Merge "Add DataProcessor to process raw history map for UI."

src/com/android/settings/fuelgauge/batteryusage/BatteryLevelData.java

@@ -16,58 +16,66 @@
 
 package com.android.settings.fuelgauge.batteryusage;
 
-import android.util.Log;
-
-import com.google.common.collect.ImmutableList;
+import androidx.annotation.NonNull;
+import androidx.core.util.Preconditions;
 
 import java.util.List;
 
 /** Wraps the battery timestamp and level data used for battery usage chart. */
 public final class BatteryLevelData {
-
     /** A container for the battery timestamp and level data. */
     public static final class PeriodBatteryLevelData {
-        private static final String TAG = "PeriodBatteryLevelData";
+        // The length of mTimestamps and mLevels must be the same. mLevels[index] might be null when
+        // there is no level data for the corresponding timestamp.
+        private final List<Long> mTimestamps;
+        private final List<Integer> mLevels;
 
-        private final ImmutableList<Long> mTimestamps;
-        private final ImmutableList<Integer> mLevels;
-
-        public PeriodBatteryLevelData(List<Long> timestamps, List<Integer> levels) {
-            if (timestamps.size() != levels.size()) {
-                Log.e(TAG, "Different sizes of timestamps and levels. Timestamp: "
-                        + timestamps.size() + ", Level: " + levels.size());
-                mTimestamps = ImmutableList.of();
-                mLevels = ImmutableList.of();
-                return;
-            }
-            mTimestamps = ImmutableList.copyOf(timestamps);
-            mLevels = ImmutableList.copyOf(levels);
+        public PeriodBatteryLevelData(
+                @NonNull List<Long> timestamps, @NonNull List<Integer> levels) {
+            Preconditions.checkArgument(timestamps.size() == levels.size(),
+                    /* errorMessage= */ "Timestamp: " + timestamps.size() + ", Level: "
+                            + levels.size());
+            mTimestamps = timestamps;
+            mLevels = levels;
         }
 
-        public ImmutableList<Long> getTimestamps() {
+        public List<Long> getTimestamps() {
             return mTimestamps;
         }
 
-        public ImmutableList<Integer> getLevels() {
+        public List<Integer> getLevels() {
             return mLevels;
         }
     }
 
+    /**
+     * There could be 2 cases for the daily battery levels:
+     * 1) length is 2: The usage data is within 1 day. Only contains start and end data, such as
+     *    data of 2022-01-01 06:00 and 2022-01-01 16:00.
+     * 2) length > 2: The usage data is more than 1 days. The data should be the start, end and 0am
+     *    data of every day between the start and end, such as data of 2022-01-01 06:00,
+     *    2022-01-02 00:00, 2022-01-03 00:00 and 2022-01-03 08:00.
+     */
     private final PeriodBatteryLevelData mDailyBatteryLevels;
-    private final ImmutableList<PeriodBatteryLevelData> mHourlyBatteryLevelsPerDay;
+    // The size of hourly data must be the size of daily data - 1.
+    private final List<PeriodBatteryLevelData> mHourlyBatteryLevelsPerDay;
 
     public BatteryLevelData(
-            PeriodBatteryLevelData dailyBatteryLevels,
-            List<PeriodBatteryLevelData> hourlyBatteryLevelsPerDay) {
+            @NonNull PeriodBatteryLevelData dailyBatteryLevels,
+            @NonNull List<PeriodBatteryLevelData> hourlyBatteryLevelsPerDay) {
+        final long dailySize = dailyBatteryLevels.getTimestamps().size();
+        final long hourlySize = hourlyBatteryLevelsPerDay.size();
+        Preconditions.checkArgument(hourlySize == dailySize - 1,
+                /* errorMessage= */ "DailySize: " + dailySize + ", HourlySize: " + hourlySize);
         mDailyBatteryLevels = dailyBatteryLevels;
-        mHourlyBatteryLevelsPerDay = ImmutableList.copyOf(hourlyBatteryLevelsPerDay);
+        mHourlyBatteryLevelsPerDay = hourlyBatteryLevelsPerDay;
     }
 
     public PeriodBatteryLevelData getDailyBatteryLevels() {
         return mDailyBatteryLevels;
     }
 
-    public ImmutableList<PeriodBatteryLevelData> getHourlyBatteryLevelsPerDay() {
+    public List<PeriodBatteryLevelData> getHourlyBatteryLevelsPerDay() {
         return mHourlyBatteryLevelsPerDay;
     }
 }

