/*
 * Copyright (C) 2008 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.providers.settings;

import android.annotation.NonNull;
import android.app.ActivityManager;
import android.app.IActivityManager;
import android.app.backup.IBackupManager;
import android.content.ContentResolver;
import android.content.ContentValues;
import android.content.Context;
import android.content.Intent;
import android.content.res.Configuration;
import android.icu.util.ULocale;
import android.media.AudioManager;
import android.media.RingtoneManager;
import android.net.Uri;
import android.os.LocaleList;
import android.os.RemoteException;
import android.os.ServiceManager;
import android.os.UserHandle;
import android.provider.Settings;
import android.telephony.TelephonyManager;
import android.text.TextUtils;
import android.util.ArraySet;

import com.android.internal.annotations.VisibleForTesting;
import com.android.internal.app.LocalePicker;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Locale;

public class SettingsHelper {
    private static final String TAG = "SettingsHelper";
    private static final String SILENT_RINGTONE = "_silent";
    private static final String SETTINGS_REPLACED_KEY = "backup_skip_user_facing_data";
    private static final String SETTING_ORIGINAL_KEY_SUFFIX = "_original";
    private static final float FLOAT_TOLERANCE = 0.01f;

    private Context mContext;
    private AudioManager mAudioManager;
    private TelephonyManager mTelephonyManager;

    /**
     * A few settings elements are special in that a restore of those values needs to
     * be post-processed by relevant parts of the OS.  A restore of any settings element
     * mentioned in this table will therefore cause the system to send a broadcast with
     * the {@link Intent#ACTION_SETTING_RESTORED} action, with extras naming the
     * affected setting and supplying its pre-restore value for comparison.
     *
     * @see Intent#ACTION_SETTING_RESTORED
     * @see System#SETTINGS_TO_BACKUP
     * @see Secure#SETTINGS_TO_BACKUP
     * @see Global#SETTINGS_TO_BACKUP
     *
     * {@hide}
     */
    private static final ArraySet<String> sBroadcastOnRestore;
    static {
        sBroadcastOnRestore = new ArraySet<String>(4);
        sBroadcastOnRestore.add(Settings.Secure.ENABLED_NOTIFICATION_LISTENERS);
        sBroadcastOnRestore.add(Settings.Secure.ENABLED_VR_LISTENERS);
        sBroadcastOnRestore.add(Settings.Secure.ENABLED_ACCESSIBILITY_SERVICES);
        sBroadcastOnRestore.add(Settings.Global.BLUETOOTH_ON);
        sBroadcastOnRestore.add(Settings.Secure.UI_NIGHT_MODE);
        sBroadcastOnRestore.add(Settings.Secure.DARK_THEME_CUSTOM_START_TIME);
        sBroadcastOnRestore.add(Settings.Secure.DARK_THEME_CUSTOM_END_TIME);
        sBroadcastOnRestore.add(Settings.Secure.ACCESSIBILITY_DISPLAY_MAGNIFICATION_NAVBAR_ENABLED);
    }

    private interface SettingsLookup {
        public String lookup(ContentResolver resolver, String name, int userHandle);
    }

    private static SettingsLookup sSystemLookup = new SettingsLookup() {
        public String lookup(ContentResolver resolver, String name, int userHandle) {
            return Settings.System.getStringForUser(resolver, name, userHandle);
        }
    };

    private static SettingsLookup sSecureLookup = new SettingsLookup() {
        public String lookup(ContentResolver resolver, String name, int userHandle) {
            return Settings.Secure.getStringForUser(resolver, name, userHandle);
        }
    };

    private static SettingsLookup sGlobalLookup = new SettingsLookup() {
        public String lookup(ContentResolver resolver, String name, int userHandle) {
            return Settings.Global.getStringForUser(resolver, name, userHandle);
        }
    };

    public SettingsHelper(Context context) {
        mContext = context;
        mAudioManager = (AudioManager) context
                .getSystemService(Context.AUDIO_SERVICE);
        mTelephonyManager = (TelephonyManager) context
                .getSystemService(Context.TELEPHONY_SERVICE);
    }

    /**
     * Sets the property via a call to the appropriate API, if any, and returns
     * whether or not the setting should be saved to the database as well.
     * @param name the name of the setting
     * @param value the string value of the setting
     * @return whether to continue with writing the value to the database. In
     * some cases the data will be written by the call to the appropriate API,
     * and in some cases the property value needs to be modified before setting.
     */
    public void restoreValue(Context context, ContentResolver cr, ContentValues contentValues,
            Uri destination, String name, String value, int restoredFromSdkInt) {
        if (isReplacedSystemSetting(name)) {
            return;
        }

