feat: add React SettingsContext with useSettings and useTheme hooks

src/context/SettingsContext.tsx

@@ -0,0 +1,132 @@
+import React, {
+  createContext,
+  useCallback,
+  useContext,
+  useEffect,
+  useMemo,
+  useState,
+} from 'react';
+
+export interface Settings {
+  showSettings: boolean;
+  openLinkInNewTab: boolean;
+  theme: string;
+  titleFontSize: string;
+  listSpacing: string;
+}
+
+interface SettingsContextValue {
+  settings: Settings;
+  toggleSettings: () => void;
+  toggleOpenLinksInNewTab: () => void;
+  setTheme: (theme: string) => void;
+  setFont: (size: string) => void;
+  setSpacing: (spacing: string) => void;
+}
+
+const SettingsContext = createContext<SettingsContextValue | undefined>(undefined);
+
+function loadInitialSettings(): Settings {
+  return {
+    showSettings: false,
+    openLinkInNewTab: localStorage.getItem('openLinkInNewTab')
+      ? JSON.parse(localStorage.getItem('openLinkInNewTab')!)
+      : false,
+    theme: 'default',
+    titleFontSize: localStorage.getItem('titleFontSize') ?? '16',
+    listSpacing: localStorage.getItem('listSpacing') ?? '0',
+  };
+}
+
+export const SettingsProvider: React.FC<{ children: React.ReactNode }> = ({ children }) => {
+  const [settings, setSettings] = useState<Settings>(loadInitialSettings);
+
+  const updateSettings = useCallback((patch: Partial<Settings>) => {
+    setSettings((prev) => ({ ...prev, ...patch }));
+  }, []);
+
+  const setTheme = useCallback(
+    (theme: string) => {
+      updateSettings({ theme });
+      localStorage.setItem('theme', theme);
+    },
+    [updateSettings],
+  );
+
+  useEffect(() => {
+    const savedTheme = localStorage.getItem('theme');
+    if (savedTheme) {
+      updateSettings({ theme: savedTheme });
+    } else {
+      const prefersDark = window.matchMedia('(prefers-color-scheme: dark)').matches;
+      setTheme(prefersDark ? 'night' : 'default');
+    }
+  }, [setTheme, updateSettings]);
+
+  useEffect(() => {
+    const mediaQuery = window.matchMedia('(prefers-color-scheme: dark)');
+    const handler = (event: MediaQueryListEvent) => {
+      setTheme(event.matches ? 'night' : 'default');
+    };
+    mediaQuery.addEventListener('change', handler);
+    return () => {
+      mediaQuery.removeEventListener('change', handler);
+    };
+  }, [setTheme]);
+
+  const toggleSettings = useCallback(() => {
+    updateSettings({ showSettings: !settings.showSettings });
+  }, [settings.showSettings, updateSettings]);
+
+  const toggleOpenLinksInNewTab = useCallback(() => {
+    const next = !settings.openLinkInNewTab;
+    updateSettings({ openLinkInNewTab: next });
+    localStorage.setItem('openLinkInNewTab', JSON.stringify(next));
+  }, [settings.openLinkInNewTab, updateSettings]);
+
+  const setFont = useCallback(
+    (size: string) => {
+      updateSettings({ titleFontSize: size });
+      localStorage.setItem('titleFontSize', size);
+    },
+    [updateSettings],
+  );
+
+  const setSpacing = useCallback(
+    (spacing: string) => {
+      updateSettings({ listSpacing: spacing });
+      localStorage.setItem('listSpacing', spacing);
+    },
+    [updateSettings],
+  );
+
+  const value = useMemo<SettingsContextValue>(
+    () => ({
+      settings,
+      toggleSettings,
+      toggleOpenLinksInNewTab,
+      setTheme,
+      setFont,
+      setSpacing,
+    }),
+    [settings, toggleSettings, toggleOpenLinksInNewTab, setTheme, setFont, setSpacing],
+  );
+
+  return <SettingsContext.Provider value={value}>{children}</SettingsContext.Provider>;
+};
+
+export function useSettings(): SettingsContextValue {
+  const ctx = useContext(SettingsContext);
+  if (ctx === undefined) {
+    throw new Error('useSettings must be used within a SettingsProvider');
+  }
+  return ctx;
+}
+
+export function useTheme(): {
+  theme: string;
+  setTheme: (theme: string) => void;
+} {
+  const { settings, setTheme } = useSettings();
+  return useMemo(() => ({ theme: settings.theme, setTheme }), [settings.theme, setTheme]);
+}