/*
 * Copyright (C) 2017 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.dialer.notification;

import android.annotation.TargetApi;
import android.app.NotificationChannel;
import android.app.NotificationManager;
import android.content.Context;
import android.media.AudioAttributes;
import android.os.Build.VERSION_CODES;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.os.BuildCompat;
import android.telecom.PhoneAccountHandle;
import android.util.ArraySet;
import com.android.dialer.common.Assert;
import com.android.dialer.common.LogUtil;
import java.util.Set;

/** Creates all notification channels for Dialer. */
@TargetApi(VERSION_CODES.O)
public final class NotificationChannelManager {

  /**
   * Creates all the notification channels Dialer will need. This method is called at app startup
   * and must be fast. Currently it takes between 3 to 7 milliseconds on a Pixel XL.
   *
   * <p>An alternative approach would be to lazily create channels when we actualy post a
   * notification. The advatange to precreating channels is that:
   *
   * <ul>
   *   <li>channels will be available to user right away. For example, users can customize voicemail
   *       sounds when they first get their device without waiting for a voicemail to arrive first.
   *   <li>code that posts a notification can be simpler
   *   <li>channel management code is simpler and it's easier to ensure that the correct set of
   *       channels are visible.
   *       <ul>
   */
  public static void initChannels(@NonNull Context context) {
    Assert.checkArgument(BuildCompat.isAtLeastO());
    Assert.isNotNull(context);

    NotificationManager notificationManager = context.getSystemService(NotificationManager.class);
    Set<String> desiredChannelIds = getAllDesiredChannelIds(context);
    Set<String> existingChannelIds = getAllExistingChannelIds(context);

    if (desiredChannelIds.equals(existingChannelIds)) {
      return;
    }
    LogUtil.i(
        "NotificationChannelManager.initChannels",
        "doing an expensive initialization of all notification channels");
    LogUtil.i(
        "NotificationChannelManager.initChannels", "desired channel IDs: " + desiredChannelIds);
    LogUtil.i(
        "NotificationChannelManager.initChannels", "existing channel IDs: " + existingChannelIds);

    // Delete any old channels that we don't use any more. This is safe because if we're recreate
    // this later then any user settings will be restored. An example is SIM specific voicemail
    // channel that gets deleted when the user removes the SIM and is then restored when the user
    // re-inserts the SIM.
    for (String existingChannelId : existingChannelIds) {
      if (!desiredChannelIds.contains(existingChannelId)) {
        notificationManager.deleteNotificationChannel(existingChannelId);
      }
    }

    // Just recreate all desired channels. We won't do this often so it's ok to do this now.
    createIncomingCallChannel(context);
    createOngoingCallChannel(context);
    createMissedCallChannel(context);
    createDefaultChannel(context);
    VoicemailChannelUtils.createAllChannels(context);
  }

  @NonNull
  public static String getVoicemailChannelId(
      @NonNull Context context, @Nullable PhoneAccountHandle handle) {
    Assert.checkArgument(BuildCompat.isAtLeastO());
    Assert.isNotNull(context);
    return VoicemailChannelUtils.getChannelId(context, handle);
  }

  private static Set<String> getAllExistingChannelIds(@NonNull Context context) {
    Set<String> result = new ArraySet<>();
    NotificationManager notificationManager = context.getSystemService(NotificationManager.class);
    for (NotificationChannel channel : notificationManager.getNotificationChannels()) {
      result.add(channel.getId());
    }
    return result;
  }

  private static Set<String> getAllDesiredChannelIds(@NonNull Context context) {
    Set<String> result = new ArraySet<>();
    result.add(NotificationChannelId.INCOMING_CALL);
    result.add(NotificationChannelId.ONGOING_CALL);
    result.add(NotificationChannelId.MISSED_CALL);
    result.add(NotificationChannelId.DEFAULT);
    result.addAll(VoicemailChannelUtils.getAllChannelIds(context));
    return result;
  }

  private static void createIncomingCallChannel(@NonNull Context context) {
    NotificationChannel channel =
        new NotificationChannel(
            NotificationChannelId.INCOMING_CALL,
            context.getText(R.string.notification_channel_incoming_call),
            NotificationManager.IMPORTANCE_MAX);
    channel.setShowBadge(false);
    channel.enableLights(true);
    channel.enableVibration(false);
    channel.setSound(
        null, new AudioAttributes.Builder().setUsage(AudioAttributes.USAGE_NOTIFICATION).build());
    context.getSystemService(NotificationManager.class).createNotificationChannel(channel);
  }

  private static void createOngoingCallChannel(@NonNull Context context) {
    NotificationChannel channel =
        new NotificationChannel(
            NotificationChannelId.ONGOING_CALL,
            context.getText(R.string.notification_channel_ongoing_call),
            NotificationManager.IMPORTANCE_DEFAULT);
    channel.setShowBadge(false);
    channel.enableLights(false);
    channel.enableVibration(false);
    channel.setSound(
        null, new AudioAttributes.Builder().setUsage(AudioAttributes.USAGE_NOTIFICATION).build());
    context.getSystemService(NotificationManager.class).createNotificationChannel(channel);
  }

  private static void createMissedCallChannel(@NonNull Context context) {
    NotificationChannel channel =
        new NotificationChannel(
            NotificationChannelId.MISSED_CALL,
            context.getText(R.string.notification_channel_missed_call),
            NotificationManager.IMPORTANCE_DEFAULT);
    channel.setShowBadge(true);
    channel.enableLights(true);
    channel.enableVibration(true);
    channel.setSound(
        null, new AudioAttributes.Builder().setUsage(AudioAttributes.USAGE_NOTIFICATION).build());
    context.getSystemService(NotificationManager.class).createNotificationChannel(channel);
  }

  private static void createDefaultChannel(@NonNull Context context) {
    NotificationChannel channel =
        new NotificationChannel(
            NotificationChannelId.DEFAULT,
            context.getText(R.string.notification_channel_misc),
            NotificationManager.IMPORTANCE_DEFAULT);
    channel.setShowBadge(false);
    channel.enableLights(true);
    channel.enableVibration(true);
    context.getSystemService(NotificationManager.class).createNotificationChannel(channel);
  }

  private NotificationChannelManager() {}
}