#region Using Statements

using System;
using Barotrauma.IO;
using System.Linq;
using System.Text;
using Barotrauma.Steam;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Xml.Linq;
using Barotrauma.Debugging;

#if WINDOWS
using SharpDX;
#endif

#endregion

namespace Barotrauma
{
    /// <summary>
    /// The main class.
    /// </summary>
    public static class Program
    {

#if LINUX
        /// <summary>
        /// Sets the required environment variables for the game to initialize Steamworks correctly.
        /// </summary>
        [DllImport("linux_steam_env", CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Ansi)]
        private static extern void setLinuxEnv();
#endif

        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main(string[] args)
        {
            string executableDir = "";

#if !DEBUG
            AppDomain currentDomain = AppDomain.CurrentDomain;
            currentDomain.UnhandledException += new UnhandledExceptionEventHandler(CrashHandler);
#endif

#if LINUX
            setLinuxEnv();
#endif

            Game = null;
            executableDir = Path.GetDirectoryName(System.Reflection.Assembly.GetEntryAssembly().Location);
            Directory.SetCurrentDirectory(executableDir);
            DebugConsoleCore.Init(
                newMessage: (s, c) => DebugConsole.NewMessage(s, c),
                log: DebugConsole.Log);
            StoreIntegration.Init(ref args);
            EnableNvOptimus();
            Game = new GameMain(args);
            Game.Run();
            Game.Dispose();
            FreeNvOptimus();

            CrossThread.ProcessTasks();
        }

        private static GameMain Game;

        private static void CrashHandler(object sender, UnhandledExceptionEventArgs args)
        {
            Exception unhandledException = args.ExceptionObject as Exception;
            try
            {
                Game?.Exit();
                CrashDump(Game, "crashreport.log", unhandledException);
                Game?.Dispose();
            }
            catch (Exception exceptionHandlerError)
            {
                Debug.WriteLine(exceptionHandlerError.Message);
                string slimCrashReport = "Exception handler failed: " + exceptionHandlerError.Message + "\n" + exceptionHandlerError.StackTrace;
                if (unhandledException != null)
                {
                    slimCrashReport += "\n\nInitial exception: " + unhandledException.Message + "\n" + unhandledException.StackTrace;
                }
                File.WriteAllText("crashreportslim.log", slimCrashReport);
                //exception handler is broken, we have a serious problem here!!
                return;
            }
        }

        public static void CrashMessageBox(string message, string filePath)
        {
            Microsoft.Xna.Framework.MessageBox.ShowWrapped(Microsoft.Xna.Framework.MessageBox.Flags.Error, "Oops! Barotrauma just crashed.", message);

            // Open the crash log.
            if (!string.IsNullOrWhiteSpace(filePath)) { ToolBox.OpenFileWithShell(filePath); }
        }

        static void CrashDump(GameMain game, string filePath, Exception exception)
        {
            int existingFiles = 0;
            string originalFilePath = filePath;
            while (File.Exists(filePath))
            {
                existingFiles++;
                filePath = Path.GetFileNameWithoutExtension(originalFilePath) + " (" + (existingFiles + 1) + ")" + Path.GetExtension(originalFilePath);
            }

            DebugConsole.DequeueMessages();

            Md5Hash exeHash = null;
            try
            {
                string exePath = System.Reflection.Assembly.GetEntryAssembly().Location;
                exeHash = Md5Hash.CalculateForFile(exePath, Md5Hash.StringHashOptions.BytePerfect);
            }
            catch
            {
                //do nothing, generate the rest of the crash report
            }

            StringBuilder sb = new StringBuilder();

            sb.AppendLine("Barotrauma Client crash report (generated on " + DateTime.Now + ")");
            sb.AppendLine();
            sb.AppendLine("Barotrauma seems to have crashed. Sorry for the inconvenience! ");
            sb.AppendLine();

            string dxgiErrorHelpText =
#if WINDOWS
                GetDXGIErrorHelpText(game, exception);
#else
                string.Empty;
#endif
            if (!string.IsNullOrEmpty(dxgiErrorHelpText))
            {
                sb.AppendLine(dxgiErrorHelpText);
                sb.AppendLine();
            }