src/com/android/settings/fuelgauge/batteryusage/DataProcessor.java

@@ -0,0 +1,468 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * 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 com.android.settings.fuelgauge.batteryusage;
+
+import static com.android.settings.fuelgauge.batteryusage.ConvertUtils.utcToLocalTime;
+
+import android.content.Context;
+import android.text.format.DateUtils;
+import android.util.Log;
+
+import androidx.annotation.Nullable;
+
+import com.android.internal.annotations.VisibleForTesting;
+import com.android.settingslib.fuelgauge.BatteryStatus;
+
+import java.util.ArrayList;
+import java.util.Calendar;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * A utility class to process data loaded from database and make the data easy to use for battery
+ * usage UI.
+ */
+public final class DataProcessor {
+    private static final boolean DEBUG = false;
+    private static final String TAG = "DataProcessor";
+    private static final int MIN_DAILY_DATA_SIZE = 2;
+    private static final int MIN_TIMESTAMP_DATA_SIZE = 2;
+
+    /** A fake package name to represent no BatteryEntry data. */
+    public static final String FAKE_PACKAGE_NAME = "fake_package";
+
+    private DataProcessor() {
+    }
+
+    /**
+     * @return Returns battery level data and start async task to compute battery diff usage data
+     * and load app labels + icons.
+     * Returns null if the input is invalid or not having at least 2 hours data.
+     */
+    @Nullable
+    public static BatteryLevelData getBatteryLevelData(
+            Context context,
+            @Nullable final Map<Long, Map<String, BatteryHistEntry>> batteryHistoryMap) {
+        if (batteryHistoryMap == null || batteryHistoryMap.isEmpty()) {
+            Log.d(TAG, "getBatteryLevelData() returns null");
+            return null;
+        }
+        // Process raw history map data into hourly timestamps.
+        final Map<Long, Map<String, BatteryHistEntry>> processedBatteryHistoryMap =
+                getHistoryMapWithExpectedTimestamps(context, batteryHistoryMap);
+        // Wrap and processed history map into easy-to-use format for UI rendering.
+        final BatteryLevelData batteryLevelData =
+                getLevelDataThroughProcessedHistoryMap(context, processedBatteryHistoryMap);
+
+        //TODO: Add the async task to compute diff usage data and load labels and icons.
+
+        return batteryLevelData;
+    }
+
+    /**
+     * @return Returns the processed history map which has interpolated to every hour data.
+     * The start and end timestamp must be the even hours.
+     * The keys of processed history map should contain every hour between the start and end
+     * timestamp. If there's no data in some key, the value will be the empty hashmap.
+     */
+    @VisibleForTesting
+    static Map<Long, Map<String, BatteryHistEntry>> getHistoryMapWithExpectedTimestamps(
+            Context context,
+            final Map<Long, Map<String, BatteryHistEntry>> batteryHistoryMap) {
+        final long startTime = System.currentTimeMillis();
+        final List<Long> rawTimestampList = new ArrayList<>(batteryHistoryMap.keySet());
+        final Map<Long, Map<String, BatteryHistEntry>> resultMap = new HashMap();
+        if (rawTimestampList.isEmpty()) {
+            Log.d(TAG, "empty batteryHistoryMap in getHistoryMapWithExpectedTimestamps()");
+            return resultMap;
+        }
+        Collections.sort(rawTimestampList);
+        final List<Long> expectedTimestampList = getTimestampSlots(rawTimestampList);
+        final boolean isFromFullCharge =
+                isFromFullCharge(batteryHistoryMap.get(rawTimestampList.get(0)));
+        interpolateHistory(
+                context, rawTimestampList, expectedTimestampList, isFromFullCharge,
+                batteryHistoryMap, resultMap);
+        Log.d(TAG, String.format("getHistoryMapWithExpectedTimestamps() size=%d in %d/ms",
+                resultMap.size(), (System.currentTimeMillis() - startTime)));
+        return resultMap;
+    }
+
+    @VisibleForTesting
+    @Nullable
+    static BatteryLevelData getLevelDataThroughProcessedHistoryMap(
+            Context context,
+            final Map<Long, Map<String, BatteryHistEntry>> processedBatteryHistoryMap) {
+        final List<Long> timestampList = new ArrayList<>(processedBatteryHistoryMap.keySet());
+        Collections.sort(timestampList);
+        final List<Long> dailyTimestamps = getDailyTimestamps(timestampList);
+        // There should be at least the start and end timestamps. Otherwise, return null to not show
+        // data in usage chart.
+        if (dailyTimestamps.size() < MIN_DAILY_DATA_SIZE) {
+            return null;
+        }
+
+        final List<List<Long>> hourlyTimestamps = getHourlyTimestamps(dailyTimestamps);
+        final BatteryLevelData.PeriodBatteryLevelData dailyLevelData =
+                getPeriodBatteryLevelData(context, processedBatteryHistoryMap, dailyTimestamps);
+        final List<BatteryLevelData.PeriodBatteryLevelData> hourlyLevelData =
+                getHourlyPeriodBatteryLevelData(
+                        context, processedBatteryHistoryMap, hourlyTimestamps);
+        return new BatteryLevelData(dailyLevelData, hourlyLevelData);
+    }
+
+    /**
+     * Computes expected timestamp slots for last full charge, which will return hourly timestamps
+     * between start and end two even hour values.
+     */
+    @VisibleForTesting
+    static List<Long> getTimestampSlots(final List<Long> rawTimestampList) {
