NetGuard/app/src/main/java/eu/faircode/netguard/ActivitySettings.java

package eu.faircode.netguard;

/*
    This file is part of NetGuard.

    NetGuard is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    NetGuard is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with NetGuard.  If not, see <http://www.gnu.org/licenses/>.

    Copyright 2015 by Marcel Bokhorst (M66B)
*/

import android.Manifest;
import android.annotation.TargetApi;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.SharedPreferences;
import android.content.pm.PackageManager;
import android.net.ConnectivityManager;
import android.net.wifi.WifiConfiguration;
import android.net.wifi.WifiManager;
import android.os.AsyncTask;
import android.os.Build;
import android.os.Bundle;
import android.preference.EditTextPreference;
import android.preference.MultiSelectListPreference;
import android.preference.Preference;
import android.preference.PreferenceCategory;
import android.preference.PreferenceFragment;
import android.preference.PreferenceManager;
import android.preference.PreferenceScreen;
import android.preference.SwitchPreference;
import android.support.v7.app.AppCompatActivity;
import android.telephony.PhoneStateListener;
import android.telephony.ServiceState;
import android.telephony.TelephonyManager;
import android.text.TextUtils;
import android.util.Log;
import android.util.Xml;
import android.widget.Toast;

import org.xml.sax.Attributes;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;
import org.xmlpull.v1.XmlSerializer;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParserFactory;

public class ActivitySettings extends AppCompatActivity implements SharedPreferences.OnSharedPreferenceChangeListener {
    private static final String TAG = "NetGuard.Settings";

    private boolean pro = false;
    private boolean phone_state = false;

    public static final String EXTRA_PRO = "Pro";

    private static final int REQUEST_EXPORT = 1;
    private static final int REQUEST_IMPORT = 2;
    private static final int REQUEST_METERED = 3;
    private static final int REQUEST_ROAMING_NATIONAL = 4;
    private static final int REQUEST_ROAMING_INTERNATIONAL = 5;
    private static final Intent INTENT_VPN_SETTINGS = new Intent("android.net.vpn.SETTINGS");

    protected void onCreate(Bundle savedInstanceState) {
        SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
        setTheme(prefs.getBoolean("dark_theme", false) ? R.style.AppThemeDark : R.style.AppTheme);

        super.onCreate(savedInstanceState);

        pro = getIntent().getBooleanExtra(EXTRA_PRO, false);

        getFragmentManager().beginTransaction().replace(android.R.id.content, new FragmentSettings()).commit();
        getSupportActionBar().setTitle(R.string.menu_settings);
    }

    private PreferenceScreen getPreferenceScreen() {
        return ((PreferenceFragment) getFragmentManager().findFragmentById(android.R.id.content)).getPreferenceScreen();
    }

    @Override
    protected void onPostCreate(Bundle savedInstanceState) {
        super.onPostCreate(savedInstanceState);
        PreferenceScreen screen = getPreferenceScreen();
        SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);

        // Wi-Fi home
        MultiSelectListPreference pref_wifi_homes = (MultiSelectListPreference) screen.findPreference("wifi_homes");
        Set<String> ssid = prefs.getStringSet("wifi_homes", new HashSet<String>());
        if (ssid.size() > 0)
            pref_wifi_homes.setTitle(getString(R.string.setting_wifi_home, TextUtils.join(", ", ssid)));
        else
            pref_wifi_homes.setTitle(getString(R.string.setting_wifi_home, "-"));

        WifiManager wm = (WifiManager) getSystemService(Context.WIFI_SERVICE);
        List<CharSequence> listSSID = new ArrayList<>();
        List<WifiConfiguration> configs = wm.getConfiguredNetworks();
        if (configs != null)
            for (WifiConfiguration config : configs)
                listSSID.add(config.SSID == null ? "NULL" : config.SSID);
        pref_wifi_homes.setEntries(listSSID.toArray(new CharSequence[0]));
        pref_wifi_homes.setEntryValues(listSSID.toArray(new CharSequence[0]));

        // Handle auto enable
        Preference pref_auto_enable = screen.findPreference("auto_enable");
        pref_auto_enable.setTitle(getString(R.string.setting_auto, prefs.getString("auto_enable", "0")));

