feat: add all Draw.io themes to settings panel (#835)

* feat: add all Draw.io themes to settings panel

Add all available Draw.io themes (kennedy, atlas, dark, min, sketch, simple)
to the settings panel dropdown. Previously only min and sketch were available
as a toggle button.

Changes:
- Replace the Draw.io style toggle button with a dropdown selector
- Expand theme type from "min" | "sketch" to include all 6 themes
- Update localStorage validation to accept all themes
- Update handler from toggle to direct theme selection

Closes #499

* fix: localize theme labels, tighten DrawioTheme typing, sync dark param

- Move DRAWIO_THEMES + DrawioTheme to lib/drawio-themes.ts; reuse in
  page.tsx, chat-panel.tsx and settings-dialog.tsx instead of `string`
- Localize theme dropdown labels (Dark/Minimal/Sketch/Simple) in
  en/zh/ja/zh-Hant; keep proper-noun themes (Kennedy/Atlas) as-is
- Drop trailing colon from drawioStyleDescription and remove dead
  switchTo/minimal/sketch keys in all 4 dictionaries
- Auto-sync drawio dark URL param when ui="dark" is selected
- Add aria-label to drawio-style SelectTrigger

* fix: use kennedy as default theme and label it "Default"

---------

Co-authored-by: dayuan.jiang <jdy.toh@gmail.com>

app/[lang]/page.tsx

@@ -10,6 +10,7 @@ import {
     ResizablePanelGroup,
 } from "@/components/ui/resizable"
 import { useDiagram } from "@/contexts/diagram-context"
+import { type DrawioTheme, isDrawioTheme } from "@/lib/drawio-themes"
 import { i18n, type Locale } from "@/lib/i18n/config"
 import { isIndexedDBUsable } from "@/lib/session-storage"
 
@@ -27,7 +28,7 @@ export default function Home() {
     const currentLang = (pathname.split("/")[1] || i18n.defaultLocale) as Locale
     const [isMobile, setIsMobile] = useState(false)
     const [isChatVisible, setIsChatVisible] = useState(true)
-    const [drawioUi, setDrawioUi] = useState<"min" | "sketch">("min")
+    const [drawioUi, setDrawioUi] = useState<DrawioTheme>("kennedy")
     const [darkMode, setDarkMode] = useState(false)
     const [isLoaded, setIsLoaded] = useState(false)
     const [isDrawioReady, setIsDrawioReady] = useState(false)
@@ -56,7 +57,7 @@ export default function Home() {
         }
 
         const savedUi = localStorage.getItem("drawio-theme")
-        if (savedUi === "min" || savedUi === "sketch") {
+        if (isDrawioTheme(savedUi)) {
             setDrawioUi(savedUi)
         }
 
@@ -113,10 +114,9 @@ export default function Home() {
         resetDrawioReady()
     }
 
-    const handleDrawioUiChange = () => {
+    const handleDrawioUiChange = (theme: DrawioTheme) => {
-        const newUi = drawioUi === "min" ? "sketch" : "min"
+        localStorage.setItem("drawio-theme", theme)
-        localStorage.setItem("drawio-theme", newUi)
+        setDrawioUi(theme)
-        setDrawioUi(newUi)
         setIsDrawioReady(false)
         resetDrawioReady()
     }
@@ -216,7 +216,8 @@ export default function Home() {
                                             saveAndExit: false,
                                             noSaveBtn: true,
                                             noExitBtn: true,
-                                            dark: darkMode,
+                                            dark:
+                                                darkMode || drawioUi === "dark",
                                             lang: currentLang,
                                             // Enable offline mode in Electron to disable external service calls
                                             ...(isElectron && {
@@ -264,7 +265,7 @@ export default function Home() {
                                 isVisible={isChatVisible}
                                 onToggleVisibility={toggleChatPanel}
                                 drawioUi={drawioUi}
-                                onToggleDrawioUi={handleDrawioUiChange}
+                                onDrawioUiChange={handleDrawioUiChange}
                                 darkMode={darkMode}
                                 onToggleDarkMode={handleDarkModeChange}
                                 isMobile={isMobile}

