/*
 * Copyright 2016 Victor Albertos
 *
 * 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 rx_fcm.internal;


import android.app.Activity;
import android.app.Application;
import android.os.Bundle;
import android.support.annotation.Nullable;

class ActivitiesLifecycleCallbacks {
    final Application application;
    volatile Activity liveActivityOrNull;
    Application.ActivityLifecycleCallbacks activityLifecycleCallbacks;

    public ActivitiesLifecycleCallbacks(Application application) {
        this.application = application;
        registerActivityLifeCycle();
    }

    private void registerActivityLifeCycle() {
        if (activityLifecycleCallbacks != null) application.unregisterActivityLifecycleCallbacks(activityLifecycleCallbacks);

        activityLifecycleCallbacks = new Application.ActivityLifecycleCallbacks() {
            @Override public void onActivityCreated(Activity activity, Bundle savedInstanceState) {
                liveActivityOrNull = activity;
            }

            @Override public void onActivityStarted(Activity activity) {}

            @Override public void onActivityResumed(Activity activity) {
                liveActivityOrNull = activity;
            }

            @Override public void onActivityPaused(Activity activity) {
                liveActivityOrNull = null;
            }

            @Override public void onActivityStopped(Activity activity) {}

            @Override public void onActivitySaveInstanceState(Activity activity, Bundle outState) {}

            @Override public void onActivityDestroyed(Activity activity) {}
        };

        application.registerActivityLifecycleCallbacks(activityLifecycleCallbacks);
    }

    @Nullable public Activity getLiveActivityOrNull() {
        return liveActivityOrNull;
    }

    boolean isAppOnBackground() {
        return getLiveActivityOrNull() == null;
    }

    Application getApplication() {
        return application;
    }
}
