Phase3: Billing Customerpage/Mailings

src/app/[locale]/billing/[invoiceNumber]/page.tsx

@@ -0,0 +1,35 @@
+import { redirect, notFound } from "next/navigation";
+import { getTranslations } from "next-intl/server";
+import { getSessionUser } from "@/lib/session";
+import { getInvoiceByNumberForOrg } from "@/lib/db";
+import { BackLink } from "@/components/ui/back-link";
+import { CustomerInvoiceDetail } from "@/components/billing/customer-invoice-detail";
+
+/**
+ * /billing/[invoiceNumber] — single-invoice view.
+ *
+ * Lookup is by the human-readable invoice number (the YYYY-NNNNN
+ * format printed on the PDF and in the issuance email). Org
+ * filter is enforced in the DB query — a customer trying another
+ * org's number gets 404, not 403, to avoid leaking the existence
+ * of other orgs' invoices.
+ */
+export default async function CustomerInvoiceDetailPage({
+  params,
+}: {
+  params: Promise<{ invoiceNumber: string; locale: string }>;
+}) {
+  const user = await getSessionUser();
+  if (!user) redirect("/login");
+  const { invoiceNumber } = await params;
+  const t = await getTranslations("customerBilling");
+  const detail = await getInvoiceByNumberForOrg(invoiceNumber, user.orgId);
+  if (!detail) notFound();
+
+  return (
+    <main className="max-w-3xl mx-auto px-6 py-8">
+      <BackLink href="/billing" label={t("backToBilling")} />
+      <CustomerInvoiceDetail invoice={detail.invoice} lines={detail.lines} />
+    </main>
+  );
+}

src/app/[locale]/billing/page.tsx

@@ -0,0 +1,63 @@
+import { redirect } from "next/navigation";
+import { getTranslations } from "next-intl/server";
+import { getSessionUser } from "@/lib/session";
+import { listInvoices, syncOverdueInvoices } from "@/lib/db";
+import { CustomerInvoiceList } from "@/components/billing/customer-invoice-list";
+import { RunningTotalWidget } from "@/components/billing/running-total-widget";
+
+/**
+ * /billing — customer's billing home.
+ *
+ * Shows two things:
+ *   1. RunningTotalWidget — current calendar month's accruing cost
+ *      (or the already-issued invoice for the current month, if
+ *      that ran early).
+ *   2. CustomerInvoiceList — every issued invoice for this org,
+ *      newest first. Status is reflected with a colored badge.
+ *
+ * Anyone signed in can view this. The data is org-scoped; even
+ * non-owner team members see the same view. Phase 4 will add a
+ * "settings.payByInvoice" toggle visibility-gated to owners only.
+ */
+export default async function CustomerBillingPage() {
+  const user = await getSessionUser();
+  if (!user) redirect("/login");
+  const t = await getTranslations("customerBilling");
+
+  // Sync overdue status before listing — cheap, idempotent.
+  try {
+    await syncOverdueInvoices();
+  } catch (e) {
+    console.warn("syncOverdueInvoices failed in /billing:", e);
+  }
+
+  const invoices = await listInvoices({
+    zitadelOrgId: user.orgId,
+    limit: 200,
+  });
+
+  return (
+    <main className="max-w-5xl mx-auto px-6 py-8">
+      <div className="mb-8 animate-in">
+        <h1 className="font-display text-2xl font-semibold accent-rule">
+          {t("title")}
+        </h1>
+        <p className="text-sm text-text-secondary mt-3">{t("subtitle")}</p>
+      </div>
+
+      <section className="mb-8 animate-in animate-in-delay-1">
+        <h2 className="text-xs font-semibold uppercase tracking-wider text-text-muted mb-3">
+          {t("currentPeriodHeading")}
+        </h2>
+        <RunningTotalWidget />
+      </section>
+
+      <section className="animate-in animate-in-delay-2">
+        <h2 className="text-xs font-semibold uppercase tracking-wider text-text-muted mb-3">
+          {t("historyHeading")}
+        </h2>
+        <CustomerInvoiceList invoices={invoices} />
+      </section>
+    </main>
+  );
+}

src/app/api/billing/current/route.ts

@@ -0,0 +1,75 @@
+import { NextResponse } from "next/server";
+import { getSessionUser } from "@/lib/session";
+import { computeInvoiceDraft } from "@/lib/billing";
+import { listInvoices } from "@/lib/db";
+
+/**
+ * GET /api/billing/current
+ *
+ * Running total for the current calendar month — what the
+ * customer will be billed if no further activity happens. Uses
+ * the same compute pipeline as the final invoice (LiteLLM spend,
+ * Threema usage, skill day-counting, proration) so the number
+ * the customer sees matches what they'll eventually receive
+ * within the limits of intra-month drift.
+ *
+ * If an invoice has ALREADY been issued for the current month
+ * (e.g. cron ran early, admin manually generated), we return
+ * that issued invoice instead — no point showing a draft that
+ * duplicates a real invoice.
+ *
+ * Returns:
+ *   { issued: Invoice }           // current-month invoice exists
+ *   { draft: InvoiceDraft }       // still accruing
+ *   { error: ... }                // org missing billing config
+ *
+ * Cost: 1 LiteLLM HTTP call + 1 Threema HTTP call + a handful of
+ * DB queries per skill. Sub-second typically. No caching; called
+ * on demand from the customer billing page.
+ */
+export async function GET() {
+  const user = await getSessionUser();
+  if (!user) {
+    return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
+  }
+  // Resolve current calendar month from UTC. Billing is UTC-day
+  // based throughout (see billing.ts iterDays comment), so the
+  // running total inherits that same semantics.
+  const now = new Date();
+  const year = now.getUTCFullYear();
+  const month = now.getUTCMonth() + 1; // 1-12
+  const periodMonth = `${year}-${String(month).padStart(2, "0")}`;
+
+  // 1. Has the current month already been invoiced?
+  const existing = await listInvoices({
+    zitadelOrgId: user.orgId,
+    periodMonth,
+    limit: 1,
+  });
+  if (existing.length > 0) {
+    return NextResponse.json({ issued: existing[0] });
+  }
+
+  // 2. Otherwise compute the draft. Falls through to error if the
+  //    org doesn't have a billing config yet (no Address on file).
+  try {
+    const draft = await computeInvoiceDraft({
+      zitadelOrgId: user.orgId,
+      year,
+      month,
+    });
+    return NextResponse.json({ draft });
+  } catch (e: any) {
+    // Most likely: org_billing row missing. We surface a 200 with a
+    // soft error code rather than 500 — the customer-side widget
+    // displays a helpful "complete your billing details" message
+    // instead of a stack trace.
+    return NextResponse.json(
+      {
+        error: e?.message ?? "Could not compute running total.",
+        code: e?.code ?? "COMPUTE_FAILED",
+      },
+      { status: 200 }
+    );
+  }
+}

