michael@0: /* -*- Mode: Java; c-basic-offset: 4; tab-width: 4; indent-tabs-mode: nil; -*-
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: package org.mozilla.gecko;
michael@0: 
michael@0: import android.content.BroadcastReceiver;
michael@0: import android.content.Context;
michael@0: import android.content.Intent;
michael@0: import android.content.IntentFilter;
michael@0: import android.os.BatteryManager;
michael@0: import android.os.Build;
michael@0: import android.os.SystemClock;
michael@0: import android.util.Log;
michael@0: 
michael@0: public class GeckoBatteryManager extends BroadcastReceiver {
michael@0:     private static final String LOGTAG = "GeckoBatteryManager";
michael@0: 
michael@0:     // Those constants should be keep in sync with the ones in:
michael@0:     // dom/battery/Constants.h
michael@0:     private final static double  kDefaultLevel         = 1.0;
michael@0:     private final static boolean kDefaultCharging      = true;
michael@0:     private final static double  kDefaultRemainingTime = 0.0;
michael@0:     private final static double  kUnknownRemainingTime = -1.0;
michael@0: 
michael@0:     private static long    sLastLevelChange            = 0;
michael@0:     private static boolean sNotificationsEnabled       = false;
michael@0:     private static double  sLevel                      = kDefaultLevel;
michael@0:     private static boolean sCharging                   = kDefaultCharging;
michael@0:     private static double  sRemainingTime              = kDefaultRemainingTime;
michael@0: 
michael@0:     private static GeckoBatteryManager sInstance = new GeckoBatteryManager();
michael@0: 
michael@0:     private final IntentFilter mFilter;
michael@0:     private Context mApplicationContext;
michael@0:     private boolean mIsEnabled;
michael@0: 
michael@0:     public static GeckoBatteryManager getInstance() {
michael@0:         return sInstance;
michael@0:     }
michael@0: 
michael@0:     private GeckoBatteryManager() {
michael@0:         mFilter = new IntentFilter();
michael@0:         mFilter.addAction(Intent.ACTION_BATTERY_CHANGED);
michael@0:     }
michael@0: 
michael@0:     public synchronized void start(final Context context) {
michael@0:         if (mIsEnabled) {
michael@0:             Log.w(LOGTAG, "Already started!");
michael@0:             return;
michael@0:         }
michael@0: 
michael@0:         mApplicationContext = context.getApplicationContext();
michael@0:         // registerReceiver will return null if registering fails.
michael@0:         if (mApplicationContext.registerReceiver(this, mFilter) == null) {
michael@0:             Log.e(LOGTAG, "Registering receiver failed");
michael@0:         } else {
michael@0:             mIsEnabled = true;
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     public synchronized void stop() {
michael@0:         if (!mIsEnabled) {
michael@0:             Log.w(LOGTAG, "Already stopped!");
michael@0:             return;
michael@0:         }
michael@0: 
michael@0:         mApplicationContext.unregisterReceiver(this);
michael@0:         mApplicationContext = null;
michael@0:         mIsEnabled = false;
michael@0:     }
michael@0: 
michael@0:     @Override
michael@0:     public void onReceive(Context context, Intent intent) {
michael@0:         if (!intent.getAction().equals(Intent.ACTION_BATTERY_CHANGED)) {
michael@0:             Log.e(LOGTAG, "Got an unexpected intent!");
michael@0:             return;
michael@0:         }
michael@0: 
michael@0:         boolean previousCharging = isCharging();
michael@0:         double previousLevel = getLevel();
michael@0: 
michael@0:         // NOTE: it might not be common (in 2012) but technically, Android can run
michael@0:         // on a device that has no battery so we want to make sure it's not the case
michael@0:         // before bothering checking for battery state.
michael@0:         // However, the Galaxy Nexus phone advertizes itself as battery-less which
michael@0:         // force us to special-case the logic.
michael@0:         // See the Google bug: https://code.google.com/p/android/issues/detail?id=22035
michael@0:         if (intent.getBooleanExtra(BatteryManager.EXTRA_PRESENT, false) ||
michael@0:                 Build.MODEL.equals("Galaxy Nexus")) {
michael@0:             int plugged = intent.getIntExtra(BatteryManager.EXTRA_PLUGGED, -1);
michael@0:             if (plugged == -1) {
michael@0:                 sCharging = kDefaultCharging;
michael@0:                 Log.e(LOGTAG, "Failed to get the plugged status!");
michael@0:             } else {
michael@0:                 // Likely, if plugged > 0, it's likely plugged and charging but the doc
michael@0:                 // isn't clear about that.
