/*
 * Copyright (C) 2019 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.server.wifi;

import android.annotation.Nullable;
import android.content.Context;
import android.net.MacAddress;
import android.net.wifi.SoftApConfiguration;
import android.net.wifi.WifiMigration;
import android.text.TextUtils;
import android.util.Log;

import com.android.server.wifi.util.ApConfigUtil;
import com.android.server.wifi.util.SettingsMigrationDataHolder;
import com.android.server.wifi.util.WifiConfigStoreEncryptionUtil;
import com.android.server.wifi.util.XmlUtil;

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;
import org.xmlpull.v1.XmlSerializer;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

/**
 * Store data for SoftAp
 */
public class SoftApStoreData implements WifiConfigStore.StoreData {
    private static final String TAG = "SoftApStoreData";
    private static final String XML_TAG_SECTION_HEADER_SOFTAP = "SoftAp";
    private static final String XML_TAG_SSID = "SSID";
    private static final String XML_TAG_BSSID = "Bssid";
    private static final String XML_TAG_BAND = "Band";
    private static final String XML_TAG_CHANNEL = "Channel";
    private static final String XML_TAG_HIDDEN_SSID = "HiddenSSID";
    private static final String XML_TAG_SECURITY_TYPE = "SecurityType";
    private static final String XML_TAG_WPA2_PASSPHRASE = "Wpa2Passphrase";
    private static final String XML_TAG_AP_BAND = "ApBand";
    private static final String XML_TAG_PASSPHRASE = "Passphrase";
    private static final String XML_TAG_MAX_NUMBER_OF_CLIENTS = "MaxNumberOfClients";
    private static final String XML_TAG_AUTO_SHUTDOWN_ENABLED = "AutoShutdownEnabled";
    private static final String XML_TAG_SHUTDOWN_TIMEOUT_MILLIS = "ShutdownTimeoutMillis";
    private static final String XML_TAG_CLIENT_CONTROL_BY_USER = "ClientControlByUser";
    private static final String XML_TAG_BLOCKED_CLIENT_LIST = "BlockedClientList";
    private static final String XML_TAG_ALLOWED_CLIENT_LIST = "AllowedClientList";

    private final Context mContext;
    private final SettingsMigrationDataHolder mSettingsMigrationDataHolder;
    private final DataSource mDataSource;

    /**
     * Interface define the data source for the notifier store data.
     */
    public interface DataSource {
        /**
         * Retrieve the SoftAp configuration from the data source to serialize them to disk.
         *
         * @return {@link SoftApConfiguration} Instance of SoftApConfiguration.
         */
        SoftApConfiguration toSerialize();

        /**
         * Set the SoftAp configuration in the data source after serializing them from disk.
         *
         * @param config {@link SoftApConfiguration} Instance of SoftApConfiguration.
         */
        void fromDeserialized(SoftApConfiguration config);

        /**
         * Clear internal data structure in preparation for user switch or initial store read.
         */
        void reset();

        /**
         * Indicates whether there is new data to serialize.
         */
        boolean hasNewDataToSerialize();
    }

    /**
     * Creates the SSID Set store data.
     *
     * @param dataSource The DataSource that implements the update and retrieval of the SSID set.
     */
    SoftApStoreData(Context context, SettingsMigrationDataHolder settingsMigrationDataHolder,
            DataSource dataSource) {
        mContext = context;
        mSettingsMigrationDataHolder = settingsMigrationDataHolder;
        mDataSource = dataSource;
    }

    @Override
    public void serializeData(XmlSerializer out,
            @Nullable WifiConfigStoreEncryptionUtil encryptionUtil)
            throws XmlPullParserException, IOException {
        SoftApConfiguration softApConfig = mDataSource.toSerialize();
        if (softApConfig != null) {
            XmlUtil.writeNextValue(out, XML_TAG_SSID, softApConfig.getSsid());
            if (softApConfig.getBssid() != null) {
                XmlUtil.writeNextValue(out, XML_TAG_BSSID, softApConfig.getBssid().toString());
            }
            XmlUtil.writeNextValue(out, XML_TAG_AP_BAND, softApConfig.getBand());
            XmlUtil.writeNextValue(out, XML_TAG_CHANNEL, softApConfig.getChannel());
            XmlUtil.writeNextValue(out, XML_TAG_HIDDEN_SSID, softApConfig.isHiddenSsid());
            XmlUtil.writeNextValue(out, XML_TAG_SECURITY_TYPE, softApConfig.getSecurityType());
            if (softApConfig.getSecurityType() != SoftApConfiguration.SECURITY_TYPE_OPEN) {
                XmlUtil.writeNextValue(out, XML_TAG_PASSPHRASE,
                        softApConfig.getPassphrase());
            }