        // Handle stats
        EditTextPreference pref_stats_base = (EditTextPreference) screen.findPreference("stats_base");
        EditTextPreference pref_stats_frequency = (EditTextPreference) screen.findPreference("stats_frequency");
        EditTextPreference pref_stats_samples = (EditTextPreference) screen.findPreference("stats_samples");
        pref_stats_base.setTitle(getString(R.string.setting_stats_base, prefs.getString("stats_base", "5")));
        pref_stats_frequency.setTitle(getString(R.string.setting_stats_frequency, prefs.getString("stats_frequency", "1000")));
        pref_stats_samples.setTitle(getString(R.string.setting_stats_samples, prefs.getString("stats_samples", "90")));
        PreferenceCategory stats = (PreferenceCategory) screen.findPreference("category_stats");
        if (Util.isPlayStoreInstall(this))
            screen.removePreference(stats);

        // Handle export
        Preference pref_export = screen.findPreference("export");
        pref_export.setEnabled(getIntentCreateDocument().resolveActivity(getPackageManager()) != null);
        pref_export.setOnPreferenceClickListener(new Preference.OnPreferenceClickListener() {
            @Override
            public boolean onPreferenceClick(Preference preference) {
                if (pro)
                    startActivityForResult(getIntentCreateDocument(), ActivitySettings.REQUEST_EXPORT);
                else
                    Toast.makeText(ActivitySettings.this, getString(R.string.msg_pro), Toast.LENGTH_SHORT).show();
                return true;
            }
        });

        // Handle import
        Preference pref_import = screen.findPreference("import");
        pref_import.setEnabled(getIntentCreateDocument().resolveActivity(getPackageManager()) != null);
        pref_import.setOnPreferenceClickListener(new Preference.OnPreferenceClickListener() {
            @Override
            public boolean onPreferenceClick(Preference preference) {
                if (pro)
                    startActivityForResult(getIntentOpenDocument(), ActivitySettings.REQUEST_IMPORT);
                else
                    Toast.makeText(ActivitySettings.this, getString(R.string.msg_pro), Toast.LENGTH_SHORT).show();
                return true;
            }
        });

        // Handle technical info
        Preference.OnPreferenceClickListener listener = new Preference.OnPreferenceClickListener() {
            @Override
            public boolean onPreferenceClick(Preference preference) {
                updateTechnicalInfo();
                return true;
            }
        };

        Preference pref_technical_info = screen.findPreference("technical_info");
        Preference pref_technical_network = screen.findPreference("technical_network");
        Preference pref_technical_subscription = screen.findPreference("technical_subscription");
        if (Util.isDebuggable(this)) {
            pref_technical_info.setEnabled(INTENT_VPN_SETTINGS.resolveActivity(this.getPackageManager()) != null);
            pref_technical_info.setIntent(INTENT_VPN_SETTINGS);
        }
        pref_technical_info.setOnPreferenceClickListener(listener);
        pref_technical_network.setOnPreferenceClickListener(listener);
        pref_technical_subscription.setOnPreferenceClickListener(listener);
        updateTechnicalInfo();

        // Handle devices without wifi
        if (!Util.hasWifi(this)) {
            PreferenceCategory defaults = (PreferenceCategory) screen.findPreference("category_defaults");
            defaults.removePreference(screen.findPreference("whitelist_wifi"));
            defaults.removePreference(screen.findPreference("screen_wifi"));

            PreferenceCategory options = (PreferenceCategory) screen.findPreference("category_options");
            options.removePreference(screen.findPreference("wifi_homes"));
            options.removePreference(screen.findPreference("use_metered"));
        }

        // Handle devices without telephony
        if (!Util.hasTelephony(this)) {
            PreferenceCategory defaults = (PreferenceCategory) screen.findPreference("category_defaults");
            defaults.removePreference(screen.findPreference("whitelist_other"));
            defaults.removePreference(screen.findPreference("screen_other"));
            defaults.removePreference(screen.findPreference("whitelist_roaming"));

