/*
 * Copyright (C) 2016 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.voicemailstatus;

import android.content.Context;
import android.content.SharedPreferences;
import android.database.Cursor;
import android.preference.PreferenceManager;
import android.support.annotation.Nullable;
import com.android.dialer.database.CallLogQueryHandler;

/**
 * Helper class to check whether visual voicemail is enabled.
 *
 * <p>Call isVisualVoicemailEnabled() to retrieve the result.
 *
 * <p>The result is cached and saved in a SharedPreferences, stored as a boolean in
 * PREF_KEY_HAS_ACTIVE_VOICEMAIL_PROVIDER. Every time a new instance is created, it will try to
 * restore the cached result from the SharedPreferences.
 *
 * <p>Call asyncUpdate() to make a CallLogQuery to check the actual status. This is a async call so
 * isVisualVoicemailEnabled() will not be affected immediately.
 *
 * <p>If the status has changed as a result of asyncUpdate(),
 * Callback.onVisualVoicemailEnabledStatusChanged() will be called with the new value.
 */
public class VisualVoicemailEnabledChecker implements CallLogQueryHandler.Listener {

  public static final String PREF_KEY_HAS_ACTIVE_VOICEMAIL_PROVIDER =
      "has_active_voicemail_provider";
  private SharedPreferences mPrefs;
  private boolean mHasActiveVoicemailProvider;
  private CallLogQueryHandler mCallLogQueryHandler;
  private Context mContext;
  private Callback mCallback;

  public VisualVoicemailEnabledChecker(Context context, @Nullable Callback callback) {
    mContext = context;
    mCallback = callback;
    mPrefs = PreferenceManager.getDefaultSharedPreferences(mContext);
    mHasActiveVoicemailProvider = mPrefs.getBoolean(PREF_KEY_HAS_ACTIVE_VOICEMAIL_PROVIDER, false);
  }

  /**
   * @return whether visual voicemail is enabled. Result is cached, call asyncUpdate() to update the
   *     result.
   */
  public boolean isVisualVoicemailEnabled() {
    return mHasActiveVoicemailProvider;
  }

  /**
   * Perform an async query into the system to check the status of visual voicemail. If the status
   * has changed, Callback.onVisualVoicemailEnabledStatusChanged() will be called.
   */
  public void asyncUpdate() {
    mCallLogQueryHandler = new CallLogQueryHandler(mContext, mContext.getContentResolver(), this);
    mCallLogQueryHandler.fetchVoicemailStatus();
  }

  @Override
  public void onVoicemailStatusFetched(Cursor statusCursor) {
    boolean hasActiveVoicemailProvider =
        VoicemailStatusHelper.getNumberActivityVoicemailSources(statusCursor) > 0;
    if (hasActiveVoicemailProvider != mHasActiveVoicemailProvider) {
      mHasActiveVoicemailProvider = hasActiveVoicemailProvider;
      mPrefs
          .edit()
          .putBoolean(PREF_KEY_HAS_ACTIVE_VOICEMAIL_PROVIDER, mHasActiveVoicemailProvider)
          .apply();
      if (mCallback != null) {
        mCallback.onVisualVoicemailEnabledStatusChanged(mHasActiveVoicemailProvider);
      }
    }
  }

  @Override
  public void onVoicemailUnreadCountFetched(Cursor cursor) {
    // Do nothing
  }

  @Override
  public void onMissedCallsUnreadCountFetched(Cursor cursor) {
    // Do nothing
  }

  @Override
  public boolean onCallsFetched(Cursor combinedCursor) {
    // Do nothing
    return false;
  }

  public interface Callback {

    /** Callback to notify enabled status has changed to the @param newValue */
    void onVisualVoicemailEnabledStatusChanged(boolean newValue);
  }
}