date", kind: "text", value: (d) => d.due_date ?? "" },
+  { header: "document_type", kind: "text", value: (d) => d.document_type },
+  { header: "status", kind: "text", value: (d) => d.status },
+  { header: "cancelled", kind: "text", value: (d) => (d.cancelled ? "yes" : "no") },
+  { header: "currency", kind: "text", value: (d) => d.currency },
+  { header: "supplier_name", kind: "text", value: (d) => d.supplier.name },
+  { header: "supplier_gstin", kind: "text", value: (d) => d.supplier.gstin ?? "" },
+  { header: "client_name", kind: "text", value: (d) => d.client.name },
+  { header: "client_gstin", kind: "text", value: (d) => d.client.gstin ?? "" },
+  { header: "client_gst_category", kind: "text", value: (d) => d.client.gst_category },
+  { header: "place_of_supply_code", kind: "text", value: (d) => d.client.place_of_supply.code },
+  { header: "place_of_supply", kind: "text", value: (d) => d.client.place_of_supply.name },
+  { header: "reverse_charge", kind: "text", value: (d) => (d.reverse_charge ? "yes" : "no") },
+  { header: "line", kind: "text", value: (d, i) => (d.items[i] ? String(d.items[i].line) : "") },
+  { header: "description", kind: "text", value: (d, i) => d.items[i]?.description ?? "" },
+  { header: "hsn_sac", kind: "text", value: (d, i) => d.items[i]?.hsn_sac ?? "" },
+  { header: "quantity", kind: "text", value: (d, i) => d.items[i]?.quantity ?? "" },
+  { header: "unit", kind: "text", value: (d, i) => d.items[i]?.unit ?? "" },
+  { header: "rate", kind: "amount", value: (d, i) => d.items[i]?.rate ?? "" },
+  { header: "taxable_value", kind: "amount", value: (d, i) => d.items[i]?.taxable_value ?? "" },
+  // Invoice-level amounts sit on the first row only, so summing a column never counts an invoice twice.
+  { header: "invoice_discount", kind: "amount", value: (d, i) => (i === 0 ? d.totals.discount : "") },
+  { header: "invoice_cgst", kind: "amount", value: (d, i) => (i === 0 ? d.tax.cgst.amount : "") },
+  { header: "invoice_sgst", kind: "amount", value: (d, i) => (i === 0 ? d.tax.sgst.amount : "") },
+  { header: "invoice_utgst", kind: "amount", value: (d, i) => (i === 0 ? d.tax.utgst.amount : "") },
+  { header: "invoice_igst", kind: "amount", value: (d, i) => (i === 0 ? d.tax.igst.amount : "") },
+  { header: "invoice_total", kind: "amount", value: (d, i) => (i === 0 ? d.totals.total : "") },
+];
+
+export const LINE_CSV_HEADERS: readonly string[] = LINE_COLUMNS.map((c) => c.header);
+
+/** UTF-8 BOM, CRLF, header row always present; text cells are guarded against spreadsheet formulas. */
+export function toLineItemsCsv(docs: InvoiceDocV1[]): string {
+  const lines: string[] = [LINE_COLUMNS.map((c) => csvField(c.header)).join(",")];
+  for (const doc of docs) {
+    const rows = Math.max(1, doc.items.length);
+    for (let i = 0; i < rows; i++) {
+      lines.push(LINE_COLUMNS.map((c) => csvField(c.kind === "text" ? guardFormula(c.value(doc, i)) : c.value(doc, i))).join(","));
+    }
+  }
+  return `${lines.join("\r\n")}\r\n`;
+}
+
+// ---- saving ----
+
+export type InvoiceExportFormat = "json" | "csv";
+
+const safeName = (s: string) => s.replace(/[^A-Za-z0-9._-]+/g, "-");
+
+export function invoiceExportName(docs: InvoiceDocV1[], format: InvoiceExportFormat, now: Date): string {
+  const base =
+    docs.length === 1
+      ? `voiced-invoice-${safeName(docs[0].number)}`
+      : `voiced-invoices-${docs.length}-${now.toISOString().slice(0, 10)}`;
+  return `${base}${format === "csv" ? "-lines" : ""}.${format}`;
+}
+
+export interface InvoiceExportDeps {
+  getInvoice(id: number): Promise<Invoice>;
+  listPayments(invoiceId: number): Promise<Payment[]>;
+  listClients(): Promise<Client[]>;
+  getLastExportDir(): Promise<string>;
+  save(opts: { defaultPath: string; format: InvoiceExportFormat }): Promise<string | null>;
+  writeExportFile(path: string, bytes: Uint8Array): Promise<string>;
+  now(): Date;
+}
+
+/** Reads the invoices (frozen data plus payments) in the order given; the client record is optional detail. */
+export async function loadInvoiceDocs(deps: Pick<InvoiceExportDeps, "getInvoice" | "listPayments" | "listClients">, ids: number[]): Promise<InvoiceDocV1[]> {
+  const unique = [...new Set(ids)];
+  const loaded: { invoice: Invoice; payments: Payment[] }[] = [];
+  for (const id of unique) {
+    const [invoice, payments] = await Promise.all([deps.getInvoice(id), deps.listPayments(id)]);
+    loaded.push({ invoice, payments });
+  }
+  let clients = new Map<number, Client>();
+  if (loaded.some((l) => l.invoice.clientId !== null)) {
+    try {
+      clients = new Map((await deps.listClients()).filter((c) => c.id !== null).map((c) => [c.id as number, c]));
+    } catch {
+      // The structured address is extra detail; the export is complete without it.
+    }
+  }
+  return loaded.map(({ invoice, payments }) => buildInvoiceDoc(invoice, payments, invoice.clientId === null ? null : (clients.get(invoice.clientId) ?? null)));
+}
+
+/** Exports the chosen invoices through the save dialog. Returns the path, or null if the dialog was cancelled. */
+export async function exportInvoicesV1(deps: InvoiceExportDeps, ids: number[], format: InvoiceExportFormat): Promise<{ path: string; count: number } | null> {
+  const docs = await loadInvoiceDocs(deps, ids);
+  const text = format === "csv" ? toLineItemsCsv(docs) : toInvoiceJson(docs);
+  let dir = "";
+  try {
+    dir = await deps.getLastExportDir();
+  } catch {
+    // No remembered folder: the dialog opens wherever the system prefers.
+  }
+  const chosen = await deps.save({ defaultPath: joinPath(dir, invoiceExportName(docs, format, deps.now())), format });
+  if (!chosen) return null;
+  const path = (await deps.writeExportFile(chosen, new TextEncoder().encode(text))) || chosen;
+  return { path, count: docs.length };
+}

