MultiTerm/MultiTerm.Protocols/UsbHid/UsbHidProtocolSettingsViewModel.cs

using Common.Messaging;
using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;
using CommunityToolkit.Mvvm.Messaging;
using MultiTerm.Protocols.Types;
using System.Collections.ObjectModel;

namespace MultiTerm.Protocols.UsbHid;

public partial class UsbHidProtocolSettingsViewModel : ProtocolSettingsViewModel, IUsbHidProtocolSettings
{
    public override ProtocolType ProtocolType => ProtocolType.UsbHid;

    public ushort VendorId { get; set; } = ushort.MinValue;
    public ushort ProductId { get; set; } = ushort.MinValue;

    [ObservableProperty]
    private string serialNumber = string.Empty;

    [ObservableProperty]
    private string vendorIdHex = string.Empty;

    [ObservableProperty]
    private string productIdHex = string.Empty;


    [ObservableProperty]
    private ObservableCollection<UsbHidDeviceInfo> devices = new();

    [ObservableProperty]
    private UsbHidDeviceInfo? selectedDevice;

    [RelayCommand]
    private void ReloadDevices()
    {
        UsbHidDeviceInfo? previouslySelectedDevice = null;

        // if any device is selected => temporarily store it
        if (this.SelectedDevice != null)
        {
            // shallow copy of the device
            previouslySelectedDevice = (UsbHidDeviceInfo)this.SelectedDevice.Clone();       
        }

        // reload collection
        this.Devices = new ObservableCollection<UsbHidDeviceInfo>(UsbHidProtocol.GetDevices());

        // select previously selected device again if it still exists
        if (previouslySelectedDevice != null)
        {
            var equalDevices = this.Devices.Where(d => d.Equals(previouslySelectedDevice));
            // exactly one match found => take as selected device and quit method
            if(equalDevices.Count() == 1)
            {
                this.SelectedDevice = equalDevices.First();
            }
        }

        // otherwise select first device, if none is selected yet and there are some available
        if (this.SelectedDevice == null && this.Devices.Any())
        {
            this.SelectedDevice = this.Devices.First();
        }
    }

    public UsbHidProtocolSettingsViewModel(IMessenger messenger) : base(messenger)
    {
        // load devices initially
        this.ReloadDevices();
        this.SelectedDevice = this.Devices.FirstOrDefault();
    }

    /// <summary>
    /// Updates other fields when <see cref="SelectedDevice"/> was changed.
    /// </summary>
    /// <param name="value"></param>
    partial void OnSelectedDeviceChanged(UsbHidDeviceInfo? value)
    {
        if(value != null)
        {
            this.VendorIdHex = value.VendorId;
            this.ProductIdHex = value.ProductId;
            this.SerialNumber = value.SerialNumber;
        }
    }

    public bool AreValid()
    {
        // pad left (fill up zeroes)
        this.VendorIdHex = this.VendorIdHex.PadLeft(4, '0');
        if (this.VendorIdHex.Length > 4)
        {
            this.messenger.Send<IUserInterfaceMessage>(new ProtocolSettingsInvalidUIMessage(nameof(this.VendorId), "Must consist of a maximum of 4 hexadecimal characters"));
            return false;
        }
        if (ushort.TryParse(this.VendorIdHex, System.Globalization.NumberStyles.HexNumber, null, out ushort vendorId) == false)
        {
            this.messenger.Send<IUserInterfaceMessage>(new ProtocolSettingsInvalidUIMessage(nameof(this.VendorId), "Invalid. Not a 16bit number."));
            return false;
        }
        // set internal
        this.VendorId = vendorId;

        // pad left (fill up zeroes)
        this.ProductIdHex = this.ProductIdHex.PadLeft(4, '0');
        if (this.ProductIdHex.Length > 4)
        {
            this.messenger.Send<IUserInterfaceMessage>(new ProtocolSettingsInvalidUIMessage(nameof(this.ProductId), "Must consist of a maximum of 4 hexadecimal characters"));
            return false;
        }
        if (ushort.TryParse(this.ProductIdHex, System.Globalization.NumberStyles.HexNumber, null, out ushort productId) == false)
        {
            this.messenger.Send<IUserInterfaceMessage>(new ProtocolSettingsInvalidUIMessage(nameof(this.ProductId), "Invalid. Not a 16bit number."));
            return false;
        }
        // set internal 
        this.ProductId = productId;

        return true;
    }
}