using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading;
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.Threading;

namespace Tango.PPC.Updater
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        private String _sourceFolder = AppDomain.CurrentDomain.BaseDirectory;
        private String _msProcessName = "Tango.PPC.UI";
        private String _appPath;

        public MainWindow()
        {
            //Launch debugger..
            //#if DEBUG
            //            if (!Debugger.IsAttached)
            //            {
            //                Debugger.Launch();
            //            }
            //#endif

            InitializeComponent();

            WindowStyle = WindowStyle.None;
            ResizeMode = ResizeMode.NoResize;
            WindowStartupLocation = WindowStartupLocation.Manual;
            Topmost = true; // sure?

            var screens = System.Windows.Forms.Screen.AllScreens;

            //Search for the vertical touch monitor.
            var touch_screen = screens.Where(x => x.Bounds.Height > x.Bounds.Width).LastOrDefault();

            if (touch_screen != null)
            {
                Left = touch_screen.Bounds.Left;
                Top = touch_screen.Bounds.Top;
                Width = touch_screen.Bounds.Width;
                Height = touch_screen.Bounds.Height;
            }

            ContentRendered += MainWindow_ContentRendered;
        }

        private void MainWindow_ContentRendered(object sender, EventArgs e)
        {
            Update();
        }

        private void Update()
        {
            try
            {
                Init();
                EnsureTangoIsDown();
                RemoveOldDLLFiles();
                ReplaceFiles();

                txtStatus.Text = "Update completed. Starting application...";
                DoEvents();
                Thread.Sleep(1000);
                StartTango(true);
            }
            catch (Exception ex)
            {
                ShowError($"Update failed.\n{ex.Message}");
                StartTango(false);
            }
            finally
            {
                Environment.Exit(0);
            }
        }

        private void Init()
        {
            try
            {
                _appPath = String.Join(" ", App.StartupArgs);
            }
            catch
            {
                throw new ArgumentException("Error parsing startup arguments.");
            }

            if (!Directory.Exists(_appPath))
            {
                throw new InvalidOperationException("This update utility can only be executed by the main Tango application.");
            }
        }

        private void StartTango(bool success)
        {
            Process p = new Process();
            p.StartInfo.FileName = _appPath + "\\" + _msProcessName + ".exe";
            p.StartInfo.LoadUserProfile = true;
            p.StartInfo.UseShellExecute = true;

            if (success)
            {
                p.StartInfo.Arguments = "-update_ok";
            }

            p.Start();
        }

        private void ReplaceFiles()
        {
            int maxProgress = Directory.GetFiles(_sourceFolder, "*.*", SearchOption.AllDirectories).Length;
            int progress = 0;

            foreach (string dirPath in Directory.GetDirectories(_sourceFolder, "*", SearchOption.AllDirectories))
            {
                try
                {
                    Directory.CreateDirectory(dirPath.Replace(_sourceFolder, _appPath));
                }
                catch (Exception ex)
                {
                    ShowError("Could not create directory " + Path.GetFileName(dirPath) + Environment.NewLine + ex.Message);
                }
            }

            foreach (string newPath in Directory.GetFiles(_sourceFolder, "*.*", SearchOption.AllDirectories))
            {
                try
                {
                    txtStatus.Text = "Copying file " + Path.GetFileName(newPath);
                    DoEvents();

                    File.Copy(newPath, newPath.Replace(_sourceFolder, _appPath), true);

                    prog.Maximum = maxProgress;
                    prog.Value = progress++;
                    DoEvents();

                    Thread.Sleep(10);
                }
                catch (Exception ex)
                {
                    if (!newPath.ToLower().Contains("updater.exe"))
                    {
                        ShowError("Could not create file " + Path.GetFileName(newPath) + Environment.NewLine + ex.Message);
                    }
                }
            }
        }

        private void RemoveOldDLLFiles()
        {
            foreach (string dll in Directory.GetFiles(_appPath, "*.dll"))
            {
                try
                {
                    File.Delete(dll);
                }
                catch
                {
                    ShowError($"The file '{Path.GetFileName(dll)}' could not be removed. Please close all instances of Tango and press OK.");
                    RemoveOldDLLFiles();
                    return;
                }
            }
        }

        private void EnsureTangoIsDown()
        {
            Process appProcess = null;

            int tries = 0;

            do
            {
                appProcess = Process.GetProcessesByName(_msProcessName).FirstOrDefault();
                Process p = new Process();
                p.StartInfo.CreateNoWindow = true;
                p.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
                p.StartInfo.FileName = "wmic";
                p.StartInfo.Arguments = String.Format("process where name='{0}' delete", _msProcessName);

                if (appProcess != null)
                {
                    tries++;
                    appProcess.Kill();

                    try
                    {
                        p.Start();
                    }
                    catch { }

                    Thread.Sleep(1000);
                }

                if (tries > 10)
                {
                    throw new IOException("The main Tango process seems to in a frozen state. Please restart your computer and try again.");
                }

            } while (appProcess != null);
        }

        /// <summary>
        /// Forces UI rendering.
        /// </summary>
        private void DoEvents()
        {
            Application.Current.Dispatcher.Invoke(DispatcherPriority.Background, new Action(delegate { }));
        }

        private void ShowError(String error)
        {
            MessageBox.Show(error, "Tango Update", MessageBoxButton.OK, MessageBoxImage.Error);
        }
    }
}