using HidApi;
using System.Text;

namespace UsbHidTestApp_libusb;

internal class Program
{
    private static HidApi.Device? _device;
    private static bool _continue;
    private static Thread? readThread;
    private static IEnumerable<HidApi.DeviceInfo>? lastDevices;
    private static StringComparer stringComparer = StringComparer.OrdinalIgnoreCase;

    public static bool applicationQuitRequested { get; private set; }


    static void Main(string[] args)
    {
        while (applicationQuitRequested == false)
        {
            Console.WriteLine($"----- USB HID PROTOCOL TEST APP -----");
            Console.WriteLine($"Command list:");
            Console.WriteLine($"l = list devices");
            Console.WriteLine($"c = connect");
            Console.WriteLine($"q = quit");

            var key = Console.ReadKey();

            switch (key.Key)
            {
                // list devices
                case ConsoleKey.L:
                    var hidDevices = Hid.Enumerate();
                    Console.WriteLine($"Following HID devices were found: {Environment.NewLine}");

                    foreach (var deviceInfo in hidDevices)
                    {
                        bool newDevice = false;
                        var device = deviceInfo.ConnectToDevice();
                        if (lastDevices?.Where(x => x.Path == device.GetDeviceInfo().Path).Any() == false)
                        {
                            Console.ForegroundColor = ConsoleColor.Green;
                            newDevice = true;
                        }
                        Console.WriteLine($"-- VendorId: 0x{deviceInfo.VendorId.ToString("X4")}, ProductId: 0x{deviceInfo.ProductId.ToString("X4")}, Manufacturer: {deviceInfo.ManufacturerString}, Path:");
                        Console.WriteLine($"   {deviceInfo.Path}");
                        if (newDevice)
                        {
                            Console.ForegroundColor = ConsoleColor.White;
                        }
                    }

                    lastDevices = hidDevices;

                    break;

                // connect
                case ConsoleKey.C:
                    Console.Write($"Write device vendor id as hex: ");
                    string? vendorIdString = Console.ReadLine();
                    ushort vendorId;

                    if (vendorIdString == null ||
                        vendorIdString == "" ||
                        ushort.TryParse(vendorIdString, System.Globalization.NumberStyles.HexNumber, null, out vendorId) == false)
                    {
                        Console.WriteLine($"Invalid vendor ID entered.");
                        break;
                    }

                    Console.Write($"Write product vendor id as hex: ");
                    string? productIdString = Console.ReadLine();
                    ushort productId;

                    if (productIdString == null ||
                        productIdString == "" ||
                        ushort.TryParse(productIdString, System.Globalization.NumberStyles.HexNumber, null, out productId) == false)
                    {
                        Console.WriteLine($"Invalid product ID entered.");
                        break;
                    }

                    _device = new Device(vendorId, productId);
                    if (_device == null)
                    {
                        Console.WriteLine("Could not find device.");
                        break;
                    }

                    _continue = true;
                    readThread = new Thread(Read);
                    readThread.Start();

                    var devInfo = _device.GetDeviceInfo();
                    Console.WriteLine($"Connected to device VendorId: 0x{devInfo.VendorId.ToString("X4")}, ProductId: 0x{devInfo.ProductId.ToString("X4")}, Manufacturer: {devInfo.ManufacturerString}.");
                    Console.WriteLine("Write 'quit' to end communication.");

                    while (_continue)
                    {
                        var message = Console.ReadLine();

                        if (stringComparer.Equals("quit", message))
                        {
                            _continue = false;
                        }
                        else
                        {
                            byte[] msgBytes = Encoding.ASCII.GetBytes(message!);
                            List<byte> listBytes = new List<byte>();
                            listBytes.Add((byte)' ');  // temp fix for first sign wrong
                            listBytes.AddRange(msgBytes);
                            listBytes.Add((byte)'\n');
                            _device.Write(listBytes.ToArray());
                        }
                    }

                    readThread.Join();
                    readThread = null;
                    _device.Dispose();   // "close"
                    Console.WriteLine("Closed connection to device.");


                    break;

                // quit
                case ConsoleKey.Q:
                    applicationQuitRequested = true;
                    break;

                default:
                    Console.WriteLine($"{Environment.NewLine}Did not recognize key.. {Environment.NewLine}");
                    break;
            }


        }

        Hid.Exit(); //Call at the end of your program

    }

    public static void Read()
    {
        while (_continue)
        {
            try
            {
                ReadOnlySpan<byte> readData = null;
                if(_device != null)
                {
                    readData = _device.Read(1000);
                }
                else
                {
                    Thread.Sleep(20);
                }

                if (readData != null && readData.IsEmpty == false)
                {
                    string print = Encoding.UTF8.GetString(readData);
                    //print = print.Replace("\r", "").Replace("\n", "");  // Newline Mode: none
                    //print = print.Replace("\r", "");  // Newline Mode: only print \n
                    //print = print.Replace("\0", "");  // delete null chars
                    if (String.IsNullOrEmpty(print) == false)
                    {
                        Console.WriteLine(print);
                    }
                }
            }
            catch (HidException hidex) 
            {
                Console.WriteLine($"Got HidException, device likely disconnected: {hidex}");
                Console.WriteLine($"Write 'quit' to end");
                _continue = false;
            }
        }
    }
}