            try
            {
                if (exception.StackTrace.Contains("Barotrauma.GameMain.Load"))
                {
                    //exception occurred in loading screen:
                    //assume content packages are the culprit and reset them
                    XDocument doc = XMLExtensions.TryLoadXml(GameSettings.PlayerConfigPath);
                    if (doc?.Root != null)
                    {
                        XElement newElement = new XElement(doc.Root.Name);
                        newElement.Add(doc.Root.Attributes());
                        Identifier[] contentPackageTags = { "contentpackage".ToIdentifier(), "contentpackages".ToIdentifier() };
                        newElement.Add(doc.Root.Elements().Where(e => !contentPackageTags.Contains(e.NameAsIdentifier())));
                        newElement.Add(new XElement("core",
                            new XAttribute("path", ContentPackageManager.VanillaFileList)));
                        XDocument newDoc = new XDocument(newElement);
                        newDoc.Save(GameSettings.PlayerConfigPath);
                        sb.AppendLine("To prevent further startup errors, installed mods will be disabled the next time you launch the game.");
                        sb.AppendLine();
                    }
                }
            }
            catch
            {
                //welp i guess we couldn't reset the config!
            }

            if (exeHash?.StringRepresentation != null)
            {
                sb.AppendLine(exeHash.StringRepresentation);
            }
            sb.AppendLine();
            sb.AppendLine("Game version " + GameMain.Version +
            " (" + AssemblyInfo.BuildString + ", branch " + AssemblyInfo.GitBranch + ", revision " + AssemblyInfo.GitRevision + ")");
            sb.AppendLine($"Graphics mode: {GameSettings.CurrentConfig.Graphics.Width}x{GameSettings.CurrentConfig.Graphics.Height} ({GameSettings.CurrentConfig.Graphics.DisplayMode})");
            sb.AppendLine("VSync " + (GameSettings.CurrentConfig.Graphics.VSync ? "ON" : "OFF"));
            sb.AppendLine("Language: " + GameSettings.CurrentConfig.Language);
            if (ContentPackageManager.EnabledPackages.All != null)
            {
                sb.AppendLine("Selected content packages: " + 
                    (!ContentPackageManager.EnabledPackages.All.Any() ? 
                        "None" : 
                        string.Join(", ", ContentPackageManager.EnabledPackages.All.Select(c => $"{c.Name} ({c.Hash?.ShortRepresentation ?? "unknown"})"))));
            }
            sb.AppendLine("Level seed: " + ((Level.Loaded == null) ? "no level loaded" : Level.Loaded.Seed));
            sb.AppendLine("Loaded submarine: " + ((Submarine.MainSub == null) ? "None" : Submarine.MainSub.Info.Name + " (" + Submarine.MainSub.Info.MD5Hash + ")"));
            sb.AppendLine("Selected screen: " + (Screen.Selected == null ? "None" : Screen.Selected.ToString()));
            if (SteamManager.IsInitialized)
            {
                sb.AppendLine("SteamManager initialized");
            }
            else if (EosInterface.IdQueries.IsLoggedIntoEosConnect)
            {
                sb.AppendLine("Logged in to EOS connect");
            }

            if (GameMain.Client != null)
            {
                sb.AppendLine("Client (" + (GameMain.Client.GameStarted ? "Round had started)" : "Round hadn't been started)"));
            }

            sb.AppendLine();
            sb.AppendLine("System info:");
            sb.AppendLine("    Operating system: " + System.Environment.OSVersion + (System.Environment.Is64BitOperatingSystem ? " 64 bit" : " x86"));

            if (game == null)
            {
                sb.AppendLine("    Game not initialized");
            }
            else
            {
                if (game.GraphicsDevice == null)
                {
                    sb.AppendLine("    Graphics device not set");
                }
                else
                {
                    if (game.GraphicsDevice.Adapter == null)
                    {
                        sb.AppendLine("    Graphics adapter not set");
                    }
                    else
                    {
                        sb.AppendLine("    GPU name: " + game.GraphicsDevice.Adapter.Description);
                        sb.AppendLine("    Display mode: " + game.GraphicsDevice.Adapter.CurrentDisplayMode);
                    }

                    sb.AppendLine("    GPU status: " + game.GraphicsDevice.GraphicsDeviceStatus);
                }
            }

            sb.AppendLine();
            sb.AppendLine($"Exception: {exception.Message} ({exception.GetType()})");
#if WINDOWS
            if (exception is SharpDXException sharpDxException && ((uint)sharpDxException.HResult) == 0x887A0005)
            {
                var dxDevice = (SharpDX.Direct3D11.Device)game.GraphicsDevice.Handle;
                var descriptor = ResultDescriptor.Find(dxDevice.DeviceRemovedReason)?.ApiCode ?? "UNKNOWN";
                sb.AppendLine($"Device removed reason: {descriptor} ({dxDevice.DeviceRemovedReason})");
            }
#endif
            if (exception.TargetSite != null)
            {
                sb.AppendLine("Target site: " + exception.TargetSite.ToString());
            }

