/*
 * 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.Context;
import android.database.ContentObserver;
import android.os.Handler;
import android.os.PowerManager;
import android.provider.Settings;
import android.support.annotation.VisibleForTesting;
import android.support.v7.preference.Preference;
import android.support.v7.preference.PreferenceScreen;
import com.android.settings.R;
import com.android.settings.Utils;
import com.android.settings.core.PreferenceControllerMixin;
import com.android.settings.dashboard.conditional.BatterySaverCondition;
import com.android.settings.dashboard.conditional.ConditionManager;
import com.android.settings.widget.MasterSwitchPreference;
import com.android.settingslib.core.AbstractPreferenceController;
import com.android.settingslib.core.lifecycle.Lifecycle;
import com.android.settingslib.core.lifecycle.LifecycleObserver;
import com.android.settingslib.core.lifecycle.events.OnStart;
import com.android.settingslib.core.lifecycle.events.OnStop;

import static android.os.PowerManager.ACTION_POWER_SAVE_MODE_CHANGING;

public class BatterySaverController extends AbstractPreferenceController
        implements PreferenceControllerMixin, Preference.OnPreferenceChangeListener,
        LifecycleObserver, OnStart, OnStop, BatterySaverReceiver.BatterySaverListener {
    private static final String KEY_BATTERY_SAVER = "battery_saver_summary";
    private final BatterySaverReceiver mBatteryStateChangeReceiver;
    private final PowerManager mPowerManager;
    private MasterSwitchPreference mBatterySaverPref;

    public BatterySaverController(Context context, Lifecycle lifecycle) {
        super(context);

        lifecycle.addObserver(this);
        mPowerManager = (PowerManager) mContext.getSystemService(Context.POWER_SERVICE);
        mBatteryStateChangeReceiver = new BatterySaverReceiver(context);
        mBatteryStateChangeReceiver.setBatterySaverListener(this);
    }

    @Override
    public boolean isAvailable() {
        return true;
    }

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

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

    @Override
    public void updateState(Preference preference) {
        mBatterySaverPref.setChecked(mPowerManager.isPowerSaveMode());
        updateSummary();
    }

    @Override
    public boolean onPreferenceChange(Preference preference, Object newValue) {
        final boolean saverOn = (Boolean) newValue;
        if (saverOn != mPowerManager.isPowerSaveMode()
                && !mPowerManager.setPowerSaveMode(saverOn)) {
            // Do nothing if power save mode doesn't set correctly
            return false;
        }

        refreshConditionManager();
        updateSummary();
        return true;
    }

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

        mBatteryStateChangeReceiver.setListening(true);
    }

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

    @VisibleForTesting
    void refreshConditionManager() {
        ConditionManager.get(mContext).getCondition(BatterySaverCondition.class).refreshState();
    }

    private void updateSummary() {
        final boolean mode = mPowerManager.isPowerSaveMode();
        final int format = mode ? R.string.battery_saver_on_summary
                : R.string.battery_saver_off_summary;
        final int percent = Settings.Global.getInt(mContext.getContentResolver(),
                Settings.Global.LOW_POWER_MODE_TRIGGER_LEVEL, 0);
        final int percentFormat = percent > 0 ? R.string.battery_saver_desc_turn_on_auto_pct
                : R.string.battery_saver_desc_turn_on_auto_never;

        final String summary = mContext.getString(format, mContext.getString(percentFormat,
                Utils.formatPercentage(percent)));

        mBatterySaverPref.setSummary(summary);
    }

    private final ContentObserver mObserver = new ContentObserver(new Handler()) {
        @Override
        public void onChange(boolean selfChange) {
            updateSummary();
        }
    };

    @Override
    public void onPowerSaveModeChanged() {
        mBatterySaverPref.setChecked(mPowerManager.isPowerSaveMode());
        updateSummary();
    }

    @Override
    public void onBatteryChanged(boolean pluggedIn) {
        mBatterySaverPref.setSwitchEnabled(!pluggedIn);
    }
}