            PreferenceCategory options = (PreferenceCategory) screen.findPreference("category_options");
            options.removePreference(screen.findPreference("use_metered"));
            options.removePreference(screen.findPreference("unmetered_2g"));
            options.removePreference(screen.findPreference("unmetered_3g"));
            options.removePreference(screen.findPreference("unmetered_4g"));
            options.removePreference(screen.findPreference("national_roaming"));
        }
    }

    @Override
    protected void onResume() {
        super.onResume();

        PreferenceScreen screen = getPreferenceScreen();
        SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);

        // TODO: check permision for whitelist_roaming

        // Check if permission was revoked
        if (prefs.getBoolean("unmetered_2g", false) ||
                prefs.getBoolean("unmetered_3g", false) ||
                prefs.getBoolean("unmetered_4g", false))
            if (!Util.hasPhoneStatePermission(this)) {
                prefs.edit().putBoolean("unmetered_2g", false).apply();
                prefs.edit().putBoolean("unmetered_3g", false).apply();
                prefs.edit().putBoolean("unmetered_4g", false).apply();

                ((SwitchPreference) screen.findPreference("unmetered_2g")).setChecked(false);
                ((SwitchPreference) screen.findPreference("unmetered_3g")).setChecked(false);
                ((SwitchPreference) screen.findPreference("unmetered_4g")).setChecked(false);
            }

        // Check if permission was revoked
        if (prefs.getBoolean("national_roaming", false))
            if (!Util.hasPhoneStatePermission(this)) {
                prefs.edit().putBoolean("national_roaming", false).apply();
                ((SwitchPreference) screen.findPreference("national_roaming")).setChecked(false);
            }

        // Listen for preference changes
        prefs.registerOnSharedPreferenceChangeListener(this);

        // Listen for interactive state changes
        IntentFilter ifInteractive = new IntentFilter();
        ifInteractive.addAction(Intent.ACTION_SCREEN_ON);
        ifInteractive.addAction(Intent.ACTION_SCREEN_OFF);
        registerReceiver(interactiveStateReceiver, ifInteractive);

        // Listen for connectivity updates
        IntentFilter ifConnectivity = new IntentFilter();
        ifConnectivity.addAction(ConnectivityManager.CONNECTIVITY_ACTION);
        registerReceiver(connectivityChangedReceiver, ifConnectivity);

        if (Util.hasPhoneStatePermission(this)) {
            TelephonyManager tm = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);
            tm.listen(phoneStateListener, PhoneStateListener.LISTEN_DATA_CONNECTION_STATE | PhoneStateListener.LISTEN_SERVICE_STATE);
            phone_state = true;
        }
    }

    @Override
    protected void onPause() {
        super.onPause();

        SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
        prefs.unregisterOnSharedPreferenceChangeListener(this);

        unregisterReceiver(interactiveStateReceiver);
        unregisterReceiver(connectivityChangedReceiver);

        if (phone_state) {
            TelephonyManager tm = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);
            tm.listen(phoneStateListener, PhoneStateListener.LISTEN_NONE);
            phone_state = false;
        }
    }

    @Override
    @TargetApi(Build.VERSION_CODES.M)
    public void onSharedPreferenceChanged(SharedPreferences prefs, String name) {
        if ("whitelist_wifi".equals(name) ||
                "screen_wifi".equals(name))
            SinkholeService.reload("wifi", "setting changed", this);

        else if ("whitelist_other".equals(name) ||
                "screen_other".equals(name))
            SinkholeService.reload("other", "setting changed", this);

        else if ("whitelist_roaming".equals(name)) {
            if (prefs.getBoolean(name, false)) {
                if (Util.hasPhoneStatePermission(this))
                    SinkholeService.reload("other", "setting changed", this);
                else
                    requestPermissions(new String[]{Manifest.permission.READ_PHONE_STATE}, REQUEST_ROAMING_INTERNATIONAL);
            } else
                SinkholeService.reload("other", "setting changed", this);

        } else if ("manage_system".equals(name)) {
            SharedPreferences.Editor editor = prefs.edit();
            if (prefs.getBoolean(name, false)) {
                editor.putBoolean("show_system", true);
                editor.putBoolean("show_user", true);
            } else {
                editor.putBoolean("show_user", true);
                editor.putBoolean("show_system", false);
            }
            editor.apply();
            SinkholeService.reload(null, "setting changed", this);

