fix: prevent custom logo blink with global loading state

src/components/common/Logo.tsx

@@ -4,9 +4,9 @@
  * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-SEL
  */
 
-import { useState, useEffect } from 'react';
+import { useEffect } from 'react';
 import { useTranslation } from 'react-i18next';
-import { getApiBaseUrl } from '@/services/api';
+import { useUIStore } from '@/stores/uiStore';
 
 export function DefaultLogo() {
   const { t } = useTranslation();
@@ -31,51 +31,21 @@ export function DefaultLogo() {
 
 export default function Logo() {
   const { t } = useTranslation();
-  const [logoUrl, setLogoUrl] = useState<string | null>(null);
+  const logoUrl = useUIStore((s) => s.logoUrl);
-  const [failed, setFailed] = useState(false);
+  const logoLoading = useUIStore((s) => s.logoLoading);
+  const fetchLogo = useUIStore((s) => s.fetchLogo);
 
   useEffect(() => {
-    const controller = new AbortController();
-
-    async function fetchLogo() {
-      try {
-        const response = await fetch(`${getApiBaseUrl()}/logo`, {
-          signal: controller.signal,
-        });
-        const contentType = response.headers.get('content-type') ?? '';
-
-        if (response.ok && contentType.startsWith('image/')) {
-          const blob = await response.blob();
-          if (!controller.signal.aborted) {
-            const url = URL.createObjectURL(blob);
-            setLogoUrl(url);
-          }
-        } else {
-          if (!controller.signal.aborted) setFailed(true);
-        }
-      } catch {
-        if (!controller.signal.aborted) setFailed(true);
-      }
-    }
-
     fetchLogo();
+  }, [fetchLogo]);
 
-    return () => {
-      controller.abort();
-    };
-  }, []);
-
-  useEffect(() => {
-    return () => {
   if (logoUrl) {
-        URL.revokeObjectURL(logoUrl);
-      }
-    };
-  }, [logoUrl]);
-
-  if (logoUrl && !failed) {
     return <img src={logoUrl} alt={t('logo.alt', 'Logo')} className="h-7 w-auto max-w-[220px] object-contain" />;
   }
 
+  if (logoLoading) {
+    return <span className="h-7 w-[140px] block" aria-hidden="true" />;
+  }
+
   return <DefaultLogo />;
 }

src/stores/uiStore.ts

@@ -6,17 +6,30 @@
 
 import { create } from 'zustand';
 import { persist } from 'zustand/middleware';
+import { getApiBaseUrl } from '@/services/api';
 
 export type Theme = 'light' | 'dark';
 export type ColorTheme = 'stalwart' | 'ocean' | 'forest' | 'violet';
 export type Radius = 'rounded' | 'square';
 
+let logoAbortController: AbortController | null = null;
+let logoObjectUrl: string | null = null;
+
+function revokeLogoObjectUrl() {
+  if (logoObjectUrl) {
+    URL.revokeObjectURL(logoObjectUrl);
+    logoObjectUrl = null;
+  }
+}
+
 interface UIState {
   theme: Theme;
   colorTheme: ColorTheme;
   radius: Radius;
   sidebarOpen: boolean;
   activeSection: string;
+  logoUrl: string | null;
+  logoLoading: boolean;
 
   setTheme: (theme: Theme) => void;
   setColorTheme: (colorTheme: ColorTheme) => void;
@@ -24,6 +37,9 @@ interface UIState {
   toggleSidebar: () => void;
   setSidebarOpen: (open: boolean) => void;
   setActiveSection: (section: string) => void;
+  setLogoUrl: (url: string | null) => void;
+  setLogoLoading: (loading: boolean) => void;
+  fetchLogo: () => void;
 }
 
 function applyThemeClass(theme: Theme) {
@@ -68,6 +84,49 @@ export const useUIStore = create<UIState>()(
       radius: 'rounded',
       sidebarOpen: typeof window !== 'undefined' ? (window.matchMedia?.('(min-width: 768px)').matches ?? true) : true,
       activeSection: '',
+      logoUrl: null,
+      logoLoading: false,
+
+      setLogoUrl: (url) => {
+        revokeLogoObjectUrl();
+        if (url) {
+          logoObjectUrl = url;
+        }
+        set({ logoUrl: url, logoLoading: false });
+      },
+
+      setLogoLoading: (loading) => {
+        set({ logoLoading: loading });
+      },
+
+      fetchLogo: () => {
+        const { logoUrl, logoLoading } = get();
+        if (logoUrl !== null || logoLoading) return;
+
+        set({ logoLoading: true });
+        if (logoAbortController) {
+          logoAbortController.abort();
+        }
+        logoAbortController = new AbortController();
+
+        fetch(`${getApiBaseUrl()}/logo`, {
+          signal: logoAbortController.signal,
+        })
+          .then((response) => {
+            const contentType = response.headers.get('content-type') ?? '';
+            if (response.ok && contentType.startsWith('image/')) {
+              return response.blob().then((blob) => {
+                revokeLogoObjectUrl();
+                logoObjectUrl = URL.createObjectURL(blob);
+                set({ logoUrl: logoObjectUrl, logoLoading: false });
+              });
+            }
+            set({ logoUrl: null, logoLoading: false });
+          })
+          .catch(() => {
+            set({ logoUrl: null, logoLoading: false });
+          });
+      },
 
       setTheme: (theme) => {
         applyThemeClass(theme);