Files
agent-fox/packages/web/src/lib/theme.tsx
2026-04-02 18:22:14 +08:00

65 lines
1.9 KiB
TypeScript

import { createContext, useContext, useState, useEffect, type ReactNode } from 'react';
type Theme = 'light' | 'dark' | 'system';
type ThemeContextType = {
theme: Theme;
resolved: 'light' | 'dark';
setTheme: (t: Theme) => void;
};
const ThemeContext = createContext<ThemeContextType | null>(null);
function getSystemTheme(): 'light' | 'dark' {
return window.matchMedia('(prefers-color-scheme: dark)').matches ? 'dark' : 'light';
}
function applyTheme(theme: Theme) {
const resolved = theme === 'system' ? getSystemTheme() : theme;
if (theme === 'system') {
document.documentElement.removeAttribute('data-theme');
} else {
document.documentElement.setAttribute('data-theme', theme);
}
return resolved;
}
export function ThemeProvider({ children }: { children: ReactNode }) {
const [theme, setThemeState] = useState<Theme>(() => {
return (localStorage.getItem('agent-fox-theme') as Theme) || 'system';
});
const [resolved, setResolved] = useState<'light' | 'dark'>(() => applyTheme(
(localStorage.getItem('agent-fox-theme') as Theme) || 'system'
));
const setTheme = (t: Theme) => {
localStorage.setItem('agent-fox-theme', t);
setThemeState(t);
setResolved(applyTheme(t));
};
useEffect(() => {
setResolved(applyTheme(theme));
}, [theme]);
useEffect(() => {
if (theme !== 'system') return;
const mq = window.matchMedia('(prefers-color-scheme: dark)');
const handler = () => setResolved(applyTheme('system'));
mq.addEventListener('change', handler);
return () => mq.removeEventListener('change', handler);
}, [theme]);
return (
<ThemeContext.Provider value={{ theme, resolved, setTheme }}>
{children}
</ThemeContext.Provider>
);
}
export function useTheme() {
const ctx = useContext(ThemeContext);
if (!ctx) throw new Error('useTheme must be used within ThemeProvider');
return ctx;
}