using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Net.NetworkInformation;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace KurtzPelRegionPicker
{
    /// <summary>
    /// Logique d'interaction pour MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public const string HOSTS_PATH = @"C:\Windows\System32\drivers\etc\hosts";
        public const string COMMENT = "# KurtzPelRegionPicker";
        // language=regex
        public const string IP_REGEX = @"\[(?<ip>.+)\]";

        private List<Region> _regions = new List<Region>()
        {
            new Region("Europe", "gs.live.europe.kurtzpel.playkog.com"),
            new Region("America", "gs.live.northamerica.kurtzpel.playkog.com"),
            new Region("Test", "gs.qa1.japan.kurtzpel.playkog.com")
        };

        public MainWindow()
        {
            InitializeComponent();

            ComboBox_Source_Region.ItemsSource = _regions.Where(x => x.Name != "Test");
            ComboBox_Fake_Region.ItemsSource = _regions;
        }

        private void Button_Apply_Click(object sender, RoutedEventArgs e)
        {
            if (ComboBox_Source_Region.SelectedItem is Region source && ComboBox_Fake_Region.SelectedItem is Region destination)
            {
                ApplyRegion(source, destination);

                MessageBox.Show("Region applied", "Success", MessageBoxButton.OK, MessageBoxImage.Information);
                Environment.Exit(0);
            }
        }

        private void Button_Reset_Click(object sender, RoutedEventArgs e)
        {
            ResetRegion();

            MessageBox.Show("Region reset", "Success", MessageBoxButton.OK, MessageBoxImage.Information);
        }

        private void ApplyRegion(Region source, Region destination)
        {
            string[] content = File.ReadAllLines(HOSTS_PATH);
            string[] newContent;

            if (content.Contains(COMMENT))
            {
                // Purge
                int index = content.IndexOf(COMMENT);

                var list = content.ToList();

                list.RemoveAt(index);
                list.RemoveAt(index);

                content = list.ToArray();
                File.WriteAllLines(HOSTS_PATH, content);
            }

            string line = $"{GetRealIP(destination.DNS)}    {source.DNS}";

            newContent = new string[content.Length + 2];
            content.CopyTo(newContent, 0);

            newContent[newContent.Length - 2] = COMMENT;
            newContent[newContent.Length - 1] = line;

            File.WriteAllLines(HOSTS_PATH, newContent);
        }

        private void ResetRegion()
        {
            string[] content = File.ReadAllLines(HOSTS_PATH);

            if (content.Contains(COMMENT))
            {
                // Purge
                int index = content.IndexOf(COMMENT);

                var list = content.ToList();

                list.RemoveAt(index);
                list.RemoveAt(index);

                content = list.ToArray();
                File.WriteAllLines(HOSTS_PATH, content);
            }
        }

        private string GetRealIP(string dns)
        {
            var process = new Process()
            {
                StartInfo = new ProcessStartInfo("ping.exe", $"-n 1 -w 10 {dns}")
                {
                    CreateNoWindow = true,
                    RedirectStandardOutput = true,
                    UseShellExecute = false,
                    WindowStyle = ProcessWindowStyle.Hidden
                }
            };

            process.Start();
            process.WaitForExit();

            string output = process.StandardOutput.ReadToEnd();
            string ip = Regex.Match(output, IP_REGEX).Groups["ip"].Value;

            if (ip == "")
            {
                MessageBox.Show($"Can't resolve hostname: {dns}", "Error", MessageBoxButton.OK, MessageBoxImage.Error);
                Environment.Exit(1);
            }

            return ip;
        }
    }
}