using System.Diagnostics;
using System.IO;
using System.Text.RegularExpressions;
using CefSharp;
using Microsoft.Win32;

namespace VRCX
{
    public partial class AppApi
    {
        private void OnProcessStateChanged(MonitoredProcess monitoredProcess)
        {
            if (!monitoredProcess.HasName("VRChat") && !monitoredProcess.HasName("vrserver"))
                return;

            CheckGameRunning();
        }
        
        /// <summary>
        /// Checks if the VRChat game and SteamVR are currently running and updates the browser's JavaScript function $app.updateIsGameRunning with the results.
        /// </summary>
        public void CheckGameRunning()
        {
            var isGameRunning = false;
            var isSteamVRRunning = false;

            if (ProcessMonitor.Instance.IsProcessRunning("VRChat"))
            {
                isGameRunning = true;
            }

            if (ProcessMonitor.Instance.IsProcessRunning("vrserver"))
            {
                isSteamVRRunning = true;
            }

            // TODO: fix this throwing an exception for being called before the browser is ready. somehow it gets past the checks
            if (MainForm.Instance?.Browser != null && !MainForm.Instance.Browser.IsLoading && MainForm.Instance.Browser.CanExecuteJavascriptInMainFrame)
                MainForm.Instance.Browser.ExecuteScriptAsync("$app.updateIsGameRunning", isGameRunning, isSteamVRRunning);
        }
        
        /// <summary>
        /// Kills the VRChat process if it is currently running.
        /// </summary>
        /// <returns>The number of processes that were killed (0 or 1).</returns>
        public int QuitGame()
        {
            var processes = Process.GetProcessesByName("vrchat");
            if (processes.Length == 1)
                processes[0].Kill();

            return processes.Length;
        }

        /// <summary>
        /// Starts the VRChat game process with the specified command-line arguments.
        /// </summary>
        /// <param name="arguments">The command-line arguments to pass to the VRChat game.</param>
        public void StartGame(string arguments)
        {
            // try stream first
            try
            {
                using (var key = Registry.ClassesRoot.OpenSubKey(@"steam\shell\open\command"))
                {
                    // "C:\Program Files (x86)\Steam\steam.exe" -- "%1"
                    var match = Regex.Match(key.GetValue(string.Empty) as string, "^\"(.+?)\\\\steam.exe\"");
                    if (match.Success)
                    {
                        var path = match.Groups[1].Value;
                        // var _arguments = Uri.EscapeDataString(arguments);
                        Process.Start(new ProcessStartInfo
                        {
                            WorkingDirectory = path,
                            FileName = $"{path}\\steam.exe",
                            UseShellExecute = false,
                            Arguments = $"-applaunch 438100 {arguments}"
                        }).Close();
                        return;
                    }
                }
            }
            catch
            {
            }

            // fallback
            try
            {
                using (var key = Registry.ClassesRoot.OpenSubKey(@"VRChat\shell\open\command"))
                {
                    // "C:\Program Files (x86)\Steam\steamapps\common\VRChat\launch.exe" "%1" %*
                    var match = Regex.Match(key.GetValue(string.Empty) as string, "(?!\")(.+?\\\\VRChat.*)(!?\\\\launch.exe\")");
                    if (match.Success)
                    {
                        var path = match.Groups[1].Value;
                        StartGameFromPath(path, arguments);
                    }
                }
            }
            catch
            {
            }
        }

        /// <summary>
        /// Starts the VRChat game process with the specified command-line arguments from the given path.
        /// </summary>
        /// <param name="path">The path to the VRChat game executable.</param>
        /// <param name="arguments">The command-line arguments to pass to the VRChat game.</param>
        /// <returns>True if the game was started successfully, false otherwise.</returns>
        public bool StartGameFromPath(string path, string arguments)
        {
            if (!path.EndsWith(".exe"))
                path = Path.Combine(path, "launch.exe");

            if (!File.Exists(path))
                return false;

            Process.Start(new ProcessStartInfo
            {
                WorkingDirectory = Path.GetDirectoryName(path),
                FileName = path,
                UseShellExecute = false,
                Arguments = arguments
            })?.Close();
            return true;
        }
    }
}