Phase7: Void/Refund logic

src/components/admin/billing/invoice-detail-view.tsx

@@ -4,33 +4,61 @@ import { useState, Fragment } from "react";
 import { useRouter } from "next/navigation";
 import { useTranslations } from "next-intl";
 import { Card, CardHeader } from "@/components/ui/card";
-import type { InvoiceDetail, InvoiceStatus } from "@/types";
+import type { CreditNote, InvoiceDetail, InvoiceStatus } from "@/types";
 
 interface Props {
   detail: InvoiceDetail;
+  /**
+   * Phase 7: credit notes linked to this invoice (voids + refunds).
+   * Empty array when none. Passed from the server page; client
+   * doesn't re-fetch — router.refresh() rebuilds after actions.
+   */
+  creditNotes?: CreditNote[];
 }
 
 /**
  * Renders the invoice header (status, totals, action bar) then
  * line items grouped by tenant, then billing snapshot. Actions are
- * mark-paid (POST), delete (DELETE), PDF download (link to /pdf).
+ * mark-paid (POST), void (POST), refund (POST), delete (DELETE),
+ * PDF download (link to /pdf).
+ *
+ * Phase 7 adds void + refund. The action bar shows:
+ *   - status open/overdue → Mark paid, Void, Delete
+ *   - status paid          → Refund, Delete
+ *   - status partially_refunded → Refund (for remainder), Delete
+ *   - status fully_refunded / void → Delete only (read-only otherwise)
  *
  * On successful action we router.refresh() — the server-side page
- * re-renders against the new DB state. For delete we navigate
- * away first.
+ * re-renders against the new DB state, including any new credit
+ * notes.
  */
-export function InvoiceDetailView({ detail }: Props) {
+export function InvoiceDetailView({ detail, creditNotes = [] }: Props) {
   const t = useTranslations("adminBilling");
   const router = useRouter();
   const { invoice, lines } = detail;
 
-  const [busyAction, setBusyAction] = useState<null | "mark-paid" | "delete">(
-    null
-  );
+  const [busyAction, setBusyAction] = useState<
+    null | "mark-paid" | "delete" | "void" | "refund"
+  >(null);
   const [actionError, setActionError] = useState("");
   const [noteInput, setNoteInput] = useState("");
   const [noteOpen, setNoteOpen] = useState(false);
 
+  // Phase 7 — void modal state
+  const [voidOpen, setVoidOpen] = useState(false);
+  const [voidReason, setVoidReason] = useState("");
+
+  // Phase 7 — refund modal state. Amount defaults to the full
+  // remaining refundable on open.
+  const [refundOpen, setRefundOpen] = useState(false);
+  const [refundAmount, setRefundAmount] = useState("");
+  const [refundReason, setRefundReason] = useState("");
+
+  const remainingRefundable =
+    Math.round(
+      (invoice.totalChf - invoice.refundedTotalChf) * 100
+    ) / 100;
+
   const markPaid = async () => {
     setActionError("");
     setBusyAction("mark-paid");
@@ -75,6 +103,84 @@ export function InvoiceDetailView({ detail }: Props) {
     }
   };
 