+        final List<Long> timestampSlots = new ArrayList<>();
+        final int rawTimestampListSize = rawTimestampList.size();
+        // If timestamp number is smaller than 2, the following computation is not necessary.
+        if (rawTimestampListSize < MIN_TIMESTAMP_DATA_SIZE) {
+            return timestampSlots;
+        }
+        final long rawStartTimestamp = rawTimestampList.get(0);
+        final long rawEndTimestamp = rawTimestampList.get(rawTimestampListSize - 1);
+        // No matter the start is from last full charge or 6 days ago, use the nearest even hour.
+        final long startTimestamp = getNearestEvenHourTimestamp(rawStartTimestamp);
+        // Use the even hour before the raw end timestamp as the end.
+        final long endTimestamp = getLastEvenHourBeforeTimestamp(rawEndTimestamp);
+        // If the start timestamp is later or equal the end one, return the empty list.
+        if (startTimestamp >= endTimestamp) {
+            return timestampSlots;
+        }
+        for (long timestamp = startTimestamp; timestamp <= endTimestamp;
+                timestamp += DateUtils.HOUR_IN_MILLIS) {
+            timestampSlots.add(timestamp);
+        }
+        return timestampSlots;
+    }
+
+    /**
+     * Computes expected daily timestamp slots.
+     *
+     * The valid result should be composed of 3 parts:
+     * 1) start timestamp
+     * 2) every 0am timestamp (default timezone) between the start and end
+     * 3) end timestamp
+     * Otherwise, returns an empty list.
+     */
+    @VisibleForTesting
+    static List<Long> getDailyTimestamps(final List<Long> timestampList) {
+        final List<Long> dailyTimestampList = new ArrayList<>();
+        // If timestamp number is smaller than 2, the following computation is not necessary.
+        if (timestampList.size() < MIN_TIMESTAMP_DATA_SIZE) {
+            return dailyTimestampList;
+        }
+        final long startTime = timestampList.get(0);
+        final long endTime = timestampList.get(timestampList.size() - 1);
+        long nextDay = getTimestampOfNextDay(startTime);
+        dailyTimestampList.add(startTime);
+        while (nextDay < endTime) {
+            dailyTimestampList.add(nextDay);
+            nextDay += DateUtils.DAY_IN_MILLIS;
+        }
+        dailyTimestampList.add(endTime);
+        return dailyTimestampList;
+    }
+
+    @VisibleForTesting
+    static boolean isFromFullCharge(@Nullable final Map<String, BatteryHistEntry> entryList) {
+        if (entryList == null) {
+            Log.d(TAG, "entryList is nul in isFromFullCharge()");
+            return false;
+        }
+        final List<String> entryKeys = new ArrayList<>(entryList.keySet());
+        if (entryKeys.isEmpty()) {
+            Log.d(TAG, "empty entryList in isFromFullCharge()");
+            return false;
+        }
+        // The hist entries in the same timestamp should have same battery status and level.
+        // Checking the first one should be enough.
+        final BatteryHistEntry firstHistEntry = entryList.get(entryKeys.get(0));
+        return BatteryStatus.isCharged(firstHistEntry.mBatteryStatus, firstHistEntry.mBatteryLevel);
+    }
+
+    @VisibleForTesting
+    static long[] findNearestTimestamp(final List<Long> timestamps, final long target) {
+        final long[] results = new long[] {Long.MIN_VALUE, Long.MAX_VALUE};
+        // Searches the nearest lower and upper timestamp value.
+        for (long timestamp : timestamps) {
+            if (timestamp <= target && timestamp > results[0]) {
+                results[0] = timestamp;
+            }
+            if (timestamp >= target && timestamp < results[1]) {
+                results[1] = timestamp;
+            }
+        }
+        // Uses zero value to represent invalid searching result.
+        results[0] = results[0] == Long.MIN_VALUE ? 0 : results[0];
+        results[1] = results[1] == Long.MAX_VALUE ? 0 : results[1];
+        return results;
+    }
+
+    /**
+     * @return Returns the timestamp for 0am 1 day after the given timestamp based on local
+     * timezone.
+     */
+    @VisibleForTesting
+     static long getTimestampOfNextDay(long timestamp) {
+        final Calendar nextDayCalendar = Calendar.getInstance();
+        nextDayCalendar.setTimeInMillis(timestamp);
+        nextDayCalendar.add(Calendar.DAY_OF_YEAR, 1);
+        nextDayCalendar.set(Calendar.HOUR_OF_DAY, 0);
+        nextDayCalendar.set(Calendar.MINUTE, 0);
+        nextDayCalendar.set(Calendar.SECOND, 0);
+        return nextDayCalendar.getTimeInMillis();
+    }
+
+    /**
+     * Interpolates history map based on expected timestamp slots and processes the corner case when
+     * the expected start timestamp is earlier than what we have.
+     */
+    private static void interpolateHistory(
+            Context context,
+            final List<Long> rawTimestampList,
+            final List<Long> expectedTimestampSlots,
+            final boolean isFromFullCharge,
+            final Map<Long, Map<String, BatteryHistEntry>> batteryHistoryMap,
+            final Map<Long, Map<String, BatteryHistEntry>> resultMap) {
+        if (rawTimestampList.isEmpty() || expectedTimestampSlots.isEmpty()) {
+            return;
+        }
+        final long expectedStartTimestamp = expectedTimestampSlots.get(0);
+        final long rawStartTimestamp = rawTimestampList.get(0);
+        int startIndex = 0;
+        // If the expected start timestamp is full charge or earlier than what we have, use the