        } else if ("auto_enable".equals(name)) {
            if (!pro) {
                prefs.edit().putString(name, "0").apply();
                Toast.makeText(ActivitySettings.this, getString(R.string.msg_pro), Toast.LENGTH_SHORT).show();
            }
            getPreferenceScreen().findPreference(name).setTitle(getString(R.string.setting_auto, prefs.getString(name, "0")));

        } else if ("dark_theme".equals(name)) {
            if (!pro) {
                prefs.edit().putBoolean(name, false);
                ((SwitchPreference) getPreferenceScreen().findPreference(name)).setChecked(false);
                Toast.makeText(ActivitySettings.this, getString(R.string.msg_pro), Toast.LENGTH_SHORT).show();
            }
            recreate();

        } else if ("wifi_homes".equals(name)) {
            MultiSelectListPreference pref_wifi_homes = (MultiSelectListPreference) getPreferenceScreen().findPreference(name);
            Set<String> ssid = prefs.getStringSet(name, new HashSet<String>());
            if (ssid.size() > 0)
                pref_wifi_homes.setTitle(getString(R.string.setting_wifi_home, TextUtils.join(", ", ssid)));
            else
                pref_wifi_homes.setTitle(getString(R.string.setting_wifi_home, "-"));
            SinkholeService.reload(null, "setting changed", this);

        } else if ("use_metered".equals(name))
            SinkholeService.reload(null, "setting changed", this);

        else if ("unmetered_2g".equals(name) ||
                "unmetered_3g".equals(name) ||
                "unmetered_4g".equals(name)) {
            if (prefs.getBoolean(name, false)) {
                if (Util.hasPhoneStatePermission(this))
                    SinkholeService.reload("other", "setting changed", this);
                else
                    requestPermissions(new String[]{Manifest.permission.READ_PHONE_STATE}, REQUEST_METERED);
            } else
                SinkholeService.reload("other", "setting changed", this);

        } else if ("national_roaming".equals(name)) {
            if (prefs.getBoolean(name, false)) {
                if (Util.hasPhoneStatePermission(this))
                    SinkholeService.reload("other", "setting changed", this);
                else
                    requestPermissions(new String[]{Manifest.permission.READ_PHONE_STATE}, REQUEST_ROAMING_NATIONAL);
            } else
                SinkholeService.reload("other", "setting changed", this);

        } else if ("show_stats".equals(name)) {
            if (pro)
                SinkholeService.reloadStats("setting changed", this);
            else {
                prefs.edit().putBoolean(name, false);
                ((SwitchPreference) getPreferenceScreen().findPreference(name)).setChecked(false);
                Toast.makeText(ActivitySettings.this, getString(R.string.msg_pro), Toast.LENGTH_SHORT).show();
            }

        } else if ("stats_base".equals(name)) {
            if (!Util.isPlayStoreInstall(this))
                getPreferenceScreen().findPreference(name).setTitle(getString(R.string.setting_stats_base, prefs.getString(name, "5")));

        } else if ("stats_frequency".equals(name)) {
            if (!Util.isPlayStoreInstall(this))
                getPreferenceScreen().findPreference(name).setTitle(getString(R.string.setting_stats_frequency, prefs.getString(name, "1000")));

        } else if ("stats_samples".equals(name)) {
            if (!Util.isPlayStoreInstall(this))
                getPreferenceScreen().findPreference(name).setTitle(getString(R.string.setting_stats_samples, prefs.getString(name, "90")));
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions,
                                           int[] grantResults) {
        PreferenceScreen screen = getPreferenceScreen();

        if (requestCode == REQUEST_METERED)
            if (grantResults[0] == PackageManager.PERMISSION_GRANTED)
                SinkholeService.reload("other", "permission granted", this);
            else {
                SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
                prefs.edit().putBoolean("unmetered_2g", false).apply();
                prefs.edit().putBoolean("unmetered_3g", false).apply();
                prefs.edit().putBoolean("unmetered_4g", false).apply();
                ((SwitchPreference) screen.findPreference("unmetered_2g")).setChecked(false);
                ((SwitchPreference) screen.findPreference("unmetered_3g")).setChecked(false);
                ((SwitchPreference) screen.findPreference("unmetered_4g")).setChecked(false);
            }