            XmlUtil.writeNextValue(out, XML_TAG_MAX_NUMBER_OF_CLIENTS,
                    softApConfig.getMaxNumberOfClients());
            XmlUtil.writeNextValue(out, XML_TAG_CLIENT_CONTROL_BY_USER,
                    softApConfig.isClientControlByUserEnabled());
            XmlUtil.writeNextValue(out, XML_TAG_AUTO_SHUTDOWN_ENABLED,
                    softApConfig.isAutoShutdownEnabled());
            XmlUtil.writeNextValue(out, XML_TAG_SHUTDOWN_TIMEOUT_MILLIS,
                    softApConfig.getShutdownTimeoutMillis());
            XmlUtil.writeNextSectionStart(out, XML_TAG_BLOCKED_CLIENT_LIST);
            XmlUtil.SoftApConfigurationXmlUtil.writeClientListToXml(out,
                    softApConfig.getBlockedClientList());
            XmlUtil.writeNextSectionEnd(out, XML_TAG_BLOCKED_CLIENT_LIST);

            XmlUtil.writeNextSectionStart(out, XML_TAG_ALLOWED_CLIENT_LIST);
            XmlUtil.SoftApConfigurationXmlUtil.writeClientListToXml(out,
                    softApConfig.getAllowedClientList());
            XmlUtil.writeNextSectionEnd(out, XML_TAG_ALLOWED_CLIENT_LIST);
        }
    }