+        // first data of what we have directly. This should be OK because the expected start
+        // timestamp is the nearest even hour of the raw start timestamp, their time diff is no
+        // more than 1 hour.
+        if (isFromFullCharge || expectedStartTimestamp < rawStartTimestamp) {
+            startIndex = 1;
+            resultMap.put(expectedStartTimestamp, batteryHistoryMap.get(rawStartTimestamp));
+        }
+        for (int index = startIndex; index < expectedTimestampSlots.size(); index++) {
+            final long currentSlot = expectedTimestampSlots.get(index);
+            interpolateHistoryForSlot(
+                    context, currentSlot, rawTimestampList, batteryHistoryMap, resultMap);
+        }
+    }
+
+    private static void interpolateHistoryForSlot(
+            Context context,
+            final long currentSlot,
+            final List<Long> rawTimestampList,
+            final Map<Long, Map<String, BatteryHistEntry>> batteryHistoryMap,
+            final Map<Long, Map<String, BatteryHistEntry>> resultMap) {
+        final long[] nearestTimestamps = findNearestTimestamp(rawTimestampList, currentSlot);
+        final long lowerTimestamp = nearestTimestamps[0];
+        final long upperTimestamp = nearestTimestamps[1];
+        // Case 1: upper timestamp is zero since scheduler is delayed!
+        if (upperTimestamp == 0) {
+            log(context, "job scheduler is delayed", currentSlot, null);
+            resultMap.put(currentSlot, new HashMap<>());
+            return;
+        }
+        // Case 2: upper timestamp is closed to the current timestamp.
+        if ((upperTimestamp - currentSlot) < 5 * DateUtils.SECOND_IN_MILLIS) {
+            log(context, "force align into the nearest slot", currentSlot, null);
+            resultMap.put(currentSlot, batteryHistoryMap.get(upperTimestamp));
+            return;
+        }
+        // Case 3: lower timestamp is zero before starting to collect data.
+        if (lowerTimestamp == 0) {
+            log(context, "no lower timestamp slot data", currentSlot, null);
+            resultMap.put(currentSlot, new HashMap<>());
+            return;
+        }
+        interpolateHistoryForSlot(context,
+                currentSlot, lowerTimestamp, upperTimestamp, batteryHistoryMap, resultMap);
+    }
+
+    private static void interpolateHistoryForSlot(
+            Context context,
+            final long currentSlot,
+            final long lowerTimestamp,
+            final long upperTimestamp,
+            final Map<Long, Map<String, BatteryHistEntry>> batteryHistoryMap,
+            final Map<Long, Map<String, BatteryHistEntry>> resultMap) {
+        final Map<String, BatteryHistEntry> lowerEntryDataMap =
+                batteryHistoryMap.get(lowerTimestamp);
+        final Map<String, BatteryHistEntry> upperEntryDataMap =
+                batteryHistoryMap.get(upperTimestamp);
+        // Verifies whether the lower data is valid to use or not by checking boot time.
+        final BatteryHistEntry upperEntryDataFirstEntry =
+                upperEntryDataMap.values().stream().findFirst().get();
+        final long upperEntryDataBootTimestamp =
+                upperEntryDataFirstEntry.mTimestamp - upperEntryDataFirstEntry.mBootTimestamp;
+        // Lower data is captured before upper data corresponding device is booting.
+        if (lowerTimestamp < upperEntryDataBootTimestamp) {
+            // Provides an opportunity to force align the slot directly.
+            if ((upperTimestamp - currentSlot) < 10 * DateUtils.MINUTE_IN_MILLIS) {
+                log(context, "force align into the nearest slot", currentSlot, null);
+                resultMap.put(currentSlot, upperEntryDataMap);
+            } else {
+                log(context, "in the different booting section", currentSlot, null);
+                resultMap.put(currentSlot, new HashMap<>());
+            }
+            return;
+        }
+        log(context, "apply interpolation arithmetic", currentSlot, null);
+        final Map<String, BatteryHistEntry> newHistEntryMap = new HashMap<>();
+        final double timestampLength = upperTimestamp - lowerTimestamp;
+        final double timestampDiff = currentSlot - lowerTimestamp;
+        // Applies interpolation arithmetic for each BatteryHistEntry.
+        for (String entryKey : upperEntryDataMap.keySet()) {
+            final BatteryHistEntry lowerEntry = lowerEntryDataMap.get(entryKey);
+            final BatteryHistEntry upperEntry = upperEntryDataMap.get(entryKey);
+            // Checks whether there is any abnormal battery reset conditions.
+            if (lowerEntry != null) {
+                final boolean invalidForegroundUsageTime =
+                        lowerEntry.mForegroundUsageTimeInMs > upperEntry.mForegroundUsageTimeInMs;
+                final boolean invalidBackgroundUsageTime =
+                        lowerEntry.mBackgroundUsageTimeInMs > upperEntry.mBackgroundUsageTimeInMs;
+                if (invalidForegroundUsageTime || invalidBackgroundUsageTime) {
+                    newHistEntryMap.put(entryKey, upperEntry);
+                    log(context, "abnormal reset condition is found", currentSlot, upperEntry);
+                    continue;
+                }
+            }
+            final BatteryHistEntry newEntry =
+                    BatteryHistEntry.interpolate(
+                            currentSlot,
+                            upperTimestamp,
+                            /*ratio=*/ timestampDiff / timestampLength,