src/app/api/billing/invoices/[invoiceNumber]/pdf/route.ts

@@ -0,0 +1,43 @@
+import { NextResponse } from "next/server";
+import { getSessionUser } from "@/lib/session";
+import { getInvoiceByNumberForOrg, getInvoicePdf } from "@/lib/db";
+
+/**
+ * GET /api/billing/invoices/[invoiceNumber]/pdf
+ *
+ * Customer-facing PDF download. Same Uint8Array.from() variance
+ * fix as the admin route — see /api/admin/billing/invoices/[id]/pdf
+ * for the rationale.
+ *
+ * Authorization: looks up the invoice by number with org scope
+ * baked into the query, then re-fetches the PDF blob by id. A
+ * customer can't probe another org's invoice numbers — they get
+ * 404 either way.
+ */
+export async function GET(
+  _request: Request,
+  { params }: { params: Promise<{ invoiceNumber: string }> }
+) {
+  const user = await getSessionUser();
+  if (!user) {
+    return new NextResponse("Unauthorized", { status: 401 });
+  }
+  const { invoiceNumber } = await params;
+  const detail = await getInvoiceByNumberForOrg(invoiceNumber, user.orgId);
+  if (!detail) {
+    return new NextResponse("Not found", { status: 404 });
+  }
+  const pdf = await getInvoicePdf(detail.invoice.id);
+  if (!pdf) {
+    return new NextResponse("PDF not available", { status: 404 });
+  }
+  const body = Uint8Array.from(pdf.data);
+  return new NextResponse(body, {
+    status: 200,
+    headers: {
+      "Content-Type": "application/pdf",
+      "Content-Disposition": `inline; filename="${pdf.filename}"`,
+      "Cache-Control": "private, max-age=0, must-revalidate",
+    },
+  });
+}

src/app/api/billing/invoices/[invoiceNumber]/route.ts

@@ -0,0 +1,27 @@
+import { NextResponse } from "next/server";
+import { getSessionUser } from "@/lib/session";
+import { getInvoiceByNumberForOrg } from "@/lib/db";
+
+/**
+ * GET /api/billing/invoices/[invoiceNumber]
+ *
+ * Customer-scoped detail lookup by invoice number (the human-
+ * readable YYYY-NNNNN format the customer sees on the PDF). The
+ * org filter is part of the DB query — a customer probing another
+ * org's invoice number gets the same 404 as a non-existent one.
+ */
+export async function GET(
+  _request: Request,
+  { params }: { params: Promise<{ invoiceNumber: string }> }
+) {
+  const user = await getSessionUser();
+  if (!user) {
+    return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
+  }
+  const { invoiceNumber } = await params;
+  const detail = await getInvoiceByNumberForOrg(invoiceNumber, user.orgId);
+  if (!detail) {
+    return NextResponse.json({ error: "Not found" }, { status: 404 });
+  }
+  return NextResponse.json(detail);
+}

src/app/api/billing/invoices/route.ts

@@ -0,0 +1,39 @@
+import { NextResponse } from "next/server";
+import { getSessionUser } from "@/lib/session";
+import { listInvoices, syncOverdueInvoices } from "@/lib/db";
+
+/**
+ * GET /api/billing/invoices
+ *
+ * Customer-scoped list of invoices for the caller's org. Returns
+ * a flat array of Invoice headers (no line items — those are
+ * fetched separately by /[invoiceNumber]).
+ *
+ * Status filter is implicit: we return every invoice the
+ * customer's org has, all statuses (issued/paid/overdue/void)
+ * because the customer wants a single billing-history view.
+ *
+ * Before returning we run syncOverdueInvoices() so the displayed
+ * status reflects the current date — issued invoices past their
+ * due_at flip to 'overdue'. Cheap, idempotent, and avoids needing
+ * a separate cron for this transition.
+ */
+export async function GET() {
+  const user = await getSessionUser();
+  if (!user) {
+    return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
+  }
+  // Personal accounts have an org too — they share the same shape;
+  // their invoices show up under that synthetic org id.
+  try {
+    await syncOverdueInvoices();
+  } catch (e) {
+    // Non-fatal — display stale status rather than 500.
+    console.warn("syncOverdueInvoices failed in /api/billing/invoices:", e);
+  }
+  const invoices = await listInvoices({
+    zitadelOrgId: user.orgId,
+    limit: 200,
+  });
+  return NextResponse.json(invoices);
+}

