Fixed: Play reported android.database.sqlite.SQLiteConstraintException while saving history.

* Fix: Prevent a rare `SQLiteConstraintException` that occurred when the `saveHistory()` method was called at the same time by the migration job (running on the IO thread) and the main application flow. There is very little chance of this race condition, which is why it caused only a single crash.
* Wrapped the `saveHistory()` method inside a coroutine `Mutex` to make concurrent database writes thread-safe, ensuring that only one insertion executes at a time while others wait. This prevents data loss during migration and ensures that new history entries are safely persisted in the database.

Author: MohitMaliDeveloper

core/src/main/java/org/kiwix/kiwixmobile/core/dao/HistoryRoomDao.kt

@@ -26,13 +26,17 @@ import androidx.room.TypeConverter
 import androidx.room.Update
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.sync.Mutex
+import kotlinx.coroutines.sync.withLock
 import org.kiwix.kiwixmobile.core.dao.entities.HistoryRoomEntity
 import org.kiwix.kiwixmobile.core.page.adapter.Page
 import org.kiwix.kiwixmobile.core.page.history.adapter.HistoryListItem
 import org.kiwix.kiwixmobile.core.reader.ZimReaderSource
 
 @Dao
 abstract class HistoryRoomDao : PageDao {
+  private val saveMutex = Mutex()
+
   @Query("SELECT * FROM HistoryRoomEntity ORDER BY HistoryRoomEntity.timeStamp DESC")
   abstract fun historyRoomEntity(): Flow<List<HistoryRoomEntity>>
 
@@ -65,26 +69,28 @@ abstract class HistoryRoomDao : PageDao {
   @Query("SELECT COUNT() FROM HistoryRoomEntity WHERE id = :id")
   abstract fun count(id: Int): Int
 
-  fun saveHistory(historyItem: HistoryListItem.HistoryItem) {
-    getHistoryRoomEntity(
-      historyItem.historyUrl,
-      historyItem.dateString
-    )?.let {
-      it.apply {
-        // update the existing entity
-        historyUrl = historyItem.historyUrl
-        historyTitle = historyItem.title
-        timeStamp = historyItem.timeStamp
-        dateString = historyItem.dateString
-      }
-      updateHistoryItem(it)
-    } ?: run {
-      val historyEntity = HistoryRoomEntity(historyItem)
-      if (count(historyEntity.id.toInt()) > 0) {
-        // set the default id so that room will automatically generates the database id.
-        historyEntity.id = 0
+  suspend fun saveHistory(historyItem: HistoryListItem.HistoryItem) {
+    saveMutex.withLock {
+      getHistoryRoomEntity(
+        historyItem.historyUrl,
+        historyItem.dateString
+      )?.let {
+        it.apply {
+          // update the existing entity
+          historyUrl = historyItem.historyUrl
+          historyTitle = historyItem.title
+          timeStamp = historyItem.timeStamp
+          dateString = historyItem.dateString
+        }
+        updateHistoryItem(it)
+      } ?: run {
+        val historyEntity = HistoryRoomEntity(historyItem)
+        if (count(historyEntity.id.toInt()) > 0) {
+          // set the default id so that room will automatically generates the database id.
+          historyEntity.id = 0
+        }
+        insertHistoryItem(historyEntity)
       }
-      insertHistoryItem(historyEntity)
     }
   }