+                            lowerEntry,
+                            upperEntry);
+            newHistEntryMap.put(entryKey, newEntry);
+            if (lowerEntry == null) {
+                log(context, "cannot find lower entry data", currentSlot, upperEntry);
+                continue;
+            }
+        }
+        resultMap.put(currentSlot, newHistEntryMap);
+    }
+
+    /**
+     * @return Returns the nearest even hour timestamp of the given timestamp.
+     */
+    private static long getNearestEvenHourTimestamp(long rawTimestamp) {
+        // If raw hour is even, the nearest even hour should be the even hour before raw
+        // start. The hour doesn't need to change and just set the minutes and seconds to 0.
+        // Otherwise, the nearest even hour should be raw hour + 1.
+        // For example, the nearest hour of 14:30:50 should be 14:00:00. While the nearest
+        // hour of 15:30:50 should be 16:00:00.
+        return getEvenHourTimestamp(rawTimestamp, /*addHourOfDay*/ 1);
+    }
+
+    /**
+     * @return Returns the last even hour timestamp before the given timestamp.
+     */
+    private static long getLastEvenHourBeforeTimestamp(long rawTimestamp) {
+        // If raw hour is even, the hour doesn't need to change as well.
+        // Otherwise, the even hour before raw end should be raw hour - 1.
+        // For example, the even hour before 14:30:50 should be 14:00:00. While the even
+        // hour before 15:30:50 should be 14:00:00.
+        return getEvenHourTimestamp(rawTimestamp, /*addHourOfDay*/ -1);
+    }
+
+    private static long getEvenHourTimestamp(long rawTimestamp, int addHourOfDay) {
+        final Calendar evenHourCalendar = Calendar.getInstance();
+        evenHourCalendar.setTimeInMillis(rawTimestamp);
+        // Before computing the evenHourCalendar, record raw hour based on local timezone.
+        final int rawHour = evenHourCalendar.get(Calendar.HOUR_OF_DAY);
+        if (rawHour % 2 != 0) {
+            evenHourCalendar.add(Calendar.HOUR_OF_DAY, addHourOfDay);
+        }
+        evenHourCalendar.set(Calendar.MINUTE, 0);
+        evenHourCalendar.set(Calendar.SECOND, 0);
+        evenHourCalendar.set(Calendar.MILLISECOND, 0);
+        return evenHourCalendar.getTimeInMillis();
+    }
+
+    private static List<List<Long>> getHourlyTimestamps(final List<Long> dailyTimestamps) {
+        final List<List<Long>> hourlyTimestamps = new ArrayList<>();
+        if (dailyTimestamps.size() < MIN_DAILY_DATA_SIZE) {
+            return hourlyTimestamps;
+        }
+
+        for (int dailyStartIndex = 0; dailyStartIndex < dailyTimestamps.size() - 1;
+                dailyStartIndex++) {
+            long currentTimestamp = dailyTimestamps.get(dailyStartIndex);
+            final long dailyEndTimestamp = dailyTimestamps.get(dailyStartIndex + 1);
+            final List<Long> hourlyTimestampsPerDay = new ArrayList<>();
+            while (currentTimestamp <= dailyEndTimestamp) {
+                hourlyTimestampsPerDay.add(currentTimestamp);
+                currentTimestamp += 2 * DateUtils.HOUR_IN_MILLIS;
+            }
+            hourlyTimestamps.add(hourlyTimestampsPerDay);
+        }
+        return hourlyTimestamps;
+    }
+
+    private static List<BatteryLevelData.PeriodBatteryLevelData> getHourlyPeriodBatteryLevelData(
+            Context context,
+            final Map<Long, Map<String, BatteryHistEntry>> processedBatteryHistoryMap,
+            final List<List<Long>> timestamps) {
+        final List<BatteryLevelData.PeriodBatteryLevelData> levelData = new ArrayList<>();
+        timestamps.forEach(
+                timestampList -> levelData.add(
+                        getPeriodBatteryLevelData(
+                                context, processedBatteryHistoryMap, timestampList)));
+        return levelData;
+    }
+
+    private static BatteryLevelData.PeriodBatteryLevelData getPeriodBatteryLevelData(
+            Context context,
+            final Map<Long, Map<String, BatteryHistEntry>> processedBatteryHistoryMap,
+            final List<Long> timestamps) {
+        final List<Integer> levels = new ArrayList<>();
+        timestamps.forEach(
+                timestamp -> levels.add(getLevel(context, processedBatteryHistoryMap, timestamp)));
+        return new BatteryLevelData.PeriodBatteryLevelData(timestamps, levels);
+    }
+
+    private static Integer getLevel(
+            Context context,
+            final Map<Long, Map<String, BatteryHistEntry>> processedBatteryHistoryMap,
+            final long timestamp) {
+        final Map<String, BatteryHistEntry> entryMap = processedBatteryHistoryMap.get(timestamp);
+        if (entryMap == null || entryMap.isEmpty()) {
+            Log.e(TAG, "abnormal entry list in the timestamp:"
+                    + utcToLocalTime(context, timestamp));
+            return null;
+        }
+        // Averages the battery level in each time slot to avoid corner conditions.
+        float batteryLevelCounter = 0;
+        for (BatteryHistEntry entry : entryMap.values()) {
+            batteryLevelCounter += entry.mBatteryLevel;
+        }
+        return Math.round(batteryLevelCounter / entryMap.size());
+    }
+
+    private static void log(Context context, String content, long timestamp,
+            BatteryHistEntry entry) {
+        if (DEBUG) {
+            Log.d(TAG, String.format(entry != null ? "%s %s:\n%s" : "%s %s:%s",
+                    utcToLocalTime(context, timestamp), content, entry));
+        }
+    }
+}