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

@@ -0,0 +1,148 @@
+import { useTranslations, useFormatter } from "next-intl";
+import { Card } from "@/components/ui/card";
+import type { Invoice, InvoiceLine } from "@/types";
+
+interface Props {
+  invoice: Invoice;
+  lines: InvoiceLine[];
+}
+
+const statusColors: Record<string, string> = {
+  open: "text-text-secondary bg-surface-3",
+  paid: "text-success bg-success/10",
+  overdue: "text-error bg-error/10",
+  void: "text-text-muted bg-surface-3",
+};
+
+/**
+ * Read-only invoice detail. Flat list of lines — no per-tenant
+ * grouping (one invoice per customer; the tenant context is
+ * already embedded in each line description).
+ *
+ * The download link points at /api/billing/invoices/[n]/pdf
+ * which serves the stored PDF blob inline. Customers using a
+ * link from their email will hit the same route via this page.
+ */
+export function CustomerInvoiceDetail({ invoice, lines }: Props) {
+  const t = useTranslations("customerBilling");
+  const fmt = useFormatter();
+
+  return (
+    <div className="space-y-6 animate-in">
+      <div className="flex items-start justify-between gap-4 flex-wrap">
+        <div>
+          <div className="flex items-center gap-3 mb-2">
+            <h1 className="font-display text-2xl font-semibold">
+              {invoice.invoiceNumber}
+            </h1>
+            <span
+              className={`text-[10px] uppercase tracking-wider px-2 py-1 rounded-md font-semibold ${
+                statusColors[invoice.status] ?? "text-text-muted bg-surface-3"
+              }`}
+            >
+              {t(`status.${invoice.status}` as any)}
+            </span>
+          </div>
+          <p className="text-sm text-text-secondary">
+            {fmt.dateTime(new Date(invoice.periodStart), { dateStyle: "long" })}
+            <span className="text-text-muted mx-1">→</span>
+            {fmt.dateTime(new Date(invoice.periodEnd), { dateStyle: "long" })}
+          </p>
+        </div>
+        <a
+          href={`/api/billing/invoices/${encodeURIComponent(invoice.invoiceNumber)}/pdf`}
+          target="_blank"
+          rel="noopener noreferrer"
+          className="px-4 py-2 rounded-md bg-accent text-white text-sm font-medium hover:bg-accent-dim transition-colors"
+        >
+          {t("downloadPdf")}
+        </a>
+      </div>
+
+      <Card>
+        <div className="space-y-2 mb-4">
+          <div className="flex justify-between text-sm">
+            <span className="text-text-muted">{t("billedToLabel")}</span>
+            <span>{invoice.billingSnapshot.companyName}</span>
+          </div>
+          <div className="flex justify-between text-sm">
+            <span className="text-text-muted">{t("issuedAtLabel")}</span>
+            <span>
+              {fmt.dateTime(new Date(invoice.issuedAt), { dateStyle: "medium" })}
+            </span>
+          </div>
+          <div className="flex justify-between text-sm">
+            <span className="text-text-muted">{t("dueAtLabel")}</span>
+            <span>
+              {fmt.dateTime(new Date(invoice.dueAt), { dateStyle: "medium" })}
+            </span>
+          </div>
+          {invoice.status === "paid" && invoice.paidAt && (
+            <div className="flex justify-between text-sm">
+              <span className="text-text-muted">{t("paidAtLabel")}</span>
+              <span>
+                {fmt.dateTime(new Date(invoice.paidAt), { dateStyle: "medium" })}
+              </span>
+            </div>
+          )}
+        </div>
+      </Card>
+
+      <Card>
+        <table className="w-full text-sm">
+          <thead className="text-xs text-text-muted text-left">
+            <tr>
+              <th className="pb-2">{t("descriptionCol")}</th>
+              <th className="pb-2 text-right">{t("qtyCol")}</th>
+              <th className="pb-2 text-right">{t("unitCol")}</th>
+              <th className="pb-2 text-right">{t("amountCol")}</th>
+            </tr>
+          </thead>
+          <tbody>
+            {lines.map((ln) => (
+              <tr key={ln.id} className="border-t border-border align-top">
+                <td className="py-2">{ln.description}</td>
+                <td className="py-2 text-right font-mono text-xs">
+                  {ln.quantity}
+                  {ln.unitLabel ? ` ${ln.unitLabel}` : ""}
+                </td>
+                <td className="py-2 text-right font-mono text-xs">
+                  {ln.unitPriceChf.toFixed(2)}
+                </td>
+                <td className="py-2 text-right font-mono">
+                  {ln.amountChf.toFixed(2)}
+                </td>
+              </tr>
+            ))}
+          </tbody>
+          <tfoot>
+            <tr className="border-t border-border">
+              <td colSpan={3} className="pt-3 text-right text-text-muted">
+                {t("subtotalLabel")}
+              </td>
+              <td className="pt-3 text-right font-mono">
+                {invoice.subtotalChf.toFixed(2)}
+              </td>
+            </tr>
+            <tr>
+              <td colSpan={3} className="pt-1 text-right text-text-muted">
+                {t("vatLabel", { rate: invoice.vatRate.toFixed(2) })}
+              </td>
+              <td className="pt-1 text-right font-mono">
+                {invoice.vatAmountChf.toFixed(2)}
+              </td>
+            </tr>
+            <tr>
+              <td colSpan={3} className="pt-2 text-right font-semibold">
+                {t("totalLabel")}
+              </td>
+              <td className="pt-2 text-right font-mono font-semibold text-base">
+                CHF {invoice.totalChf.toFixed(2)}
+              </td>
+            </tr>
+          </tfoot>
+        </table>
+      </Card>
+    </div>
+  );
+}