        // Will we need a post-restore broadcast for this element?
        String oldValue = null;
        boolean sendBroadcast = false;
        final SettingsLookup table;

        if (destination.equals(Settings.Secure.CONTENT_URI)) {
            table = sSecureLookup;
        } else if (destination.equals(Settings.System.CONTENT_URI)) {
            table = sSystemLookup;
        } else { /* must be GLOBAL; this was preflighted by the caller */
            table = sGlobalLookup;
        }

        if (sBroadcastOnRestore.contains(name)) {
            // TODO: http://b/22388012
            oldValue = table.lookup(cr, name, UserHandle.USER_SYSTEM);
            sendBroadcast = true;
        }

        try {
            if (Settings.System.SOUND_EFFECTS_ENABLED.equals(name)) {
                setSoundEffects(Integer.parseInt(value) == 1);
                // fall through to the ordinary write to settings
            } else if (Settings.Secure.BACKUP_AUTO_RESTORE.equals(name)) {
                setAutoRestore(Integer.parseInt(value) == 1);
            } else if (isAlreadyConfiguredCriticalAccessibilitySetting(name)) {
                return;
            } else if (Settings.System.RINGTONE.equals(name)
                    || Settings.System.NOTIFICATION_SOUND.equals(name)
                    || Settings.System.ALARM_ALERT.equals(name)) {
                setRingtone(name, value);
                return;
            }

            // Default case: write the restored value to settings
            contentValues.clear();
            contentValues.put(Settings.NameValueTable.NAME, name);
            contentValues.put(Settings.NameValueTable.VALUE, value);
            cr.insert(destination, contentValues);
        } catch (Exception e) {
            // If we fail to apply the setting, by definition nothing happened
            sendBroadcast = false;
        } finally {
            // If this was an element of interest, send the "we just restored it"
            // broadcast with the historical value now that the new value has
            // been committed and observers kicked off.
            if (sendBroadcast) {
                Intent intent = new Intent(Intent.ACTION_SETTING_RESTORED)
                        .setPackage("android").addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY)
                        .putExtra(Intent.EXTRA_SETTING_NAME, name)
                        .putExtra(Intent.EXTRA_SETTING_NEW_VALUE, value)
                        .putExtra(Intent.EXTRA_SETTING_PREVIOUS_VALUE, oldValue)
                        .putExtra(Intent.EXTRA_SETTING_RESTORED_FROM_SDK_INT, restoredFromSdkInt);
                context.sendBroadcastAsUser(intent, UserHandle.SYSTEM, null);
            }
        }
    }

    public String onBackupValue(String name, String value) {
        // Special processing for backing up ringtones & notification sounds
        if (Settings.System.RINGTONE.equals(name)
                || Settings.System.NOTIFICATION_SOUND.equals(name)
                || Settings.System.ALARM_ALERT.equals(name)) {
            if (value == null) {
                if (Settings.System.RINGTONE.equals(name)) {
                    // For ringtones, we need to distinguish between non-telephony vs telephony
                    if (mTelephonyManager != null && mTelephonyManager.isVoiceCapable()) {
                        // Backup a null ringtone as silent on voice-capable devices
                        return SILENT_RINGTONE;
                    } else {
                        // Skip backup of ringtone on non-telephony devices.
                        return null;
                    }
                } else {
                    // Backup a null notification sound or alarm alert as silent
                    return SILENT_RINGTONE;
                }
            } else {
                return getCanonicalRingtoneValue(value);
            }
        }
        // Return the original value
        return isReplacedSystemSetting(name) ? getRealValueForSystemSetting(name) : value;
    }

    /**
     * The setting value might have been replaced temporarily. If that's the case, return the real
     * value instead of the temporary one.
     */
    @VisibleForTesting
    public String getRealValueForSystemSetting(String setting) {
        // The real value irrespectively of the original setting's namespace is stored in
        // Settings.Secure.
        return Settings.Secure.getString(mContext.getContentResolver(),
                setting + SETTING_ORIGINAL_KEY_SUFFIX);
    }

