using System;
using System.Collections.Generic;
using AI.Interface;
using AI.Models;
using AI.Models.Form;
using AI.ViewModels;
using Avalonia.Threading;

namespace AI.Service
{
    /// <summary>
    /// 表单请求通知实现：收到请求后在 UI 线程向当前会话插入表单消息。
    /// </summary>
    public class FormRequestNotifier : IFormRequestNotifier
    {
        private readonly MainWindowViewModel _mainViewModel;
        private readonly IFormRegistry _registry;
        private readonly Dictionary<string, Action<ChatSession?>> _handlers;

        public const string FormIdLoadXyz = "gridding-load-xyz";
        public const string FormIdGriddingParams = "gridding-parameters";

        public FormRequestNotifier(MainWindowViewModel mainViewModel, IFormRegistry registry)
        {
            _mainViewModel = mainViewModel ?? throw new ArgumentNullException(nameof(mainViewModel));
            _registry = registry ?? throw new ArgumentNullException(nameof(registry));

            _handlers = new Dictionary<string, Action<ChatSession?>>(StringComparer.OrdinalIgnoreCase)
            {
                [FormIdLoadXyz]        = ShowXyzLoadCard,
                [FormIdGriddingParams] = ShowGriddingParamCard,
            };
        }

        /// <inheritdoc />
        public void RequestForm(string formId)
        {
            if (string.IsNullOrWhiteSpace(formId))
            {
                return;
            }

            var targetSession = CurrentSessionContext.Current;

            if (_handlers.TryGetValue(formId, out var handler))
            {
                handler(targetSession);
                return;
            }

            var definition = _registry.GetForm(formId);
            if (definition == null)
            {
                return;
            }

            Dispatcher.UIThread.Post(() => _mainViewModel.AddFormMessage(definition, targetSession));
        }

        private void ShowXyzLoadCard(ChatSession? session)
        {
            Dispatcher.UIThread.Post(() => _mainViewModel.AddXyzLoadCardMessage(session));
        }

        private void ShowGriddingParamCard(ChatSession? session)
        {
            Dispatcher.UIThread.Post(() => _mainViewModel.AddGriddingParamCardMessage(session));
        }

    }
}