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

@@ -0,0 +1,92 @@
+import { useTranslations, useFormatter } from "next-intl";
+import { Link } from "@/i18n/navigation";
+import { Card } from "@/components/ui/card";
+import type { Invoice } from "@/types";
+
+interface Props {
+  invoices: Invoice[];
+}
+
+const statusColors: Record<string, string> = {
+  open: "text-text-secondary bg-surface-3",
+  paid: "text-success bg-success/10",
+  overdue: "text-error bg-error/10",
+  void: "text-text-muted bg-surface-3 line-through",
+};
+
+/**
+ * Customer's invoice history table. Server component — gets a
+ * pre-fetched Invoice[] from /billing/page.tsx. Each row links
+ * to /billing/<invoice-number> for the full detail view.
+ *
+ * Columns: number, period, due date, total, status. Status is
+ * displayed with a colored badge so the customer can scan for
+ * outstanding ones at a glance.
+ */
+export function CustomerInvoiceList({ invoices }: Props) {
+  const t = useTranslations("customerBilling");
+  const fmt = useFormatter();
+
+  if (invoices.length === 0) {
+    return (
+      <Card>
+        <p className="text-sm text-text-muted italic text-center py-8">
+          {t("emptyHistory")}
+        </p>
+      </Card>
+    );
+  }
+
+  return (
+    <Card>
+      <table className="w-full text-sm">
+        <thead className="text-xs text-text-muted text-left">
+          <tr>
+            <th className="pb-2">{t("numberCol")}</th>
+            <th className="pb-2">{t("periodCol")}</th>
+            <th className="pb-2">{t("dueCol")}</th>
+            <th className="pb-2 text-right">{t("totalCol")}</th>
+            <th className="pb-2 text-right">{t("statusCol")}</th>
+          </tr>
+        </thead>
+        <tbody>
+          {invoices.map((inv) => (
+            <tr
+              key={inv.id}
+              className="border-t border-border hover:bg-surface-2 transition-colors"
+            >
+              <td className="py-2">
+                <Link
+                  href={`/billing/${inv.invoiceNumber}`}
+                  className="font-mono text-xs text-accent hover:underline"
+                >
+                  {inv.invoiceNumber}
+                </Link>
+              </td>
+              <td className="py-2 text-xs text-text-secondary">
+                {fmt.dateTime(new Date(inv.periodStart), { dateStyle: "medium" })}
+                <span className="text-text-muted mx-1">→</span>
+                {fmt.dateTime(new Date(inv.periodEnd), { dateStyle: "medium" })}
+              </td>
+              <td className="py-2 text-xs text-text-secondary">
+                {fmt.dateTime(new Date(inv.dueAt), { dateStyle: "medium" })}
+              </td>
+              <td className="py-2 text-right font-mono">
+                CHF {inv.totalChf.toFixed(2)}
+              </td>
+              <td className="py-2 text-right">
+                <span
+                  className={`text-[10px] uppercase tracking-wider px-2 py-1 rounded-md font-semibold ${
+                    statusColors[inv.status] ?? "text-text-muted bg-surface-3"
+                  }`}
+                >
+                  {t(`status.${inv.status}` as any)}
+                </span>
+              </td>
+            </tr>
+          ))}
+        </tbody>
+      </table>
+    </Card>
+  );
+}

src/components/billing/running-total-widget.tsx

@@ -0,0 +1,162 @@
+"use client";
+
+import { useEffect, useState } from "react";
+import { useTranslations, useFormatter } from "next-intl";
+import { Link } from "@/i18n/navigation";
+import { Card } from "@/components/ui/card";
+import type { Invoice, InvoiceDraft } from "@/types";
+
+type CurrentResponse =
+  | { issued: Invoice }
+  | { draft: InvoiceDraft }
+  | { error: string; code?: string };
+
+/**
+ * Live running total for the current calendar month.
+ *
+ * Loads /api/billing/current on mount. Three result shapes:
+ *
+ *   - { issued }   — current-month invoice already exists; we
+ *                    link to it instead of showing a draft total.
+ *   - { draft }    — still accruing; show subtotal+VAT+total and
+ *                    a small line breakdown.
+ *   - { error }    — most likely the org has no billing config
+ *                    yet; show a friendly hint, not a stack trace.
+ *
+ * Client-side because the compute can take a second or two
+ * (LiteLLM + Threema HTTP calls) and we want a loading spinner.
+ * No polling — the page is static enough that an explicit
+ * "refresh" link is good enough if the user wants newer numbers.
+ */
+export function RunningTotalWidget() {
+  const t = useTranslations("customerBilling");
+  const fmt = useFormatter();
+  const [data, setData] = useState<CurrentResponse | null>(null);
+  const [loading, setLoading] = useState(true);
+  const [refreshCounter, setRefreshCounter] = useState(0);
+
+  useEffect(() => {
+    let cancelled = false;
+    setLoading(true);
+    fetch("/api/billing/current")
+      .then(async (res) => {
+        const j = (await res.json()) as CurrentResponse;
+        if (!cancelled) setData(j);
+      })
+      .catch((e) => {
+        if (!cancelled) setData({ error: String(e), code: "FETCH_FAILED" });
+      })
+      .finally(() => {
+        if (!cancelled) setLoading(false);
+      });
+    return () => {
+      cancelled = true;
+    };
+  }, [refreshCounter]);
+
+  if (loading) {
+    return (
+      <Card>
+        <p className="text-sm text-text-muted italic py-4">{t("computing")}</p>
+      </Card>
+    );
+  }
+  if (!data || "error" in data) {
+    return (
+      <Card>
+        <p className="text-sm text-text-secondary py-2">
+          {data && "code" in data && data.code === "COMPUTE_FAILED"
+            ? t("noBillingConfig")
+            : t("currentPeriodError")}
+        </p>
+      </Card>
+    );
+  }
+  if ("issued" in data) {
+    const inv = data.issued;
+    return (
+      <Card>
+        <div className="flex items-start justify-between gap-4 flex-wrap">
+          <div>
+            <p className="text-xs text-text-muted">{t("currentInvoiceIssued")}</p>
+            <Link
+              href={`/billing/${inv.invoiceNumber}`}
+              className="font-mono text-sm text-accent hover:underline"
+            >
+              {inv.invoiceNumber}
+            </Link>
+          </div>
+          <div className="text-right">
+            <p className="text-xs text-text-muted">{t("totalLabel")}</p>
+            <p className="font-mono text-lg font-semibold">
+              CHF {inv.totalChf.toFixed(2)}
+            </p>
+          </div>
+        </div>
+      </Card>
+    );
+  }
+  // draft
+  const draft = data.draft;
+  const periodLabel = `${fmt.dateTime(new Date(draft.periodStart), {
+    dateStyle: "long",
+  })} → ${fmt.dateTime(new Date(draft.periodEnd), { dateStyle: "long" })}`;
+  return (
+    <Card>
+      <div className="flex items-start justify-between gap-4 flex-wrap mb-3">
+        <div>
+          <p className="text-xs text-text-muted">{t("accruedSoFar")}</p>
+          <p className="text-xs text-text-secondary">{periodLabel}</p>
+        </div>
+        <div className="text-right">
+          <p className="text-xs text-text-muted">{t("estimatedTotal")}</p>
+          <p className="font-mono text-2xl font-semibold text-accent">
+            CHF {draft.totalChf.toFixed(2)}
+          </p>
+          <button
+            onClick={() => setRefreshCounter((n) => n + 1)}
+            className="text-[10px] text-text-muted hover:text-text-secondary underline mt-1 cursor-pointer"
+          >
+            {t("refresh")}
+          </button>
+        </div>
+      </div>
+      {draft.lines.length > 0 && (
+        <details className="text-xs">
+          <summary className="cursor-pointer text-text-muted hover:text-text-secondary">
+            {t("breakdownToggle", { count: draft.lines.length })}
+          </summary>
+          <table className="w-full mt-2 text-xs">
+            <tbody>
+              {draft.lines.map((ln, i) => (
+                <tr key={i} className="border-t border-border">
+                  <td className="py-1 pr-2">{ln.description}</td>
+                  <td className="py-1 text-right font-mono">
+                    {ln.amountChf.toFixed(2)}
+                  </td>
+                </tr>
+              ))}
+              <tr className="border-t border-border">
+                <td className="py-1 pr-2 text-text-muted text-right">
+                  {t("subtotalLabel")}
+                </td>
+                <td className="py-1 text-right font-mono">
+                  {draft.subtotalChf.toFixed(2)}
+                </td>
+              </tr>
+              <tr>
+                <td className="py-1 pr-2 text-text-muted text-right">
+                  {t("vatLabel", { rate: draft.vatRate.toFixed(2) })}
+                </td>
+                <td className="py-1 text-right font-mono">
+                  {draft.vatAmountChf.toFixed(2)}
+                </td>
+              </tr>
+            </tbody>
+          </table>
+        </details>
+      )}
+      <p className="text-[10px] text-text-muted mt-3 italic">{t("draftNote")}</p>
+    </Card>
+  );
+}