        else if (requestCode == REQUEST_ROAMING_NATIONAL)
            if (grantResults[0] == PackageManager.PERMISSION_GRANTED)
                SinkholeService.reload("other", "permission granted", this);
            else {
                SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
                prefs.edit().putBoolean("national_roaming", false).apply();
                ((SwitchPreference) screen.findPreference("national_roaming")).setChecked(false);
            }

        else if (requestCode == REQUEST_ROAMING_INTERNATIONAL)
            if (grantResults[0] == PackageManager.PERMISSION_GRANTED)
                SinkholeService.reload("other", "permission granted", this);
            else {
                SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
                prefs.edit().putBoolean("whitelist_roaming", false).apply();
                ((SwitchPreference) screen.findPreference("whitelist_roaming")).setChecked(false);
            }
    }

    private BroadcastReceiver interactiveStateReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            Util.logExtras(intent);
            updateTechnicalInfo();
        }
    };

    private BroadcastReceiver connectivityChangedReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            Util.logExtras(intent);
            updateTechnicalInfo();
        }
    };

    private PhoneStateListener phoneStateListener = new PhoneStateListener() {
        @Override
        public void onDataConnectionStateChanged(int state) {
            updateTechnicalInfo();
        }

        @Override
        public void onServiceStateChanged(ServiceState serviceState) {
            updateTechnicalInfo();
        }
    };

    private void updateTechnicalInfo() {
        PreferenceScreen screen = getPreferenceScreen();
        Preference pref_technical_info = screen.findPreference("technical_info");
        Preference pref_technical_network = screen.findPreference("technical_network");
        Preference pref_technical_subscription = screen.findPreference("technical_subscription");

        pref_technical_info.setSummary(Util.getGeneralInfo(this));
        pref_technical_network.setSummary(Util.getNetworkInfo(this));
        pref_technical_subscription.setSummary(Util.getSubscriptionInfo(this));
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, final Intent data) {
        Log.i(TAG, "onActivityResult request=" + requestCode + " result=" + requestCode + " ok=" + (resultCode == RESULT_OK));
        if (requestCode == REQUEST_EXPORT) {
            if (resultCode == RESULT_OK && data != null)
                handleExport(data);

        } else if (requestCode == REQUEST_IMPORT) {
            if (resultCode == RESULT_OK && data != null)
                handleImport(data);

        } else {
            Log.w(TAG, "Unknown activity result request=" + requestCode);
            super.onActivityResult(requestCode, resultCode, data);
        }
    }

    private void handleExport(final Intent data) {
        new AsyncTask<Object, Object, Throwable>() {
            @Override
            protected Throwable doInBackground(Object... objects) {
                OutputStream out = null;
                try {
                    out = getContentResolver().openOutputStream(data.getData());
                    Log.i(TAG, "Writing URI=" + data.getData());
                    xmlExport(out);
                    return null;
                } catch (Throwable ex) {
                    Log.e(TAG, ex.toString() + "\n" + Log.getStackTraceString(ex));
                    Util.sendCrashReport(ex, ActivitySettings.this);
                    return ex;
                } finally {
                    if (out != null)
                        try {
                            out.close();
                        } catch (IOException ex) {
                            Log.e(TAG, ex.toString() + "\n" + Log.getStackTraceString(ex));
                        }
                }
            }

            @Override
            protected void onPostExecute(Throwable ex) {
                if (ex == null)
                    Toast.makeText(ActivitySettings.this, R.string.msg_completed, Toast.LENGTH_LONG).show();
                else
                    Toast.makeText(ActivitySettings.this, ex.toString(), Toast.LENGTH_LONG).show();
            }
        }.execute();
    }

    private static Intent getIntentCreateDocument() {
        Intent intent = new Intent(Intent.ACTION_CREATE_DOCUMENT);
        intent.addCategory(Intent.CATEGORY_OPENABLE);
        intent.setType("text/xml");
        intent.putExtra(Intent.EXTRA_TITLE, "netguard.xml");
        return intent;
    }

