Performance improvements: structural sharing & moderation opts context (#3785)

* Fix: correctly apply structural sharing to preferences object

* Move moderation opts into a context

* Fix import

* Remove log

* Pass userdid directly

* Pass moderationPrefs directly

src/state/preferences/moderation-opts.tsx

@@ -0,0 +1,61 @@
+import React, {createContext, useContext, useMemo} from 'react'
+import {BSKY_LABELER_DID, ModerationOpts} from '@atproto/api'
+
+import {useHiddenPosts, useLabelDefinitions} from '#/state/preferences'
+import {DEFAULT_LOGGED_OUT_LABEL_PREFERENCES} from '#/state/queries/preferences/moderation'
+import {useSession} from '#/state/session'
+import {usePreferencesQuery} from '../queries/preferences'
+
+export const moderationOptsContext = createContext<ModerationOpts | undefined>(
+  undefined,
+)
+
+// used in the moderation state devtool
+export const moderationOptsOverrideContext = createContext<
+  ModerationOpts | undefined
+>(undefined)
+
+export function useModerationOpts() {
+  return useContext(moderationOptsContext)
+}
+
+export function Provider({children}: React.PropsWithChildren<{}>) {
+  const override = useContext(moderationOptsOverrideContext)
+  const {currentAccount} = useSession()
+  const prefs = usePreferencesQuery()
+  const {labelDefs} = useLabelDefinitions()
+  const hiddenPosts = useHiddenPosts() // TODO move this into pds-stored prefs
+
+  const userDid = currentAccount?.did
+  const moderationPrefs = prefs.data?.moderationPrefs
+  const value = useMemo<ModerationOpts | undefined>(() => {
+    if (override) {
+      return override
+    }
+    if (!moderationPrefs) {
+      return undefined
+    }
+    return {
+      userDid,
+      prefs: {
+        ...moderationPrefs,
+        labelers: moderationPrefs.labelers.length
+          ? moderationPrefs.labelers
+          : [
+              {
+                did: BSKY_LABELER_DID,
+                labels: DEFAULT_LOGGED_OUT_LABEL_PREFERENCES,
+              },
+            ],
+        hiddenPosts: hiddenPosts || [],
+      },
+      labelDefs,
+    }
+  }, [override, userDid, labelDefs, moderationPrefs, hiddenPosts])
+
+  return (
+    <moderationOptsContext.Provider value={value}>
+      {children}
+    </moderationOptsContext.Provider>
+  )
+}