src/lib/payments.ts

@@ -23,9 +23,11 @@ export interface Payment {
   reference: string;
   notes: string;
   createdAt: string;
+  /** Payment Entry name on ERPNext once the payment was sent. */
+  erpnextPaymentEntry?: string | null;
 }
 
-export type PaymentInput = Omit<Payment, "id" | "createdAt">;
+export type PaymentInput = Omit<Payment, "id" | "createdAt" | "erpnextPaymentEntry">;
 
 type TagType = "red" | "green" | "blue" | "gray" | "warm-gray" | "cool-gray" | "purple";
 

src/lib/settingsTab.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it } from "vitest";
-import { SETTINGS_TABS, loadSettingsTab, parseSettingsTab, saveSettingsTab } from "./settingsTab";
+import { SETTINGS_TABS, loadSettingsTab, parseSettingsTab, requestSettingsTab, saveSettingsTab } from "./settingsTab";
 
 describe("settings tab persistence", () => {
   it("maps stored ids to indexes and falls back to the first tab", () => {
@@ -14,4 +14,10 @@ describe("settings tab persistence", () => {
     expect(() => saveSettingsTab(2)).not.toThrow();
     expect(() => saveSettingsTab(99)).not.toThrow();
   });
+
+  it("honours a requested tab once, then goes back to the stored one", () => {
+    requestSettingsTab("integrations");
+    expect(loadSettingsTab()).toBe(SETTINGS_TABS.findIndex((t) => t.id === "integrations"));
+    expect(loadSettingsTab()).toBe(0);
+  });
 });

src/lib/settingsTab.ts

@@ -9,6 +9,7 @@ export const SETTINGS_TABS = [
   { id: "templates", label: "Templates & export" },
   { id: "fonts", label: "Fonts" },
   { id: "data", label: "Data" },
+  { id: "integrations", label: "Integrations" },
 ] as const;
 
 export type SettingsTabId = (typeof SETTINGS_TABS)[number]["id"];
@@ -19,8 +20,21 @@ export function parseSettingsTab(value: string | null | undefined): number {
   return index < 0 ? 0 : index;
 }
 
+/** A tab another screen asked for; used once by the next Settings mount, so it works without localStorage. */
+let requested: SettingsTabId | null = null;
+
+/** Makes the next opening of Settings land on `id` (for "Set up in Settings" links). */
+export function requestSettingsTab(id: SettingsTabId): void {
+  requested = id;
+}
+
 /** The last Settings tab this viewer used. A per-viewer convenience only. */
 export function loadSettingsTab(): number {
+  if (requested) {
+    const index = parseSettingsTab(requested);
+    requested = null;
+    return index;
+  }
   try {
     return parseSettingsTab(localStorage.getItem(KEY));
   } catch {