+  // Phase 7 — void: marks an unpaid invoice as cancelled and issues
+  // a credit note. Backend rejects if the invoice is paid (use
+  // refund) or already voided/refunded.
+  const voidInvoice = async () => {
+    if (!voidReason.trim()) {
+      setActionError(t("voidReasonRequired"));
+      return;
+    }
+    setActionError("");
+    setBusyAction("void");
+    try {
+      const res = await fetch(
+        `/api/admin/billing/invoices/${invoice.id}/void`,
+        {
+          method: "POST",
+          headers: { "Content-Type": "application/json" },
+          body: JSON.stringify({ reason: voidReason }),
+        }
+      );
+      const j = await res.json().catch(() => ({}));
+      if (!res.ok) throw new Error(j.error || `HTTP ${res.status}`);
+      setVoidOpen(false);
+      setVoidReason("");
+      router.refresh();
+    } catch (e: any) {
+      setActionError(e.message);
+    } finally {
+      setBusyAction(null);
+    }
+  };
+
+  // Phase 7 — refund: paid invoices only. Amount may be partial;
+  // backend caps at remaining refundable.
+  const refundInvoice = async () => {
+    const amt = parseFloat(refundAmount);
+    if (!isFinite(amt) || amt <= 0) {
+      setActionError(t("refundAmountInvalid"));
+      return;
+    }
+    if (amt - remainingRefundable > 0.005) {
+      setActionError(
+        t("refundAmountExceeds", {
+          max: remainingRefundable.toFixed(2),
+        })
+      );
+      return;
+    }
+    if (!refundReason.trim()) {
+      setActionError(t("refundReasonRequired"));
+      return;
+    }
+    setActionError("");
+    setBusyAction("refund");
+    try {
+      const res = await fetch(
+        `/api/admin/billing/invoices/${invoice.id}/refund`,
+        {
+          method: "POST",
+          headers: { "Content-Type": "application/json" },
+          body: JSON.stringify({
+            amountChf: Math.round(amt * 100) / 100,
+            reason: refundReason,
+          }),
+        }
+      );
+      const j = await res.json().catch(() => ({}));
+      if (!res.ok) throw new Error(j.error || `HTTP ${res.status}`);
+      setRefundOpen(false);
+      setRefundAmount("");
+      setRefundReason("");
+      router.refresh();
+    } catch (e: any) {
+      setActionError(e.message);
+    } finally {
+      setBusyAction(null);
+    }
+  };
+
   // Group lines by tenant for display (matches PDF layout).
   const linesByTenant = new Map<string | null, typeof lines>();
   for (const ln of lines) {
@@ -171,6 +277,129 @@ export function InvoiceDetailView({ detail }: Props) {
               )}
             </>
           )}
+          {/* Phase 7 — Void: visible only for open/overdue invoices.
+              Same gating as Mark Paid but mutually exclusive with it
+              via the chosen action. Opens a small inline form so
+              the admin can enter a reason; reason is required and
+              lands on the credit-note PDF. */}
+          {(invoice.status === "open" || invoice.status === "overdue") && (
+            <>
+              {!voidOpen ? (
+                <button
+                  onClick={() => {
+                    setVoidOpen(true);
+                    setNoteOpen(false);
+                    setRefundOpen(false);
+                  }}
+                  disabled={busyAction !== null}
+                  className="px-4 py-2 rounded-md border border-error text-error text-sm disabled:opacity-50 hover:bg-error/10"
+                >
+                  {t("voidBtn")}
+                </button>
+              ) : (
+                <div className="flex items-center gap-2 flex-grow">
+                  <input
+                    type="text"
+                    placeholder={t("voidReasonPlaceholder")}
+                    value={voidReason}
+                    onChange={(e) => setVoidReason(e.target.value)}
+                    maxLength={500}
+                    className="flex-grow px-3 py-1.5 rounded-md border border-border bg-surface-2 text-sm"
+                    autoFocus
+                  />
+                  <button
+                    onClick={voidInvoice}
+                    disabled={busyAction !== null}
+                    className="px-3 py-1.5 rounded-md bg-error text-white text-sm disabled:opacity-50"
+                  >
+                    {busyAction === "void" ? t("saving") : t("confirmVoid")}
+                  </button>
+                  <button
+                    onClick={() => {
+                      setVoidOpen(false);
+                      setVoidReason("");
+                    }}
+                    className="px-3 py-1.5 rounded-md border border-border text-sm"
+                  >
+                    {t("cancel")}
+                  </button>
+                </div>
+              )}
+            </>
+          )}
+          {/* Phase 7 — Refund: paid invoices, including ones already
+              partially refunded (as long as some refundable amount
+              remains). Opens an inline form with amount + reason.
+              The remaining-refundable hint helps admin pick the
+              right number. */}
+          {(invoice.status === "paid" ||
+            invoice.status === "partially_refunded") &&
+            remainingRefundable > 0 && (
+              <>
+                {!refundOpen ? (
+                  <button
+                    onClick={() => {
+                      setRefundOpen(true);
+                      setNoteOpen(false);
+                      setVoidOpen(false);
+                      setRefundAmount(remainingRefundable.toFixed(2));
+                    }}
+                    disabled={busyAction !== null}
+                    className="px-4 py-2 rounded-md border border-error text-error text-sm disabled:opacity-50 hover:bg-error/10"
+                  >
+                    {t("refundBtn")}
+                  </button>
+                ) : (
+                  <div className="flex flex-col gap-2 flex-grow">
+                    <div className="text-xs text-text-muted">
+                      {t("refundRemainingHint", {
+                        max: remainingRefundable.toFixed(2),
+                      })}
+                    </div>
+                    <div className="flex items-center gap-2">
+                      <input
+                        type="number"
+                        step="0.01"
+                        min="0.01"
+                        max={remainingRefundable}
+                        placeholder="CHF"
+                        value={refundAmount}
+                        onChange={(e) => setRefundAmount(e.target.value)}
+                        className="w-28 px-3 py-1.5 rounded-md border border-border bg-surface-2 text-sm font-mono"
+                        autoFocus
+                      />
+                      <input
+                        type="text"
+                        placeholder={t("refundReasonPlaceholder")}
+                        value={refundReason}
+                        onChange={(e) => setRefundReason(e.target.value)}
+                        maxLength={500}
+                        className="flex-grow px-3 py-1.5 rounded-md border border-border bg-surface-2 text-sm"
+                      />
+                      <button
+                        onClick={refundInvoice}
+                        disabled={busyAction !== null}
+                        className="px-3 py-1.5 rounded-md bg-error text-white text-sm disabled:opacity-50"
+                      >
+                        {busyAction === "refund"
+                          ? t("saving")
+                          : t("confirmRefund")}
+                      </button>
+                      <button
+                        onClick={() => {
+                          setRefundOpen(false);
+                          setRefundAmount("");
+                          setRefundReason("");
+                        }}
+                        className="px-3 py-1.5 rounded-md border border-border text-sm"
+                      >
+                        {t("cancel")}
+                      </button>
+                    </div>
+                  </div>
+                )}
+              </>
+            )}
           <button
             onClick={deleteInvoice}
             disabled={busyAction !== null}
@@ -189,8 +418,90 @@ export function InvoiceDetailView({ detail }: Props) {
             {invoice.paidMethodDetail}
           </div>
         )}
+        {/* Phase 7 — void/refund summary lines, shown when applicable.
+            Surfaces the auditing context that the columns alone don't
+            (who voided, what the reason was, how much has been
+            refunded vs how much remains). */}
+        {invoice.voidedAt && (
+          <div className="mt-3 text-xs text-text-muted">
+            {t("voidedOnLabel")}: {invoice.voidedAt} · {invoice.voidedBy}
+            {invoice.voidReason ? ` · ${invoice.voidReason}` : ""}
+          </div>
+        )}
+        {invoice.refundedTotalChf > 0 && (
+          <div className="mt-3 text-xs text-text-muted">
+            {t("refundedTotalLabel")}: CHF{" "}
+            {invoice.refundedTotalChf.toFixed(2)} ·{" "}
+            {t("refundedRemainingLabel")}: CHF{" "}
+            {remainingRefundable.toFixed(2)}
+          </div>
+        )}
       </Card>
 
