✨ save darkmode choice

Co-authored-by: Félix Legrelle <legrelle.f@gmail.com>

site/source/contexts/DarkModeContext.tsx

@@ -2,6 +2,25 @@ import React from 'react'
 
 type DarkModeContextType = [boolean, (darkMode: boolean) => void]
 
+const persistDarkMode = (darkMode: boolean) => {
+	localStorage.setItem('darkMode', darkMode.toString())
+}
+
+const getDefaultDarkMode = () => {
+	if (localStorage.getItem('darkMode')) {
+		return localStorage.getItem('darkMode') === 'true'
+	}
+
+	if (import.meta.env.DEV && typeof window !== 'undefined') {
+		return (
+			window.matchMedia &&
+			window.matchMedia('(prefers-color-scheme: dark)').matches
+		)
+	}
+
+	return false
+}
+
 export const DarkModeContext = React.createContext<DarkModeContextType>([
 	false,
 	() => {
@@ -11,14 +30,11 @@ export const DarkModeContext = React.createContext<DarkModeContextType>([
 ])
 
 export const DarkModeProvider: React.FC = ({ children }) => {
-	const [darkMode, _setDarkMode] = React.useState<boolean>(
-		import.meta.env.DEV && typeof window !== 'undefined' ?
-			(window.matchMedia && window.matchMedia('(prefers-color-scheme: dark)').matches) :
-			false
-	)
+	const [darkMode, _setDarkMode] = React.useState<boolean>(getDefaultDarkMode())
 
 	const setDarkMode = (darkMode: boolean) => {
 		_setDarkMode(darkMode)
+		persistDarkMode(darkMode)
 
 		// https://www.youtube.com/watch?v=Pr8ETbGz35Q
 		// eslint-disable-next-line no-console
@@ -26,7 +42,7 @@ export const DarkModeProvider: React.FC = ({ children }) => {
 	}
 
 	return (
-		<DarkModeContext.Provider value={[ darkMode, setDarkMode ]}>
+		<DarkModeContext.Provider value={[darkMode, setDarkMode]}>
 			{children}
 		</DarkModeContext.Provider>
 	)