Threema QR: on-demand modal + auto-open on first add

src/components/channel-users/channel-users.tsx

@@ -3,6 +3,7 @@
 import { useState, useCallback } from "react";
 import { useTranslations } from "next-intl";
 import { useRouter } from "next/navigation";
+import { ThreemaQrModal } from "./threema-qr-modal";
 
 /** Maps channel IDs to the instructions for finding the user ID. */
 const CHANNEL_ID_HELP: Record<string, string> = {
@@ -51,6 +52,14 @@ export function ChannelUsers({
   const [inputValues, setInputValues] = useState<Record<string, string>>({});
   const [channelUsers, setChannelUsers] =
     useState<Record<string, string[]>>(initialChannelUsers);
+  /** Which channel's QR helper modal is open, if any. */
+  const [showQrFor, setShowQrFor] = useState<string | null>(null);
+  /**
+   * Tracks channels for which we've already auto-opened the helper
+   * modal on this page load. Prevents the modal from re-popping every
+   * time the user refocuses the input after dismissing it.
+   */
+  const [autoOpened, setAutoOpened] = useState<Set<string>>(() => new Set());
 
   const updateChannelUsers = useCallback(
     async (updated: Record<string, string[]>) => {
@@ -216,9 +225,19 @@ export function ChannelUsers({
             className="bg-surface-2 border border-border rounded-lg p-4"
           >
             <div className="flex items-center justify-between mb-3">
-              <h4 className="text-sm font-medium text-text-primary capitalize">
-                {channel}
-              </h4>
+              <div className="flex items-center gap-2">
+                <h4 className="text-sm font-medium text-text-primary capitalize">
+                  {channel}
+                </h4>
+                {channel === "threema" && (
+                  <button
+                    onClick={() => setShowQrFor("threema")}
+                    className="text-xs font-medium text-accent hover:text-accent-dim cursor-pointer underline underline-offset-2"
+                  >
+                    {t("threemaSetup.showQr")}
+                  </button>
+                )}
+              </div>
               <span className="text-xs text-text-muted tabular-nums">
                 {users.length} {t("users")}
               </span>
@@ -266,6 +285,17 @@ export function ChannelUsers({
                       [channel]: e.target.value,
                     }))
                   }
+                  onFocus={() => {
+                    // For threema specifically, open the QR helper the
+                    // first time the user clicks into the input on this
+                    // page load. We don't repeat after dismiss — the
+                    // "Show QR" button next to the channel name covers
+                    // re-opens on demand.
+                    if (channel === "threema" && !autoOpened.has("threema")) {
+                      setShowQrFor("threema");
+                      setAutoOpened((prev) => new Set(prev).add("threema"));
+                    }
+                  }}
                   onKeyDown={(e) => {
                     if (e.key === "Enter") handleAdd(channel);
                   }}
@@ -284,6 +314,11 @@ export function ChannelUsers({
           </div>
         );
       })}
+
+      <ThreemaQrModal
+        open={showQrFor === "threema"}
+        onClose={() => setShowQrFor(null)}
+      />
     </div>
   );
 }

src/components/channel-users/threema-qr-modal.tsx

@@ -0,0 +1,82 @@
+"use client";
+
+import { useTranslations } from "next-intl";
+import { useEffect } from "react";
+import { THREEMA_GATEWAY } from "@/lib/threema-gateway-config";
+
+interface ThreemaQrModalProps {
+  open: boolean;
+  onClose: () => void;
+}
+
+/**
+ * On-demand modal showing the QR for adding the assistant on Threema.
+ * Triggered by the "Show QR" button in the threema channel card and
+ * closes on overlay click, ESC, or the close button.
+ *
+ * Uses a plain <img> not next/image — image optimization adds nothing
+ * for a 57KB static PNG and removes a potential source of rendering
+ * bugs in the Next.js standalone build.
+ */
+export function ThreemaQrModal({ open, onClose }: ThreemaQrModalProps) {
+  const t = useTranslations("channelUsers.threemaSetup");
+
+  useEffect(() => {
+    if (!open) return;
+    function onKey(e: KeyboardEvent) {
+      if (e.key === "Escape") onClose();
+    }
+    window.addEventListener("keydown", onKey);
+    return () => window.removeEventListener("keydown", onKey);
+  }, [open, onClose]);
+
+  if (!open) return null;
+
+  return (
+    <div
+      onClick={onClose}
+      className="fixed inset-0 z-50 flex items-center justify-center bg-black/60 backdrop-blur-sm p-4"
+    >
+      <div
+        onClick={(e) => e.stopPropagation()}
+        className="w-full max-w-md bg-surface-1 border border-border rounded-2xl p-6 shadow-2xl shadow-black/40 space-y-4"
+      >
+        <div className="flex items-start justify-between">
+          <h3 className="text-base font-semibold text-text-primary">
+            {t("title")}
+          </h3>
+          <button
+            onClick={onClose}
+            className="text-text-muted hover:text-text-primary text-xl leading-none"
+            aria-label="Close"
+          >
+            ×
+          </button>
+        </div>
+
+        <div className="flex justify-center">
+          <div className="bg-white p-3 rounded-md">
+            {/* eslint-disable-next-line @next/next/no-img-element */}
+            <img
+              src={THREEMA_GATEWAY.qrCodePath}
+              alt={t("qrAlt", { gateway: THREEMA_GATEWAY.displayName })}
+              width={220}
+              height={220}
+              style={{ display: "block" }}
+            />
+          </div>
+        </div>
+
+        <p className="text-center text-xs text-text-muted font-mono">
+          {THREEMA_GATEWAY.displayName}
+        </p>
+
+        <ol className="list-decimal list-inside text-xs text-text-secondary space-y-1.5">
+          <li>{t("step1")}</li>
+          <li>{t("step2")}</li>
+          <li>{t("step3")}</li>
+        </ol>
+      </div>
+    </div>
+  );
+}