+      {/* Phase 7 — linked credit notes panel. Hidden when there are
+          none (most invoices). When present, lists each credit note
+          with kind, amount, reason, issued date, and PDF download. */}
+      {creditNotes.length > 0 && (
+        <Card>
+          <CardHeader>{t("creditNotesPanelTitle")}</CardHeader>
+          <table className="w-full text-sm">
+            <thead className="text-xs text-text-muted text-left">
+              <tr>
+                <th className="pb-2">{t("creditNoteNumberHeader")}</th>
+                <th className="pb-2">{t("creditNoteKindHeader")}</th>
+                <th className="pb-2 text-right">
+                  {t("creditNoteAmountHeader")}
+                </th>
+                <th className="pb-2">{t("creditNoteReasonHeader")}</th>
+                <th className="pb-2">{t("creditNoteIssuedHeader")}</th>
+                <th className="pb-2 text-right">{t("creditNotePdfHeader")}</th>
+              </tr>
+            </thead>
+            <tbody>
+              {creditNotes.map((cn) => (
+                <tr key={cn.id} className="border-t border-border">
+                  <td className="py-2 font-mono text-xs">
+                    {cn.creditNoteNumber}
+                  </td>
+                  <td className="py-2">
+                    <span className="px-2 py-0.5 rounded text-xs text-error bg-error/10">
+                      {t(`creditNoteKind_${cn.kind}` as any)}
+                    </span>
+                  </td>
+                  <td className="py-2 text-right font-mono">
+                    CHF {cn.amountChf.toFixed(2)}
+                  </td>
+                  <td className="py-2 text-text-secondary text-xs">
+                    {cn.reason ?? "—"}
+                  </td>
+                  <td className="py-2 text-xs text-text-muted">
+                    {cn.issuedAt.slice(0, 10)}
+                  </td>
+                  <td className="py-2 text-right">
+                    {cn.hasPdf ? (
+                      <a
+                        href={`/api/credit-notes/${encodeURIComponent(
+                          cn.creditNoteNumber
+                        )}/pdf`}
+                        target="_blank"
+                        rel="noopener noreferrer"
+                        className="text-accent hover:underline text-xs"
+                      >
+                        {t("downloadPdfBtn")}
+                      </a>
+                    ) : (
+                      <span className="text-text-muted text-xs italic">
+                        {t("creditNoteNoPdf")}
+                      </span>
+                    )}
+                  </td>
+                </tr>
+              ))}
+            </tbody>
+          </table>
+        </Card>
+      )}
+
       {/* Lines */}
       <Card>
         <CardHeader>{t("lineItemsTitle")}</CardHeader>
@@ -296,7 +607,9 @@ function StatusPill({ status }: { status: InvoiceStatus }) {
         ? "bg-error/15 text-error"
         : status === "void" || status === "uncollectible"
           ? "bg-text-muted/15 text-text-muted"
-          : "bg-accent/15 text-accent";
+          : status === "partially_refunded" || status === "fully_refunded"
+            ? "bg-error/15 text-error"
+            : "bg-accent/15 text-accent";
   return (
     <span
       className={`inline-block px-2 py-0.5 rounded text-xs font-medium ${color}`}

