MultiTerm/MultiTerm.Core/ViewModel/TerminalViewModel.cs

using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;
using MultiTerm.Core.Types;
using MultiTerm.Protocols;
using MultiTerm.Protocols.Types;

namespace MultiTerm.Core.ViewModel;

public abstract partial class TerminalViewModel : ObservableObject, ITerminalViewModel
{
    public abstract string Title { get; }
    public abstract TerminalViewType ViewType { get; }  
    public ProtocolType ProtocolType { get; set; }
    public ICommunicationProtocol? CommunicationProtocol { get; set; }
    
    public event EventHandler? ClosingEvent;

    private IProtocolSettingsViewModel? protocolSettings;

    public IProtocolSettingsViewModel? ProtocolSettings
    {
        get { return protocolSettings; }
        set 
        { 
            protocolSettings = value; 
            // register event handler for connection request from viewmodel
            if(value != null)
            {
                protocolSettings!.ConnectRequested += OnViewModelRequestedConnect; ; ;
                protocolSettings!.DisconnectRequested += OnViewModelRequestedDisconnect;
            }
        }
    }

    /// <summary>
    /// Method to override if any closing actions are required.
    /// Closing can be cancelled using the return value.
    /// </summary>
    /// <returns>true if closing is allowed. false if it shall be cancelled.</returns>
    protected virtual bool ClosingActions() { return true; }

    [RelayCommand]
    public void CloseRequest()
    {
        if (this.ClosingActions() == true)
        {
            ClosingEvent?.Invoke(this, EventArgs.Empty);
        }
    }

    private void OnViewModelRequestedConnect(object? sender, ConnectionRequestEventArgs e)
    {
        // guard uninitialized CommunicationProtocol
        if (CommunicationProtocol == null) { throw new Exception($"To call '{nameof(OnViewModelRequestedConnect)}()', CommunicationProtocol must not be null!"); }

        e.Success = this.CommunicationProtocol.Connect(e.Settings);
    }

    private void OnViewModelRequestedDisconnect(object? sender, EventArgs e)
    {
        // guard uninitialized CommunicationProtocol
        if (CommunicationProtocol == null) { throw new Exception($"To call '{nameof(OnViewModelRequestedConnect)}()', CommunicationProtocol must not be null!"); }

        this.CommunicationProtocol.Disconnect();
    }
}