    @Override
    public void deserializeData(XmlPullParser in, int outerTagDepth,
            @WifiConfigStore.Version int version,
            @Nullable WifiConfigStoreEncryptionUtil encryptionUtil)
            throws XmlPullParserException, IOException {
        // Ignore empty reads.
        if (in == null) {
            return;
        }
        SoftApConfiguration.Builder softApConfigBuilder = new SoftApConfiguration.Builder();
        int securityType = SoftApConfiguration.SECURITY_TYPE_OPEN;
        String passphrase = null;
        String ssid = null;
        String bssid = null;
        // Note that, during deserializaion, we may read the old band encoding (XML_TAG_BAND)
        // or the new band encoding (XML_TAG_AP_BAND) that is used after the introduction of the
        // 6GHz band. If the old encoding is found, a conversion is done.
        int channel = -1;
        int apBand = -1;
        List<MacAddress> blockedList = new ArrayList<>();
        List<MacAddress> allowedList = new ArrayList<>();
        boolean autoShutdownEnabledTagPresent = false;
        try {
            while (!XmlUtil.isNextSectionEnd(in, outerTagDepth)) {
                if (in.getAttributeValue(null, "name") != null) {
                    String[] valueName = new String[1];
                    Object value = XmlUtil.readCurrentValue(in, valueName);
                    if (TextUtils.isEmpty(valueName[0])) {
                        throw new XmlPullParserException("Missing value name");
                    }
                    switch (valueName[0]) {
                        case XML_TAG_SSID:
                            ssid = (String) value;
                            softApConfigBuilder.setSsid((String) value);
                            break;
                        case XML_TAG_BSSID:
                            bssid = (String) value;
                            softApConfigBuilder.setBssid(MacAddress.fromString(bssid));
                            break;
                        case XML_TAG_BAND:
                            apBand = ApConfigUtil.convertWifiConfigBandToSoftApConfigBand(
                                    (int) value);
                            break;
                        case XML_TAG_AP_BAND:
                            apBand = (int) value;
                            break;
                        case XML_TAG_CHANNEL:
                            channel = (int) value;
                            break;
                        case XML_TAG_HIDDEN_SSID:
                            softApConfigBuilder.setHiddenSsid((boolean) value);
                            break;
                        case XML_TAG_SECURITY_TYPE:
                            securityType = (int) value;
                            break;
                        case XML_TAG_WPA2_PASSPHRASE:
                        case XML_TAG_PASSPHRASE:
                            passphrase = (String) value;
                            break;
                        case XML_TAG_MAX_NUMBER_OF_CLIENTS:
                            softApConfigBuilder.setMaxNumberOfClients((int) value);
                            break;
                        case XML_TAG_AUTO_SHUTDOWN_ENABLED:
                            softApConfigBuilder.setAutoShutdownEnabled((boolean) value);
                            autoShutdownEnabledTagPresent = true;
                            break;
                        case XML_TAG_SHUTDOWN_TIMEOUT_MILLIS:
                            if (value instanceof Integer) {
                                softApConfigBuilder
                                        .setShutdownTimeoutMillis(Long.valueOf((int) value));
                            } else if (value instanceof Long) {
                                softApConfigBuilder.setShutdownTimeoutMillis((long) value);
                            }
                            break;
                        case XML_TAG_CLIENT_CONTROL_BY_USER:
                            softApConfigBuilder.setClientControlByUserEnabled((boolean) value);
                            break;
                        default:
                            Log.w(TAG, "Ignoring unknown value name " + valueName[0]);
                            break;
                    }
                } else {
                    String tagName = in.getName();
                    List<MacAddress> parseredList;
                    if (tagName == null) {
                        throw new XmlPullParserException("Unexpected null tag found");
                    }
                    switch (tagName) {
                        case XML_TAG_BLOCKED_CLIENT_LIST:
                            parseredList =
                                    XmlUtil.SoftApConfigurationXmlUtil.parseClientListFromXml(
                                    in, outerTagDepth + 1);
                            if (parseredList != null) blockedList = new ArrayList<>(parseredList);
                            break;
                        case XML_TAG_ALLOWED_CLIENT_LIST:
                            parseredList =
                                    XmlUtil.SoftApConfigurationXmlUtil.parseClientListFromXml(
                                    in, outerTagDepth + 1);
                            if (parseredList != null) allowedList = new ArrayList<>(parseredList);
                            break;
                        default:
                            Log.w(TAG, "Ignoring unknown tag found: " + tagName);
                            break;
                    }
                }
            }
            softApConfigBuilder.setBlockedClientList(blockedList);
            softApConfigBuilder.setAllowedClientList(allowedList);
            // Set channel and band
            if (channel == 0) {
                softApConfigBuilder.setBand(apBand);
            } else {
                softApConfigBuilder.setChannel(channel, apBand);
            }

            // We should at-least have SSID restored from store.
            if (ssid == null) {
                Log.e(TAG, "Failed to parse SSID");
                return;
            }
            if (securityType != SoftApConfiguration.SECURITY_TYPE_OPEN) {
                softApConfigBuilder.setPassphrase(passphrase, securityType);
            }
            if (!autoShutdownEnabledTagPresent) {
                // Migrate data out of settings.
                WifiMigration.SettingsMigrationData migrationData =
                        mSettingsMigrationDataHolder.retrieveData();
                if (migrationData == null) {
                    Log.e(TAG, "No migration data present");
                } else {
                    softApConfigBuilder.setAutoShutdownEnabled(
                            migrationData.isSoftApTimeoutEnabled());
                }
            }
        } catch (IllegalArgumentException e) {
            Log.e(TAG, "Failed to parse configuration" + e);
            return;
        }
        mDataSource.fromDeserialized(softApConfigBuilder.setSsid(ssid).build());
    }

    @Override
    public void resetData() {
        mDataSource.reset();
    }

    @Override
    public boolean hasNewDataToSerialize() {
        return mDataSource.hasNewDataToSerialize();
    }

    @Override
    public String getName() {
        return XML_TAG_SECTION_HEADER_SOFTAP;
    }

    @Override
    public @WifiConfigStore.StoreFileId int getStoreFileId() {
        return WifiConfigStore.STORE_FILE_SHARED_SOFTAP; // Shared softap store.
    }
}