src/components/billing/customer-credit-note-list.tsx

@@ -0,0 +1,101 @@
+import { useTranslations, useFormatter } from "next-intl";
+import { Card } from "@/components/ui/card";
+import type { CreditNote } from "@/types";
+
+interface Props {
+  creditNotes: CreditNote[];
+}
+
+const kindColors: Record<string, string> = {
+  // Voids = the invoice was cancelled; gentle red.
+  void: "text-error bg-error/10",
+  // Refunds = money returned; also red but slightly differentiated.
+  refund: "text-error bg-error/10",
+};
+
+/**
+ * Phase 7 — customer's credit-note history below the invoice list.
+ *
+ * Hidden entirely when the org has zero credit notes (most orgs in
+ * normal operation). When present, each row shows the credit-note
+ * number, the invoice it relates to, kind (void / refund), amount,
+ * and a download link to the PDF.
+ *
+ * No detail page — clicking the PDF link opens the document inline
+ * (browser PDF viewer), which IS the credit-note detail view. A
+ * separate per-credit-note web page would duplicate what's in the
+ * PDF and add no value.
+ */
+export function CustomerCreditNoteList({ creditNotes }: Props) {
+  const t = useTranslations("customerBilling");
+  const fmt = useFormatter();
+
+  if (creditNotes.length === 0) {
+    return null;
+  }
+
+  return (
+    <Card>
+      <table className="w-full text-sm">
+        <thead className="text-xs text-text-muted text-left">
+          <tr>
+            <th className="pb-2">{t("creditNoteNumberCol")}</th>
+            <th className="pb-2">{t("creditNoteInvoiceCol")}</th>
+            <th className="pb-2">{t("creditNoteIssuedCol")}</th>
+            <th className="pb-2 text-right">{t("creditNoteAmountCol")}</th>
+            <th className="pb-2 text-right">{t("creditNoteKindCol")}</th>
+            <th className="pb-2 text-right">{t("creditNotePdfCol")}</th>
+          </tr>
+        </thead>
+        <tbody>
+          {creditNotes.map((cn) => (
+            <tr
+              key={cn.id}
+              className="border-t border-border align-middle"
+            >
+              <td className="py-2 font-mono text-xs">
+                {cn.creditNoteNumber}
+              </td>
+              <td className="py-2 font-mono text-xs text-text-secondary">
+                {cn.invoiceNumber}
+              </td>
+              <td className="py-2 text-text-secondary">
+                {fmt.dateTime(new Date(cn.issuedAt), { dateStyle: "medium" })}
+              </td>
+              <td className="py-2 text-right font-mono">
+                CHF {cn.amountChf.toFixed(2)}
+              </td>
+              <td className="py-2 text-right">
+                <span
+                  className={`px-2 py-0.5 rounded text-xs ${
+                    kindColors[cn.kind] ?? ""
+                  }`}
+                >
+                  {t(`creditNoteKind_${cn.kind}` as any)}
+                </span>
+              </td>
+              <td className="py-2 text-right">
+                {cn.hasPdf ? (
+                  <a
+                    href={`/api/credit-notes/${encodeURIComponent(
+                      cn.creditNoteNumber
+                    )}/pdf`}
+                    className="text-accent hover:underline text-xs"
+                    target="_blank"
+                    rel="noopener noreferrer"
+                  >
+                    {t("downloadPdf")}
+                  </a>
+                ) : (
+                  <span className="text-text-muted text-xs italic">
+                    {t("creditNoteNoPdf")}
+                  </span>
+                )}
+              </td>
+            </tr>
+          ))}
+        </tbody>
+      </table>
+    </Card>
+  );
+}

src/components/billing/customer-invoice-list.tsx

@@ -12,6 +12,13 @@ const statusColors: Record<string, string> = {
   paid: "text-success bg-success/10",
   overdue: "text-error bg-error/10",
   void: "text-text-muted bg-surface-3 line-through",
+  // Phase 7: refund states. Red tinting matches the credit-note
+  // PDF accent so customers reading the table get a visual cue
+  // that something was credited back. partially_refunded reads
+  // as a partial state (mixed colour), fully_refunded reads as
+  // closed (line-through like void).
+  partially_refunded: "text-error bg-error/10",
+  fully_refunded: "text-text-muted bg-error/10 line-through",
 };
 
 /**