src/components/layout/nav-shell.tsx

@@ -74,6 +74,20 @@ function NavBar() {
                   {t("settings")}
                 </NavLink>
               )}
+            {/* Phase 3: Billing visible to anyone signed in. The
+                page is org-scoped server-side — non-owner members
+                see the same invoice history their owner does, but
+                actions like "configure billing details" are gated
+                separately on the settings page. Personal accounts
+                see their own (single-tenant) invoices. */}
+            {user && (
+              <NavLink
+                href="/billing"
+                active={pathname.startsWith("/billing")}
+              >
+                {t("billing")}
+              </NavLink>
+            )}
             {/* Feature 5: Support is available to every signed-in
                 user. Customers see their own tickets only; platform
                 admins see the queue. */}

src/lib/billing.ts

@@ -61,6 +61,7 @@ import { listTenants } from "./k8s";
 import { getTeamSpendLogsV2 } from "./litellm";
 import { getUsage as getThreemaUsage } from "./threema-relay";
 import { renderInvoicePdf } from "./billing-pdf";
+import { sendInvoiceIssuedEmail } from "./email";
 import { formatLineDescription } from "./billing-i18n";
 
 // ---------------------------------------------------------------------------
@@ -779,6 +780,50 @@ export async function generateInvoice(opts: {
     // Pass 2: store the PDF bytes.
     await updateInvoicePdf(placeholder.id, pdfBuffer, filename);
     const finalInvoice = await getInvoiceById(placeholder.id);
+
+    // Phase 3: best-effort notification to the billing contact.
+    // We send AFTER the PDF is fully persisted (so the deep link
+    // in the email immediately resolves to a downloadable PDF) but
+    // BEFORE returning, since the cron caller doesn't otherwise
+    // know to trigger this. Failure is logged, never thrown — a
+    // mail-server hiccup must not roll back an issued invoice.
+    // The recipient is the billing email captured in the invoice
+    // snapshot (immutable; reflects who was on file at issue time).
+    try {
+      const settled = finalInvoice ?? placeholder;
+      const snapshot = settled.billingSnapshot;
+      if (snapshot.billingEmail) {
+        const supportedLocales: Array<"en" | "de" | "fr" | "it"> = [
+          "en", "de", "fr", "it",
+        ];
+        const locale = supportedLocales.includes(settled.locale as any)
+          ? (settled.locale as "en" | "de" | "fr" | "it")
+          : "de";
+        await sendInvoiceIssuedEmail({
+          to: snapshot.billingEmail,
+          contactName: snapshot.companyName, // no separate contact-name field
+          companyName: snapshot.companyName,
+          invoiceNumber: settled.invoiceNumber,
+          totalChf: settled.totalChf,
+          currency: "CHF",
+          dueAt: settled.dueAt,
+          lineCount: draft.lines.length,
+          periodStart: settled.periodStart,
+          periodEnd: settled.periodEnd,
+          locale,
+        });
+      } else {
+        console.warn(
+          `Invoice ${settled.invoiceNumber} issued but billing snapshot has no email — notification skipped.`
+        );
+      }
+    } catch (e) {
+      console.error(
+        `Invoice ${placeholder.invoiceNumber} issued; notification email failed:`,
+        e
+      );
+    }
+
     return { draft, invoice: finalInvoice ?? placeholder };
   } catch (e) {
     // Render failed — leave the persisted row in place so admin can

src/lib/db.ts

@@ -2407,6 +2407,38 @@ export async function getInvoiceDetail(
   return { invoice, lines: lines.rows.map(rowToInvoiceLine) };
 }
 
+/**
+ * Phase 3 — customer-scoped lookup by human-readable invoice
+ * number with ownership enforcement in a single query. The org
+ * filter is part of the WHERE clause so a customer can't probe
+ * another org's invoice numbers (which are sequential and easy
+ * to guess) and get a different status code (404 vs 403) than
+ * for their own — both miss-and-not-yours return null.
+ *
+ * Used by /api/billing/invoices/[invoiceNumber] and the
+ * /billing/[invoiceNumber] customer page.
+ */
+export async function getInvoiceByNumberForOrg(
+  invoiceNumber: string,
+  zitadelOrgId: string
+): Promise<InvoiceDetail | null> {
+  await ensureSchema();
+  const head = await getPool().query(
+    `SELECT ${INVOICE_LIST_COLUMNS} FROM invoices
+       WHERE invoice_number = $1 AND zitadel_org_id = $2
+       LIMIT 1`,
+    [invoiceNumber, zitadelOrgId]
+  );
+  if (head.rows.length === 0) return null;
+  const invoice = rowToInvoice(head.rows[0]);
+  const lines = await getPool().query(
+    `SELECT * FROM invoice_lines WHERE invoice_id = $1
+     ORDER BY display_order, id`,
+    [invoice.id]
+  );
+  return { invoice, lines: lines.rows.map(rowToInvoiceLine) };
+}
+
 /**
  * Fetch the PDF bytes for an invoice. Returns null if no PDF was
  * stored (shouldn't happen in v1; defensive against partial state).

