[APP-511] metrics overhaul: frontend work (#506)

* WIP

* fix types and update imports

* wip

* tagged events that should be server side

* remove server-side analytics

* remove useless import

* add additional profile header events

* remove useless import

* track follow/unfollow clicks

* add missing types

src/lib/analytics/analytics.tsx

@@ -0,0 +1,128 @@
+import React from 'react'
+import {AppState, AppStateStatus} from 'react-native'
+import {
+  createClient,
+  AnalyticsProvider,
+  useAnalytics as useAnalyticsOrig,
+  ClientMethods,
+} from '@segment/analytics-react-native'
+import {RootStoreModel, AppInfo} from 'state/models/root-store'
+import {useStores} from 'state/models/root-store'
+import {sha256} from 'js-sha256'
+import {ScreenEvent, TrackEvent} from './types'
+
+const segmentClient = createClient({
+  writeKey: '8I6DsgfiSLuoONyaunGoiQM7A6y2ybdI',
+  trackAppLifecycleEvents: false,
+})
+
+export function useAnalytics() {
+  const store = useStores()
+  const methods: ClientMethods = useAnalyticsOrig()
+  return React.useMemo(() => {
+    if (store.session.hasSession) {
+      return {
+        screen: methods.screen as ScreenEvent, // ScreenEvents defines all the possible screen names
+        track: methods.track as TrackEvent, // TrackEvents defines all the possible track events and their properties
+        identify: methods.identify,
+        flush: methods.flush,
+        group: methods.group,
+        alias: methods.alias,
+        reset: methods.reset,
+      }
+    }
+    // dont send analytics pings for anonymous users
+    return {
+      screen: () => Promise<void>,
+      track: () => Promise<void>,
+      identify: () => Promise<void>,
+      flush: () => Promise<void>,
+      group: () => Promise<void>,
+      alias: () => Promise<void>,
+      reset: () => Promise<void>,
+    }
+  }, [store, methods])
+}
+
+export function init(store: RootStoreModel) {
+  store.onSessionLoaded(() => {
+    const sess = store.session.currentSession
+    if (sess) {
+      if (sess.email) {
+        store.log.debug('Ping w/hash')
+        const email_hashed = sha256(sess.email)
+        segmentClient.identify(email_hashed, {email_hashed})
+      } else {
+        store.log.debug('Ping w/o hash')
+        segmentClient.identify()
+      }
+    }
+  })
+
+  // NOTE
+  // this is a copy of segment's own lifecycle event tracking
+  // we handle it manually to ensure that it never fires while the app is backgrounded
+  // -prf
+  segmentClient.isReady.onChange(() => {
+    if (AppState.currentState !== 'active') {
+      store.log.debug('Prevented a metrics ping while the app was backgrounded')
+      return
+    }
+    const context = segmentClient.context.get()
+    if (typeof context?.app === 'undefined') {
+      store.log.debug('Aborted metrics ping due to unavailable context')
+      return
+    }
+
+    const oldAppInfo = store.appInfo
+    const newAppInfo = context.app as AppInfo
+    store.setAppInfo(newAppInfo)
+    store.log.debug('Recording app info', {new: newAppInfo, old: oldAppInfo})
+
+    if (typeof oldAppInfo === 'undefined') {
+      if (store.session.hasSession) {
+        segmentClient.track('Application Installed', {
+          version: newAppInfo.version,
+          build: newAppInfo.build,
+        })
+      }
+    } else if (newAppInfo.version !== oldAppInfo.version) {
+      if (store.session.hasSession) {
+        segmentClient.track('Application Updated', {
+          version: newAppInfo.version,
+          build: newAppInfo.build,
+          previous_version: oldAppInfo.version,
+          previous_build: oldAppInfo.build,
+        })
+      }
+    }
+    if (store.session.hasSession) {
+      segmentClient.track('Application Opened', {
+        from_background: false,
+        version: newAppInfo.version,
+        build: newAppInfo.build,
+      })
+    }
+  })
+
+  let lastState: AppStateStatus = AppState.currentState
+  AppState.addEventListener('change', (state: AppStateStatus) => {
+    if (state === 'active' && lastState !== 'active') {
+      const context = segmentClient.context.get()
+      segmentClient.track('Application Opened', {
+        from_background: true,
+        version: context?.app?.version,
+        build: context?.app?.build,
+      })
+    } else if (state !== 'active' && lastState === 'active') {
+      segmentClient.track('Application Backgrounded')
+    }
+    lastState = state
+  })
+}
+
+export function Provider({children}: React.PropsWithChildren<{}>) {
+  return (
+    <AnalyticsProvider client={segmentClient}>{children}</AnalyticsProvider>
+  )
+}