61 lines
1.4 KiB
TypeScript
61 lines
1.4 KiB
TypeScript
"use client";
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import {
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createContext,
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useCallback,
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useContext,
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useEffect,
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useState,
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type ReactNode,
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} from "react";
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import {
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DEFAULT_THEME,
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type ThemeMode,
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persistTheme,
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readStoredTheme,
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} from "@/lib/theme";
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interface ThemeContextValue {
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theme: ThemeMode;
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setTheme: (mode: ThemeMode) => void;
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toggleTheme: () => void;
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}
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const ThemeContext = createContext<ThemeContextValue | null>(null);
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export function ThemeProvider({ children }: { children: ReactNode }) {
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// 首屏必須與 SSR 一致（DEFAULT_THEME）；localStorage 在 useEffect 讀取，避免 hydration mismatch。
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const [theme, setThemeState] = useState<ThemeMode>(DEFAULT_THEME);
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useEffect(() => {
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const stored = readStoredTheme();
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if (stored) setThemeState(stored);
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}, []);
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const setTheme = useCallback((mode: ThemeMode) => {
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setThemeState(mode);
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persistTheme(mode);
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}, []);
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const toggleTheme = useCallback(() => {
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setThemeState((prev) => {
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const next = prev === "dark" ? "light" : "dark";
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persistTheme(next);
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return next;
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});
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}, []);
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return (
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<ThemeContext.Provider value={{ theme, setTheme, toggleTheme }}>
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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() {
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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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} |