src/lib/email.ts

@@ -900,3 +900,117 @@ export async function sendSkillActivationRejectionEmail(params: {
     console.error("Failed to send skill activation rejection email:", err);
   }
 }
+
+// ---------------------------------------------------------------------------
+// Invoice issuance — Phase 3
+// ---------------------------------------------------------------------------
+
+/**
+ * Notify the billing contact when a new invoice has been issued.
+ * Includes a brief summary (total + due date + line count) so the
+ * recipient can triage without opening the portal, plus a deep
+ * link to /billing/<invoice number> where they can download the
+ * PDF. The PDF itself is NOT attached — it lives in the portal,
+ * keeps mail payloads small, and avoids the audit-trail headache
+ * of "which copy is authoritative".
+ */
+export async function sendInvoiceIssuedEmail(params: {
+  to: string;
+  contactName: string;
+  companyName: string;
+  invoiceNumber: string;
+  totalChf: number;
+  currency: string; // "CHF" — passed for future-proofing
+  dueAt: string;    // ISO date
+  lineCount: number;
+  periodStart: string; // ISO date
+  periodEnd: string;   // ISO date
+  locale: "de" | "en" | "fr" | "it";
+}): Promise<void> {
+  // All four locales — the email is sent in the invoice's locale,
+  // which was frozen at issue time. No fallback to admin's locale.
+  const L = params.locale;
+  const subjectsByLocale: Record<typeof L, string> = {
+    en: `New invoice ${params.invoiceNumber} from PieCed IT — ${params.currency} ${params.totalChf.toFixed(2)}`,
+    de: `Neue Rechnung ${params.invoiceNumber} von PieCed IT — ${params.currency} ${params.totalChf.toFixed(2)}`,
+    fr: `Nouvelle facture ${params.invoiceNumber} de PieCed IT — ${params.currency} ${params.totalChf.toFixed(2)}`,
+    it: `Nuova fattura ${params.invoiceNumber} da PieCed IT — ${params.currency} ${params.totalChf.toFixed(2)}`,
+  };
+  const greetingsByLocale: Record<typeof L, string> = {
+    en: `Hello ${params.contactName},`,
+    de: `Sehr geehrte/r ${params.contactName},`,
+    fr: `Bonjour ${params.contactName},`,
+    it: `Gentile ${params.contactName},`,
+  };
+  const introByLocale: Record<typeof L, string> = {
+    en: `A new invoice has been issued for ${params.companyName}.`,
+    de: `Für ${params.companyName} wurde eine neue Rechnung ausgestellt.`,
+    fr: `Une nouvelle facture a été émise pour ${params.companyName}.`,
+    it: `È stata emessa una nuova fattura per ${params.companyName}.`,
+  };
+  const labels: Record<typeof L, Record<string, string>> = {
+    en: { number: "Invoice", period: "Period", total: "Total", due: "Due by", lines: "Line items", cta: "View invoice & download PDF", signoff: "Best regards", brand: "PieCed IT" },
+    de: { number: "Rechnung", period: "Zeitraum", total: "Gesamt", due: "Zahlbar bis", lines: "Positionen", cta: "Rechnung ansehen & PDF herunterladen", signoff: "Mit freundlichen Grüssen", brand: "PieCed IT" },
+    fr: { number: "Facture", period: "Période", total: "Total", due: "À régler avant", lines: "Lignes", cta: "Voir la facture & télécharger le PDF", signoff: "Cordialement", brand: "PieCed IT" },
+    it: { number: "Fattura", period: "Periodo", total: "Totale", due: "Scadenza", lines: "Voci", cta: "Visualizza fattura & scarica PDF", signoff: "Cordiali saluti", brand: "PieCed IT" },
+  };
+  const l = labels[L];
+
+  const safeName = escapeHtml(params.contactName);
+  const safeCompany = escapeHtml(params.companyName);
+  const safeNumber = escapeHtml(params.invoiceNumber);
+  const totalFmt = `${params.currency} ${params.totalChf.toFixed(2)}`;
+  const periodFmt = `${params.periodStart.slice(0, 10)} → ${params.periodEnd.slice(0, 10)}`;
+  const dueFmt = params.dueAt.slice(0, 10);
+
+  // Both bodies built in the invoice's locale.
+  const link = `https://app.pieced.ch/billing/${encodeURIComponent(params.invoiceNumber)}`;
+
+  try {
+    await getTransporter().sendMail({
+      from: getFrom(),
+      to: params.to,
+      subject: subjectsByLocale[L],
+      text: [
+        greetingsByLocale[L],
+        "",
+        introByLocale[L],
+        "",
+        `${l.number}:  ${params.invoiceNumber}`,
+        `${l.period}:  ${periodFmt}`,
+        `${l.total}:   ${totalFmt}`,
+        `${l.due}:     ${dueFmt}`,
+        `${l.lines}:   ${params.lineCount}`,
+        "",
+        `${l.cta}:`,
+        link,
+        "",
+        `${l.signoff},`,
+        l.brand,
+      ].join("\n"),
+      html: `
+        <div style="font-family: -apple-system, BlinkMacSystemFont, sans-serif; max-width: 560px; padding: 24px; background: #1a1a1a; color: #e5e5e5;">
+          <h2 style="margin: 0 0 16px; color: #10B981;">${escapeHtml(introByLocale[L])}</h2>
+          <p>${escapeHtml(greetingsByLocale[L])}</p>
+          <p>${escapeHtml(introByLocale[L])}</p>
+          <table style="width:100%; border-collapse:collapse; margin:16px 0; font-size:14px;">
+            <tr><td style="color:#888; padding:6px 0; width:120px;">${l.number}</td><td><strong>${safeNumber}</strong></td></tr>
+            <tr><td style="color:#888; padding:6px 0;">${l.period}</td><td>${escapeHtml(periodFmt)}</td></tr>
+            <tr><td style="color:#888; padding:6px 0;">${l.total}</td><td style="color:#10B981; font-weight:600;">${escapeHtml(totalFmt)}</td></tr>
+            <tr><td style="color:#888; padding:6px 0;">${l.due}</td><td>${escapeHtml(dueFmt)}</td></tr>
+            <tr><td style="color:#888; padding:6px 0;">${l.lines}</td><td>${params.lineCount}</td></tr>
+          </table>
+          <p>
+            <a href="${link}" style="display:inline-block; padding:10px 24px; background:#10B981; color:#fff; text-decoration:none; border-radius:8px; font-weight:500;">
+              ${l.cta}
+            </a>
+          </p>
+          <hr style="border:none; border-top:1px solid #333; margin:24px 0;" />
+          <p style="color:#666; font-size:12px;">${l.brand}</p>
+        </div>
+      `,
+    });
+  } catch (err) {
+    console.error("Failed to send invoice issued email:", err);
+  }
+}