src/styles/carbon.scss

@@ -698,3 +698,76 @@ body {
 .voiced-detail__unarchived p {
   margin-bottom: 1rem;
 }
+
+/* Settings, Integrations, ERPNext */
+.voiced-erp__section > h3 {
+  margin-bottom: 0.5rem;
+}
+
+.voiced-erp__fields {
+  display: grid;
+  gap: 1rem;
+  max-width: 40rem;
+  margin-top: 1rem;
+}
+
+.voiced-erp__label {
+  font-size: 0.75rem;
+  color: var(--cds-text-secondary);
+  margin-bottom: 0.25rem;
+}
+
+.voiced-erp__secret > * + * {
+  margin-top: 0.5rem;
+}
+
+.voiced-erp__result > * + * {
+  margin-top: 0.75rem;
+}
+
+.voiced-erp__uoms {
+  border: 0;
+  padding: 0;
+  display: grid;
+  gap: 1rem;
+}
+
+.voiced-erp__uoms legend {
+  font-size: 0.75rem;
+  color: var(--cds-text-secondary);
+}
+
+.voiced-erp__error {
+  color: var(--cds-text-error);
+  font-size: 0.75rem;
+}
+
+/* ERPNext column and bulk-send bar on the invoices list */
+.voiced-history__bulk {
+  display: flex;
+  flex-wrap: wrap;
+  align-items: center;
+  gap: 0.5rem;
+  margin-bottom: 1rem;
+}
+
+.voiced-erp__results {
+  list-style: none;
+  margin-top: 1rem;
+  max-height: 16rem;
+  overflow: auto;
+}
+
+.voiced-erp__results li {
+  padding: 0.25rem 0;
+  border-bottom: 1px solid var(--cds-border-subtle);
+}
+
+.voiced-erp__panel {
+  border: 1px solid var(--cds-border-subtle);
+  padding: 1rem;
+}
+
+.voiced-erp__panel > * + * {
+  margin-top: 0.75rem;
+}

src/views/AppSettings.tsx

@@ -41,6 +41,7 @@ import { ImagePicker } from "../components/ImagePicker";
 import { LogoBranding } from "../components/LogoBranding";
 import DataBackupPanel from "../components/DataBackupPanel";
 import DiagnosticsPanel from "../components/DiagnosticsPanel";
+import ErpnextSettingsPanel from "../components/ErpnextSettingsPanel";
 import { FontOverrideTable } from "../components/FontOverrideTable";
 import { useToast } from "../components/ToastProvider";
 import { SETTINGS_TABS, loadSettingsTab, saveSettingsTab } from "../lib/settingsTab";
@@ -159,7 +160,7 @@ export default function AppSettings({
   return (
     <div className="voiced-page">
       <h1 className="voiced-page__title">Settings</h1>
-      <p className="voiced-page__subtitle">Business details, branding, defaults and bank accounts.</p>
+      <p className="voiced-page__subtitle">Business details, branding, defaults, bank accounts and integrations.</p>
 
       <Tabs selectedIndex={tab} onChange={({ selectedIndex }) => selectTab(selectedIndex)}>
         <TabList aria-label="Settings sections" contained scrollIntoView>
@@ -171,6 +172,7 @@ export default function AppSettings({
           <Tab>Templates &amp; export</Tab>
           <Tab>Fonts</Tab>
           <Tab>Data</Tab>
+          <Tab>Integrations</Tab>
         </TabList>
         <TabPanels>
             <TabPanel>
@@ -516,6 +518,9 @@ export default function AppSettings({
             <TabPanel>
               <DataBackupPanel />
             </TabPanel>
+            <TabPanel>
+              <ErpnextSettingsPanel active={tab === SETTINGS_TABS.findIndex((t) => t.id === "integrations")} />
+            </TabPanel>
         </TabPanels>
       </Tabs>
 

src/views/InvoiceDetail.tsx

@@ -3,6 +3,7 @@ import {
   Button,
   InlineLoading,
   InlineNotification,
+  Link,
   Modal,
   OverflowMenu,
   OverflowMenuItem,
@@ -28,6 +29,20 @@ import { toDraftPayload } from "../lib/draft";
 import { invoiceToFormState } from "../lib/duplicate";
 import type { ExportMode } from "../lib/filename";
 import { useInvoiceExport } from "../hooks/useInvoiceExport";
+import { useGenericExport } from "../hooks/useGenericExport";
+import { openInErpnext } from "../lib/erpnextActions";
+import type { ErpnextConfig, ErpnextPushResult, ErpnextSyncStatus } from "../lib/erpnext";
+import {
+  canOpenInErpnext,
+  describePaymentPush,
+  describePush,
+  failedPush,
+  formatSyncedAt,
+  isConfigured,
+  paymentPushDisabledReason,
+  pushDisabledReason,
+  syncTag,
+} from "../lib/erpnextUi";
 import { useReturnFocus } from "../hooks/useReturnFocus";
 import ExportFeedback from "../components/ExportFeedback";
 import PdfPreview from "../components/PdfPreview";
@@ -41,6 +56,8 @@ interface Props {
   onBack: () => void;
   /** A draft was created from this invoice; the shell opens it in the New invoice form. */
   onDuplicated: (draftId: number) => void;
+  /** Goes to Settings, Integrations. */
+  onOpenSettings: () => void;
 }
 
 interface Frozen {
@@ -74,7 +91,7 @@ function Field({ label, children }: { label: string; children: React.ReactNode }
   );
 }
 
