package org.pihole.dnsproxy;

import android.app.Notification;
import android.app.NotificationChannel;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.app.Service;

import android.content.Context;
import android.content.Intent;

import android.net.DhcpInfo;
import android.net.VpnService;
import android.net.wifi.WifiManager;

import android.util.Log;

import java.net.InetAddress;

public class DNSProxyService extends VpnService {

    public static String LOG_TAG = "org.pihole.dnsproxy.log";
    public static String NOTIFICATION = "org.pihole.dnsproxy.service";
    public static String NOTIFICATION_CHANNEL_ID = "PiholeDNSProxy";
    public static String ACTION_START = "org.pihole.dnsproxy.service.START";
    public static String ACTION_STOP = "org.pihole.dnsproxy.service.STOP";

    public static String PIHOLE_ADDRESS = "";

    private static DNSProxyConnection connection;

    @Override
    public int onStartCommand(Intent intent, int flags, int startId)    {
        if (intent.getAction().equals(DNSProxyService.ACTION_START)) {
            this.start();

            return Service.START_STICKY;
        } else {
            this.stop();

            return Service.START_NOT_STICKY;
        }
    }

    @Override
    public void onDestroy() {
        this.stop();

        super.onDestroy();
    }

    public VpnService.Builder newBuilder() {
        return new VpnService.Builder();
    }

    public static boolean isRunning()
    {
        return DNSProxyService.connection != null;
    }

    public void start() {
        this.setPiholeAddress();

        DNSProxyService.connection = new DNSProxyConnection(this);
        DNSProxyService.connection.start();

        this.startForeground();

        // send notification when started
        Intent notification = new Intent(DNSProxyService.NOTIFICATION);
        sendBroadcast(notification);
    }

    public void stop() {
        DNSProxyService.connection.stop();
        DNSProxyService.connection = null;

        stopForeground(true);

        // send notification when stopped
        Intent notification = new Intent(DNSProxyService.NOTIFICATION);
        sendBroadcast(notification);
    }

    private void setPiholeAddress() {
        WifiManager manager = (WifiManager) getSystemService(WIFI_SERVICE);
        DhcpInfo info = manager.getDhcpInfo();

        byte[] addressBytes = {
            (byte) (0xff & info.dns1),
            (byte) (0xff & (info.dns1 >> 8)),
            (byte) (0xff & (info.dns1 >> 16)),
            (byte) (0xff & (info.dns1 >> 24)),
        };

        try {
            DNSProxyService.PIHOLE_ADDRESS = InetAddress.getByAddress(addressBytes).toString().replaceAll("/", "");
        } catch (Exception e) {
            DNSProxyService.PIHOLE_ADDRESS = "";
        }
    }

    private void startForeground() {
        NotificationManager manager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);

        NotificationChannel channel = new NotificationChannel(
            DNSProxyService.NOTIFICATION_CHANNEL_ID, DNSProxyService.NOTIFICATION_CHANNEL_ID, NotificationManager.IMPORTANCE_DEFAULT
        );
        manager.createNotificationChannel(channel);

        Notification notification = new Notification.Builder(this, DNSProxyService.NOTIFICATION_CHANNEL_ID)
            .setSmallIcon(R.drawable.logo)
            .setContentTitle("Pihole DNS Proxy")
            .setContentText("Running with " + DNSProxyService.PIHOLE_ADDRESS)
            // .setContentIntent(PendingIntent.getActivity(this, 0, new Intent(MainActivity.class), PendingIntent.FLAG_IMMUTABLE))
            .build();

        startForeground(1, notification);
    }
}