src/messages/de.json

@@ -15,7 +15,8 @@
     "team": "Team",
     "settings": "Einstellungen",
     "optional": "optional",
-    "support": "Support"
+    "support": "Support",
+    "billing": "Abrechnung"
   },
   "login": {
     "title": "PieCed Portal",
@@ -695,5 +696,47 @@
     "reasonLabel": "Grund (wird dem Kunden angezeigt)",
     "reasonPlaceholder": "Erklären Sie, warum die Aktivierung nicht erfolgen kann — z. B. fehlende Kundendaten, Hardware nicht verfügbar usw.",
     "reasonRequired": "Ein Grund ist für die Ablehnung erforderlich."
+  },
+  "customerBilling": {
+    "title": "Abrechnung",
+    "subtitle": "Aktueller Zeitraum und Rechnungshistorie. Ausgestellte Rechnungen stehen als PDF-Download bereit.",
+    "backToBilling": "Zurück zur Abrechnung",
+    "currentPeriodHeading": "Aktueller Zeitraum",
+    "historyHeading": "Rechnungshistorie",
+    "computing": "Berechne aktuellen Periodenbetrag…",
+    "currentPeriodError": "Aktueller Periodenbetrag konnte nicht geladen werden. Bitte später erneut versuchen.",
+    "noBillingConfig": "Abrechnungsdaten sind noch nicht hinterlegt. Sobald die Rechnungsadresse Ihrer Organisation eingetragen ist, erscheint hier der laufende Betrag.",
+    "accruedSoFar": "Bisher in diesem Monat",
+    "estimatedTotal": "Geschätzter Gesamtbetrag",
+    "currentInvoiceIssued": "Aktueller Monat bereits abgerechnet",
+    "refresh": "aktualisieren",
+    "breakdownToggle": "Aufschlüsselung anzeigen ({count} Positionen)",
+    "draftNote": "Live-Schätzung. Die endgültige Rechnung kann durch Monatsendrundung, nachgemeldete Nutzungsdaten oder manuelle Anpassungen leicht abweichen.",
+    "emptyHistory": "Noch keine Rechnungen ausgestellt. Nach Abschluss Ihres ersten Monats erscheinen sie hier.",
+    "numberCol": "Nummer",
+    "periodCol": "Zeitraum",
+    "dueCol": "Fällig",
+    "totalCol": "Gesamt",
+    "statusCol": "Status",
+    "descriptionCol": "Beschreibung",
+    "qtyCol": "Menge",
+    "unitCol": "Einzelpreis",
+    "amountCol": "Betrag",
+    "billedToLabel": "Rechnungsempfänger",
+    "issuedAtLabel": "Ausgestellt",
+    "dueAtLabel": "Zahlbar bis",
+    "paidAtLabel": "Bezahlt am",
+    "subtotalLabel": "Zwischensumme",
+    "vatLabel": "MWST ({rate}%)",
+    "totalLabel": "Gesamt",
+    "downloadPdf": "PDF herunterladen",
+    "status": {
+      "draft": "Entwurf",
+      "open": "Offen",
+      "paid": "Bezahlt",
+      "overdue": "Überfällig",
+      "void": "Storniert",
+      "uncollectible": "Uneinbringlich"
+    }
   }
 }

src/messages/en.json

@@ -15,7 +15,8 @@
     "team": "Team",
     "settings": "Settings",
     "optional": "optional",
-    "support": "Support"
+    "support": "Support",
+    "billing": "Billing"
   },
   "login": {
     "title": "PieCed Portal",
@@ -695,5 +696,47 @@
     "reasonLabel": "Reason (shown to the customer)",
     "reasonPlaceholder": "Explain why this can't be activated — e.g. missing customer data, hardware unavailable, etc.",
     "reasonRequired": "A reason is required to reject."
+  },
+  "customerBilling": {
+    "title": "Billing",
+    "subtitle": "Your current period and invoice history. Issued invoices are available as PDF downloads.",
+    "backToBilling": "Back to billing",
+    "currentPeriodHeading": "Current period",
+    "historyHeading": "Invoice history",
+    "computing": "Computing current period total…",
+    "currentPeriodError": "Could not load the current period total. Please try again later.",
+    "noBillingConfig": "Billing details haven't been configured yet. Once your organization's billing address is on file, this widget will show the running total.",
+    "accruedSoFar": "Accrued this month",
+    "estimatedTotal": "Estimated total",
+    "currentInvoiceIssued": "Current month already invoiced",
+    "refresh": "refresh",
+    "breakdownToggle": "Show breakdown ({count} line items)",
+    "draftNote": "Live estimate. The final invoice may differ slightly due to end-of-month rounding, late-arriving usage data, or manual adjustments.",
+    "emptyHistory": "No invoices issued yet. Once your first month closes, you'll see it here.",
+    "numberCol": "Number",
+    "periodCol": "Period",
+    "dueCol": "Due",
+    "totalCol": "Total",
+    "statusCol": "Status",
+    "descriptionCol": "Description",
+    "qtyCol": "Qty",
+    "unitCol": "Unit",
+    "amountCol": "Amount",
+    "billedToLabel": "Billed to",
+    "issuedAtLabel": "Issued",
+    "dueAtLabel": "Due by",
+    "paidAtLabel": "Paid on",
+    "subtotalLabel": "Subtotal",
+    "vatLabel": "VAT ({rate}%)",
+    "totalLabel": "Total",
+    "downloadPdf": "Download PDF",
+    "status": {
+      "draft": "Draft",
+      "open": "Open",
+      "paid": "Paid",
+      "overdue": "Overdue",
+      "void": "Void",
+      "uncollectible": "Uncollectible"
+    }
   }
 }

