82 lines
2.4 KiB
TypeScript
82 lines
2.4 KiB
TypeScript
import { createContext, useContext, useEffect, useState } from 'react'
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export type Theme = 'light' | 'dark' | 'system'
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export type ResolvedTheme = 'light' | 'dark'
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interface ThemeContextValue {
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theme: Theme
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resolved: ResolvedTheme
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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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function resolveTheme(theme: Theme): ResolvedTheme {
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if (theme !== 'system') return theme
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if (typeof window === 'undefined') return 'dark'
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return window.matchMedia('(prefers-color-scheme: dark)').matches ? 'dark' : 'light'
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}
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function updateMetaThemeColor(resolved: ResolvedTheme) {
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if (typeof document === 'undefined') return
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const meta = document.querySelector('meta[name="theme-color"]')
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if (!meta) return
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meta.setAttribute('content', resolved === 'dark' ? '#0A0A0B' : '#FAFAFA')
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}
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export function ThemeProvider({ children }: { children: React.ReactNode }) {
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const [theme, setThemeState] = useState<Theme>(() => {
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try {
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const saved = localStorage.getItem('theme')
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if (saved === 'light' || saved === 'dark' || saved === 'system') return saved
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} catch {}
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return 'system'
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})
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const [resolved, setResolved] = useState<ResolvedTheme>(() => resolveTheme(theme))
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useEffect(() => {
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const nextResolved = resolveTheme(theme)
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setResolved(nextResolved)
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const root = document.documentElement
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root.classList.remove('light', 'dark')
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root.classList.add(nextResolved)
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try {
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localStorage.setItem('theme', theme)
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} catch {}
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updateMetaThemeColor(nextResolved)
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}, [theme])
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useEffect(() => {
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if (theme !== 'system') return
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const media = window.matchMedia('(prefers-color-scheme: dark)')
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const handler = () => {
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const nextResolved = resolveTheme('system')
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setResolved(nextResolved)
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document.documentElement.classList.remove('light', 'dark')
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document.documentElement.classList.add(nextResolved)
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updateMetaThemeColor(nextResolved)
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}
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media.addEventListener('change', handler)
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return () => media.removeEventListener('change', handler)
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}, [theme])
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const setTheme = (next: Theme) => {
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setThemeState(next)
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}
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return (
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<ThemeContext.Provider value={{ theme, resolved, setTheme }}>
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{children}
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</ThemeContext.Provider>
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)
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}
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export function useTheme(): ThemeContextValue {
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const ctx = useContext(ThemeContext)
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if (!ctx) {
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throw new Error('useTheme must be used within ThemeProvider')
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}
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return ctx
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}
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