-export default function InvoiceDetail({ invoiceId, settings, onBack, onDuplicated }: Props) {
+export default function InvoiceDetail({ invoiceId, settings, onBack, onDuplicated, onOpenSettings }: Props) {
   const toast = useToast();
   const [invoice, setInvoice] = useState<Invoice | null>(null);
   const [payments, setPayments] = useState<Payment[]>([]);
@@ -88,6 +105,12 @@ export default function InvoiceDetail({ invoiceId, settings, onBack, onDuplicate
   const [cancelOpen, setCancelOpen] = useState(false);
   const [reason, setReason] = useState("");
   const [duplicating, setDuplicating] = useState(false);
+  const [erpCfg, setErpCfg] = useState<ErpnextConfig | null>(null);
+  const [erpSync, setErpSync] = useState<ErpnextSyncStatus | undefined>(undefined);
+  const [lastPush, setLastPush] = useState<ErpnextPushResult | null>(null);
+  const [sendingErp, setSendingErp] = useState(false);
+  const [sendingPayment, setSendingPayment] = useState<number | null>(null);
+  const generic = useGenericExport();
   useReturnFocus(deleteTarget !== null);
   useReturnFocus(cancelOpen);
 
@@ -123,14 +146,31 @@ export default function InvoiceDetail({ invoiceId, settings, onBack, onDuplicate
     }
   }, []);
 
+  /** ERPNext is optional: when it cannot be read the panel just stays out of the way. */
+  const loadErp = useCallback(async (id: number, gen: number) => {
+    try {
+      const [cfg, sync] = await Promise.all([api.erpnextGetConfig(), api.erpnextSyncStatus(id)]);
+      if (gen !== generation.current) return;
+      setErpCfg(cfg);
+      setErpSync(sync);
+    } catch {
+      if (gen === generation.current) {
+        setErpCfg(null);
+        setErpSync(undefined);
+      }
+    }
+  }, []);
+
   useEffect(() => {
     const gen = ++generation.current;
     setInvoice(null);
     setPdf(null);
     setArchive(null);
+    setLastPush(null);
     void loadData(invoiceId, gen);
     void loadPdf(invoiceId, gen);
-  }, [invoiceId, loadData, loadPdf]);
+    void loadErp(invoiceId, gen);
+  }, [invoiceId, loadData, loadPdf, loadErp]);
 
   const refresh = () => loadData(invoiceId, generation.current);
 
@@ -194,6 +234,44 @@ export default function InvoiceDetail({ invoiceId, settings, onBack, onDuplicate
     }
   };
 
+  /** `submit` undefined keeps what the invoice already is in ERPNext. A failure is shown, never thrown. */
+  const onSendErp = async (submit: boolean) => {
+    if (!invoice) return;
+    setSendingErp(true);
+    let result: ErpnextPushResult;
+    try {
+      result = await api.erpnextPushInvoice(invoice.id, submit);
+    } catch (e) {
+      result = failedPush(invoice.id, invoice.number, e);
+    }
+    setLastPush(result);
+    const note = describePush(result);
+    toast[note.kind](note.title, note.subtitle);
+    await loadErp(invoiceId, generation.current);
+    setSendingErp(false);
+  };
+
+  const onOpenErp = async () => {
+    try {
+      await openInErpnext(invoiceId);
+    } catch (e) {
+      toast.error("Could not open ERPNext", String(e));
+    }
+  };
+
+  const onSendPayment = async (paymentId: number) => {
+    setSendingPayment(paymentId);
+    try {
+      const note = describePaymentPush(await api.erpnextPushPayment(paymentId));
+      toast[note.kind](note.title, note.subtitle);
+      await refresh();
+    } catch (e) {
+      toast.error("Could not send the payment", String(e));
+    } finally {
+      setSendingPayment(null);
+    }
+  };
+
   const onDeletePayment = async () => {
     if (!deleteTarget) return;
     const target = deleteTarget;
@@ -231,6 +309,12 @@ export default function InvoiceDetail({ invoiceId, settings, onBack, onDuplicate
   const balance = invoice.balancePaise ?? 0;
   const canPay = invoice.status === "issued" && balance > 0;
   const half = invoice.taxRate / 2;
+  const erpOn = isConfigured(erpCfg);
+  const erpTag = syncTag(erpSync);
+  const erpBlocked = pushDisabledReason({ cfg: erpCfg, vendorRegistered: settings.gstRegistration !== "unregistered", invoiceStatus: invoice.status });
+  const erpHasState = Boolean(erpSync && erpSync.status !== "none");
+  const erpSubmitted = erpSync?.status === "synced" && erpSync.remoteDocstatus === 1;
+  const showPaymentErp = erpOn || payments.some((p) => p.erpnextPaymentEntry);
 
   return (
     <div className="voiced-page voiced-detail">
@@ -284,6 +368,8 @@ export default function InvoiceDetail({ invoiceId, settings, onBack, onDuplicate
         </Button>
         <OverflowMenu aria-label="More actions" iconDescription="More actions" flipped size="md" disabled={busy}>
           <OverflowMenuItem itemText="Re-render with current template" onClick={() => onExport("searchable", "rerender")} />
+          <OverflowMenuItem itemText="Export as voiced.invoice.v1 (JSON)" hasDivider onClick={() => void generic.run([invoice.id], "json")} />
+          <OverflowMenuItem itemText="Export line items (CSV)" onClick={() => void generic.run([invoice.id], "csv")} />
           {invoice.status === "issued" ? (
             <OverflowMenuItem
               itemText={payments.length > 0 ? "Cancel invoice (delete payments first)" : "Cancel invoice"}
@@ -416,6 +502,104 @@ export default function InvoiceDetail({ invoiceId, settings, onBack, onDuplicate
             {invoice.notes ? <p className="voiced-detail__pre voiced-muted">{invoice.notes}</p> : null}
           </section>
 
