Bills: editing a paid bill saves and keeps its payment in sync

Editing a paid bill now updates the linked payment along with the bill: when the
amount changes and the bill has a single bill payment, the bank transaction, the
check, and the paid amount are all updated to the new total. The whole save is
wrapped in error handling and the bill_items insert is now error-checked, so any
failure surfaces a clear toast instead of silently appearing to 'not save'.
Also refreshes the transactions/accounts caches after a bill edit.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/pages/accounting/AccountingBillsPage.tsx

@@ -46,6 +46,7 @@ export default function AccountingBillsPage() {
   const parseFn = parseBill;
   const [open, setOpen] = useState(false);
   const [editId, setEditId] = useState<string | null>(null);
+  const [editBill, setEditBill] = useState<any | null>(null);
   const [search, setSearch] = useState("");
   const [statusFilter, setStatusFilter] = useState<string>("all");
   const [autoOnly, setAutoOnly] = useState(false);
@@ -130,7 +131,7 @@ export default function AccountingBillsPage() {
   const total = +(subtotal + tax).toFixed(2);
 
   const resetForm = () => {
-    setEditId(null);
+    setEditId(null); setEditBill(null);
     setVendorId(""); setNumber(""); setDueDate(""); setTaxPct(0); setNotes("");
     setItems([{ description: "", quantity: 1, rate: 0, account_id: null }]);
     setFile(null); setFilePreview(null); setUploadedUrl(null);
@@ -139,6 +140,7 @@ export default function AccountingBillsPage() {
 
   const openEdit = async (b: any) => {
     setEditId(b.id);
+    setEditBill(b);
     // The dropdown is keyed by public vendor id; map the stored accounting
     // vendor back to its source public vendor when one exists.
     let pubVendorId = "";
@@ -261,6 +263,7 @@ export default function AccountingBillsPage() {
   const save = async (keepOpen = false) => {
     if (!number.trim()) return toast.error("Bill number required");
     if (!vendorId) return toast.error("Select a vendor (Pay to) before saving");
+    try {
     let attachmentUrl = uploadedUrl;
     if (file && !attachmentUrl) attachmentUrl = await uploadFileObj(file);
 
@@ -291,8 +294,27 @@ export default function AccountingBillsPage() {
       }).eq("id", editId);
       if (error) return toast.error(error.message);
       await accounting.from("bill_items").delete().eq("bill_id", editId);
-      await accounting.from("bill_items").insert(itemRows(editId));
+      const { error: biErr } = await accounting.from("bill_items").insert(itemRows(editId));
+      if (biErr) return toast.error(biErr.message);
+
+      // Keep an already-paid bill's payment in sync with the edited amount. When
+      // the total changed and the bill has a single linked bill payment, update
+      // that payment (bank transaction + check) and the paid amount to match.
+      const wasPaid = Number(editBill?.paid_amount ?? 0) > 0;
+      const amountChanged = Math.abs(Number(editBill?.total ?? 0) - total) > 0.005;
+      if (wasPaid && amountChanged) {
+        const { data: pays } = await accounting.from("transactions").select("id").eq("bill_id", editId);
+        if ((pays?.length ?? 0) === 1) {
+          await accounting.from("transactions").update({ amount: total }).eq("bill_id", editId);
+          await accounting.from("checks").update({ amount: total }).eq("source_bill_id", editId);
+          await accounting.from("bills").update({ paid_amount: total, status: total > 0 ? "paid" : "open" }).eq("id", editId);
+          toast.success("Bill and payment updated");
+        } else {
+          toast.warning("Bill updated — it has split/partial payments, so review the payment(s) manually.");
+        }
+      } else {
         toast.success("Bill updated");
+      }
     } else {
       const { data: bill, error } = await accounting.from("bills").insert({
         company_id: cid, vendor_id: acctVendorId, number,
@@ -308,6 +330,11 @@ export default function AccountingBillsPage() {
     resetForm();
     if (!keepOpen) setOpen(false);
     qc.invalidateQueries({ queryKey: ["bills", cid] });
+    qc.invalidateQueries({ queryKey: ["transactions", cid] });
+    qc.invalidateQueries({ queryKey: ["accounts", cid] });
+    } catch (e: any) {
+      toast.error(e?.message ?? "Failed to save bill");
+    }
   };
 
   // ── Read-only bill detail view ──