/*
 * 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.voicemail.impl;

import android.content.Context;
import android.os.Bundle;
import android.support.annotation.VisibleForTesting;
import android.support.annotation.WorkerThread;
import android.telecom.PhoneAccountHandle;
import android.telephony.TelephonyManager;
import android.text.TextUtils;
import com.android.voicemail.VoicemailComponent;
import com.android.voicemail.impl.settings.VisualVoicemailSettingsUtil;
import java.lang.reflect.Method;

/** Handles migration of data from the visual voicemail client in telephony before O. */
public final class PreOMigrationHandler {

  // Hidden system APIs to access pre O VVM data
  // Bundle getVisualVoicemailSettings()
  private static final String METHOD_GET_VISUAL_VOICEMAIL_SETTINGS = "getVisualVoicemailSettings";

  /**
   * Key in bundle returned by {@link #METHOD_GET_VISUAL_VOICEMAIL_SETTINGS}, indicating whether
   * visual voicemail was enabled or disabled by the user. If the user never explicitly changed this
   * setting, this key will not exist.
   */
  private static final String EXTRA_VISUAL_VOICEMAIL_ENABLED_BY_USER_BOOL =
      "android.telephony.extra.VISUAL_VOICEMAIL_ENABLED_BY_USER_BOOL";

  /**
   * Key in bundle returned by {@link #METHOD_GET_VISUAL_VOICEMAIL_SETTINGS}, indicating the
   * voicemail access PIN scrambled during the auto provisioning process. The user is expected to
   * reset their PIN if this value is not {@code null}.
   */
  private static final String EXTRA_VOICEMAIL_SCRAMBLED_PIN_STRING =
      "android.telephony.extra.VOICEMAIL_SCRAMBLED_PIN_STRING";

  @VisibleForTesting static final String PRE_O_MIGRATION_FINISHED = "pre_o_migration_finished";

  @WorkerThread
  public static void migrate(Context context, PhoneAccountHandle phoneAccountHandle) {
    Assert.isNotMainThread();
    VisualVoicemailPreferences preferences =
        new VisualVoicemailPreferences(context, phoneAccountHandle);
    if (preferences.getBoolean(PRE_O_MIGRATION_FINISHED, false)) {
      VvmLog.i("PreOMigrationHandler", phoneAccountHandle + " already migrated");
      return;
    }
    VvmLog.i("PreOMigrationHandler", "migrating " + phoneAccountHandle);
    migrateSettings(context, phoneAccountHandle);

    preferences.edit().putBoolean(PRE_O_MIGRATION_FINISHED, true).apply();
  }

  private static void migrateSettings(Context context, PhoneAccountHandle phoneAccountHandle) {
    VvmLog.i("PreOMigrationHandler.migrateSettings", "migrating settings");
    TelephonyManager telephonyManager =
        context
            .getSystemService(TelephonyManager.class)
            .createForPhoneAccountHandle(phoneAccountHandle);
    if (telephonyManager == null) {
      VvmLog.e("PreOMigrationHandler.migrateSettings", "invalid PhoneAccountHandle");
      return;
    }
    Bundle legacySettings;
    try {
      Method method = TelephonyManager.class.getMethod(METHOD_GET_VISUAL_VOICEMAIL_SETTINGS);
      legacySettings = (Bundle) method.invoke(telephonyManager);
    } catch (ReflectiveOperationException | ClassCastException e) {
      VvmLog.i("PreOMigrationHandler.migrateSettings", "unable to retrieve settings from system");
      return;
    }

    if (legacySettings.containsKey(EXTRA_VISUAL_VOICEMAIL_ENABLED_BY_USER_BOOL)) {
      boolean enabled = legacySettings.getBoolean(EXTRA_VISUAL_VOICEMAIL_ENABLED_BY_USER_BOOL);
      VvmLog.i("PreOMigrationHandler.migrateSettings", "setting VVM enabled to " + enabled);
      VisualVoicemailSettingsUtil.setEnabled(context, phoneAccountHandle, enabled);
    }

    if (legacySettings.containsKey(EXTRA_VOICEMAIL_SCRAMBLED_PIN_STRING)) {
      String scrambledPin = legacySettings.getString(EXTRA_VOICEMAIL_SCRAMBLED_PIN_STRING);
      if (!TextUtils.isEmpty(scrambledPin)) {
        VvmLog.i("PreOMigrationHandler.migrateSettings", "migrating scrambled PIN");
        VoicemailComponent.get(context)
            .getVoicemailClient()
            .createPinChanger(context, phoneAccountHandle)
            .setScrambledPin(scrambledPin);
      }
    }
  }
}