+          <section aria-labelledby="detail-erpnext">
+            <h2 id="detail-erpnext" className="voiced-detail__h2">
+              ERPNext
+            </h2>
+            {!erpOn && !erpHasState ? (
+              <p className="voiced-muted">
+                ERPNext is not set up.{" "}
+                <Link
+                  href="#"
+                  onClick={(e: React.MouseEvent) => {
+                    e.preventDefault();
+                    onOpenSettings();
+                  }}
+                >
+                  Set it up in Settings, Integrations
+                </Link>
+                .
+              </p>
+            ) : (
+              <div className="voiced-erp__panel">
+                <dl>
+                  <Field label="Status">
+                    <Tag type={erpTag.type} size="sm" title={erpTag.tooltip}>
+                      {erpTag.label}
+                    </Tag>
+                  </Field>
+                  {erpSync?.remoteName ? <Field label="ERPNext document">{erpSync.remoteName}</Field> : null}
+                  {erpSync?.syncedAt ? <Field label="Last synced">{formatSyncedAt(erpSync.syncedAt)}</Field> : null}
+                  {erpSync?.status === "synced" ? <Field label="PDF">{erpSync.attached ? "Attached in ERPNext" : "Not attached"}</Field> : null}
+                </dl>
+                {erpSync && (erpSync.status === "error" || erpSync.status === "conflict") && erpSync.lastError ? (
+                  <InlineNotification
+                    kind={erpSync.status === "conflict" ? "warning" : "error"}
+                    lowContrast
+                    hideCloseButton
+                    title={erpSync.status === "conflict" ? "Conflict with ERPNext" : "The last send failed"}
+                    subtitle={erpSync.lastError}
+                  />
+                ) : null}
+                {lastPush && lastPush.warnings.length > 0 ? (
+                  <InlineNotification kind="warning" lowContrast hideCloseButton title="Sent with notes" subtitle={lastPush.warnings.join(" ")} />
+                ) : null}
+                {erpOn ? (
+                  <>
+                    <div className="voiced-header-action">
+                      {erpSubmitted ? (
+                        <Button kind="tertiary" size="sm" disabled={sendingErp || erpBlocked !== null} onClick={() => void onSendErp(true)}>
+                          {sendingErp ? "Sending…" : "Re-send"}
+                        </Button>
+                      ) : (
+                        <>
+                          <Button kind="tertiary" size="sm" disabled={sendingErp || erpBlocked !== null} onClick={() => void onSendErp(false)}>
+                            {sendingErp ? "Sending…" : erpHasState ? "Re-send as draft" : "Send as draft"}
+                          </Button>
+                          <Button kind="primary" size="sm" disabled={sendingErp || erpBlocked !== null} onClick={() => void onSendErp(true)}>
+                            Send &amp; submit
+                          </Button>
+                        </>
+                      )}
+                      {canOpenInErpnext(erpSync) ? (
+                        <Button kind="ghost" size="sm" onClick={() => void onOpenErp()}>
+                          Open in ERPNext
+                        </Button>
+                      ) : null}
+                    </div>
+                    {erpBlocked ? (
+                      <p className="voiced-muted">
+                        {erpBlocked}{" "}
+                        <Link
+                          href="#"
+                          onClick={(e: React.MouseEvent) => {
+                            e.preventDefault();
+                            onOpenSettings();
+                          }}
+                        >
+                          Open Settings
+                        </Link>
+                      </p>
+                    ) : null}
+                  </>
+                ) : (
+                  <p className="voiced-muted">
+                    ERPNext is not set up any more, so nothing can be sent.{" "}
+                    <Link
+                      href="#"
+                      onClick={(e: React.MouseEvent) => {
+                        e.preventDefault();
+                        onOpenSettings();
+                      }}
+                    >
+                      Open Settings
+                    </Link>
+                  </p>
+                )}
+              </div>
+            )}
+          </section>
+
           <section aria-labelledby="detail-payments">
             <h2 id="detail-payments" className="voiced-detail__h2">
               Payments
@@ -432,6 +616,7 @@ export default function InvoiceDetail({ invoiceId, settings, onBack, onDuplicate
                       <TableHeader>Reference</TableHeader>
                       <TableHeader className="voiced-num">Received</TableHeader>
                       <TableHeader className="voiced-num">TDS</TableHeader>
+                      {showPaymentErp ? <TableHeader>ERPNext</TableHeader> : null}
                       <TableHeader>
                         <span className="cds--assistive-text">Actions</span>
                       </TableHeader>
@@ -448,6 +633,35 @@ export default function InvoiceDetail({ invoiceId, settings, onBack, onDuplicate
                         </TableCell>
                         <TableCell className="voiced-num">{formatPaise(p.amountPaise)}</TableCell>
                         <TableCell className="voiced-num">{formatPaise(p.tdsPaise)}</TableCell>
+                        {showPaymentErp ? (
+                          <TableCell>
+                            {p.erpnextPaymentEntry ? (
+                              <>
+                                <Tag type="green" size="sm">
+                                  Sent
+                                </Tag>{" "}
+                                <span className="voiced-muted">{p.erpnextPaymentEntry}</span>
+                              </>
+                            ) : (
+                              (() => {
+                                const reason = paymentPushDisabledReason({ cfg: erpCfg, sync: erpSync, entry: p.erpnextPaymentEntry });
+                                return (
+                                  <>
+                                    <Button
+                                      kind="ghost"
+                                      size="sm"
+                                      disabled={reason !== null || sendingPayment !== null}
+                                      onClick={() => void onSendPayment(p.id)}
+                                    >
+                                      {sendingPayment === p.id ? "Sending…" : "Send payment to ERPNext"}
+                                    </Button>
+                                    {reason ? <div className="voiced-muted">{reason}</div> : null}
+                                  </>
+                                );
+                              })()
+                            )}
+                          </TableCell>
+                        ) : null}
                         <TableCell>
                           <Button
                             kind="ghost"
@@ -507,7 +721,7 @@ export default function InvoiceDetail({ invoiceId, settings, onBack, onDuplicate
       >
         <p>
           {deleteTarget
-            ? `${formatPaise(deleteTarget.amountPaise + deleteTarget.tdsPaise)} (cash ${formatPaise(deleteTarget.amountPaise)}, TDS ${formatPaise(deleteTarget.tdsPaise)}) received on ${formatDate(deleteTarget.paidOn)}. The invoice balance goes back up by that amount.`
+            ? `${formatPaise(deleteTarget.amountPaise + deleteTarget.tdsPaise)} (cash ${formatPaise(deleteTarget.amountPaise)}, TDS ${formatPaise(deleteTarget.tdsPaise)}) received on ${formatDate(deleteTarget.paidOn)}. The invoice balance goes back up by that amount.${deleteTarget.erpnextPaymentEntry ? ` It was sent to ERPNext as ${deleteTarget.erpnextPaymentEntry}; that entry is not removed there.` : ""}`
             : ""}
         </p>
       </Modal>

