52 lines
1.6 KiB
TypeScript
52 lines
1.6 KiB
TypeScript
'use client';
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import { createContext, useContext, useEffect, useMemo, useState } from 'react';
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type Theme = 'light' | 'dark' | 'system';
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interface ThemeContextValue {
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theme: Theme;
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resolvedTheme: 'light' | 'dark';
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setTheme: (theme: Theme) => void;
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}
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const ThemeContext = createContext<ThemeContextValue | null>(null);
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export function ThemeProvider({ children }: { children: React.ReactNode }) {
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const [theme, setThemeState] = useState<Theme>('system');
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const [resolvedTheme, setResolvedTheme] = useState<'light' | 'dark'>('light');
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useEffect(() => {
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const stored = localStorage.getItem('docs-theme') as Theme | null;
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if (stored) setThemeState(stored);
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}, []);
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useEffect(() => {
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const root = document.documentElement;
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const media = window.matchMedia('(prefers-color-scheme: dark)');
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const apply = () => {
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const next = theme === 'system' ? (media.matches ? 'dark' : 'light') : theme;
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setResolvedTheme(next);
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root.classList.toggle('dark', next === 'dark');
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};
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apply();
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media.addEventListener('change', apply);
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return () => media.removeEventListener('change', apply);
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}, [theme]);
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const setTheme = (next: Theme) => {
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setThemeState(next);
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localStorage.setItem('docs-theme', next);
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};
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const value = useMemo(() => ({ theme, resolvedTheme, setTheme }), [theme, resolvedTheme]);
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return <ThemeContext.Provider value={value}>{children}</ThemeContext.Provider>;
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}
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export function useTheme() {
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const ctx = useContext(ThemeContext);
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if (!ctx) throw new Error('useTheme must be used within ThemeProvider');
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return ctx;
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}
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