move ThemeProvider and ThemeToggle components

lightrag_webui/src/components/ThemeProvider.tsx

@@ -0,0 +1,57 @@
+import { createContext, useEffect, useState } from 'react'
+import { Theme, useSettingsStore } from '@/stores/settings'
+
+type ThemeProviderProps = {
+  children: React.ReactNode
+}
+
+type ThemeProviderState = {
+  theme: Theme
+  setTheme: (theme: Theme) => void
+}
+
+const initialState: ThemeProviderState = {
+  theme: 'system',
+  setTheme: () => null
+}
+
+const ThemeProviderContext = createContext<ThemeProviderState>(initialState)
+
+/**
+ * Component that provides the theme state and setter function to its children.
+ */
+export default function ThemeProvider({ children, ...props }: ThemeProviderProps) {
+  const [theme, setTheme] = useState<Theme>(useSettingsStore.getState().theme)
+
+  useEffect(() => {
+    const root = window.document.documentElement
+    root.classList.remove('light', 'dark')
+
+    if (theme === 'system') {
+      const systemTheme = window.matchMedia('(prefers-color-scheme: dark)').matches
+        ? 'dark'
+        : 'light'
+      root.classList.add(systemTheme)
+      setTheme(systemTheme)
+      return
+    }
+
+    root.classList.add(theme)
+  }, [theme])
+
+  const value = {
+    theme,
+    setTheme: (theme: Theme) => {
+      useSettingsStore.getState().setTheme(theme)
+      setTheme(theme)
+    }
+  }
+
+  return (
+    <ThemeProviderContext.Provider {...props} value={value}>
+      {children}
+    </ThemeProviderContext.Provider>
+  )
+}
+
+export { ThemeProviderContext }