src/views/InvoiceHistory.tsx

@@ -1,6 +1,7 @@
 import { useEffect, useMemo, useState } from "react";
 import {
   Button,
+  Checkbox,
   InlineLoading,
   Link,
   OverflowMenu,
@@ -43,6 +44,11 @@ import {
 import type { ExportMode } from "../lib/filename";
 import type { ExportSource } from "../lib/exportFlow";
 import { useInvoiceExport } from "../hooks/useInvoiceExport";
+import { useGenericExport } from "../hooks/useGenericExport";
+import { openInErpnext } from "../lib/erpnextActions";
+import type { ErpnextConfig, ErpnextSyncStatus } from "../lib/erpnext";
+import { canOpenInErpnext, indexSyncStatuses, isConfigured, pushDisabledReason, sendableSelection, syncTag } from "../lib/erpnextUi";
+import SendToErpnextModal, { type SendTarget } from "../components/SendToErpnextModal";
 import ExportFeedback from "../components/ExportFeedback";
 import { useToast } from "../components/ToastProvider";
 import type { InvoiceSummary, Settings } from "../lib/types";
@@ -52,6 +58,8 @@ interface Props {
   active: boolean;
   /** Opens the detail page of an invoice. */
   onOpen: (id: number) => void;
+  /** Goes to Settings, Integrations. */
+  onOpenSettings: () => void;
 }
 
 const PAGE_SIZES = [25, 50, 100];
@@ -65,7 +73,7 @@ const COLUMNS: { key: SortKey; label: string; numeric?: boolean }[] = [
   { key: "status", label: "Status" },
 ];
 
-export default function InvoiceHistory({ settings, active, onOpen }: Props) {
+export default function InvoiceHistory({ settings, active, onOpen, onOpenSettings }: Props) {
   const toast = useToast();
   const [rows, setRows] = useState<InvoiceSummary[]>([]);
   const [loading, setLoading] = useState(true);
@@ -76,15 +84,36 @@ export default function InvoiceHistory({ settings, active, onOpen }: Props) {
   const [pageSize, setPageSize] = useState(PAGE_SIZES[0]);
   const exp = useInvoiceExport({ settings, bank: null });
   const [exportingHistory, setExportingHistory] = useState(false);
+  const [erpCfg, setErpCfg] = useState<ErpnextConfig | null>(null);
+  const [syncs, setSyncs] = useState<Map<number, ErpnextSyncStatus>>(new Map());
+  const [selected, setSelected] = useState<Set<number>>(new Set());
+  const [sendTargets, setSendTargets] = useState<{ invoices: SendTarget[]; skipped: number } | null>(null);
+  const generic = useGenericExport();
+
+  /** One bulk call for every row's ERPNext status. ERPNext is optional, so a failure here only hides the column. */
+  const loadErpnext = async () => {
+    try {
+      const [cfg, list] = await Promise.all([api.erpnextGetConfig(), api.erpnextSyncStatuses()]);
+      setErpCfg(cfg);
+      setSyncs(indexSyncStatuses(list));
+    } catch {
+      setErpCfg(null);
+      setSyncs(new Map());
+    }
+  };
 
   const load = async () => {
     try {
-      setRows(await api.listInvoices());
+      const list = await api.listInvoices();
+      setRows(list);
+      // Keep only selections that still exist.
+      setSelected((prev) => new Set([...prev].filter((id) => list.some((r) => r.id === id))));
     } catch (e) {
       toast.error("Could not load invoices", String(e));
     } finally {
       setLoading(false);
     }
+    void loadErpnext();
   };
 
