/*
 * Copyright (C) 2016 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;

import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.res.Resources;
import android.os.AsyncTask;
import android.os.BatteryManager;
import android.os.BatteryStats;
import android.os.BatteryStats.HistoryItem;
import android.os.Bundle;
import android.os.SystemClock;
import android.support.annotation.WorkerThread;
import android.text.format.Formatter;
import android.util.SparseIntArray;

import com.android.internal.os.BatteryStatsHelper;
import com.android.settings.Utils;
import com.android.settings.graph.UsageView;
import com.android.settings.overlay.FeatureFactory;
import com.android.settingslib.R;
import com.android.settingslib.utils.PowerUtil;
import com.android.settingslib.utils.StringUtil;

public class BatteryInfo {

    public CharSequence chargeLabel;
    public CharSequence remainingLabel;
    public int batteryLevel;
    public boolean discharging = true;
    public long remainingTimeUs = 0;
    public long averageTimeToDischarge = Estimate.AVERAGE_TIME_TO_DISCHARGE_UNKNOWN;
    public String batteryPercentString;
    public String statusLabel;
    private boolean mCharging;
    private BatteryStats mStats;
    private static final String LOG_TAG = "BatteryInfo";
    private long timePeriod;

    public interface Callback {
        void onBatteryInfoLoaded(BatteryInfo info);
    }

    public void bindHistory(final UsageView view, BatteryDataParser... parsers) {
        final Context context = view.getContext();
        BatteryDataParser parser = new BatteryDataParser() {
            SparseIntArray points = new SparseIntArray();
            long startTime;
            int lastTime = -1;
            byte lastLevel;

            @Override
            public void onParsingStarted(long startTime, long endTime) {
                this.startTime = startTime;
                timePeriod = endTime - startTime;
                view.clearPaths();
                // Initially configure the graph for history only.
                view.configureGraph((int) timePeriod, 100);
            }

            @Override
            public void onDataPoint(long time, HistoryItem record) {
                lastTime = (int) time;
                lastLevel = record.batteryLevel;
                points.put(lastTime, lastLevel);
            }

            @Override
            public void onDataGap() {
                if (points.size() > 1) {
                    view.addPath(points);
                }
                points.clear();
            }

            @Override
            public void onParsingDone() {
                onDataGap();

                // Add projection if we have an estimate.
                if (remainingTimeUs != 0) {
                    PowerUsageFeatureProvider provider = FeatureFactory.getFactory(context)
                            .getPowerUsageFeatureProvider(context);
                    if (!mCharging && provider.isEnhancedBatteryPredictionEnabled(context)) {
                        points = provider.getEnhancedBatteryPredictionCurve(context, startTime);
                    } else {
                        // Linear extrapolation.
                        if (lastTime >= 0) {
                            points.put(lastTime, lastLevel);
                            points.put((int) (timePeriod +
                                            PowerUtil.convertUsToMs(remainingTimeUs)),
                                    mCharging ? 100 : 0);
                        }
                    }
                }

                // If we have a projection, reconfigure the graph to show it.
                if (points != null && points.size() > 0) {
                    int maxTime = points.keyAt(points.size() - 1);
                    view.configureGraph(maxTime, 100);
                    view.addProjectedPath(points);
                }
            }
        };
        BatteryDataParser[] parserList = new BatteryDataParser[parsers.length + 1];
        for (int i = 0; i < parsers.length; i++) {
            parserList[i] = parsers[i];
        }
        parserList[parsers.length] = parser;
        parse(mStats, parserList);
        String timeString = context.getString(R.string.charge_length_format,
                Formatter.formatShortElapsedTime(context, timePeriod));
        String remaining = "";
        if (remainingTimeUs != 0) {
            remaining = context.getString(R.string.remaining_length_format,
                    Formatter.formatShortElapsedTime(context, remainingTimeUs / 1000));
        }
        view.setBottomLabels(new CharSequence[]{timeString, remaining});
    }

    public static void getBatteryInfo(final Context context, final Callback callback) {
        BatteryInfo.getBatteryInfo(context, callback, false /* shortString */);
    }

    public static void getBatteryInfo(final Context context, final Callback callback,
            boolean shortString) {
        final long startTime = System.currentTimeMillis();
        BatteryStatsHelper statsHelper = new BatteryStatsHelper(context, true);
        statsHelper.create((Bundle) null);
        BatteryUtils.logRuntime(LOG_TAG, "time to make batteryStatsHelper", startTime);
        BatteryInfo.getBatteryInfo(context, callback, statsHelper, shortString);
    }

    public static void getBatteryInfo(final Context context, final Callback callback,
            BatteryStatsHelper statsHelper, boolean shortString) {
        final long startTime = System.currentTimeMillis();
        BatteryStats stats = statsHelper.getStats();
        BatteryUtils.logRuntime(LOG_TAG, "time for getStats", startTime);
        getBatteryInfo(context, callback, stats, shortString);
    }

    public static void getBatteryInfo(final Context context, final Callback callback,
            BatteryStats stats, boolean shortString) {
        new AsyncTask<Void, Void, BatteryInfo>() {
            @Override
            protected BatteryInfo doInBackground(Void... params) {
                final long startTime = System.currentTimeMillis();
                PowerUsageFeatureProvider provider =
                        FeatureFactory.getFactory(context).getPowerUsageFeatureProvider(context);
                final long elapsedRealtimeUs =
                        PowerUtil.convertMsToUs(SystemClock.elapsedRealtime());