components/chat-panel.tsx

@@ -32,6 +32,7 @@ import { useSessionManager } from "@/hooks/use-session-manager"
 import { useValidateDiagram } from "@/hooks/use-validate-diagram"
 import { getApiEndpoint } from "@/lib/base-path"
 import { findCachedResponse } from "@/lib/cached-responses"
+import type { DrawioTheme } from "@/lib/drawio-themes"
 import { formatMessage } from "@/lib/i18n/utils"
 import { isPdfFile, isTextFile } from "@/lib/pdf-utils"
 import { sanitizeMessages } from "@/lib/session-storage"
@@ -68,8 +69,8 @@ interface ChatMessage {
 interface ChatPanelProps {
     isVisible: boolean
     onToggleVisibility: () => void
-    drawioUi: "min" | "sketch"
+    drawioUi: DrawioTheme
-    onToggleDrawioUi: () => void
+    onDrawioUiChange: (theme: DrawioTheme) => void
     darkMode: boolean
     onToggleDarkMode: () => void
     isMobile?: boolean
@@ -110,7 +111,7 @@ export default function ChatPanel({
     isVisible,
     onToggleVisibility,
     drawioUi,
-    onToggleDrawioUi,
+    onDrawioUiChange,
     darkMode,
     onToggleDarkMode,
     isMobile = false,
@@ -1442,7 +1443,7 @@ export default function ChatPanel({
                 open={showSettingsDialog}
                 onOpenChange={setShowSettingsDialog}
                 drawioUi={drawioUi}
-                onToggleDrawioUi={onToggleDrawioUi}
+                onDrawioUiChange={onDrawioUiChange}
                 darkMode={darkMode}
                 onToggleDarkMode={onToggleDarkMode}
                 minimalStyle={minimalStyle}

components/settings-dialog.tsx

@@ -25,6 +25,7 @@ import { Switch } from "@/components/ui/switch"
 import { Textarea } from "@/components/ui/textarea"
 import { useDictionary } from "@/hooks/use-dictionary"
 import { getApiEndpoint } from "@/lib/base-path"
+import type { DrawioTheme } from "@/lib/drawio-themes"
 import { i18n, type Locale } from "@/lib/i18n/config"
 import { STORAGE_KEYS } from "@/lib/storage"
 
@@ -63,8 +64,8 @@ const LANGUAGE_LABELS: Record<Locale, string> = {
 interface SettingsDialogProps {
     open: boolean
     onOpenChange: (open: boolean) => void
-    drawioUi: "min" | "sketch"
+    drawioUi: DrawioTheme
-    onToggleDrawioUi: () => void
+    onDrawioUiChange: (theme: DrawioTheme) => void
     darkMode: boolean
     onToggleDarkMode: () => void
     minimalStyle?: boolean
@@ -90,7 +91,7 @@ function SettingsContent({
     open,
     onOpenChange,
     drawioUi,
-    onToggleDrawioUi,
+    onDrawioUiChange,
     darkMode,
     onToggleDarkMode,
     minimalStyle = false,
@@ -432,23 +433,40 @@ function SettingsContent({
                     {/* Draw.io Style */}
                     <SettingItem
                         label={dict.settings.drawioStyle}
-                        description={`${dict.settings.drawioStyleDescription} ${
+                        description={dict.settings.drawioStyleDescription}
-                            drawioUi === "min"
-                                ? dict.settings.minimal
-                                : dict.settings.sketch
-                        }`}
                     >
-                        <Button
+                        <Select
-                            id="drawio-ui"
+                            value={drawioUi}
-                            variant="outline"
+                            onValueChange={(v) =>
-                            onClick={onToggleDrawioUi}
+                                onDrawioUiChange(v as DrawioTheme)
-                            className="h-9 w-[120px] rounded-xl border-border-subtle hover:bg-interactive-hover font-normal"
+                            }
                         >
-                            {dict.settings.switchTo}{" "}
+                            <SelectTrigger
-                            {drawioUi === "min"
+                                id="drawio-ui-select"
-                                ? dict.settings.sketch
+                                aria-label={dict.settings.drawioStyle}
-                                : dict.settings.minimal}
+                                className="w-[120px] h-9 rounded-xl"
-                        </Button>
+                            >
+                                <SelectValue />
+                            </SelectTrigger>
+                            <SelectContent>
+                                <SelectItem value="kennedy">
+                                    {dict.settings.themeDefault}
+                                </SelectItem>
+                                <SelectItem value="atlas">Atlas</SelectItem>
+                                <SelectItem value="dark">
+                                    {dict.settings.themeDark}
+                                </SelectItem>
+                                <SelectItem value="min">
+                                    {dict.settings.themeMinimal}
+                                </SelectItem>
+                                <SelectItem value="sketch">
+                                    {dict.settings.themeSketch}
+                                </SelectItem>
+                                <SelectItem value="simple">
+                                    {dict.settings.themeSimple}
+                                </SelectItem>
+                            </SelectContent>
+                        </Select>
                     </SettingItem>
 