   // The view stays mounted, so refetch every time it is shown again (a payment may have been recorded).
@@ -113,6 +142,44 @@ export default function InvoiceHistory({ settings, active, onOpen }: Props) {
   const onSort = (key: SortKey) =>
     setSort((s) => (s.key === key ? { key, dir: s.dir === "asc" ? "desc" : "asc" } : { key, dir: key === "date" || key === "total" || key === "balance" ? "desc" : "asc" }));
 
+  const erpOn = isConfigured(erpCfg);
+  const vendorRegistered = settings.gstRegistration !== "unregistered";
+  const showErpColumn = erpOn || syncs.size > 0;
+  const selectedRows = rows.filter((r) => selected.has(r.id));
+  const blockedReason = pushDisabledReason({ cfg: erpCfg, vendorRegistered });
+  const pageAllSelected = shown.length > 0 && shown.every((r) => selected.has(r.id));
+  const toggleOne = (id: number, on: boolean) =>
+    setSelected((prev) => {
+      const next = new Set(prev);
+      if (on) next.add(id);
+      else next.delete(id);
+      return next;
+    });
+  const togglePage = (on: boolean) =>
+    setSelected((prev) => {
+      const next = new Set(prev);
+      for (const r of shown) {
+        if (on) next.add(r.id);
+        else next.delete(r.id);
+      }
+      return next;
+    });
+  const askSend = (list: InvoiceSummary[]) => {
+    const { send, skipped } = sendableSelection(list);
+    if (send.length === 0) {
+      toast.warning("Nothing to send", "Only issued invoices are sent to ERPNext.");
+      return;
+    }
+    setSendTargets({ invoices: send.map((r) => ({ id: r.id, number: r.number })), skipped });
+  };
+  const onOpenErpnext = async (id: number) => {
+    try {
+      await openInErpnext(id);
+    } catch (e) {
+      toast.error("Could not open ERPNext", String(e));
+    }
+  };
+
   const onExport = async (id: number, mode: ExportMode, source: ExportSource) => {
     setBusyId(id);
     try {
@@ -259,6 +326,38 @@ export default function InvoiceHistory({ settings, active, onOpen }: Props) {
             </span>
           </div>
 
