Move all database queries off the ui thread & add a ViewModel for MainActivity (#4786)

- Move all database queries off the ui thread - this is a massive
performance improvement
- ViewModel for MainActivity - this makes MainActivity smaller and
network requests won't be retried when rotating the screen
- removes the Push Notification Migration feature. We had it long
enough, all users who want push notifications should be migrated by now
- AccountEntity is now immutable
- converted BaseActivity to Kotlin
- The header image of Accounts is now cached as well

app/src/test/java/com/keylesspalace/tusky/MainActivityTest.kt

@@ -3,7 +3,10 @@ package com.keylesspalace.tusky
 import android.app.Activity
 import android.app.NotificationManager
 import android.content.ComponentName
+import android.content.Context
 import android.content.Intent
+import androidx.lifecycle.viewmodel.initializer
+import androidx.lifecycle.viewmodel.viewModelFactory
 import androidx.test.ext.junit.runners.AndroidJUnit4
 import androidx.test.platform.app.InstrumentationRegistry
 import androidx.viewpager2.widget.ViewPager2
@@ -12,13 +15,15 @@ import at.connyduck.calladapter.networkresult.NetworkResult
 import com.keylesspalace.tusky.appstore.EventHub
 import com.keylesspalace.tusky.components.accountlist.AccountListActivity
 import com.keylesspalace.tusky.components.systemnotifications.NotificationHelper
+import com.keylesspalace.tusky.db.AccountManager
 import com.keylesspalace.tusky.db.entity.AccountEntity
 import com.keylesspalace.tusky.entity.Account
 import com.keylesspalace.tusky.entity.Notification
 import com.keylesspalace.tusky.entity.TimelineAccount
+import com.keylesspalace.tusky.network.MastodonApi
 import com.keylesspalace.tusky.util.getSerializableExtraCompat
 import java.util.Date
-import kotlinx.coroutines.test.TestScope
+import kotlinx.coroutines.flow.MutableStateFlow
 import org.junit.After
 import org.junit.Assert.assertEquals
 import org.junit.Assert.assertNotNull
@@ -128,17 +133,20 @@ class MainActivityTest {
     private fun startMainActivity(intent: Intent): Activity {
         val controller = Robolectric.buildActivity(MainActivity::class.java, intent)
         val activity = controller.get()
-        activity.eventHub = EventHub()
-        activity.accountManager = mock {
+        val eventHub = EventHub()
+        activity.eventHub = eventHub
+        val accountManager: AccountManager = mock {
+            on { accounts } doReturn listOf(accountEntity)
+            on { accountsFlow } doReturn MutableStateFlow(listOf(accountEntity))
             on { activeAccount } doReturn accountEntity
         }
-        activity.draftsAlert = mock {}
-        activity.shareShortcutHelper = mock {}
-        activity.externalScope = TestScope()
-        activity.mastodonApi = mock {
+        activity.accountManager = accountManager
+        activity.draftsAlert = mock { }
+        val api: MastodonApi = mock {
             onBlocking { accountVerifyCredentials() } doReturn NetworkResult.success(account)
             onBlocking { announcements() } doReturn NetworkResult.success(emptyList())
         }
+        activity.mastodonApi = api
         activity.preferences = mock(defaultAnswer = {
             when (it.method.returnType) {
                 String::class.java -> "test"
@@ -146,6 +154,20 @@ class MainActivityTest {
                 else -> null
             }
         })
+        val viewModel = MainViewModel(
+            context = mock {
+                on { getSystemService(Context.NOTIFICATION_SERVICE) } doReturn mock<NotificationManager>()
+            },
+            api = api,
+            eventHub = eventHub,
+            accountManager = accountManager,
+            shareShortcutHelper = mock()
+        )
+        val testViewModelFactory = viewModelFactory {
+            initializer { viewModel }
+        }
+        activity.viewModelProviderFactory = testViewModelFactory
+
         controller.create().start()
         return activity
     }