using System;
using System.Diagnostics;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Net;
using System.Threading.Tasks;
using System.Windows.Forms;
using Microsoft.Win32;

namespace TBMM
{
    partial class MainForm
    {
        public void UpdateButton(Button button, bool enabled)
        {
            if (enabled)
            {
                if (button.ForeColor == Color.Green)
                    button.ForeColor = Color.Lime;
                else if(button.ForeColor == Color.DarkRed)
                    button.ForeColor = Color.Red;
                else if (button.ForeColor == Color.FromArgb(127, 65, 0))
                    button.ForeColor = Color.DarkOrange;
                button.FlatAppearance.MouseOverBackColor = Color.FromArgb(0, 40, 0);
                button.FlatAppearance.MouseDownBackColor = Color.Green;
            }
            else
            {
                if (button.ForeColor == Color.Lime)
                    button.ForeColor = Color.Green;
                else if (button.ForeColor == Color.Red)
                    button.ForeColor = Color.DarkRed;
                else if (button.ForeColor == Color.DarkOrange)
                    button.ForeColor = Color.FromArgb(127, 65, 0);
                button.FlatAppearance.MouseOverBackColor = Color.Black;
                button.FlatAppearance.MouseDownBackColor = Color.Black;
            }
        }

        public string GetGameFolder()
        {
            using var key =
                Registry.LocalMachine.OpenSubKey(
                    @"SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall\Techblox Launcher") ??
                Registry.LocalMachine.OpenSubKey(
                    @"SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Techblox Launcher");
            string launcherPath = key?.GetValue("DisplayIcon") is string launcherExecutable
                ? Directory.GetParent(launcherExecutable)?.FullName
                : null;
            launcherPath ??= Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData),
                "Techblox Launcher");
            string launcherConfig = Path.Combine(launcherPath, "launcher_settings.ini");
            if (!File.Exists(launcherConfig)) return null;
            string path = File.ReadLines(launcherConfig)
                .FirstOrDefault(line => line.StartsWith("133062..GAME_PATH="))
                ?.Substring("133062..GAME_PATH=".Length).Replace("/TBMM/", "/");
            if (path != null) path = (path + "StandaloneWindows64").Replace('/', Path.DirectorySeparatorChar);
            if (path != null && GetExe(path) != null) return path;
            return null;
        }

        public string SelectGameFolder()
        {
            var ofd = new OpenFileDialog();
            ofd.Filter = "Techblox executable|Techblox.exe|Techblox Preview executable|TechbloxPreview.exe";
            ofd.Title = "Game location";
            ofd.CheckFileExists = true;
            ofd.ShowDialog();
            return string.IsNullOrWhiteSpace(ofd.FileName) ? null : Directory.GetParent(ofd.FileName)?.FullName;
        }

        private (EventHandler, Task) CheckStartGame(string command)
        {
            var tcs = new TaskCompletionSource<object>();
            return ((sender, e) =>
            {
                Action act = async () =>
                {
                    if (((sender as Process)?.ExitCode ?? 0) != 0)
                    {
                        status.Text = "Status: Patching failed";
                        return;
                    }

                    var patched = CheckIfPatched();
                    if (patched == GameState.Patched)
                    {
                        Process process = null;
                        if (command != null)
                        {
                            await CheckModUpdatesAsync();
                            process = Process.Start(command);
                        }
                        else if (Environment.OSVersion.Platform == PlatformID.Win32NT)
                        {
                            process = Process.Start(new ProcessStartInfo(GamePath("\\" + GetExe()))
                            {
                                WorkingDirectory = GamePath("\\") //Mods are only loaded if the working directory is correct
                            });
                        }
                        if (process is null)
                            throw new NullReferenceException("Game process is null");
                        process.EnableRaisingEvents = true;
                        process.Exited += HandleGameExit;
                        _gameProcess = (process, true);
                        patched = CheckIfPatched(); // Set in-game status
                    }

                    EndWork(patched, false);
                    tcs.SetResult(null);
                };
                if (InvokeRequired)
                    Invoke(act);
                else
                    act();
            }, tcs.Task);
        }

        private void HandleGameExit(object sender, EventArgs e)
        {
            Debug.WriteLine("Handling game exit");
            _gameProcess = (null, false);
            if (InvokeMethod(CheckIfPatched) != GameState.Patched || Configuration.KeepPatched)
                return;
            InvokeMethod(() => ExecutePatcher(false)).Exited += (_, _) =>
            {
                if (InvokeMethod(CheckIfPatched) == GameState.Patched)
                {
                    MessageBox.Show("Failed to unpatch game, launching through the launcher will fail because of anticheat. " +
                                    "Check the output in the panel on the right.\n\n" +
                                    "Please try starting the game again by clicking Play.", "Patcher error",
                        MessageBoxButtons.OK, MessageBoxIcon.Error);
                }
            };
        }

        private (Process Process, bool ExitHandlerAdded) _gameProcess = (null, false);