    private static Intent getIntentOpenDocument() {
        Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
        intent.addCategory(Intent.CATEGORY_OPENABLE);
        intent.setType("text/xml");
        return intent;
    }

    private void handleImport(final Intent data) {
        new AsyncTask<Object, Object, Throwable>() {
            @Override
            protected Throwable doInBackground(Object... objects) {
                InputStream in = null;
                try {
                    in = getContentResolver().openInputStream(data.getData());
                    Log.i(TAG, "Reading URI=" + data.getData());
                    xmlImport(in);
                    return null;
                } catch (Throwable ex) {
                    Log.e(TAG, ex.toString() + "\n" + Log.getStackTraceString(ex));
                    Util.sendCrashReport(ex, ActivitySettings.this);
                    return ex;
                } finally {
                    if (in != null)
                        try {
                            in.close();
                        } catch (IOException ex) {
                            Log.e(TAG, ex.toString() + "\n" + Log.getStackTraceString(ex));
                        }
                }
            }

            @Override
            protected void onPostExecute(Throwable ex) {
                if (ex == null) {
                    Toast.makeText(ActivitySettings.this, R.string.msg_completed, Toast.LENGTH_LONG).show();
                    recreate();
                } else
                    Toast.makeText(ActivitySettings.this, ex.toString(), Toast.LENGTH_LONG).show();
            }
        }.execute();
    }

    private void xmlExport(OutputStream out) throws IOException {
        XmlSerializer serializer = Xml.newSerializer();
        serializer.setOutput(out, "UTF-8");
        serializer.startDocument(null, true);
        serializer.setFeature("http://xmlpull.org/v1/doc/features.html#indent-output", true);
        serializer.startTag(null, "netguard");

        serializer.startTag(null, "application");
        xmlExport(PreferenceManager.getDefaultSharedPreferences(this), serializer);
        serializer.endTag(null, "application");

        serializer.startTag(null, "wifi");
        xmlExport(getSharedPreferences("wifi", Context.MODE_PRIVATE), serializer);
        serializer.endTag(null, "wifi");

        serializer.startTag(null, "mobile");
        xmlExport(getSharedPreferences("other", Context.MODE_PRIVATE), serializer);
        serializer.endTag(null, "mobile");

        serializer.startTag(null, "screen_wifi");
        xmlExport(getSharedPreferences("screen_wifi", Context.MODE_PRIVATE), serializer);
        serializer.endTag(null, "screen_wifi");

        serializer.startTag(null, "screen_other");
        xmlExport(getSharedPreferences("screen_other", Context.MODE_PRIVATE), serializer);
        serializer.endTag(null, "screen_other");

        serializer.endTag(null, "netguard");
        serializer.endDocument();
        serializer.flush();
    }

    private void xmlExport(SharedPreferences prefs, XmlSerializer serializer) throws IOException {
        Map<String, ?> settings = prefs.getAll();
        for (String key : settings.keySet()) {
            Object value = settings.get(key);

            if ("imported".equals(key))
                continue;

            if (value instanceof Boolean) {
                serializer.startTag(null, "setting");
                serializer.attribute(null, "key", key);
                serializer.attribute(null, "type", "boolean");
                serializer.attribute(null, "value", value.toString());
                serializer.endTag(null, "setting");

            } else if (value instanceof Integer) {
                serializer.startTag(null, "setting");
                serializer.attribute(null, "key", key);
                serializer.attribute(null, "type", "integer");
                serializer.attribute(null, "value", value.toString());
                serializer.endTag(null, "setting");

            } else if (value instanceof String) {
                serializer.startTag(null, "setting");
                serializer.attribute(null, "key", key);
                serializer.attribute(null, "type", "string");
                serializer.attribute(null, "value", value.toString());
                serializer.endTag(null, "setting");

            } else if (value instanceof Set) {
                Set<String> set = (Set<String>) value;
                serializer.startTag(null, "setting");
                serializer.attribute(null, "key", key);
                serializer.attribute(null, "type", "set");
                serializer.attribute(null, "value", TextUtils.join("\n", set));
                serializer.endTag(null, "setting");