src/messages/fr.json

@@ -15,7 +15,8 @@
     "team": "Équipe",
     "settings": "Paramètres",
     "optional": "facultatif",
-    "support": "Support"
+    "support": "Support",
+    "billing": "Facturation"
   },
   "login": {
     "title": "Portail PieCed",
@@ -695,5 +696,47 @@
     "reasonLabel": "Motif (visible par le client)",
     "reasonPlaceholder": "Expliquez pourquoi l'activation ne peut pas se faire — ex. données client manquantes, matériel indisponible, etc.",
     "reasonRequired": "Un motif est requis pour refuser."
+  },
+  "customerBilling": {
+    "title": "Facturation",
+    "subtitle": "Période en cours et historique des factures. Les factures émises sont disponibles en téléchargement PDF.",
+    "backToBilling": "Retour à la facturation",
+    "currentPeriodHeading": "Période en cours",
+    "historyHeading": "Historique des factures",
+    "computing": "Calcul du total de la période en cours…",
+    "currentPeriodError": "Impossible de charger le total de la période en cours. Veuillez réessayer plus tard.",
+    "noBillingConfig": "Les informations de facturation ne sont pas encore configurées. Une fois l'adresse de facturation de votre organisation enregistrée, le total en cours apparaîtra ici.",
+    "accruedSoFar": "Cumulé ce mois",
+    "estimatedTotal": "Total estimé",
+    "currentInvoiceIssued": "Mois en cours déjà facturé",
+    "refresh": "actualiser",
+    "breakdownToggle": "Afficher le détail ({count} lignes)",
+    "draftNote": "Estimation en direct. La facture finale peut légèrement varier en raison d'arrondis de fin de mois, de données d'utilisation tardives ou d'ajustements manuels.",
+    "emptyHistory": "Aucune facture émise pour le moment. Après la clôture de votre premier mois, elles apparaîtront ici.",
+    "numberCol": "Numéro",
+    "periodCol": "Période",
+    "dueCol": "Échéance",
+    "totalCol": "Total",
+    "statusCol": "Statut",
+    "descriptionCol": "Description",
+    "qtyCol": "Qté",
+    "unitCol": "Prix unitaire",
+    "amountCol": "Montant",
+    "billedToLabel": "Facturé à",
+    "issuedAtLabel": "Émise le",
+    "dueAtLabel": "À régler avant",
+    "paidAtLabel": "Payée le",
+    "subtotalLabel": "Sous-total",
+    "vatLabel": "TVA ({rate}%)",
+    "totalLabel": "Total",
+    "downloadPdf": "Télécharger le PDF",
+    "status": {
+      "draft": "Brouillon",
+      "open": "Ouverte",
+      "paid": "Payée",
+      "overdue": "En retard",
+      "void": "Annulée",
+      "uncollectible": "Irrécouvrable"
+    }
   }
 }

src/messages/it.json

@@ -15,7 +15,8 @@
     "team": "Team",
     "settings": "Impostazioni",
     "optional": "facoltativo",
-    "support": "Supporto"
+    "support": "Supporto",
+    "billing": "Fatturazione"
   },
   "login": {
     "title": "Portale PieCed",
@@ -695,5 +696,47 @@
     "reasonLabel": "Motivo (mostrato al cliente)",
     "reasonPlaceholder": "Spiega perché l'attivazione non può procedere — es. dati cliente mancanti, hardware non disponibile, ecc.",
     "reasonRequired": "Un motivo è necessario per rifiutare."
+  },
+  "customerBilling": {
+    "title": "Fatturazione",
+    "subtitle": "Periodo corrente e cronologia delle fatture. Le fatture emesse sono disponibili come download PDF.",
+    "backToBilling": "Torna alla fatturazione",
+    "currentPeriodHeading": "Periodo corrente",
+    "historyHeading": "Cronologia fatture",
+    "computing": "Calcolo del totale del periodo corrente…",
+    "currentPeriodError": "Impossibile caricare il totale del periodo corrente. Riprova più tardi.",
+    "noBillingConfig": "I dati di fatturazione non sono ancora configurati. Una volta registrato l'indirizzo di fatturazione della tua organizzazione, il totale corrente apparirà qui.",
+    "accruedSoFar": "Accumulato questo mese",
+    "estimatedTotal": "Totale stimato",
+    "currentInvoiceIssued": "Mese corrente già fatturato",
+    "refresh": "aggiorna",
+    "breakdownToggle": "Mostra dettaglio ({count} voci)",
+    "draftNote": "Stima in tempo reale. La fattura finale può variare leggermente per arrotondamenti di fine mese, dati di utilizzo in ritardo o aggiustamenti manuali.",
+    "emptyHistory": "Nessuna fattura emessa ancora. Dopo la chiusura del primo mese, appariranno qui.",
+    "numberCol": "Numero",
+    "periodCol": "Periodo",
+    "dueCol": "Scadenza",
+    "totalCol": "Totale",
+    "statusCol": "Stato",
+    "descriptionCol": "Descrizione",
+    "qtyCol": "Qtà",
+    "unitCol": "Prezzo unitario",
+    "amountCol": "Importo",
+    "billedToLabel": "Fatturato a",
+    "issuedAtLabel": "Emessa il",
+    "dueAtLabel": "Scadenza",
+    "paidAtLabel": "Pagata il",
+    "subtotalLabel": "Subtotale",
+    "vatLabel": "IVA ({rate}%)",
+    "totalLabel": "Totale",
+    "downloadPdf": "Scarica PDF",
+    "status": {
+      "draft": "Bozza",
+      "open": "Aperta",
+      "paid": "Pagata",
+      "overdue": "In ritardo",
+      "void": "Annullata",
+      "uncollectible": "Inesigibile"
+    }
   }
 }