1 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "chrome/browser/chromeos/low_battery_observer.h"
6
7 #include "base/utf_string_conversions.h"
8 #include "chrome/common/time_format.h"
9 #include "grit/generated_resources.h"
10 #include "grit/theme_resources.h"
11 #include "ui/base/l10n/l10n_util.h"
12
13 namespace chromeos {
14
LowBatteryObserver(Profile * profile)15 LowBatteryObserver::LowBatteryObserver(Profile* profile)
16 : notification_(profile, "battery.chromeos",
17 IDR_NOTIFICATION_LOW_BATTERY,
18 l10n_util::GetStringUTF16(IDS_LOW_BATTERY_TITLE)),
19 remaining_(0) {}
20
~LowBatteryObserver()21 LowBatteryObserver::~LowBatteryObserver() {
22 Hide();
23 }
24
PowerChanged(PowerLibrary * object)25 void LowBatteryObserver::PowerChanged(PowerLibrary* object) {
26 const int limit_min = 15; // Notification will show when remaining number
27 // of minutes is <= limit.
28 const int limit_max = 30; // Notification will hid when remaining number
29 // of minutes is > limit_max.
30 const int critical = 5; // Notification will be forced visible if hidden
31 // by user when time remaining <= critical.
32
33 base::TimeDelta remaining = object->battery_time_to_empty();
34 int remaining_minutes = remaining.InMinutes();
35
36 // To simplify the logic - we handle the case of calculating the remaining
37 // time as if we were on line power.
38 // remaining time of zero means still calculating, this is denoted by
39 // base::TimeDelta().
40 bool line_power = object->line_power_on() || remaining == base::TimeDelta();
41
42 // The urgent flag is used to re-notify the user if the power level
43 // goes critical. We only want to do this once even if the time remaining
44 // goes back up (so long as it doesn't go above limit_max.
45 bool urgent = !line_power &&
46 (notification_.urgent() || remaining_minutes <= critical);
47
48 // This is a simple state machine with two states and three edges:
49 // States: visible_, !visible_
50 // Edges: hide: is visible_ to !visible_ triggered if we transition
51 // to line_power, we're calculating our time remaining,
52 // or our time remaining has climbed higher than
53 // limit_max (either by reduced user an undetected transition
54 // to/from line_power).
55 // update: is visible_ to _visible triggered when we didn't hide
56 // and the minutes remaining changed from what's shown.
57 // show: is !visible_ to visible_ triggered when we're on battery,
58 // we know the remaining time, and that time is less than limit.
59
60 if (notification_.visible()) {
61 if (line_power || remaining_minutes > limit_max) {
62 Hide();
63 } else if (remaining_minutes != remaining_) {
64 Show(remaining, urgent);
65 }
66 } else {
67 if (!line_power && remaining_minutes <= limit_min) {
68 Show(remaining, urgent);
69 }
70 }
71 }
72
Show(base::TimeDelta remaining,bool urgent)73 void LowBatteryObserver::Show(base::TimeDelta remaining, bool urgent) {
74 notification_.Show(l10n_util::GetStringFUTF16(IDS_LOW_BATTERY_MESSAGE,
75 TimeFormat::TimeRemaining(remaining)), urgent, true);
76 remaining_ = remaining.InMinutes();
77 }
78
Hide()79 void LowBatteryObserver::Hide() {
80 notification_.Hide();
81 }
82
83 } // namespace chromeos
84