using DiscordRPC;
using System;
using System.Diagnostics;
using System.Linq;
using System.Runtime.InteropServices;

namespace Chilong
{
    class Program

    {
        private static DiscordRpcClient client;
        private static Process cdisplayex;
        private static string windowTitle;

        [DllImport("User32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
        public static extern IntPtr FindWindow(string lpClassName, string lpWindowName);

        [DllImport("User32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
        public static extern IntPtr FindWindowEx(IntPtr hwndParent, IntPtr hwndChildAfter, string lpszClass, string lpszWindow);

        public const int WM_GETTEXT = 0x000D;
        public const int WM_GETTEXTLENGTH = 0x000E;

        [DllImport("User32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        public static extern int SendMessage(IntPtr hWnd, uint msg, int wParam, IntPtr lParam);

        [DllImport("User32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        public static extern int SendMessage(IntPtr hWnd, uint msg, int wParam, StringBuilder lParam);

        static void Main(string[] args)
        {
            Initialize();
            if (Process.GetProcesses().Where(x => x.ProcessName.StartsWith("CDisplayEx")).Count() == 0)
                return;

            while (true)
            {
                Update();
                if (Process.GetProcesses().Where(x => x.ProcessName.StartsWith("CDisplayEx")).Count() == 0)
                {
                    Deinitialize();
                    Console.WriteLine("Thanks for using Chilong!");
                    return;
                }
            }
        }

        private static void Initialize()
        {
            client = new DiscordRpcClient("815595590515032074");

            if(Process.GetProcesses().Where(x => x.ProcessName.StartsWith("CDisplayEx")).Count() == 0)
            {
                Console.WriteLine("SumatraPDF was not found! Is it open?");
                return;
            }
            cdisplayex = Process.GetProcesses().Where(x => x.ProcessName.StartsWith("CDisplayEx")).ToList()[0];
            windowTitle = cdisplayex.MainWindowTitle;

            client.OnReady += (sender, e) =>
            {
                Console.WriteLine("Received Ready from user {0}", e.User.Username);
            };
            client.OnPresenceUpdate += (sender, e) =>
            {
                Console.WriteLine("Received Update! {0}", e.Presence);
            };

            try
            {
                client.Initialize();
                Console.WriteLine("Successfully connected to client!");
            }
            catch(Exception e)
            {
                Console.WriteLine($"Connection to client was not successful!\nERROR: {e.Message}");
                return;
            }

            try { SetNewPresence(); }
            catch(Exception e)
            {
                Console.WriteLine($"Setting presence was not successful!\nERROR: {e.Message}");
                return;
            }
        }
        private static void Update()
        {
            client.OnPresenceUpdate += (sender, e) =>
            {
                Console.WriteLine("Received Update! {0}", e.Presence);
            };
            client.Invoke();
            OnUpdate();
        }
        private static void Deinitialize()
        {
            client.ClearPresence();
            client.Dispose();
        }

        private static void OnUpdate()
        {
            Process process;
            try
            {
                process = Process.GetProcesses().Where(x => x.ProcessName.StartsWith("CDisplayEx")).ToList()[0];
            }
            catch(Exception) { return; }

            if (process.MainWindowTitle != windowTitle)
            {
                cdisplayex = process;
                windowTitle = cdisplayex.MainWindowTitle;
                SetNewPresence();
            }
        }

        private static void SetNewPresence()
        {
            string details = cdisplayex.MainWindowTitle;
            if(details == " " || details == "")
                details = "Picking a New File";

            client.SetPresence(new RichPresence
            {
                Details = details,
                State = "State Placeholder",
                Timestamps = new Timestamps(DateTime.UtcNow),
                Assets = new Assets()
                {
                    LargeImageKey = "cdisplayex",
                    LargeImageText = "cdisplayex"
                }
            });
            Console.WriteLine("Presence successfully set!");
        }
    }

    public class StringBuilder
    {
        public StringBuilder(int v)
        {
            V = v;
        }

        public int V { get; }
        public int Capacity { get; internal set; }
    }
}