/*
 * Copyright (C) 2017 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.ContentResolver;
import android.content.Context;
import android.database.ContentObserver;
import android.os.Handler;
import android.os.Looper;
import android.os.PowerManager;
import android.provider.Settings;
import android.provider.Settings.Global;

import androidx.preference.Preference;
import androidx.preference.PreferenceScreen;

import com.android.settings.R;
import com.android.settings.Utils;
import com.android.settings.core.BasePreferenceController;
import com.android.settingslib.core.lifecycle.LifecycleObserver;
import com.android.settingslib.core.lifecycle.events.OnStart;
import com.android.settingslib.core.lifecycle.events.OnStop;
import com.android.settingslib.fuelgauge.BatterySaverUtils;

/** Controller to update the battery saver entry preference. */
public class BatterySaverController extends BasePreferenceController
        implements LifecycleObserver, OnStart, OnStop, BatterySaverReceiver.BatterySaverListener {
    private static final String KEY_BATTERY_SAVER = "battery_saver_summary";
    private final BatterySaverReceiver mBatteryStateChangeReceiver;
    private final PowerManager mPowerManager;
    private Preference mBatterySaverPref;
    private final ContentObserver mObserver =
            new ContentObserver(new Handler(Looper.getMainLooper())) {
                @Override
                public void onChange(boolean selfChange) {
                    updateSummary();
                }
            };

    public BatterySaverController(Context context) {
        super(context, KEY_BATTERY_SAVER);

        mPowerManager = mContext.getSystemService(PowerManager.class);
        mBatteryStateChangeReceiver = new BatterySaverReceiver(context);
        mBatteryStateChangeReceiver.setBatterySaverListener(this);
        BatterySaverUtils.revertScheduleToNoneIfNeeded(context);
    }

    @Override
    public int getAvailabilityStatus() {
        return AVAILABLE;
    }

    @Override
    public String getPreferenceKey() {
        return KEY_BATTERY_SAVER;
    }

    @Override
    public void displayPreference(PreferenceScreen screen) {
        super.displayPreference(screen);
        mBatterySaverPref = screen.findPreference(KEY_BATTERY_SAVER);
    }

    @Override
    public void onStart() {
        mContext.getContentResolver()
                .registerContentObserver(
                        Settings.Global.getUriFor(Settings.Global.LOW_POWER_MODE_TRIGGER_LEVEL),
                        true /* notifyForDescendants */,
                        mObserver);

        mBatteryStateChangeReceiver.setListening(true);
        updateSummary();
    }

    @Override
    public void onStop() {
        mContext.getContentResolver().unregisterContentObserver(mObserver);
        mBatteryStateChangeReceiver.setListening(false);
    }

    @Override
    public CharSequence getSummary() {
        final boolean isPowerSaveOn = mPowerManager.isPowerSaveMode();
        if (isPowerSaveOn) {
            return mContext.getString(R.string.battery_saver_on_summary);
        }

        final ContentResolver resolver = mContext.getContentResolver();
        final int mode =
                Settings.Global.getInt(
                        resolver,
                        Global.AUTOMATIC_POWER_SAVE_MODE,
                        PowerManager.POWER_SAVE_MODE_TRIGGER_PERCENTAGE);
        if (mode == PowerManager.POWER_SAVE_MODE_TRIGGER_PERCENTAGE) {
            final int percent =
                    Settings.Global.getInt(
                            resolver, Settings.Global.LOW_POWER_MODE_TRIGGER_LEVEL, 0);
            return percent != 0
                    ? mContext.getString(
                            R.string.battery_saver_off_scheduled_summary,
                            Utils.formatPercentage(percent))
                    : mContext.getString(R.string.battery_saver_off_summary);
        } else {
            return mContext.getString(R.string.battery_saver_pref_auto_routine_summary);
        }
    }

    private void updateSummary() {
        if (mBatterySaverPref != null) {
            mBatterySaverPref.setSummary(getSummary());
        }
    }

    @Override
    public void onPowerSaveModeChanged() {
        updateSummary();
    }

    @Override
    public void onBatteryChanged(boolean pluggedIn) {}
}