            } else
                Log.e(TAG, "Unknown key=" + key);
        }
    }

    private void xmlImport(InputStream in) throws IOException, SAXException, ParserConfigurationException {
        SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
        prefs.edit().putBoolean("enabled", false).apply();
        SinkholeService.stop("import", this);

        XMLReader reader = SAXParserFactory.newInstance().newSAXParser().getXMLReader();
        XmlImportHandler handler = new XmlImportHandler();
        reader.setContentHandler(handler);
        reader.parse(new InputSource(in));

        xmlImport(handler.application, prefs);
        xmlImport(handler.wifi, getSharedPreferences("wifi", Context.MODE_PRIVATE));
        xmlImport(handler.mobile, getSharedPreferences("other", Context.MODE_PRIVATE));
        xmlImport(handler.unused, getSharedPreferences("unused", Context.MODE_PRIVATE));
        xmlImport(handler.screen_wifi, getSharedPreferences("screen_wifi", Context.MODE_PRIVATE));
        xmlImport(handler.screen_other, getSharedPreferences("screen_other", Context.MODE_PRIVATE));
        xmlImport(handler.roaming, getSharedPreferences("roaming", Context.MODE_PRIVATE));

        // Upgrade imported settings
        Receiver.upgrade(true, this);

        // Refresh UI
        prefs.edit().putBoolean("imported", true).apply();
    }

    private void xmlImport(Map<String, Object> settings, SharedPreferences prefs) {
        SharedPreferences.Editor editor = prefs.edit();

        // Clear existing setting
        for (String key : prefs.getAll().keySet())
            if (!"enabled".equals(key))
                editor.remove(key);

        // Apply new settings
        for (String key : settings.keySet()) {
            Object value = settings.get(key);
            if (value instanceof Boolean)
                editor.putBoolean(key, (Boolean) value);
            else if (value instanceof Integer)
                editor.putInt(key, (Integer) value);
            else if (value instanceof String)
                editor.putString(key, (String) value);
            else if (value instanceof Set)
                editor.putStringSet(key, (Set<String>) value);
            else
                Log.e(TAG, "Unknown type=" + value.getClass());
        }

        editor.apply();
    }

    private class XmlImportHandler extends DefaultHandler {
        public boolean enabled = false;
        public Map<String, Object> application = new HashMap<>();
        public Map<String, Object> wifi = new HashMap<>();
        public Map<String, Object> mobile = new HashMap<>();
        public Map<String, Object> unused = new HashMap<>();
        public Map<String, Object> screen_wifi = new HashMap<>();
        public Map<String, Object> screen_other = new HashMap<>();
        public Map<String, Object> roaming = new HashMap<>();
        private Map<String, Object> current = null;

        @Override
        public void startElement(String uri, String localName, String qName, Attributes attributes) {
            if (qName.equals("netguard"))
                ; // Ignore

            else if (qName.equals("application"))
                current = application;

            else if (qName.equals("wifi"))
                current = wifi;

            else if (qName.equals("mobile"))
                current = mobile;

            else if (qName.equals("unused"))
                current = unused;

            else if (qName.equals("screen_wifi"))
                current = screen_wifi;

            else if (qName.equals("screen_other"))
                current = screen_other;

            else if (qName.equals("roaming"))
                current = roaming;

            else if (qName.equals("setting")) {
                String key = attributes.getValue("key");
                String type = attributes.getValue("type");
                String value = attributes.getValue("value");

                if (current == null)
                    Log.e(TAG, "No current key=" + key);
                else {
                    if ("enabled".equals(key))
                        enabled = Boolean.parseBoolean(value);
                    else {
                        if ("boolean".equals(type))
                            current.put(key, Boolean.parseBoolean(value));
                        else if ("integer".equals(type))
                            current.put(key, Integer.parseInt(value));
                        else if ("string".equals(type))
                            current.put(key, value);
                        else if ("set".equals(type)) {
                            Set<String> set = new HashSet<>();
                            for (String s : value.split("\n"))
                                set.add(s);
                            current.put(key, set);
                        } else
                            Log.e(TAG, "Unknown type key=" + key);
                    }
                }

            } else
                Log.e(TAG, "Unknown element qname=" + qName);
        }
    }
}