Move sync on collections change listener; add delay

app/src/androidTest/kotlin/at/bitfire/davdroid/TestModules.kt

@@ -8,19 +8,18 @@ import at.bitfire.davdroid.push.PushRegistrationWorkerManager
 import at.bitfire.davdroid.repository.DavCollectionRepository
 import at.bitfire.davdroid.startup.StartupPlugin
 import at.bitfire.davdroid.startup.TasksAppWatcher
-import at.bitfire.davdroid.sync.worker.SyncWorkerManager
 import dagger.Module
 import dagger.hilt.components.SingletonComponent
 import dagger.hilt.testing.TestInstallIn
 import dagger.multibindings.Multibinds
 
-// remove SyncWorkerModule from Android tests
+// remove SyncOnCollectionsChangeListenerModule from Android tests
 @Module
 @TestInstallIn(
     components = [SingletonComponent::class],
-    replaces = [SyncWorkerManager.SyncWorkerManagerModule::class]
+    replaces = [SyncOnCollectionsChangeListenerModule::class]
 )
-abstract class TestSyncWorkerManagerModule {
+abstract class SyncOnCollectionsChangeListenerModule {
     // provides empty set of listeners
     @Multibinds
     abstract fun empty(): Set<DavCollectionRepository.OnChangeListener>

app/src/main/kotlin/at/bitfire/davdroid/repository/SyncOnCollectionsChangeListener.kt

@@ -0,0 +1,58 @@
+/*
+ * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
+ */
+
+package at.bitfire.davdroid.repository
+
+import android.accounts.Account
+import at.bitfire.davdroid.sync.worker.SyncWorkerManager
+import dagger.Binds
+import dagger.Module
+import dagger.hilt.InstallIn
+import dagger.hilt.components.SingletonComponent
+import dagger.multibindings.IntoSet
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.launch
+import java.util.logging.Logger
+import javax.inject.Inject
+
+/**
+ * Enqueues a sync worker after a short delay when the collection list changes.
+ */
+class SyncOnCollectionsChangeListener @Inject constructor(
+    private val workerManager: SyncWorkerManager,
+    private val logger: Logger
+): DavCollectionRepository.OnChangeListener {
+
+    var delayedOneTimeSyncWorkerJob: Job? = null
+
+    override fun onCollectionsChanged(account: Account?) {
+        account?.let {
+            // Start sync after a short delay to avoid multiple syncs in a short time when multiple
+            // collections change quickly, e.g. at collection refresh or users first time setup.
+            delayedOneTimeSyncWorkerJob?.cancel()
+            delayedOneTimeSyncWorkerJob = CoroutineScope(Dispatchers.IO).launch {
+                delay(7000)
+                logger.info("Collections changed, scheduling sync")
+                workerManager.enqueueOneTimeAllAuthorities(it)
+            }
+        }
+    }
+
+
+
+    /**
+     * Hilt module that registers [SyncOnCollectionsChangeListener] in [DavCollectionRepository].
+     */
+    @Module
+    @InstallIn(SingletonComponent::class)
+    interface SyncOnCollectionsChangeListenerModule {
+        @Binds
+        @IntoSet
+        fun listener(impl: SyncOnCollectionsChangeListener): DavCollectionRepository.OnChangeListener
+    }
+
+}

app/src/main/kotlin/at/bitfire/davdroid/sync/worker/SyncWorkerManager.kt

@@ -25,7 +25,6 @@ import androidx.work.WorkManager
 import androidx.work.WorkQuery
 import androidx.work.WorkRequest
 import at.bitfire.davdroid.push.PushNotificationManager
-import at.bitfire.davdroid.repository.DavCollectionRepository
 import at.bitfire.davdroid.sync.SyncDataType
 import at.bitfire.davdroid.sync.TasksAppManager
 import at.bitfire.davdroid.sync.worker.BaseSyncWorker.Companion.INPUT_ACCOUNT_NAME
@@ -37,13 +36,8 @@ import at.bitfire.davdroid.sync.worker.BaseSyncWorker.Companion.INPUT_UPLOAD
 import at.bitfire.davdroid.sync.worker.BaseSyncWorker.Companion.InputResync
 import at.bitfire.davdroid.sync.worker.BaseSyncWorker.Companion.NO_RESYNC
 import at.bitfire.davdroid.sync.worker.BaseSyncWorker.Companion.commonTag
-import dagger.Binds
 import dagger.Lazy
-import dagger.Module
-import dagger.hilt.InstallIn
 import dagger.hilt.android.qualifiers.ApplicationContext
-import dagger.hilt.components.SingletonComponent
-import dagger.multibindings.IntoSet
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.map
 import java.util.concurrent.TimeUnit
@@ -149,7 +143,7 @@ class SyncWorkerManager @Inject constructor(
         }
         WorkManager.getInstance(context).enqueueUniqueWork(
             name,
-            /* If sync is already running, just continue.
+            /* If sync is already running, continue that sync and don't append a new one.
             Existing retried work will not be replaced (for instance when
             PeriodicSyncWorker enqueues another scheduled sync). */
             ExistingWorkPolicy.KEEP,
@@ -291,28 +285,4 @@ class SyncWorkerManager @Inject constructor(
             }
     }
 
-    /**
-     * Listener that enqueues a push registration worker when the collection list changes.
-     */
-    class CollectionsListener @Inject constructor(
-        private val workerManager: SyncWorkerManager
-    ): DavCollectionRepository.OnChangeListener {
-
-        override fun onCollectionsChanged(account: Account?) {
-            account?.let { workerManager.enqueueOneTimeAllAuthorities(it) }
-        }
-
-    }
-
-    /**
-     * Hilt module that registers [CollectionsListener] in [DavCollectionRepository].
-     */
-    @Module
-    @InstallIn(SingletonComponent::class)
-    interface SyncWorkerManagerModule {
-        @Binds
-        @IntoSet
-        fun listener(impl: CollectionsListener): DavCollectionRepository.OnChangeListener
-    }
-
 }