                Intent batteryBroadcast = context.registerReceiver(null,
                        new IntentFilter(Intent.ACTION_BATTERY_CHANGED));
                // 0 means we are discharging, anything else means charging
                boolean discharging =
                        batteryBroadcast.getIntExtra(BatteryManager.EXTRA_PLUGGED, -1) == 0;

                if (discharging && provider != null
                        && provider.isEnhancedBatteryPredictionEnabled(context)) {
                    Estimate estimate = provider.getEnhancedBatteryPrediction(context);
                    if(estimate != null) {
                        BatteryUtils
                                .logRuntime(LOG_TAG, "time for enhanced BatteryInfo", startTime);
                        return BatteryInfo.getBatteryInfo(context, batteryBroadcast, stats,
                                estimate, elapsedRealtimeUs, shortString);
                    }
                }
                long prediction = discharging
                        ? stats.computeBatteryTimeRemaining(elapsedRealtimeUs) : 0;
                Estimate estimate = new Estimate(
                        PowerUtil.convertUsToMs(prediction),
                        false, /* isBasedOnUsage */
                        Estimate.AVERAGE_TIME_TO_DISCHARGE_UNKNOWN);
                BatteryUtils.logRuntime(LOG_TAG, "time for regular BatteryInfo", startTime);
                return BatteryInfo.getBatteryInfo(context, batteryBroadcast, stats,
                        estimate, elapsedRealtimeUs, shortString);
            }

            @Override
            protected void onPostExecute(BatteryInfo batteryInfo) {
                final long startTime = System.currentTimeMillis();
                callback.onBatteryInfoLoaded(batteryInfo);
                BatteryUtils.logRuntime(LOG_TAG, "time for callback", startTime);
            }
        }.execute();
    }

    @WorkerThread
    public static BatteryInfo getBatteryInfoOld(Context context, Intent batteryBroadcast,
            BatteryStats stats, long elapsedRealtimeUs, boolean shortString) {
        Estimate estimate = new Estimate(
                PowerUtil.convertUsToMs(stats.computeBatteryTimeRemaining(elapsedRealtimeUs)),
                false,
                Estimate.AVERAGE_TIME_TO_DISCHARGE_UNKNOWN);
        return getBatteryInfo(context, batteryBroadcast, stats, estimate, elapsedRealtimeUs,
                shortString);
    }

    @WorkerThread
    public static BatteryInfo getBatteryInfo(Context context, Intent batteryBroadcast,
            BatteryStats stats, Estimate estimate, long elapsedRealtimeUs, boolean shortString) {
        final long startTime = System.currentTimeMillis();
        BatteryInfo info = new BatteryInfo();
        info.mStats = stats;
        info.batteryLevel = Utils.getBatteryLevel(batteryBroadcast);
        info.batteryPercentString = Utils.formatPercentage(info.batteryLevel);
        info.mCharging = batteryBroadcast.getIntExtra(BatteryManager.EXTRA_PLUGGED, 0) != 0;
        info.averageTimeToDischarge = estimate.averageDischargeTime;
        final Resources resources = context.getResources();

        info.statusLabel = Utils.getBatteryStatus(resources, batteryBroadcast);
        if (!info.mCharging) {
            updateBatteryInfoDischarging(context, shortString, estimate, info);
        } else {
            updateBatteryInfoCharging(context, batteryBroadcast, stats, elapsedRealtimeUs, info);
        }
        BatteryUtils.logRuntime(LOG_TAG, "time for getBatteryInfo", startTime);
        return info;
    }

    private static void updateBatteryInfoCharging(Context context, Intent batteryBroadcast,
            BatteryStats stats, long elapsedRealtimeUs, BatteryInfo info) {
        final Resources resources = context.getResources();
        final long chargeTime = stats.computeChargeTimeRemaining(elapsedRealtimeUs);
        final int status = batteryBroadcast.getIntExtra(BatteryManager.EXTRA_STATUS,
                BatteryManager.BATTERY_STATUS_UNKNOWN);
        info.discharging = false;
        if (chargeTime > 0 && status != BatteryManager.BATTERY_STATUS_FULL) {
            info.remainingTimeUs = chargeTime;
            CharSequence timeString = StringUtil.formatElapsedTime(context,
                    PowerUtil.convertUsToMs(info.remainingTimeUs), false /* withSeconds */);
            int resId = R.string.power_charging_duration;
            info.remainingLabel = context.getString(
                    R.string.power_remaining_charging_duration_only, timeString);
            info.chargeLabel = context.getString(resId, info.batteryPercentString, timeString);
        } else {
            final String chargeStatusLabel = resources.getString(
                    R.string.battery_info_status_charging_lower);
            info.remainingLabel = null;
            info.chargeLabel = info.batteryLevel == 100 ? info.batteryPercentString :
                    resources.getString(R.string.power_charging, info.batteryPercentString,
                            chargeStatusLabel);
        }
    }