            if (exception.StackTrace != null)
            {
                sb.AppendLine("Stack trace: ");
                sb.AppendLine(exception.StackTrace.CleanupStackTrace());
                sb.AppendLine();
            }

            if (exception.InnerException != null)
            {
                sb.AppendLine("InnerException: " + exception.InnerException.Message);
                if (exception.InnerException.TargetSite != null)
                {
                    sb.AppendLine("Target site: " + exception.InnerException.TargetSite.ToString());
                }
                if (exception.InnerException.StackTrace != null)
                {
                    sb.AppendLine("Stack trace: ");
                    sb.AppendLine(exception.InnerException.StackTrace.CleanupStackTrace());
                }
            }

            if (GameAnalyticsManager.SendUserStatistics)
            {
                //send crash report before appending debug console messages (which may contain non-anonymous information)
                string crashHeader = exception.Message;
                if (exception.TargetSite != null)
                {
                    crashHeader += " " + exception.TargetSite.ToString();
                }
                //log the message separately, so the same error messages get grouped as the same error in GA
                //(the full crash report tends to always have some differences between clients, so they get displayed separately)
                GameAnalyticsManager.AddErrorEvent(GameAnalyticsManager.ErrorSeverity.Critical, crashHeader);
                GameAnalyticsManager.AddErrorEvent(GameAnalyticsManager.ErrorSeverity.Critical, crashHeader + "\n\n" + sb.ToString());
                GameAnalyticsManager.ShutDown();
            }

            sb.AppendLine("Last debug messages:");
            for (int i = DebugConsole.Messages.Count - 1; i >= 0; i--)
            {
                sb.AppendLine("[" + DebugConsole.Messages[i].Time + "] " + DebugConsole.Messages[i].Text);
            }

            string crashReport = sb.ToString();

            File.WriteAllText(filePath, crashReport);

            if (GameSettings.CurrentConfig.SaveDebugConsoleLogs
                || GameSettings.CurrentConfig.VerboseLogging) { DebugConsole.SaveLogs(); }

            string msg = string.Empty;
            if (GameAnalyticsManager.SendUserStatistics)
            {
                msg = "A crash report (\"" + filePath + "\") was saved in the root folder of the game and sent to the developers.";
            }
            else
            {
                msg = "A crash report (\"" + filePath + "\") was saved in the root folder of the game. The error was not sent to the developers because user statistics have been disabled, but" +
                    " if you'd like to help fix this bug, you may post it on Barotrauma's GitHub issue tracker: https://github.com/Regalis11/Barotrauma/issues/";
            }
            if (string.IsNullOrEmpty(dxgiErrorHelpText))
            {
                msg += "\n\n" + dxgiErrorHelpText;
            }
            CrashMessageBox(msg, filePath);
        }

#if WINDOWS
        private static string GetDXGIErrorHelpText(GameMain game, Exception exception)
        {
            string text = string.Empty;
            if (exception is SharpDXException sharpDxException && ((uint)sharpDxException.HResult) == 0x887A0005)
            {
                var dxDevice = (SharpDX.Direct3D11.Device)game.GraphicsDevice.Handle;
                var descriptor = ResultDescriptor.Find(dxDevice.DeviceRemovedReason)?.ApiCode ?? "UNKNOWN";

                text += 
                    $"The crash was caused by the DirectX error {descriptor} ({dxDevice.DeviceRemovedReason}). " +
                    "This is a common DirectX error that can be related to various different issues, such as outdated drivers, RAM problems or an overclocked or otherwise overstressed GPU. " +
                    "There are several potential ways to fix the issue: ensuring your graphics drivers and DirectX installation are up-to-date, disabling overclocking and adjusting various GPU-specific settings. " +
                    $"You may also be able to find potential solutions to the problem by using the error code {descriptor} ({dxDevice.DeviceRemovedReason}) and your GPU manufacturer as search terms.";
            }
            return text;
        }
#endif

        private static IntPtr nvApi64Dll = IntPtr.Zero;
        private static void EnableNvOptimus()
        {
#if WINDOWS && X64
            // We force load nvapi64.dll so nvidia gives us the dedicated GPU on optimus laptops.
            // This is not a method for getting optimus that is documented by nvidia, but it works, so...
            if (NativeLibrary.TryLoad("nvapi64.dll", out nvApi64Dll))
            {
                DebugConsole.Log("Loaded nvapi64.dll successfully");
            }
#endif
        }

        private static void FreeNvOptimus()
        {
#warning TODO: determine if we can do this safely
            //NativeLibrary.Free(nvApi64Dll);
        }
        
    }
}