/*
 * 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.settingslib.deviceinfo;

import android.content.Context;
import android.net.ConnectivityManager;
import android.net.LinkAddress;
import android.net.LinkProperties;
import android.net.wifi.WifiManager;

import androidx.annotation.VisibleForTesting;
import androidx.preference.Preference;
import androidx.preference.PreferenceScreen;

import com.android.settingslib.R;
import com.android.settingslib.core.lifecycle.Lifecycle;

import java.util.Iterator;

/**
 * Preference controller for IP address
 */
public abstract class AbstractIpAddressPreferenceController
        extends AbstractConnectivityPreferenceController {

    @VisibleForTesting
    static final String KEY_IP_ADDRESS = "wifi_ip_address";

    private static final String[] CONNECTIVITY_INTENTS = {
            ConnectivityManager.CONNECTIVITY_ACTION,
            WifiManager.ACTION_LINK_CONFIGURATION_CHANGED,
            WifiManager.NETWORK_STATE_CHANGED_ACTION,
    };

    private Preference mIpAddress;
    private final ConnectivityManager mCM;

    public AbstractIpAddressPreferenceController(Context context, Lifecycle lifecycle) {
        super(context, lifecycle);
        mCM = context.getSystemService(ConnectivityManager.class);
    }

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

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

    @Override
    public void displayPreference(PreferenceScreen screen) {
        super.displayPreference(screen);
        mIpAddress = screen.findPreference(KEY_IP_ADDRESS);
        updateConnectivity();
    }

    @Override
    protected String[] getConnectivityIntents() {
        return CONNECTIVITY_INTENTS;
    }

    @Override
    protected void updateConnectivity() {
        String ipAddress = getDefaultIpAddresses(mCM);
        if (ipAddress != null) {
            mIpAddress.setSummary(ipAddress);
        } else {
            mIpAddress.setSummary(R.string.status_unavailable);
        }
    }

    /**
     * Returns the default link's IP addresses, if any, taking into account IPv4 and IPv6 style
     * addresses.
     * @param cm ConnectivityManager
     * @return the formatted and newline-separated IP addresses, or null if none.
     */
    private static String getDefaultIpAddresses(ConnectivityManager cm) {
        LinkProperties prop = cm.getLinkProperties(cm.getActiveNetwork());
        return formatIpAddresses(prop);
    }

    private static String formatIpAddresses(LinkProperties prop) {
        if (prop == null) return null;
        Iterator<LinkAddress> iter = prop.getAllLinkAddresses().iterator();
        // If there are no entries, return null
        if (!iter.hasNext()) return null;
        // Concatenate all available addresses, newline separated
        StringBuilder addresses = new StringBuilder();
        while (iter.hasNext()) {
            addresses.append(iter.next().getAddress().getHostAddress());
            if (iter.hasNext()) addresses.append("\n");
        }
        return addresses.toString();
    }
}