        private bool CheckIfGameIsRunning()
        {
            Debug.WriteLine($"Check if game is running: {_gameProcess}");
            switch (_gameProcess.Process)
            {
                case { HasExited: false }:
                    Debug.WriteLine("Game has not exited");
                    return true;
                case { HasExited: true }:
                    Debug.WriteLine("Game has seemingly exited without handling, probably as part of the exit handler");
                    return false;
                default:
                    Debug.WriteLine($"Process seems to be null: {_gameProcess}");
                    _gameProcess = (Process.GetProcessesByName(GetExe(withExtension: false)).FirstOrDefault(), false);
                    Debug.WriteLine($"Game process exited already, got new process object: {_gameProcess}");

                    if (_gameProcess.Process == null) return false;
                    if (_gameProcess.Process.HasExited)
                    {
                        Debug.WriteLine($"Game has exited already: {_gameProcess}");
                        _gameProcess = (null, false);
                        return false;
                    }
                    else
                    {
                        Debug.WriteLine($"Game is still running");
                        if (_gameProcess.ExitHandlerAdded) return true;
                        Debug.WriteLine("Game running and no exit handler yet, adding it");
                        _gameProcess.Process.Exited += HandleGameExit;
                        _gameProcess.Process.EnableRaisingEvents = true;
                        _gameProcess.ExitHandlerAdded = true;
                        return true;
                    }
            }
        }

        private async Task CheckModUpdatesAsync()
        {
            var updatable = mods.Values.Where(mod => mod.Updatable).ToArray();
            if (updatable.Length == 0)
                return;
            if (MessageBox.Show("Mod update(s) available!\n\n"
                + updatable.Select(mod => mod.Name + " " + mod.LatestVersion).Aggregate((a, b) => a + "\n")
                + "\n\nDo you want to update them now? You can also update later by opening TBMM.",
                "Update(s) available", MessageBoxButtons.YesNo) == DialogResult.No)
                return;
            foreach (var mod in updatable)
                await InstallMod(mod);
            MessageBox.Show("Mods updated");
        }

        public WebClient GetClient()
        {
            var client = new WebClient();
            client.Headers.Clear();
            client.Headers[HttpRequestHeader.Accept] = "application/json";
            client.BaseAddress = "https://git.exmods.org";
            return client;
        }

        public T InvokeMethod<T>(Func<T> func)
        {
            if (InvokeRequired)
                return (T)Invoke(func);
            else
                return func();
        }

        private bool working = false;
        /// <summary>
        /// Some simple "locking", only allow one operation at a time
        /// </summary>
        /// <returns>Whether the work can begin</returns>
        public bool BeginWork()
        {
            if (working) return false;
            working = true;
            UpdateButton(playbtn, false);
            UpdateButton(installbtn, false);
            UpdateButton(uninstallbtn, false);
            UpdateButton(settingsbtn, false);
            return true;
        }

        public void EndWork(GameState state, bool desc = true)
        {
            working = false;
            if (state != GameState.InGame)
                UpdateButton(playbtn, true);
            UpdateButton(settingsbtn, true);
            if (desc)
                modlist_SelectedIndexChanged(modlist, null);
        }

        /// <summary>
        /// Path must start with \
        /// </summary>
        /// <param name="path"></param>
        /// <param name="gamepath"></param>
        /// <returns></returns>
        public string GamePath(string path, string gamepath = null)
        {
            return ((gamepath ?? Configuration.GamePath) + path).Replace('\\', Path.DirectorySeparatorChar);
        }

        public string GetExe(string path = null, bool withExtension = true)
        {
            if (File.Exists(GamePath("\\Techblox.exe", path)))
                return "Techblox" + (withExtension ? ".exe" : "");
            if (File.Exists(GamePath("\\TechbloxPreview.exe", path)))
                return "TechbloxPreview" + (withExtension ? ".exe" : "");
            return null;
        }

        private bool CheckNoExe()
        {
            return CheckNoExe(out _);
        }

        private bool CheckNoExe(out string path)
        {
            path = GetExe();
            if (path == null)
            {
                MessageBox.Show("Techblox not found! Set the correct path in Settings.");
                return true;
            }
            return false;
        }

        public DateTime GetGameVersionAsDate()
        {
            if (Configuration.GamePath == null) return default;
            using var fs = File.OpenRead(GamePath($"\\{GetExe(withExtension: false)}_Data\\globalgamemanagers"));
            using var sr = new StreamReader(fs);
            char[] data = new char[512];
            while(!sr.EndOfStream)
            {
                Array.Copy(data, 256, data, 0, 256);
                int read = sr.ReadBlock(data, 256, 256);
                for (int i = 0; i < data.Length - 11; i++)
                {
                    if (data[i] == '2')
                    {
                        string date = new string(data, i, 11);
                        if (date.StartsWith("202") && DateTime.TryParse(date, out var ret))
                            return ret;
                    }
                }
            }

            return default;
        }
    }
}