From e3c261dd9ee9b46cb055e61e3035e732a6208ad9 Mon Sep 17 00:00:00 2001
From: MohitMaliFtechiz <futuretechnoworld.mohit@gmail.com>
Date: Thu, 27 Feb 2025 20:55:14 +0530
Subject: [PATCH] Fixed: Duplicate download completed notifications showing.

* Two notifications were shown for a completed download when the app was in the background, the download was about to complete, and the app was then opened.
* This occurred because `DownloadMonitorService` pushed a download complete notification before detaching, while the app's lifecycle triggered Fetch to push another notification for the same completed download.
* The fix ensures that any previously completed notification is removed before showing a new one.
---
 .../downloadManager/DownloadMonitorService.kt |  8 +++++--
 .../FetchDownloadNotificationManager.kt       | 22 +++++++++++++++++++
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/core/src/main/java/org/kiwix/kiwixmobile/core/downloader/downloadManager/DownloadMonitorService.kt b/core/src/main/java/org/kiwix/kiwixmobile/core/downloader/downloadManager/DownloadMonitorService.kt
index a52b9fbb9..bb8e750e7 100644
--- a/core/src/main/java/org/kiwix/kiwixmobile/core/downloader/downloadManager/DownloadMonitorService.kt
+++ b/core/src/main/java/org/kiwix/kiwixmobile/core/downloader/downloadManager/DownloadMonitorService.kt
@@ -48,6 +48,8 @@ import org.kiwix.kiwixmobile.core.main.CoreMainActivity
 import org.kiwix.kiwixmobile.core.utils.DOWNLOAD_NOTIFICATION_CHANNEL_ID
 import javax.inject.Inject
 
+const val THIRTY_TREE = 33
+
 class DownloadMonitorService : Service() {
   private val updater = PublishSubject.create<() -> Unit>()
   private var updaterDisposable: Disposable? = null
@@ -265,7 +267,6 @@ class DownloadMonitorService : Service() {
     }
   }
 
-  @Suppress("MagicNumber")
   private fun showDownloadCompletedNotification(download: Download) {
     downloadNotificationChannel()
     val notificationBuilder = getNotificationBuilder(download.id)
@@ -287,7 +288,10 @@ class DownloadMonitorService : Service() {
     // notification. If we use the same ID, changing the foreground notification for another
     // ongoing download cancels the previous notification for that id, preventing the download
     // complete notification from being displayed.
-    val downloadCompleteNotificationId = download.id + 33
+    val downloadCompleteNotificationId = download.id + THIRTY_TREE
+    // Cancel the complete download notification if already shown due to the application's
+    // lifecycle fetch. See #4237 for more details.
+    cancelNotificationForId(download.id - THIRTY_TREE)
     notificationManager.notify(downloadCompleteNotificationId, notificationBuilder.build())
   }
 
diff --git a/core/src/main/java/org/kiwix/kiwixmobile/core/downloader/downloadManager/FetchDownloadNotificationManager.kt b/core/src/main/java/org/kiwix/kiwixmobile/core/downloader/downloadManager/FetchDownloadNotificationManager.kt
index e4da6d4b8..073078480 100644
--- a/core/src/main/java/org/kiwix/kiwixmobile/core/downloader/downloadManager/FetchDownloadNotificationManager.kt
+++ b/core/src/main/java/org/kiwix/kiwixmobile/core/downloader/downloadManager/FetchDownloadNotificationManager.kt
@@ -181,6 +181,28 @@ class FetchDownloadNotificationManager @Inject constructor(
       else -> notificationBuilder.setTimeoutAfter(DEFAULT_NOTIFICATION_TIMEOUT_AFTER_RESET)
     }
     notificationCustomisation(downloadNotification, notificationBuilder, context)
+    // Remove the already shown notification if any, because fetch now pushes a
+    // download complete notification.
+    removeNotificationIfAlreadyShowingForCompletedDownload(downloadNotification)
+  }
+
+  /**
+   * We are adding 33 to the groupId (which is the download ID) because the download
+   * complete notification is shown by DownloadMonitorService. If the application resumes
+   * just before the download completes, Fetch in the application might also push a
+   * download complete notification.
+   *
+   * To avoid duplicate notifications, we clear the previous notification if it is already shown.
+   * See #4237 for more information.
+   *
+   * @see DownloadMonitorService.showDownloadCompletedNotification
+   */
+  private fun removeNotificationIfAlreadyShowingForCompletedDownload(
+    downloadNotification: DownloadNotification
+  ) {
+    if (downloadNotification.isCompleted) {
+      downloadNotificationManager.cancel(downloadNotification.groupId + THIRTY_TREE)
+    }
   }
 
   @SuppressLint("UnspecifiedImmutableFlag")