Add persistent state provider (#1830)

* Add persistent state provider

* Catch write error

* Handle read errors, update error msgs

* Fix lint

* Don't provide initial state to loader

* Remove colorMode from shell state

* Idea: hook into persisted context from other files

* Migrate settings to new hook

* Rework persisted state to split individual contexts

* Tweak persisted schema and validation

---------

Co-authored-by: Paul Frazee <pfrazee@gmail.com>

src/state/shell/color-mode.tsx

@@ -0,0 +1,56 @@
+import React from 'react'
+import {isWeb} from '#/platform/detection'
+import * as persisted from '#/state/persisted'
+
+type StateContext = persisted.Schema['colorMode']
+type SetContext = (v: persisted.Schema['colorMode']) => void
+
+const stateContext = React.createContext<StateContext>('system')
+const setContext = React.createContext<SetContext>(
+  (_: persisted.Schema['colorMode']) => {},
+)
+
+export function Provider({children}: React.PropsWithChildren<{}>) {
+  const [state, setState] = React.useState(persisted.get('colorMode'))
+
+  const setStateWrapped = React.useCallback(
+    (colorMode: persisted.Schema['colorMode']) => {
+      setState(colorMode)
+      persisted.write('colorMode', colorMode)
+      updateDocument(colorMode)
+    },
+    [setState],
+  )
+
+  React.useEffect(() => {
+    return persisted.onUpdate(() => {
+      setState(persisted.get('colorMode'))
+      updateDocument(persisted.get('colorMode'))
+    })
+  }, [setStateWrapped])
+
+  return (
+    <stateContext.Provider value={state}>
+      <setContext.Provider value={setStateWrapped}>
+        {children}
+      </setContext.Provider>
+    </stateContext.Provider>
+  )
+}
+
+export function useColorMode() {
+  return React.useContext(stateContext)
+}
+
+export function useSetColorMode() {
+  return React.useContext(setContext)
+}
+
+function updateDocument(colorMode: string) {
+  if (isWeb && typeof window !== 'undefined') {
+    const html = window.document.documentElement
+    // remove any other color mode classes
+    html.className = html.className.replace(/colorMode--\w+/g, '')
+    html.classList.add(`colorMode--${colorMode}`)
+  }
+}

src/state/shell/index.tsx

@@ -2,6 +2,7 @@ import React from 'react'
 import {Provider as DrawerOpenProvider} from './drawer-open'
 import {Provider as DrawerSwipableProvider} from './drawer-swipe-disabled'
 import {Provider as MinimalModeProvider} from './minimal-mode'
+import {Provider as ColorModeProvider} from './color-mode'
 
 export {useIsDrawerOpen, useSetDrawerOpen} from './drawer-open'
 export {
@@ -9,12 +10,15 @@ export {
   useSetDrawerSwipeDisabled,
 } from './drawer-swipe-disabled'
 export {useMinimalShellMode, useSetMinimalShellMode} from './minimal-mode'
+export {useColorMode, useSetColorMode} from './color-mode'
 
 export function Provider({children}: React.PropsWithChildren<{}>) {
   return (
     <DrawerOpenProvider>
       <DrawerSwipableProvider>
-        <MinimalModeProvider>{children}</MinimalModeProvider>
+        <MinimalModeProvider>
+          <ColorModeProvider>{children}</ColorModeProvider>
+        </MinimalModeProvider>
       </DrawerSwipableProvider>
     </DrawerOpenProvider>
   )