Revert^4 "Removing all restored backups except one so we don't have old backups"

To prevent the error I introduce the method restorePreviousState().

This reverts commit 1234090589be2f8b99284737be23113c19fd0239.

Reason for revert: Fixing presubmit breaks

Bug: 325285743
Flag:  ACONFIG narrow_grid_restore disabled
Test: BackupAndRestoreDBSelectionTest
Change-Id: I63666c29eb91dada4243af019ab0538c40bc0f78
diff --git a/src/com/android/launcher3/InvariantDeviceProfile.java b/src/com/android/launcher3/InvariantDeviceProfile.java
index 42d4d50..2e0f676 100644
--- a/src/com/android/launcher3/InvariantDeviceProfile.java
+++ b/src/com/android/launcher3/InvariantDeviceProfile.java
@@ -72,6 +72,7 @@
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
+import java.util.Objects;
 import java.util.stream.Collectors;
 
 public class InvariantDeviceProfile {
@@ -578,6 +579,45 @@
     }
 
     /**
+     * Returns the GridOption associated to the given file name or null if the fileName is not
+     * supported.
+     * Ej, launcher.db -> "normal grid", launcher_4_by_4.db -> "practical grid"
+     */
+    public GridOption getGridOptionFromFileName(Context context, String fileName) {
+        return parseAllGridOptions(context).stream()
+                .filter(gridOption -> Objects.equals(gridOption.dbFile, fileName))
+                .findFirst()
+                .orElse(null);
+    }
+
+    /**
+     * Returns the name of the given size on the current device or empty string if the size is not
+     * supported. Ej. 4x4 -> normal, 5x4 -> practical, etc.
+     * (Note: the name of the grid can be different for the same grid size depending of
+     * the values of the InvariantDeviceProfile)
+     *
+     */
+    public String getGridNameFromSize(Context context, Point size) {
+        return parseAllGridOptions(context).stream()
+                .filter(gridOption -> gridOption.numColumns == size.x
+                        && gridOption.numRows == size.y)
+                .map(gridOption -> gridOption.name)
+                .findFirst()
+                .orElse("");
+    }
+
+    /**
+     * Returns the grid option for the given gridName on the current device (Note: the gridOption
+     * be different for the same gridName depending on the values of the InvariantDeviceProfile).
+     */
+    public GridOption getGridOptionFromName(Context context, String gridName) {
+        return parseAllGridOptions(context).stream()
+                .filter(gridOption -> Objects.equals(gridOption.name, gridName))
+                .findFirst()
+                .orElse(null);
+    }
+
+    /**
      * @return all the grid options that can be shown on the device
      */
     public List<GridOption> parseAllGridOptions(Context context) {
diff --git a/src/com/android/launcher3/provider/RestoreDbTask.java b/src/com/android/launcher3/provider/RestoreDbTask.java
index 22bc13b..f2b7d18 100644
--- a/src/com/android/launcher3/provider/RestoreDbTask.java
+++ b/src/com/android/launcher3/provider/RestoreDbTask.java
@@ -50,8 +50,10 @@
 import androidx.annotation.VisibleForTesting;
 import androidx.annotation.WorkerThread;
 
+import com.android.launcher3.Flags;
 import com.android.launcher3.InvariantDeviceProfile;
 import com.android.launcher3.LauncherAppState;
+import com.android.launcher3.LauncherFiles;
 import com.android.launcher3.LauncherPrefs;
 import com.android.launcher3.LauncherSettings;
 import com.android.launcher3.LauncherSettings.Favorites;
@@ -121,7 +123,48 @@
         // executed again.
         LauncherPrefs.get(context).removeSync(RESTORE_DEVICE);
 
-        idp.reinitializeAfterRestore(context);
+        if (Flags.narrowGridRestore()) {
+            String oldPhoneFileName = idp.dbFile;
+            removeOldDBs(context, oldPhoneFileName);
+            trySettingPreviousGidAsCurrent(context, idp, oldPhoneFileName);
+        } else {
+            idp.reinitializeAfterRestore(context);
+        }
+    }
+
+    /**
+     * Try setting the gird used in the previous phone to the new one. If the current device doesn't
+     * support the previous grid option it will not be set.
+     */
+    private static void trySettingPreviousGidAsCurrent(Context context, InvariantDeviceProfile idp,
+            String oldPhoneDbFileName) {
+        InvariantDeviceProfile.GridOption gridOption = idp.getGridOptionFromFileName(context,
+                oldPhoneDbFileName);
+        if (gridOption != null) {
+            /*
+             * We do this because in some cases different devices have different names for grid
+             * options, in one device the grid option "normal" can be 4x4 while in other it
+             * could be "practical". Calling this changes the current device grid to the same
+             * we had in the other phone, in the case the current phone doesn't support the grid
+             * option we use the default and migrate the db to the default. Migration occurs on
+             * {@code GridSizeMigrationUtil#migrateGridIfNeeded}
+             */
+            idp.setCurrentGrid(context, gridOption.name);
+        }
+    }
+
+    /**
+     * Only keep the last database used on the previous device.
+     */
+    private static void removeOldDBs(Context context, String oldPhoneDbFileName) {
+        // At this point idp.dbFile contains the name of the dbFile from the previous phone
+        LauncherFiles.GRID_DB_FILES.stream()
+                .filter(dbName -> !dbName.equals(oldPhoneDbFileName))
+                .forEach(dbName -> {
+                    if (context.getDatabasePath(dbName).delete()) {
+                        FileLog.d(TAG, "Removed old grid db file: " + dbName);
+                    }
+                });
     }
 
     private static boolean performRestore(Context context, ModelDbController controller) {