+          <div className="voiced-history__bulk" role="group" aria-label="Actions for the selected invoices">
+            <span aria-live="polite">{selected.size} selected</span>
+            <Button kind="tertiary" size="md" disabled={selected.size === 0 || blockedReason !== null} onClick={() => askSend(selectedRows)}>
+              Send selected to ERPNext
+            </Button>
+            <Button kind="ghost" size="md" disabled={selected.size === 0 || generic.busy} onClick={() => void generic.run([...selected], "json")}>
+              Export selected (voiced.invoice.v1 JSON)
+            </Button>
+            <Button kind="ghost" size="md" disabled={selected.size === 0 || generic.busy} onClick={() => void generic.run([...selected], "csv")}>
+              Export selected (line items CSV)
+            </Button>
+            {selected.size > 0 ? (
+              <Button kind="ghost" size="md" onClick={() => setSelected(new Set())}>
+                Clear selection
+              </Button>
+            ) : null}
+            {blockedReason !== null && selected.size > 0 ? (
+              <span className="voiced-muted">
+                {blockedReason}{" "}
+                <Link
+                  href="#"
+                  onClick={(e: React.MouseEvent) => {
+                    e.preventDefault();
+                    onOpenSettings();
+                  }}
+                >
+                  Open Settings
+                </Link>
+              </span>
+            ) : null}
+          </div>
+
           {sorted.length === 0 ? (
             <div className="voiced-empty">No invoices match these filters.</div>
           ) : (
@@ -266,6 +365,9 @@ export default function InvoiceHistory({ settings, active, onOpen }: Props) {
               <Table aria-label="Invoices">
                 <TableHead>
                   <TableRow>
+                    <TableHeader>
+                      <Checkbox id="historySelectPage" labelText="Select all invoices on this page" hideLabel checked={pageAllSelected} onChange={(_e, { checked }) => togglePage(checked)} />
+                    </TableHeader>
                     {COLUMNS.map((c) => (
                       <TableHeader
                         key={c.key}
@@ -278,6 +380,7 @@ export default function InvoiceHistory({ settings, active, onOpen }: Props) {
                         {c.label}
                       </TableHeader>
                     ))}
+                    {showErpColumn ? <TableHeader>ERPNext</TableHeader> : null}
                     <TableHeader>
                       <span className="cds--assistive-text">Actions</span>
                     </TableHeader>
@@ -286,8 +389,20 @@ export default function InvoiceHistory({ settings, active, onOpen }: Props) {
                 <TableBody>
                   {shown.map((row) => {
                     const badge = statusBadge(row.status, row.paymentStatus);
+                    const sync = syncs.get(row.id);
+                    const erpTag = syncTag(sync);
+                    const rowBlocked = pushDisabledReason({ cfg: erpCfg, vendorRegistered, invoiceStatus: row.status });
                     return (
                       <TableRow key={row.id} className="voiced-history__row" onClick={() => onOpen(row.id)}>
+                        <TableCell onClick={(e: React.MouseEvent) => e.stopPropagation()}>
+                          <Checkbox
+                            id={`historySelect-${row.id}`}
+                            labelText={`Select invoice ${row.number}`}
+                            hideLabel
+                            checked={selected.has(row.id)}
+                            onChange={(_e, { checked }) => toggleOne(row.id, checked)}
+                          />
+                        </TableCell>
                         <TableCell>
                           <Link
                             href="#"
@@ -314,6 +429,13 @@ export default function InvoiceHistory({ settings, active, onOpen }: Props) {
                             </Tag>
                           ) : null}
                         </TableCell>
+                        {showErpColumn ? (
+                          <TableCell>
+                            <Tag type={erpTag.type} size="sm" title={erpTag.tooltip}>
+                              {erpTag.label}
+                            </Tag>
+                          </TableCell>
+                        ) : null}
                         <TableCell onClick={(e: React.MouseEvent) => e.stopPropagation()}>
                           <OverflowMenu
                             aria-label={`Actions for invoice ${row.number}`}
@@ -325,6 +447,17 @@ export default function InvoiceHistory({ settings, active, onOpen }: Props) {
                             <OverflowMenuItem itemText="Open" onClick={() => onOpen(row.id)} />
                             <OverflowMenuItem itemText="Export PDF (original as issued)" onClick={() => void onExport(row.id, "searchable", "original")} />
                             <OverflowMenuItem itemText="Export flattened PDF" onClick={() => void onExport(row.id, "flattened", "original")} />
+                            <OverflowMenuItem itemText="Export as voiced.invoice.v1 (JSON)" hasDivider onClick={() => void generic.run([row.id], "json")} />
+                            {erpOn || syncs.size > 0 ? (
+                              <OverflowMenuItem
+                                itemText="Send to ERPNext"
+                                hasDivider
+                                disabled={rowBlocked !== null}
+                                title={rowBlocked ?? undefined}
+                                onClick={() => askSend([row])}
+                              />
+                            ) : null}
+                            {canOpenInErpnext(sync) && erpOn ? <OverflowMenuItem itemText="Open in ERPNext" onClick={() => void onOpenErpnext(row.id)} /> : null}
                           </OverflowMenu>
                         </TableCell>
                       </TableRow>
@@ -363,6 +496,31 @@ export default function InvoiceHistory({ settings, active, onOpen }: Props) {
           )}
         </>
       )}
+
+      {!erpOn && !loading && rows.length > 0 ? (
+        <p className="voiced-muted" style={{ marginTop: "1rem" }}>
+          ERPNext is not set up.{" "}
+          <Link
+            href="#"
+            onClick={(e: React.MouseEvent) => {
+              e.preventDefault();
+              onOpenSettings();
+            }}
+          >
+            Set it up in Settings, Integrations
+          </Link>{" "}
+          to send invoices to it.
+        </p>
+      ) : null}
+
+      <SendToErpnextModal
+        open={sendTargets !== null}
+        invoices={sendTargets?.invoices ?? []}
+        skipped={sendTargets?.skipped ?? 0}
+        defaultSubmit={erpCfg?.submitOnPush ?? false}
+        onClose={() => setSendTargets(null)}
+        onFinished={() => void loadErpnext()}
+      />
     </div>
   );
 }

src/views/NewInvoice.tsx

@@ -59,6 +59,7 @@ import { SHORTCUT_LIST, useShortcuts } from "../hooks/useShortcuts";
 import PageSetupControls from "../components/PageSetupControls";
 import { useInvoicePdf } from "../hooks/useInvoicePdf";
 import { useInvoiceExport } from "../hooks/useInvoiceExport";
+import { autoPushIssued } from "../lib/erpnextUi";
 import ExportButton, { ExportModePicker } from "../components/ExportButton";
 import ExportFeedback from "../components/ExportFeedback";
 import { createExportDeps } from "../lib/exportDeps";
@@ -649,6 +650,16 @@ export default function NewInvoice({ settings, onSettingsChange, active, onActiv
     detachDraft();
     api.listClients().then(setClients).catch(() => {});
     void refreshDrafts();
+    // "Send on issue": in the background, so it never delays or fails the issue; the result arrives as a toast.
+    void autoPushIssued(
+      { getConfig: api.erpnextGetConfig, push: api.erpnextPushInvoice },
+      outcome.invoice,
+      settings.gstRegistration !== "unregistered",
+    )
+      .then((note) => {
+        if (note) toast[note.kind](note.title, note.subtitle);
+      })
+      .catch(() => {});
     // Unarchived invoices export by rendering and archiving first (see exportInvoice), so this still works.
     await exp.start(outcome.invoice, mode, "original");
     setSaving(false);