    @VisibleForTesting
    public boolean isReplacedSystemSetting(String setting) {
        // This list should not be modified.
        if (!Settings.System.SCREEN_OFF_TIMEOUT.equals(setting)) {
            return false;
        }
        // If this flag is set, values for the system settings from the list above have been
        // temporarily replaced. We don't want to back up the temporary value or run restore for
        // such settings.
        // TODO(154822946): Remove this logic in the next release.
        return Settings.Secure.getInt(mContext.getContentResolver(), SETTINGS_REPLACED_KEY,
                /* def */ 0) != 0;
    }

    /**
     * Sets the ringtone of type specified by the name.
     *
     * @param name should be Settings.System.RINGTONE, Settings.System.NOTIFICATION_SOUND
     * or Settings.System.ALARM_ALERT.
     * @param value can be a canonicalized uri or "_silent" to indicate a silent (null) ringtone.
     */
    private void setRingtone(String name, String value) {
        // If it's null, don't change the default
        if (value == null) return;
        final Uri ringtoneUri;
        if (SILENT_RINGTONE.equals(value)) {
            ringtoneUri = null;
        } else {
            Uri canonicalUri = Uri.parse(value);
            ringtoneUri = mContext.getContentResolver().uncanonicalize(canonicalUri);
            if (ringtoneUri == null) {
                // Unrecognized or invalid Uri, don't restore
                return;
            }
        }
        final int ringtoneType = getRingtoneType(name);

        RingtoneManager.setActualDefaultRingtoneUri(mContext, ringtoneType, ringtoneUri);
    }

    private int getRingtoneType(String name) {
        switch (name) {
            case Settings.System.RINGTONE:
                return RingtoneManager.TYPE_RINGTONE;
            case Settings.System.NOTIFICATION_SOUND:
                return RingtoneManager.TYPE_NOTIFICATION;
            case Settings.System.ALARM_ALERT:
                return RingtoneManager.TYPE_ALARM;
            default:
                throw new IllegalArgumentException("Incorrect ringtone name: " + name);
        }
    }

    private String getCanonicalRingtoneValue(String value) {
        final Uri ringtoneUri = Uri.parse(value);
        final Uri canonicalUri = mContext.getContentResolver().canonicalize(ringtoneUri);
        return canonicalUri == null ? null : canonicalUri.toString();
    }

    private boolean isAlreadyConfiguredCriticalAccessibilitySetting(String name) {
        // These are the critical accessibility settings that are required for users with
        // accessibility needs to be able to interact with the device. If these settings are
        // already configured, we will not overwrite them. If they are already set,
        // it means that the user has performed a global gesture to enable accessibility or set
        // these settings in the Accessibility portion of the Setup Wizard, and definitely needs
        // these features working after the restore.
        switch (name) {
            case Settings.Secure.ACCESSIBILITY_ENABLED:
            case Settings.Secure.TOUCH_EXPLORATION_ENABLED:
            case Settings.Secure.ACCESSIBILITY_DISPLAY_DALTONIZER_ENABLED:
            case Settings.Secure.ACCESSIBILITY_DISPLAY_MAGNIFICATION_ENABLED:
            case Settings.Secure.ACCESSIBILITY_DISPLAY_MAGNIFICATION_NAVBAR_ENABLED:
                return Settings.Secure.getInt(mContext.getContentResolver(), name, 0) != 0;
            case Settings.Secure.TOUCH_EXPLORATION_GRANTED_ACCESSIBILITY_SERVICES:
            case Settings.Secure.ENABLED_ACCESSIBILITY_SERVICES:
            case Settings.Secure.ACCESSIBILITY_DISPLAY_DALTONIZER:
                return !TextUtils.isEmpty(Settings.Secure.getString(
                        mContext.getContentResolver(), name));
            case Settings.Secure.ACCESSIBILITY_DISPLAY_MAGNIFICATION_SCALE:
                float defaultScale = mContext.getResources().getFraction(
                        R.fraction.def_accessibility_display_magnification_scale, 1, 1);
                float currentScale = Settings.Secure.getFloat(
                        mContext.getContentResolver(), name, defaultScale);
                return Math.abs(currentScale - defaultScale) >= FLOAT_TOLERANCE;
            case Settings.System.FONT_SCALE:
                return Settings.System.getFloat(mContext.getContentResolver(), name, 1.0f) != 1.0f;
            default:
                return false;
        }
    }

    private void setAutoRestore(boolean enabled) {
        try {
            IBackupManager bm = IBackupManager.Stub.asInterface(
                    ServiceManager.getService(Context.BACKUP_SERVICE));
            if (bm != null) {
                bm.setAutoRestore(enabled);
            }
        } catch (RemoteException e) {}
    }

    private void setSoundEffects(boolean enable) {
        if (enable) {
            mAudioManager.loadSoundEffects();
        } else {
            mAudioManager.unloadSoundEffects();
        }
    }

