Remotely/Desktop.UI/ViewModels/ChatWindowViewModel.cs

using Avalonia.Controls;
using System.Collections.ObjectModel;
using System.Text.Json;
using System.Windows.Input;
using Microsoft.Extensions.Logging;
using Remotely.Desktop.Shared.Reactive;
using Microsoft.Extensions.DependencyInjection;
using Remotely.Shared.Models;
using Remotely.Desktop.Shared.Services;

namespace Remotely.Desktop.UI.ViewModels;

public interface IChatWindowViewModel : IBrandedViewModelBase
{
    ObservableCollection<ChatMessage> ChatMessages { get; }
    string ChatSessionHeader { get; }
    ICommand CloseCommand { get; }
    string InputText { get; set; }
    ICommand MinimizeCommand { get; }
    string OrganizationName { get; set; }
    string SenderName { get; set; }

    Task SendChatMessage();
}

public class ChatWindowViewModel : BrandedViewModelBase, IChatWindowViewModel
{
    private readonly StreamWriter? _streamWriter;

    [ActivatorUtilitiesConstructor]
    public ChatWindowViewModel(
        StreamWriter streamWriter,
        string organizationName,
        IBrandingProvider brandingProvider,
        IUiDispatcher dispatcher,
        ILogger<ChatWindowViewModel> logger)
        : base(brandingProvider, dispatcher, logger)
    {
        _streamWriter = streamWriter;
        if (!string.IsNullOrWhiteSpace(organizationName))
        {
            OrganizationName = organizationName;
        }
        CloseCommand = new RelayCommand<Window>(CloseWindow);
        MinimizeCommand = new RelayCommand<Window>(MinimizeWindow);
    }


    public ObservableCollection<ChatMessage> ChatMessages { get; } = new ObservableCollection<ChatMessage>();

    public string ChatSessionHeader => $"Chat session with {OrganizationName}";

    public ICommand CloseCommand { get; }

    public string InputText
    {
        get => Get<string>() ?? string.Empty;
        set => Set(value);
    }

    public ICommand MinimizeCommand { get; }

    public string OrganizationName
    {
        get => Get<string>() ?? "your IT provider";
        set
        {
            Set(value);
            NotifyPropertyChanged(nameof(ChatSessionHeader));
        }
    }

    public string SenderName
    {
        get => Get<string>() ?? "a technician";
        set => Set(value);
    }

    public async Task SendChatMessage()
    {
        if (string.IsNullOrWhiteSpace(InputText) ||
            _streamWriter is null)
        {
            return;
        }

        try
        {
            var chatMessage = new ChatMessage(string.Empty, InputText);
            InputText = string.Empty;
            await _streamWriter.WriteLineAsync(JsonSerializer.Serialize(chatMessage));
            await _streamWriter.FlushAsync();
            chatMessage.SenderName = "You";
            ChatMessages.Add(chatMessage);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error sending chat message");
        }
    }

    private void CloseWindow(Window? obj)
    {
        obj?.Close();
    }

    private void MinimizeWindow(Window? obj)
    {
        if (obj is not null)
        {
            obj.WindowState = WindowState.Minimized;
        }
    }
}