                     {/* Diagram Style */}

lib/drawio-themes.ts

@@ -0,0 +1,17 @@
+export const DRAWIO_THEMES = [
+    "kennedy",
+    "atlas",
+    "dark",
+    "min",
+    "sketch",
+    "simple",
+] as const
+
+export type DrawioTheme = (typeof DRAWIO_THEMES)[number]
+
+export function isDrawioTheme(value: unknown): value is DrawioTheme {
+    return (
+        typeof value === "string" &&
+        (DRAWIO_THEMES as readonly string[]).includes(value)
+    )
+}

lib/i18n/dictionaries/en.json

@@ -102,10 +102,12 @@
         "theme": "Theme",
         "themeDescription": "Dark/Light mode for interface and DrawIO canvas.",
         "drawioStyle": "DrawIO Style",
-        "drawioStyleDescription": "Canvas style:",
+        "drawioStyleDescription": "Canvas style",
-        "switchTo": "Switch to",
+        "themeDefault": "Default",
-        "minimal": "Minimal",
+        "themeDark": "Dark",
-        "sketch": "Sketch",
+        "themeMinimal": "Minimal",
+        "themeSketch": "Sketch",
+        "themeSimple": "Simple",
         "diagramStyle": "Diagram Style",
         "diagramStyleDescription": "Toggle between minimal and styled diagram output.",
         "sendShortcut": "Send Shortcut",

lib/i18n/dictionaries/ja.json

@@ -102,10 +102,12 @@
         "theme": "テーマ",
         "themeDescription": "インターフェースと DrawIO キャンバスのダーク/ライトモード。",
         "drawioStyle": "DrawIO スタイル",
-        "drawioStyleDescription": "キャンバススタイル：",
+        "drawioStyleDescription": "キャンバススタイル",
-        "switchTo": "切り替え",
+        "themeDefault": "デフォルト",
-        "minimal": "ミニマル",
+        "themeDark": "ダーク",
-        "sketch": "スケッチ",
+        "themeMinimal": "ミニマル",
+        "themeSketch": "スケッチ",
+        "themeSimple": "シンプル",
         "diagramStyle": "ダイアグラムスタイル",
         "diagramStyleDescription": "ミニマルとスタイル付きの出力を切り替えます。",
         "sendShortcut": "送信ショートカット",

lib/i18n/dictionaries/zh-Hant.json

@@ -102,10 +102,12 @@
         "theme": "主題",
         "themeDescription": "介面和 DrawIO 畫布的深色/淺色模式。",
         "drawioStyle": "DrawIO 樣式",
-        "drawioStyleDescription": "畫布樣式：",
+        "drawioStyleDescription": "畫布樣式",
-        "switchTo": "切換到",
+        "themeDefault": "預設",
-        "minimal": "簡約",
+        "themeDark": "深色",
-        "sketch": "草圖",
+        "themeMinimal": "簡約",
+        "themeSketch": "草圖",
+        "themeSimple": "簡單",
         "diagramStyle": "圖表樣式",
         "diagramStyleDescription": "切換簡約與精緻圖表輸出模式。",
         "sendShortcut": "傳送快捷鍵",

lib/i18n/dictionaries/zh.json

@@ -102,10 +102,12 @@
         "theme": "主题",
         "themeDescription": "界面和 DrawIO 画布的深色/浅色模式。",
         "drawioStyle": "DrawIO 样式",
-        "drawioStyleDescription": "画布样式：",
+        "drawioStyleDescription": "画布样式",
-        "switchTo": "切换到",
+        "themeDefault": "默认",
-        "minimal": "简约",
+        "themeDark": "深色",
-        "sketch": "草图",
+        "themeMinimal": "简约",
+        "themeSketch": "草图",
+        "themeSimple": "简单",
         "diagramStyle": "图表样式",
         "diagramStyleDescription": "切换简约与精致图表输出模式。",
         "sendShortcut": "发送快捷键",