tests/robotests/src/com/android/settings/fuelgauge/batteryusage/DataProcessorTest.java

@@ -0,0 +1,454 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * 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 com.android.settings.fuelgauge.batteryusage;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import static org.mockito.Mockito.spy;
+
+import android.content.ContentValues;
+import android.content.Context;
+import android.text.format.DateUtils;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.MockitoAnnotations;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.RuntimeEnvironment;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Calendar;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.TimeZone;
+
+@RunWith(RobolectricTestRunner.class)
+public class DataProcessorTest {
+    private static final String FAKE_ENTRY_KEY = "fake_entry_key";
+
+    private Context mContext;
+
+    @Before
+    public void setUp() {
+        MockitoAnnotations.initMocks(this);
+        TimeZone.setDefault(TimeZone.getTimeZone("GMT+8"));
+
+        mContext = spy(RuntimeEnvironment.application);
+    }
+
+    @Test
+    public void getBatteryLevelData_emptyHistoryMap_returnNull() {
+        assertThat(DataProcessor.getBatteryLevelData(mContext, null)).isNull();
+        assertThat(DataProcessor.getBatteryLevelData(mContext, new HashMap<>())).isNull();
+    }
+
+    @Test
+    public void getBatteryLevelData_notEnoughData_returnNull() {
+        // The timestamps are within 1 hour.
+        final long[] timestamps = {1000000L, 2000000L, 3000000L};
+        final int[] levels = {100, 99, 98};
+        final Map<Long, Map<String, BatteryHistEntry>> batteryHistoryMap =
+                createHistoryMap(timestamps, levels);
+
+        assertThat(DataProcessor.getBatteryLevelData(mContext, batteryHistoryMap)).isNull();
+    }
+
+    @Test
+    public void getBatteryLevelData_returnExpectedResult() {
+        // Timezone GMT+8: 2022-01-01 00:00:00, 2022-01-01 01:00:00, 2022-01-01 02:00:00
+        final long[] timestamps = {1640966400000L, 1640970000000L, 1640973600000L};
+        final int[] levels = {100, 99, 98};
+        final Map<Long, Map<String, BatteryHistEntry>> batteryHistoryMap =
+                createHistoryMap(timestamps, levels);
+
+        final BatteryLevelData resultData =
+                DataProcessor.getBatteryLevelData(mContext, batteryHistoryMap);
+
+        final List<Long> expectedDailyTimestamps = List.of(timestamps[0], timestamps[2]);
+        final List<Integer> expectedDailyLevels = List.of(levels[0], levels[2]);
+        final List<List<Long>> expectedHourlyTimestamps = List.of(expectedDailyTimestamps);
+        final List<List<Integer>> expectedHourlyLevels = List.of(expectedDailyLevels);
+        verifyExpectedBatteryLevelData(
+                resultData,
+                expectedDailyTimestamps,
+                expectedDailyLevels,
+                expectedHourlyTimestamps,
+                expectedHourlyLevels);
+    }
+
+    @Test
+    public void getHistoryMapWithExpectedTimestamps_emptyHistoryMap_returnEmptyMap() {
+        assertThat(DataProcessor
+                .getHistoryMapWithExpectedTimestamps(mContext, new HashMap<>()))
+                .isEmpty();
+    }
+
+    @Test
+    public void getHistoryMapWithExpectedTimestamps_returnExpectedMap() {
+        // Timezone GMT+8
+        final long[] timestamps = {
+                1640966700000L, // 2022-01-01 00:05:00
+                1640970180000L, // 2022-01-01 01:03:00
+                1640973840000L, // 2022-01-01 02:04:00
+                1640978100000L, // 2022-01-01 03:15:00
+                1640981400000L  // 2022-01-01 04:10:00
+        };
+        final int[] levels = {100, 94, 90, 82, 50};
+        final Map<Long, Map<String, BatteryHistEntry>> batteryHistoryMap =
+                createHistoryMap(timestamps, levels);
+
+        final Map<Long, Map<String, BatteryHistEntry>> resultMap =
+                DataProcessor.getHistoryMapWithExpectedTimestamps(mContext, batteryHistoryMap);
+
+        // Timezone GMT+8
+        final long[] expectedTimestamps = {
+                1640966400000L, // 2022-01-01 00:00:00
+                1640970000000L, // 2022-01-01 01:00:00
+                1640973600000L, // 2022-01-01 02:00:00
+                1640977200000L, // 2022-01-01 03:00:00
+                1640980800000L  // 2022-01-01 04:00:00
+        };
+        final int[] expectedLevels = {100, 94, 90, 84, 56};
+        assertThat(resultMap).hasSize(expectedLevels.length);
+        for (int index = 0; index < expectedLevels.length; index++) {
+            assertThat(resultMap.get(expectedTimestamps[index]).get(FAKE_ENTRY_KEY).mBatteryLevel)
+                    .isEqualTo(expectedLevels[index]);
+        }
+    }
+
+    @Test
+    public void getLevelDataThroughProcessedHistoryMap_notEnoughData_returnNull() {
+        final long[] timestamps = {100L};
+        final int[] levels = {100};
+        final Map<Long, Map<String, BatteryHistEntry>> batteryHistoryMap =
+                createHistoryMap(timestamps, levels);
+
+        assertThat(
+                DataProcessor.getLevelDataThroughProcessedHistoryMap(mContext, batteryHistoryMap))
+                .isNull();
+    }
+
+    @Test
+    public void getLevelDataThroughProcessedHistoryMap_OneDayData_returnExpectedResult() {
+        // Timezone GMT+8
+        final long[] timestamps = {
+                1640966400000L, // 2022-01-01 00:00:00
+                1640970000000L, // 2022-01-01 01:00:00
+                1640973600000L, // 2022-01-01 02:00:00
+                1640977200000L, // 2022-01-01 03:00:00
+                1640980800000L  // 2022-01-01 04:00:00
+        };
+        final int[] levels = {100, 94, 90, 82, 50};
+        final Map<Long, Map<String, BatteryHistEntry>> batteryHistoryMap =
+                createHistoryMap(timestamps, levels);
+
+        final BatteryLevelData resultData =
+                DataProcessor.getLevelDataThroughProcessedHistoryMap(mContext, batteryHistoryMap);
+
+        final List<Long> expectedDailyTimestamps = List.of(timestamps[0], timestamps[4]);
+        final List<Integer> expectedDailyLevels = List.of(levels[0], levels[4]);
+        final List<List<Long>> expectedHourlyTimestamps = List.of(
+                List.of(timestamps[0], timestamps[2], timestamps[4])
+        );
+        final List<List<Integer>> expectedHourlyLevels = List.of(
+                List.of(levels[0], levels[2], levels[4])
