1 files changed, 136 insertions, 0 deletions
diff --git a/src/lib/statsig/statsig.tsx b/src/lib/statsig/statsig.tsx
new file mode 100644
index 000000000..68c63de61
--- /dev/null
+++ b/src/lib/statsig/statsig.tsx
@@ -0,0 +1,136 @@
+import React from 'react'
+import {Platform} from 'react-native'
+import {AppState, AppStateStatus} from 'react-native'
+import {sha256} from 'js-sha256'
+import {
+  Statsig,
+  StatsigProvider,
+  useGate as useStatsigGate,
+} from 'statsig-react-native-expo'
+
+import {logger} from '#/logger'
+import {useSession} from '../../state/session'
+import {LogEvents} from './events'
+
+export type {LogEvents}
+
+const statsigOptions = {
+  environment: {
+    tier: process.env.NODE_ENV === 'development' ? 'development' : 'production',
+  },
+  // Don't block on waiting for network. The fetched config will kick in on next load.
+  // This ensures the UI is always consistent and doesn't update mid-session.
+  // Note this makes cold load (no local storage) and private mode return `false` for all gates.
+  initTimeoutMs: 1,
+}
+
+type FlatJSONRecord = Record<
+  string,
+  | string
+  | number
+  | boolean
+  | null
+  | undefined
+  // Technically not scalar but Statsig will stringify it which works for us:
+  | string[]
+>
+
+let getCurrentRouteName: () => string | null | undefined = () => null
+
+export function attachRouteToLogEvents(
+  getRouteName: () => string | null | undefined,
+) {
+  getCurrentRouteName = getRouteName
+}
+
+export function logEvent<E extends keyof LogEvents>(
+  eventName: E & string,
+  rawMetadata: LogEvents[E] & FlatJSONRecord,
+) {
+  try {
+    const fullMetadata = {
+      ...rawMetadata,
+    } as Record<string, string> // Statsig typings are unnecessarily strict here.
+    fullMetadata.routeName = getCurrentRouteName() ?? '(Uninitialized)'
+    if (Statsig.initializeCalled()) {
+      Statsig.logEvent(eventName, null, fullMetadata)
+    }
+  } catch (e) {
+    // A log should never interrupt the calling code, whatever happens.
+    logger.error('Failed to log an event', {message: e})
+  }
+}
+
+export function useGate(gateName: string) {
+  const {isLoading, value} = useStatsigGate(gateName)
+  if (isLoading) {
+    // This should not happen because of waitForInitialization={true}.
+    console.error('Did not expected isLoading to ever be true.')
+  }
+  return value
+}
+
+function toStatsigUser(did: string | undefined) {
+  let userID: string | undefined
+  if (did) {
+    userID = sha256(did)
+  }
+  return {
+    userID,
+    platform: Platform.OS,
+  }
+}
+
+let lastState: AppStateStatus = AppState.currentState
+let lastActive = lastState === 'active' ? performance.now() : null
+AppState.addEventListener('change', (state: AppStateStatus) => {
+  if (state === lastState) {
+    return
+  }
+  lastState = state
+  if (state === 'active') {
+    lastActive = performance.now()
+    logEvent('state:foreground', {})
+  } else {
+    let secondsActive = 0
+    if (lastActive != null) {
+      secondsActive = Math.round((performance.now() - lastActive) / 1e3)
+    }
+    lastActive = null
+    logEvent('state:background', {
+      secondsActive,
+    })
+  }
+})
+
+export function Provider({children}: {children: React.ReactNode}) {
+  const {currentAccount} = useSession()
+  const currentStatsigUser = React.useMemo(
+    () => toStatsigUser(currentAccount?.did),
+    [currentAccount?.did],
+  )
+
+  React.useEffect(() => {
+    function refresh() {
+      // Intentionally refetching the config using the JS SDK rather than React SDK
+      // so that the new config is stored in cache but isn't used during this session.
+      // It will kick in for the next reload.
+      Statsig.updateUser(currentStatsigUser)
+    }
+    const id = setInterval(refresh, 3 * 60e3 /* 3 min */)
+    return () => clearInterval(id)
+  }, [currentStatsigUser])
+
+  return (
+    <StatsigProvider
+      sdkKey="client-SXJakO39w9vIhl3D44u8UupyzFl4oZ2qPIkjwcvuPsV"
+      mountKey={currentStatsigUser.userID}
+      user={currentStatsigUser}
+      // This isn't really blocking due to short initTimeoutMs above.
+      // However, it ensures `isLoading` is always `false`.
+      waitForInitialization={true}
+      options={statsigOptions}>
+      {children}
+    </StatsigProvider>
+  )
+}