    /* package */ byte[] getLocaleData() {
        Configuration conf = mContext.getResources().getConfiguration();
        return conf.getLocales().toLanguageTags().getBytes();
    }

    private static Locale toFullLocale(@NonNull Locale locale) {
        if (locale.getScript().isEmpty() || locale.getCountry().isEmpty()) {
            return ULocale.addLikelySubtags(ULocale.forLocale(locale)).toLocale();
        }
        return locale;
    }

    /**
     * Merging the locale came from backup server and current device locale.
     *
     * Merge works with following rules.
     * - The backup locales are appended to the current locale with keeping order.
     *   e.g. current locale "en-US,zh-CN" and backup locale "ja-JP,ko-KR" are merged to
     *   "en-US,zh-CH,ja-JP,ko-KR".
     *
     * - Duplicated locales are dropped.
     *   e.g. current locale "en-US,zh-CN" and backup locale "ja-JP,zh-Hans-CN,en-US" are merged to
     *   "en-US,zh-CN,ja-JP".
     *
     * - Unsupported locales are dropped.
     *   e.g. current locale "en-US" and backup locale "ja-JP,zh-CN" but the supported locales
     *   are "en-US,zh-CN", the merged locale list is "en-US,zh-CN".
     *
     * - The final result locale list only contains the supported locales.
     *   e.g. current locale "en-US" and backup locale "zh-Hans-CN" and supported locales are
     *   "en-US,zh-CN", the merged locale list is "en-US,zh-CN".
     *
     * @param restore The locale list that came from backup server.
     * @param current The device's locale setting.
     * @param supportedLocales The list of language tags supported by this device.
     */
    @VisibleForTesting
    public static LocaleList resolveLocales(LocaleList restore, LocaleList current,
            String[] supportedLocales) {
        final HashMap<Locale, Locale> allLocales = new HashMap<>(supportedLocales.length);
        for (String supportedLocaleStr : supportedLocales) {
            final Locale locale = Locale.forLanguageTag(supportedLocaleStr);
            allLocales.put(toFullLocale(locale), locale);
        }

        final ArrayList<Locale> filtered = new ArrayList<>(current.size());
        for (int i = 0; i < current.size(); i++) {
            final Locale locale = current.get(i);
            allLocales.remove(toFullLocale(locale));
            filtered.add(locale);
        }

        for (int i = 0; i < restore.size(); i++) {
            final Locale locale = allLocales.remove(toFullLocale(restore.get(i)));
            if (locale != null) {
                filtered.add(locale);
            }
        }

        if (filtered.size() == current.size()) {
            return current;  // Nothing added to current locale list.
        }

        return new LocaleList(filtered.toArray(new Locale[filtered.size()]));
    }

    /**
     * Sets the locale specified. Input data is the byte representation of comma separated
     * multiple BCP-47 language tags. For backwards compatibility, strings of the form
     * {@code ll_CC} are also accepted, where {@code ll} is a two letter language
     * code and {@code CC} is a two letter country code.
     *
     * @param data the comma separated BCP-47 language tags in bytes.
     */
    /* package */ void setLocaleData(byte[] data, int size) {
        final Configuration conf = mContext.getResources().getConfiguration();

        // Replace "_" with "-" to deal with older backups.
        final String localeCodes = new String(data, 0, size).replace('_', '-');
        final LocaleList localeList = LocaleList.forLanguageTags(localeCodes);
        if (localeList.isEmpty()) {
            return;
        }

        final String[] supportedLocales = LocalePicker.getSupportedLocales(mContext);
        final LocaleList currentLocales = conf.getLocales();

        final LocaleList merged = resolveLocales(localeList, currentLocales, supportedLocales);
        if (merged.equals(currentLocales)) {
            return;
        }

        try {
            IActivityManager am = ActivityManager.getService();
            Configuration config = am.getConfiguration();
            config.setLocales(merged);
            // indicate this isn't some passing default - the user wants this remembered
            config.userSetLocale = true;

            am.updatePersistentConfiguration(config);
        } catch (RemoteException e) {
            // Intentionally left blank
        }
    }

    /**
     * Informs the audio service of changes to the settings so that
     * they can be re-read and applied.
     */
    void applyAudioSettings() {
        AudioManager am = new AudioManager(mContext);
        am.reloadAudioSettings();
    }
}