    private static void updateBatteryInfoDischarging(Context context, boolean shortString,
            Estimate estimate, BatteryInfo info) {
        final long drainTimeUs = PowerUtil.convertMsToUs(estimate.estimateMillis);
        if (drainTimeUs > 0) {
            info.remainingTimeUs = drainTimeUs;
            info.remainingLabel = PowerUtil.getBatteryRemainingStringFormatted(
                    context,
                    PowerUtil.convertUsToMs(drainTimeUs),
                    null /* percentageString */,
                    estimate.isBasedOnUsage && !shortString
            );
            info.chargeLabel = PowerUtil.getBatteryRemainingStringFormatted(
                    context,
                    PowerUtil.convertUsToMs(drainTimeUs),
                    info.batteryPercentString,
                    estimate.isBasedOnUsage && !shortString
            );
        } else {
            info.remainingLabel = null;
            info.chargeLabel = info.batteryPercentString;
        }
    }

    public interface BatteryDataParser {
        void onParsingStarted(long startTime, long endTime);

        void onDataPoint(long time, HistoryItem record);

        void onDataGap();

        void onParsingDone();
    }

    public static void parse(BatteryStats stats, BatteryDataParser... parsers) {
        long startWalltime = 0;
        long endWalltime = 0;
        long historyStart = 0;
        long historyEnd = 0;
        long curWalltime = startWalltime;
        long lastWallTime = 0;
        long lastRealtime = 0;
        int lastInteresting = 0;
        int pos = 0;
        boolean first = true;
        if (stats.startIteratingHistoryLocked()) {
            final HistoryItem rec = new HistoryItem();
            while (stats.getNextHistoryLocked(rec)) {
                pos++;
                if (first) {
                    first = false;
                    historyStart = rec.time;
                }
                if (rec.cmd == HistoryItem.CMD_CURRENT_TIME
                        || rec.cmd == HistoryItem.CMD_RESET) {
                    // If there is a ridiculously large jump in time, then we won't be
                    // able to create a good chart with that data, so just ignore the
                    // times we got before and pretend like our data extends back from
                    // the time we have now.
                    // Also, if we are getting a time change and we are less than 5 minutes
                    // since the start of the history real time, then also use this new
                    // time to compute the base time, since whatever time we had before is
                    // pretty much just noise.
                    if (rec.currentTime > (lastWallTime + (180 * 24 * 60 * 60 * 1000L))
                            || rec.time < (historyStart + (5 * 60 * 1000L))) {
                        startWalltime = 0;
                    }
                    lastWallTime = rec.currentTime;
                    lastRealtime = rec.time;
                    if (startWalltime == 0) {
                        startWalltime = lastWallTime - (lastRealtime - historyStart);
                    }
                }
                if (rec.isDeltaData()) {
                    lastInteresting = pos;
                    historyEnd = rec.time;
                }
            }
        }
        stats.finishIteratingHistoryLocked();
        endWalltime = lastWallTime + historyEnd - lastRealtime;

        int i = 0;
        final int N = lastInteresting;

        for (int j = 0; j < parsers.length; j++) {
            parsers[j].onParsingStarted(startWalltime, endWalltime);
        }
        if (endWalltime > startWalltime && stats.startIteratingHistoryLocked()) {
            final HistoryItem rec = new HistoryItem();
            while (stats.getNextHistoryLocked(rec) && i < N) {
                if (rec.isDeltaData()) {
                    curWalltime += rec.time - lastRealtime;
                    lastRealtime = rec.time;
                    long x = (curWalltime - startWalltime);
                    if (x < 0) {
                        x = 0;
                    }
                    for (int j = 0; j < parsers.length; j++) {
                        parsers[j].onDataPoint(x, rec);
                    }
                } else {
                    long lastWalltime = curWalltime;
                    if (rec.cmd == HistoryItem.CMD_CURRENT_TIME
                            || rec.cmd == HistoryItem.CMD_RESET) {
                        if (rec.currentTime >= startWalltime) {
                            curWalltime = rec.currentTime;
                        } else {
                            curWalltime = startWalltime + (rec.time - historyStart);
                        }
                        lastRealtime = rec.time;
                    }

                    if (rec.cmd != HistoryItem.CMD_OVERFLOW
                            && (rec.cmd != HistoryItem.CMD_CURRENT_TIME
                            || Math.abs(lastWalltime - curWalltime) > (60 * 60 * 1000))) {
                        for (int j = 0; j < parsers.length; j++) {
                            parsers[j].onDataGap();
                        }
                    }
                }
                i++;
            }
        }

        stats.finishIteratingHistoryLocked();

        for (int j = 0; j < parsers.length; j++) {
            parsers[j].onParsingDone();
        }
    }
}