using System;
using System.Diagnostics;
using System.IO;
using System.Threading;
using System.Windows.Forms;
using Microsoft.Win32;

using Shadowsocks.Controller;
using Shadowsocks.Util;
using Shadowsocks.View;

namespace Shadowsocks
{
    static class Program
    {
        private static ShadowsocksController _controller;
        // XXX: Don't change this name
        private static MenuViewController _viewController;

        /// <summary>
        /// 应用程序的主入口点。
        /// </summary>
        [STAThread]
        static void Main()
        {
            // Check OS since we are using dual-mode socket
            if (!Utils.IsWinVistaOrHigher())
            {
                MessageBox.Show(I18N.GetString("Unsupported operating system, use Windows Vista at least."),
                "Shadowsocks Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                return;
            }

            Utils.ReleaseMemory(true);
            using (Mutex mutex = new Mutex(false, $"Global\\Shadowsocks_{Application.StartupPath.GetHashCode()}"))
            {
                Application.SetUnhandledExceptionMode(UnhandledExceptionMode.CatchException);
                // handle UI exceptions
                Application.ThreadException += Application_ThreadException;
                // handle non-UI exceptions
                AppDomain.CurrentDomain.UnhandledException += CurrentDomain_UnhandledException;
                Application.ApplicationExit += Application_ApplicationExit;
                SystemEvents.PowerModeChanged += SystemEvents_PowerModeChanged;
                Application.EnableVisualStyles();
                Application.SetCompatibleTextRenderingDefault(false);
                Application.ApplicationExit += (sender, args) => HotKeys.Destroy();

                if (!mutex.WaitOne(0, false))
                {
                    Process[] oldProcesses = Process.GetProcessesByName("Shadowsocks");
                    if (oldProcesses.Length > 0)
                    {
                        Process oldProcess = oldProcesses[0];
                    }
                    MessageBox.Show(I18N.GetString("Find Shadowsocks icon in your notify tray.")
                        + Environment.NewLine
                        + I18N.GetString("If you want to start multiple Shadowsocks, make a copy in another directory."),
                        I18N.GetString("Shadowsocks is already running."));
                    return;
                }
                Directory.SetCurrentDirectory(Application.StartupPath);
#if DEBUG
                Logging.OpenLogFile();

                // truncate privoxy log file while debugging
                string privoxyLogFilename = Utils.GetTempPath("privoxy.log");
                if (File.Exists(privoxyLogFilename))
                    using (new FileStream(privoxyLogFilename, FileMode.Truncate)) { }
#else
                Logging.OpenLogFile();
#endif
                _controller = new ShadowsocksController();
                _viewController = new MenuViewController(_controller);
                HotKeys.Init();
                _controller.Start();
                Application.Run();
            }
        }

        private static int exited = 0;
        private static void CurrentDomain_UnhandledException(object sender, UnhandledExceptionEventArgs e)
        {
            if (Interlocked.Increment(ref exited) == 1)
            {
                Logging.Error(e.ExceptionObject?.ToString());
                MessageBox.Show(
                    $"{I18N.GetString("Unexpected error, shadowsocks will exit. Please report to")} https://github.com/shadowsocks/shadowsocks-windows/issues {Environment.NewLine}{e.ExceptionObject?.ToString()}",
                    "Shadowsocks non-UI Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                Application.Exit();
            }
        }

        private static void Application_ThreadException(object sender, ThreadExceptionEventArgs e)
        {
            string errorMsg = $"Exception Type: {e.Exception.GetType().Name}{Environment.NewLine}Stack Trace:{Environment.NewLine}{e.Exception.StackTrace}";
            Logging.Error(errorMsg);
            MessageBox.Show(
                $"{I18N.GetString("Unexpected error, shadowsocks will exit. Please report to")} https://github.com/shadowsocks/shadowsocks-windows/issues {Environment.NewLine}{errorMsg}",
                "Shadowsocks UI Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
            Application.Exit();
        }

        private static void SystemEvents_PowerModeChanged(object sender, PowerModeChangedEventArgs e)
        {
            switch (e.Mode)
            {
                case PowerModes.Resume:
                    Logging.Info("os wake up");
                    if (_controller != null)
                    {
                        System.Timers.Timer timer = new System.Timers.Timer(5 * 1000);
                        timer.Elapsed += Timer_Elapsed;
                        timer.AutoReset = false;
                        timer.Enabled = true;
                        timer.Start();
                    }
                    break;
                case PowerModes.Suspend:
                    _controller?.Stop();
                    Logging.Info("os suspend");
                    break;
            }
        }

        private static void Timer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
        {
            try
            {
                _controller?.Start();
            }
            catch (Exception ex)
            {
                Logging.LogUsefulException(ex);
            }
            finally
            {
                try
                {
                    System.Timers.Timer timer = (System.Timers.Timer)sender;
                    timer.Enabled = false;
                    timer.Stop();
                    timer.Dispose();
                }
                catch (Exception ex)
                {
                    Logging.LogUsefulException(ex);
                }
            }
        }

        private static void Application_ApplicationExit(object sender, EventArgs e)
        {
            if (_controller != null)
            {
                _controller.Stop();
                _controller = null;
            }
        }
    }
}