tubestation/mobile/android/base/tabqueue/TabQueueService.java

/* -*- Mode: Java; c-basic-offset: 4; tab-width: 4; indent-tabs-mode: nil; -*-
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

package org.mozilla.gecko.tabqueue;

import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.content.res.Resources;
import android.graphics.PixelFormat;
import android.os.Handler;
import android.os.HandlerThread;
import android.os.IBinder;
import android.util.Log;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.TextView;
import org.mozilla.gecko.BrowserApp;
import org.mozilla.gecko.GeckoProfile;
import org.mozilla.gecko.R;
import org.mozilla.gecko.mozglue.ContextUtils;


import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;


/**
 * On launch this Service displays a View over the currently running process with an action to open the url in Fennec
 * immediately.  If the user takes no action, allowing the runnable to be processed after the specified
 * timeout (TOAST_TIMEOUT), the url is added to a file which is then read in Fennec on next launch, this allows the
 * user to quickly queue urls to open without having to open Fennec each time. If the Service receives an Intent whilst
 * the created View is still active, the old url is immediately processed and the View is re-purposed with the new
 * Intent data.
 * <p/>
 * The SYSTEM_ALERT_WINDOW permission is used to allow us to insert a View from this Service which responds to user
 * interaction, whilst still allowing whatever is in the background to be seen and interacted with.
 * <p/>
 * Using an Activity to do this doesn't seem to work as there's an issue to do with the native android intent resolver
 * dialog not being hidden when the toast is shown.  Using an IntentService instead of a Service doesn't work as
 * each new Intent received kicks off the IntentService lifecycle anew which means that a new View is created each time,
 * meaning that we can't quickly queue the current data and re-purpose the View.  The asynchronous nature of the
 * IntentService is another prohibitive factor.
 * <p/>
 * General approach taken is similar to the FB chat heads functionality:
 * http://stackoverflow.com/questions/15975988/what-apis-in-android-is-facebook-using-to-create-chat-heads
 */
public class TabQueueService extends Service {
    private static final String LOGTAG = "Gecko" + TabQueueService.class.getSimpleName();

    private static final long TOAST_TIMEOUT = 3000;

    private WindowManager windowManager;
    private View toastLayout;
    private Button openNowButton;
    private Handler tabQueueHandler;
    private WindowManager.LayoutParams toastLayoutParams;
    private volatile StopServiceRunnable stopServiceRunnable;
    private HandlerThread handlerThread;
    private ExecutorService executorService;

    @Override
    public IBinder onBind(Intent intent) {
        // Not used
        return null;
    }

    @Override
    public void onCreate() {
        super.onCreate();
        executorService = Executors.newSingleThreadExecutor();

        handlerThread = new HandlerThread("TabQueueHandlerThread");
        handlerThread.start();
        tabQueueHandler = new Handler(handlerThread.getLooper());

        windowManager = (WindowManager) getSystemService(WINDOW_SERVICE);

        LayoutInflater layoutInflater = (LayoutInflater) getSystemService(LAYOUT_INFLATER_SERVICE);
        toastLayout = layoutInflater.inflate(R.layout.button_toast, null);

        final Resources resources = getResources();

        TextView messageView = (TextView) toastLayout.findViewById(R.id.toast_message);
        messageView.setText(resources.getText(R.string.tab_queue_toast_message));

        openNowButton = (Button) toastLayout.findViewById(R.id.toast_button);
        openNowButton.setText(resources.getText(R.string.tab_queue_toast_action));

        toastLayoutParams = new WindowManager.LayoutParams(
                WindowManager.LayoutParams.WRAP_CONTENT,
                WindowManager.LayoutParams.WRAP_CONTENT,
                WindowManager.LayoutParams.TYPE_PHONE,
                WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL |
                        WindowManager.LayoutParams.FLAG_WATCH_OUTSIDE_TOUCH |
                        WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE,
                PixelFormat.TRANSLUCENT);

        toastLayoutParams.gravity = Gravity.BOTTOM | Gravity.CENTER_HORIZONTAL;
    }

    @Override
    public int onStartCommand(final Intent intent, final int flags, final int startId) {
        if (stopServiceRunnable != null) {
            // If we're already displaying a toast, keep displaying it but store the previous url.
            // The open button will refer to the most recently opened link.
            tabQueueHandler.removeCallbacks(stopServiceRunnable);
            stopServiceRunnable.run(false);
        } else {
            windowManager.addView(toastLayout, toastLayoutParams);
        }

        stopServiceRunnable = new StopServiceRunnable(startId) {
            @Override
            public void onRun() {
                addURLToTabQueue(intent, TabQueueHelper.FILE_NAME);
                stopServiceRunnable = null;
            }
        };

        openNowButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(final View view) {
                tabQueueHandler.removeCallbacks(stopServiceRunnable);
                stopServiceRunnable = null;


                Intent forwardIntent = new Intent(intent);
                forwardIntent.setClass(getApplicationContext(), BrowserApp.class);
                forwardIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                startActivity(forwardIntent);

                removeView();
            }
        });

        tabQueueHandler.postDelayed(stopServiceRunnable, TOAST_TIMEOUT);

        return START_FLAG_REDELIVERY;
    }

    private void removeView() {
        windowManager.removeView(toastLayout);
    }

    private void addURLToTabQueue(final Intent intent, final String filename) {
        if (intent == null) {
            // This should never happen, but let's return silently instead of crashing if it does.
            Log.w(LOGTAG, "Error adding URL to tab queue - invalid intent passed in.");
            return;
        }
        final ContextUtils.SafeIntent safeIntent = new ContextUtils.SafeIntent(intent);
        final String intentData = safeIntent.getDataString();

        // As we're doing disk IO, let's run this stuff in a separate thread.
        executorService.submit(new Runnable() {
            @Override
            public void run() {
                Context applicationContext = getApplicationContext();
                final GeckoProfile profile = GeckoProfile.get(applicationContext);
                int tabsQueued = TabQueueHelper.queueURL(profile, intentData, filename);
                TabQueueHelper.showNotification(applicationContext, tabsQueued);
            }
        });
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        tabQueueHandler = null;
        handlerThread.quit();
    }

    /**
     * A modified Runnable which additionally removes the view from the window view hierarchy and stops the service
     * when run, unless explicitly instructed not to.
     */
    private abstract class StopServiceRunnable implements Runnable {

        private final int startId;

        public StopServiceRunnable(final int startId) {
            this.startId = startId;
        }

        public void run(final boolean shouldStopService) {
            onRun();

            if (shouldStopService) {
                removeView();
            }

            stopSelfResult(startId);
        }

        public void run() {
            run(true);
        }

        public abstract void onRun();
    }
}