+        );
+        verifyExpectedBatteryLevelData(
+                resultData,
+                expectedDailyTimestamps,
+                expectedDailyLevels,
+                expectedHourlyTimestamps,
+                expectedHourlyLevels);
+    }
+
+    @Test
+    public void getLevelDataThroughProcessedHistoryMap_MultipleDaysData_returnExpectedResult() {
+        // Timezone GMT+8
+        final long[] timestamps = {
+                1641038400000L, // 2022-01-01 20:00:00
+                1641060000000L, // 2022-01-02 02:00:00
+                1641067200000L, // 2022-01-02 04:00:00
+                1641081600000L, // 2022-01-02 08:00:00
+        };
+        final int[] levels = {100, 94, 90, 82};
+        final Map<Long, Map<String, BatteryHistEntry>> batteryHistoryMap =
+                createHistoryMap(timestamps, levels);
+
+        final BatteryLevelData resultData =
+                DataProcessor.getLevelDataThroughProcessedHistoryMap(mContext, batteryHistoryMap);
+
+        final List<Long> expectedDailyTimestamps = List.of(
+                1641038400000L, // 2022-01-01 20:00:00
+                1641052800000L, // 2022-01-02 00:00:00
+                1641081600000L  // 2022-01-02 08:00:00
+        );
+        final List<Integer> expectedDailyLevels = new ArrayList<>();
+        expectedDailyLevels.add(100);
+        expectedDailyLevels.add(null);
+        expectedDailyLevels.add(82);
+        final List<List<Long>> expectedHourlyTimestamps = List.of(
+                List.of(
+                        1641038400000L, // 2022-01-01 20:00:00
+                        1641045600000L, // 2022-01-01 22:00:00
+                        1641052800000L  // 2022-01-02 00:00:00
+                ),
+                List.of(
+                        1641052800000L, // 2022-01-02 00:00:00
+                        1641060000000L, // 2022-01-02 02:00:00
+                        1641067200000L, // 2022-01-02 04:00:00
+                        1641074400000L, // 2022-01-02 06:00:00
+                        1641081600000L  // 2022-01-02 08:00:00
+                )
+        );
+        final List<Integer> expectedHourlyLevels1 = new ArrayList<>();
+        expectedHourlyLevels1.add(100);
+        expectedHourlyLevels1.add(null);
+        expectedHourlyLevels1.add(null);
+        final List<Integer> expectedHourlyLevels2 = new ArrayList<>();
+        expectedHourlyLevels2.add(null);
+        expectedHourlyLevels2.add(94);
+        expectedHourlyLevels2.add(90);
+        expectedHourlyLevels2.add(null);
+        expectedHourlyLevels2.add(82);
+        final List<List<Integer>> expectedHourlyLevels = List.of(
+                expectedHourlyLevels1,
+                expectedHourlyLevels2
+        );
+        verifyExpectedBatteryLevelData(
+                resultData,
+                expectedDailyTimestamps,
+                expectedDailyLevels,
+                expectedHourlyTimestamps,
+                expectedHourlyLevels);
+    }
+
+    @Test
+    public void getTimestampSlots_emptyRawList_returnEmptyList() {
+        final List<Long> resultList =
+                DataProcessor.getTimestampSlots(new ArrayList<>());
+        assertThat(resultList).isEmpty();
+    }
+
+    @Test
+    public void getTimestampSlots_startWithEvenHour_returnExpectedResult() {
+        final Calendar startCalendar = Calendar.getInstance();
+        startCalendar.set(2022, 6, 5, 6, 30, 50); // 2022-07-05 06:30:50
+        final Calendar endCalendar = Calendar.getInstance();
+        endCalendar.set(2022, 6, 5, 22, 30, 50); // 2022-07-05 22:30:50
+
+        final Calendar expectedStartCalendar = Calendar.getInstance();
+        expectedStartCalendar.set(2022, 6, 5, 6, 0, 0); // 2022-07-05 06:00:00
+        final Calendar expectedEndCalendar = Calendar.getInstance();
+        expectedEndCalendar.set(2022, 6, 5, 22, 0, 0); // 2022-07-05 22:00:00
+        verifyExpectedTimestampSlots(
+                startCalendar, endCalendar, expectedStartCalendar, expectedEndCalendar);
+    }
+
+    @Test
+    public void getTimestampSlots_startWithOddHour_returnExpectedResult() {
+        final Calendar startCalendar = Calendar.getInstance();
+        startCalendar.set(2022, 6, 5, 5, 0, 50); // 2022-07-05 05:00:50
+        final Calendar endCalendar = Calendar.getInstance();
+        endCalendar.set(2022, 6, 6, 21, 00, 50); // 2022-07-06 21:00:50
+
+        final Calendar expectedStartCalendar = Calendar.getInstance();
+        expectedStartCalendar.set(2022, 6, 5, 6, 00, 00); // 2022-07-05 06:00:00
+        final Calendar expectedEndCalendar = Calendar.getInstance();
+        expectedEndCalendar.set(2022, 6, 6, 20, 00, 00); // 2022-07-06 20:00:00
+        verifyExpectedTimestampSlots(
+                startCalendar, endCalendar, expectedStartCalendar, expectedEndCalendar);
+    }
+
+    @Test
+    public void getDailyTimestamps_notEnoughData_returnEmptyList() {
+        assertThat(DataProcessor.getDailyTimestamps(new ArrayList<>())).isEmpty();
+        assertThat(DataProcessor.getDailyTimestamps(List.of(100L))).isEmpty();
+    }
+
+    @Test
+    public void getDailyTimestamps_OneDayData_returnExpectedList() {
+        // Timezone GMT+8
+        final List<Long> timestamps = List.of(
+                1640966400000L, // 2022-01-01 00:00:00
+                1640970000000L, // 2022-01-01 01:00:00
+                1640973600000L, // 2022-01-01 02:00:00
+                1640977200000L, // 2022-01-01 03:00:00
+                1640980800000L  // 2022-01-01 04:00:00
+        );
+
+        final List<Long> expectedTimestamps = List.of(
+                1640966400000L, // 2022-01-01 00:00:00
+                1640980800000L  // 2022-01-01 04:00:00
+        );
+        assertThat(DataProcessor.getDailyTimestamps(timestamps)).isEqualTo(expectedTimestamps);
+    }
+
+    @Test
+    public void getDailyTimestamps_MultipleDaysData_returnExpectedList() {
+        // Timezone GMT+8
+        final List<Long> timestamps = List.of(
+                1640988000000L, // 2022-01-01 06:00:00
+                1641060000000L, // 2022-01-02 02:00:00
+                1641160800000L, // 2022-01-03 06:00:00
+                1641254400000L  // 2022-01-04 08:00:00
+        );
+
+        final List<Long> expectedTimestamps = List.of(
+                1640988000000L, // 2022-01-01 06:00:00
+                1641052800000L, // 2022-01-02 00:00:00
+                1641139200000L, // 2022-01-03 00:00:00
