using System.Collections.ObjectModel;

namespace MeetingAssistant.Workflow;

public sealed class WorkflowRulesEditorChatViewModel
{
    private readonly IWorkflowRulesEditorChatPipeline pipeline;

    public WorkflowRulesEditorChatViewModel(IWorkflowRulesEditorChatPipeline pipeline)
    {
        this.pipeline = pipeline;
    }

    public ObservableCollection<WorkflowRulesEditorChatMessage> Messages { get; } = [];

    public string Draft { get; set; } = "";

    public bool IsThinking { get; private set; }

    public event EventHandler? Changed;

    public async Task SendAsync(CancellationToken cancellationToken = default)
    {
        var prompt = Draft.Trim();
        if (string.IsNullOrWhiteSpace(prompt) || IsThinking)
        {
            return;
        }

        Draft = "";
        var priorConversation = Messages.ToList();
        Messages.Add(new WorkflowRulesEditorChatMessage(WorkflowRulesEditorChatRole.User, prompt));
        IsThinking = true;
        OnChanged();

        try
        {
            var result = await pipeline.SendAsync(
                priorConversation,
                prompt,
                cancellationToken);
            Messages.Clear();
            foreach (var message in result.Conversation)
            {
                Messages.Add(message);
            }
        }
        catch (Exception exception) when (exception is not OperationCanceledException)
        {
            Messages.Add(new WorkflowRulesEditorChatMessage(
                WorkflowRulesEditorChatRole.Agent,
                $"Rules editor failed: {exception.Message}"));
        }
        finally
        {
            IsThinking = false;
            OnChanged();
        }
    }

    private void OnChanged()
    {
        Changed?.Invoke(this, EventArgs.Empty);
    }
}