michael@0:                 sCharging = plugged != 0;
michael@0:             }
michael@0: 
michael@0:             if (sCharging != previousCharging) {
michael@0:                 sRemainingTime = kUnknownRemainingTime;
michael@0:                 // The new remaining time is going to take some time to show up but
michael@0:                 // it's the best way to show a not too wrong value.
michael@0:                 sLastLevelChange = 0;
michael@0:             }
michael@0: 
michael@0:             // We need two doubles because sLevel is a double.
michael@0:             double current =  (double)intent.getIntExtra(BatteryManager.EXTRA_LEVEL, -1);
michael@0:             double max = (double)intent.getIntExtra(BatteryManager.EXTRA_SCALE, -1);
michael@0:             if (current == -1 || max == -1) {
michael@0:                 Log.e(LOGTAG, "Failed to get battery level!");
michael@0:                 sLevel = kDefaultLevel;
michael@0:             } else {
michael@0:                 sLevel = current / max;
michael@0:             }
michael@0: 
michael@0:             if (sLevel == 1.0 && sCharging) {
michael@0:                 sRemainingTime = kDefaultRemainingTime;
michael@0:             } else if (sLevel != previousLevel) {
michael@0:                 // Estimate remaining time.
michael@0:                 if (sLastLevelChange != 0) {
michael@0:                     // Use elapsedRealtime() because we want to track time across device sleeps.
michael@0:                     long currentTime = SystemClock.elapsedRealtime();
michael@0:                     long dt = (currentTime - sLastLevelChange) / 1000;
michael@0:                     double dLevel = sLevel - previousLevel;
michael@0: 
michael@0:                     if (sCharging) {
michael@0:                         if (dLevel < 0) {
michael@0:                             Log.w(LOGTAG, "When charging, level should increase!");
michael@0:                             sRemainingTime = kUnknownRemainingTime;
michael@0:                         } else {
michael@0:                             sRemainingTime = Math.round(dt / dLevel * (1.0 - sLevel));
michael@0:                         }
michael@0:                     } else {
michael@0:                         if (dLevel > 0) {
michael@0:                             Log.w(LOGTAG, "When discharging, level should decrease!");
michael@0:                             sRemainingTime = kUnknownRemainingTime;
michael@0:                         } else {
michael@0:                             sRemainingTime = Math.round(dt / -dLevel * sLevel);
michael@0:                         }
michael@0:                     }
michael@0: 
michael@0:                     sLastLevelChange = currentTime;
michael@0:                 } else {
michael@0:                     // That's the first time we got an update, we can't do anything.
michael@0:                     sLastLevelChange = SystemClock.elapsedRealtime();
michael@0:                 }
michael@0:             }
michael@0:         } else {
michael@0:             sLevel = kDefaultLevel;
michael@0:             sCharging = kDefaultCharging;
michael@0:             sRemainingTime = kDefaultRemainingTime;
michael@0:         }
michael@0: 
michael@0:         /*
michael@0:          * We want to inform listeners if the following conditions are fulfilled:
michael@0:          *  - we have at least one observer;
michael@0:          *  - the charging state or the level has changed.
michael@0:          *
michael@0:          * Note: no need to check for a remaining time change given that it's only
michael@0:          * updated if there is a level change or a charging change.
michael@0:          *
michael@0:          * The idea is to prevent doing all the way to the DOM code in the child
michael@0:          * process to finally not send an event.
michael@0:          */
michael@0:         if (sNotificationsEnabled &&
michael@0:                 (previousCharging != isCharging() || previousLevel != getLevel())) {
michael@0:             GeckoAppShell.notifyBatteryChange(getLevel(), isCharging(), getRemainingTime());
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     public static boolean isCharging() {
michael@0:         return sCharging;
michael@0:     }
michael@0: 
michael@0:     public static double getLevel() {
michael@0:         return sLevel;
michael@0:     }
michael@0: 
michael@0:     public static double getRemainingTime() {
michael@0:         return sRemainingTime;
michael@0:     }
michael@0: 
michael@0:     public static void enableNotifications() {
michael@0:         sNotificationsEnabled = true;
michael@0:     }
michael@0: 
michael@0:     public static void disableNotifications() {
michael@0:         sNotificationsEnabled = false;
michael@0:     }
michael@0: 
michael@0:     public static double[] getCurrentInformation() {
michael@0:         return new double[] { getLevel(), isCharging() ? 1.0 : 0.0, getRemainingTime() };
michael@0:     }
michael@0: }