+                1641225600000L, // 2022-01-04 00:00:00
+                1641254400000L  // 2022-01-04 08:00:00
+        );
+        assertThat(DataProcessor.getDailyTimestamps(timestamps)).isEqualTo(expectedTimestamps);
+    }
+
+    @Test
+    public void isFromFullCharge_emptyData_returnFalse() {
+        assertThat(DataProcessor.isFromFullCharge(null)).isFalse();
+        assertThat(DataProcessor.isFromFullCharge(new HashMap<>())).isFalse();
+    }
+
+    @Test
+    public void isFromFullCharge_notChargedData_returnFalse() {
+        final Map<String, BatteryHistEntry> entryMap = new HashMap<>();
+        final ContentValues values = new ContentValues();
+        values.put("batteryLevel", 98);
+        final BatteryHistEntry entry = new BatteryHistEntry(values);
+        entryMap.put(FAKE_ENTRY_KEY, entry);
+
+        assertThat(DataProcessor.isFromFullCharge(entryMap)).isFalse();
+    }
+
+    @Test
+    public void isFromFullCharge_chargedData_returnTrue() {
+        final Map<String, BatteryHistEntry> entryMap = new HashMap<>();
+        final ContentValues values = new ContentValues();
+        values.put("batteryLevel", 100);
+        final BatteryHistEntry entry = new BatteryHistEntry(values);
+        entryMap.put(FAKE_ENTRY_KEY, entry);
+
+        assertThat(DataProcessor.isFromFullCharge(entryMap)).isTrue();
+    }
+
+    @Test
+    public void findNearestTimestamp_returnExpectedResult() {
+        long[] results = DataProcessor.findNearestTimestamp(
+                Arrays.asList(10L, 20L, 30L, 40L), /*target=*/ 15L);
+        assertThat(results).isEqualTo(new long[] {10L, 20L});
+
+        results = DataProcessor.findNearestTimestamp(
+                Arrays.asList(10L, 20L, 30L, 40L), /*target=*/ 10L);
+        assertThat(results).isEqualTo(new long[] {10L, 10L});
+
+        results = DataProcessor.findNearestTimestamp(
+                Arrays.asList(10L, 20L, 30L, 40L), /*target=*/ 5L);
+        assertThat(results).isEqualTo(new long[] {0L, 10L});
+
+        results = DataProcessor.findNearestTimestamp(
+                Arrays.asList(10L, 20L, 30L, 40L), /*target=*/ 50L);
+        assertThat(results).isEqualTo(new long[] {40L, 0L});
+    }
+
+    @Test
+    public void getTimestampOfNextDay_returnExpectedResult() {
+        // 2021-02-28 06:00:00 => 2021-03-01 00:00:00
+        assertThat(DataProcessor.getTimestampOfNextDay(1614463200000L))
+                .isEqualTo(1614528000000L);
+        // 2021-12-31 16:00:00 => 2022-01-01 00:00:00
+        assertThat(DataProcessor.getTimestampOfNextDay(1640937600000L))
+                .isEqualTo(1640966400000L);
+    }
+
+    private static Map<Long, Map<String, BatteryHistEntry>> createHistoryMap(
+            final long[] timestamps, final int[] levels) {
+        final Map<Long, Map<String, BatteryHistEntry>> batteryHistoryMap = new HashMap<>();
+        for (int index = 0; index < timestamps.length; index++) {
+            final Map<String, BatteryHistEntry> entryMap = new HashMap<>();
+            final ContentValues values = new ContentValues();
+            values.put(BatteryHistEntry.KEY_BATTERY_LEVEL, levels[index]);
+            final BatteryHistEntry entry = new BatteryHistEntry(values);
+            entryMap.put(FAKE_ENTRY_KEY, entry);
+            batteryHistoryMap.put(timestamps[index], entryMap);
+        }
+        return batteryHistoryMap;
+    }
+
+    private static void verifyExpectedBatteryLevelData(
+            final BatteryLevelData resultData,
+            final List<Long> expectedDailyTimestamps,
+            final List<Integer> expectedDailyLevels,
+            final List<List<Long>> expectedHourlyTimestamps,
+            final List<List<Integer>> expectedHourlyLevels) {
+        final BatteryLevelData.PeriodBatteryLevelData dailyResultData =
+                resultData.getDailyBatteryLevels();
+        final List<BatteryLevelData.PeriodBatteryLevelData> hourlyResultData =
+                resultData.getHourlyBatteryLevelsPerDay();
+        verifyExpectedDailyBatteryLevelData(
+                dailyResultData, expectedDailyTimestamps, expectedDailyLevels);
+        verifyExpectedHourlyBatteryLevelData(
+                hourlyResultData, expectedHourlyTimestamps, expectedHourlyLevels);
+    }
+
+    private static void verifyExpectedDailyBatteryLevelData(
+            final BatteryLevelData.PeriodBatteryLevelData dailyResultData,
+            final List<Long> expectedDailyTimestamps,
+            final List<Integer> expectedDailyLevels) {
+        assertThat(dailyResultData.getTimestamps()).isEqualTo(expectedDailyTimestamps);
+        assertThat(dailyResultData.getLevels()).isEqualTo(expectedDailyLevels);
+    }
+
+    private static void verifyExpectedHourlyBatteryLevelData(
+            final List<BatteryLevelData.PeriodBatteryLevelData> hourlyResultData,
+            final List<List<Long>> expectedHourlyTimestamps,
+            final List<List<Integer>> expectedHourlyLevels) {
+        final int expectedHourlySize = expectedHourlyTimestamps.size();
+        assertThat(hourlyResultData).hasSize(expectedHourlySize);
+        for (int dailyIndex = 0; dailyIndex < expectedHourlySize; dailyIndex++) {
+            assertThat(hourlyResultData.get(dailyIndex).getTimestamps())
+                    .isEqualTo(expectedHourlyTimestamps.get(dailyIndex));
+            assertThat(hourlyResultData.get(dailyIndex).getLevels())
+                    .isEqualTo(expectedHourlyLevels.get(dailyIndex));
+        }
+    }
+
+    private static void verifyExpectedTimestampSlots(
+            final Calendar start,
+            final Calendar end,
+            final Calendar expectedStart,
+            final Calendar expectedEnd) {
+        expectedStart.set(Calendar.MILLISECOND, 0);
+        expectedEnd.set(Calendar.MILLISECOND, 0);
+        final ArrayList<Long> timestampSlots = new ArrayList<>();
+        timestampSlots.add(start.getTimeInMillis());
+        timestampSlots.add(end.getTimeInMillis());
+        final List<Long> resultList =
+                DataProcessor.getTimestampSlots(timestampSlots);
+
+        for (int index = 0; index < resultList.size(); index++) {
+            final long expectedTimestamp =
+                    expectedStart.getTimeInMillis() + index * DateUtils.HOUR_IN_MILLIS;
+            assertThat(resultList.get(index)).isEqualTo(expectedTimestamp);
+        }
+        assertThat(resultList.get(resultList.size() - 1))
+                .isEqualTo(expectedEnd.getTimeInMillis());
+    }
+
+}