Extract the not-strictly-modes-related parts of ZenModesBackend

So that when it's moved to SettingsLib, it doesn't need to carry that baggage.

Bug: 346519570
Test: atest com.android.settings.notification.modes
Flag: android.app.modes_ui
Change-Id: I7911a521d96f5dbac2c2395171d324b7b54b8b07

src/com/android/settings/notification/modes/ZenHelperBackend.java

@@ -0,0 +1,119 @@
+/*
+ * Copyright (C) 2024 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.notification.modes;
+
+import android.annotation.Nullable;
+import android.app.INotificationManager;
+import android.content.Context;
+import android.content.pm.ParceledListSlice;
+import android.database.Cursor;
+import android.os.ServiceManager;
+import android.provider.ContactsContract;
+import android.service.notification.ConversationChannelWrapper;
+import android.util.Log;
+
+import androidx.annotation.VisibleForTesting;
+
+import com.android.settings.R;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Class used for Settings-system_server interactions that are not <em>directly</em> related to
+ * Mode management, but still used in the UI of its Settings pages (such as listing priority
+ * conversations, contacts, etc).
+ */
+class ZenHelperBackend {
+
+    private static final String TAG = "ZenHelperBackend";
+
+    @Nullable // Until first usage
+    private static ZenHelperBackend sInstance;
+
+    private final Context mContext;
+    private final INotificationManager mInm;
+
+    static ZenHelperBackend getInstance(Context context) {
+        if (sInstance == null) {
+            sInstance = new ZenHelperBackend(context.getApplicationContext());
+        }
+        return sInstance;
+    }
+
+    ZenHelperBackend(Context context) {
+        mContext = context;
+        mInm = INotificationManager.Stub.asInterface(
+                ServiceManager.getService(Context.NOTIFICATION_SERVICE));
+    }
+
+    /**
+     * Returns all of a user's packages that have at least one channel that will bypass DND
+     */
+    List<String> getPackagesBypassingDnd(int userId,
+            boolean includeConversationChannels) {
+        try {
+            return mInm.getPackagesBypassingDnd(userId, includeConversationChannels);
+        } catch (Exception e) {
+            Log.w(TAG, "Error calling NoMan", e);
+            return new ArrayList<>();
+        }
+    }
+
+    @SuppressWarnings("unchecked")
+    ParceledListSlice<ConversationChannelWrapper> getConversations(boolean onlyImportant) {
+        try {
+            return mInm.getConversations(onlyImportant);
+        } catch (Exception e) {
+            Log.w(TAG, "Error calling NoMan", e);
+            return ParceledListSlice.emptyList();
+        }
+    }
+
+    List<String> getStarredContacts() {
+        try (Cursor cursor = queryStarredContactsData()) {
+            return getStarredContacts(cursor);
+        }
+    }
+
+    @VisibleForTesting
+    List<String> getStarredContacts(Cursor cursor) {
+        List<String> starredContacts = new ArrayList<>();
+        if (cursor != null && cursor.moveToFirst()) {
+            do {
+                String contact = cursor.getString(0);
+                starredContacts.add(contact != null ? contact :
+                        mContext.getString(R.string.zen_mode_starred_contacts_empty_name));
+
+            } while (cursor.moveToNext());
+        }
+        return starredContacts;
+    }
+
+    private Cursor queryStarredContactsData() {
+        return mContext.getContentResolver().query(ContactsContract.Contacts.CONTENT_URI,
+                new String[]{ContactsContract.Contacts.DISPLAY_NAME_PRIMARY},
+                ContactsContract.Data.STARRED + "=1", null,
+                ContactsContract.Data.TIMES_CONTACTED);
+    }
+
+    Cursor queryAllContactsData() {
+        return mContext.getContentResolver().query(ContactsContract.Contacts.CONTENT_URI,
+                new String[]{ContactsContract.Contacts.DISPLAY_NAME_PRIMARY},
+                null, null, null);
+    }
+}