1 /*
2  * Copyright (C) 2019 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License
15  */
16 
17 package com.android.settingslib.fuelgauge
18 
19 import android.content.Context
20 import android.provider.Settings
21 import java.time.Duration
22 import java.time.Instant
23 
24 const val AVERAGE_TIME_TO_DISCHARGE_UNKNOWN = -1
25 const val ESTIMATE_MILLIS_UNKNOWN = -1
26 
27 class Estimate(
28     val estimateMillis: Long,
29     val isBasedOnUsage: Boolean,
30     val averageDischargeTime: Long
31 ) {
32     companion object {
33         /**
34          * Returns the cached estimate if it is available and fresh. Will return null if estimate is
35          * unavailable or older than 2 minutes.
36          *
37          * @param context A valid context
38          * @return An [Estimate] object with the latest battery estimates.
39          */
40         @JvmStatic
getCachedEstimateIfAvailablenull41         fun getCachedEstimateIfAvailable(context: Context): Estimate? {
42             // if time > 2 min return null or the estimate otherwise
43             val resolver = context.contentResolver
44             val lastUpdateTime = Instant.ofEpochMilli(
45                     Settings.Global.getLong(
46                             resolver, Settings.Global.BATTERY_ESTIMATES_LAST_UPDATE_TIME, -1))
47             return if (Duration.between(lastUpdateTime,
48                             Instant.now()).compareTo(Duration.ofMinutes(1)) > 0) {
49                 null
50             } else Estimate(
51                     Settings.Global.getLong(resolver,
52                             Settings.Global.TIME_REMAINING_ESTIMATE_MILLIS,
53                             ESTIMATE_MILLIS_UNKNOWN.toLong()),
54                     Settings.Global.getInt(resolver,
55                             Settings.Global.TIME_REMAINING_ESTIMATE_BASED_ON_USAGE, 0) == 1,
56                     Settings.Global.getLong(resolver, Settings.Global.AVERAGE_TIME_TO_DISCHARGE,
57                             AVERAGE_TIME_TO_DISCHARGE_UNKNOWN.toLong()))
58         }
59 
60         /**
61          * Stores an estimate to the cache along with a timestamp. Can be obtained via
62          * [.getCachedEstimateIfAvailable].
63          *
64          * @param context A valid context
65          * @param estimate the [Estimate] object to store
66          */
67         @JvmStatic
storeCachedEstimatenull68         fun storeCachedEstimate(context: Context, estimate: Estimate) {
69             // store the estimate and update the timestamp
70             val resolver = context.contentResolver
71             Settings.Global.putLong(resolver, Settings.Global.TIME_REMAINING_ESTIMATE_MILLIS,
72                     estimate.estimateMillis)
73             Settings.Global.putInt(resolver, Settings.Global.TIME_REMAINING_ESTIMATE_BASED_ON_USAGE,
74                     if (estimate.isBasedOnUsage) 1 else 0)
75             Settings.Global.putLong(resolver, Settings.Global.AVERAGE_TIME_TO_DISCHARGE,
76                     estimate.averageDischargeTime)
77             Settings.Global.putLong(resolver, Settings.Global.BATTERY_ESTIMATES_LAST_UPDATE_TIME,
78                     System.currentTimeMillis())
79         }
80 
81         /**
82          * Returns when the estimate was last updated as an Instant
83          */
84         @JvmStatic
getLastCacheUpdateTimenull85         fun getLastCacheUpdateTime(context: Context): Instant {
86             return Instant.ofEpochMilli(
87                     Settings.Global.getLong(
88                             context.contentResolver,
89                             Settings.Global.BATTERY_ESTIMATES_LAST_UPDATE_TIME,
90                             -1))
91         }
92     }
93 }
94