[Settings] Hide subscriptions not existed within device

For non-active subscriptions, the one inserted in slot
but turned off need to be visible to the user. However,
the one un-plugged need to be invisble.

Since SubscriptionUtil#getSelectableSubscriptionInfoList() didn't cover all the cases required. Create this one to fit into the criteria required here.

Note: subscriptions with same group UUID will be displayed seperately.

Bug: 191228344
Test: local
Change-Id: Ia68c23b007164b7520456cb6c7427ca142558b59
(cherry picked from commit 75f1450bbf)
(cherry picked from commit 0726f263a8)

src/com/android/settings/network/helper/SubscriptionGrouping.java

@@ -0,0 +1,96 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.settings.network.helper;
+
+import android.os.ParcelUuid;
+
+import androidx.annotation.Keep;
+import androidx.annotation.VisibleForTesting;
+
+import com.android.settings.network.helper.SubscriptionAnnotation;
+
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.function.UnaryOperator;
+import java.util.stream.Collectors;
+
+/**
+ * A UnaryOperator for converting a list of SubscriptionAnnotation into
+ * another list of SubscriptionAnnotation based on group UUID.
+ * Only one SubscriptionAnnotation with entries with same (valid) group UUID would be kept.
+ *
+ * Here's an example when applying this operation as a finisher of SelectableSubscriptions:
+ *
+ * Callable<SubscriptionAnnotation> callable = (new SelectableSubscriptions(context, true))
+ *         .addFinisher(new SubscriptionGrouping());
+ *
+ * List<SubscriptionAnnotation> result = ExecutorService.submit(callable).get()
+ */
+public class SubscriptionGrouping
+        implements UnaryOperator<List<SubscriptionAnnotation>> {
+
+    // implementation of UnaryOperator
+    public List<SubscriptionAnnotation> apply(List<SubscriptionAnnotation> listOfSubscriptions) {
+        // group by GUID
+        Map<ParcelUuid, List<SubscriptionAnnotation>> groupedSubInfoList =
+                listOfSubscriptions.stream()
+                .filter(Objects::nonNull)
+                .collect(Collectors.groupingBy(subAnno -> getGroupUuid(subAnno)));
+
+        // select best one from subscription(s) within the same group
+        groupedSubInfoList.replaceAll((uuid, annoList) -> {
+            if ((uuid == SubscriptionAnnotation.EMPTY_UUID) || (annoList.size() <= 1)) {
+                return annoList;
+            }
+            return Collections.singletonList(selectBestFromList(annoList));
+        });
+
+        // build a stream of subscriptions
+        return groupedSubInfoList.values()
+                .stream().flatMap(List::stream).collect(Collectors.toList());
+    }
+
+    @Keep
+    @VisibleForTesting
+    protected ParcelUuid getGroupUuid(SubscriptionAnnotation subAnno) {
+        ParcelUuid groupUuid = subAnno.getGroupUuid();
+        return (groupUuid == null) ? SubscriptionAnnotation.EMPTY_UUID : groupUuid;
+    }
+
+    protected SubscriptionAnnotation selectBestFromList(List<SubscriptionAnnotation> annoList) {
+        Comparator<SubscriptionAnnotation> annoSelector = (anno1, anno2) -> {
+            if (anno1.isDisplayAllowed() != anno2.isDisplayAllowed()) {
+                return anno1.isDisplayAllowed() ? -1 : 1;
+            }
+            if (anno1.isActive() != anno2.isActive()) {
+                return anno1.isActive() ? -1 : 1;
+            }
+            if (anno1.isExisted() != anno2.isExisted()) {
+                return anno1.isExisted() ? -1 : 1;
+            }
+            return 0;
+        };
+        annoSelector = annoSelector
+                // eSIM in front of pSIM
+                .thenComparingInt(anno -> -anno.getType())
+                // subscription ID in reverse order
+                .thenComparingInt(anno -> -anno.getSubscriptionId());
+        return annoList.stream().sorted(annoSelector).findFirst().orElse(null);
+    }
+}