using AI.Models;

namespace AI.ViewModels
{
    /// <summary>
    /// 会话列表项的 ViewModel
    /// </summary>
    public class ChatSessionItemViewModel : ViewModelBase
    {
        private readonly ChatSession _session;
        private bool _isSelected;

        public ChatSessionItemViewModel(ChatSession session)
        {
            _session = session ?? throw new ArgumentNullException(nameof(session));
        }

        /// <summary>
        /// 会话ID
        /// </summary>
        public string Id => _session.Id;

        /// <summary>
        /// 会话标题
        /// </summary>
        public string Title
        {
            get => _session.Title;
            set
            {
                if (_session.Title != value)
                {
                    _session.Title = value;
                    OnPropertyChanged();
                }
            }
        }

        /// <summary>
        /// 创建时间
        /// </summary>
        public DateTime CreatedAt => _session.CreatedAt;

        /// <summary>
        /// 最后更新时间
        /// </summary>
        public DateTime UpdatedAt => _session.UpdatedAt;

        /// <summary>
        /// 消息数量
        /// </summary>
        public int MessageCount => _session.MessageCount;

        /// <summary>
        /// 是否被选中
        /// </summary>
        public bool IsSelected
        {
            get => _isSelected;
            set => SetProperty(ref _isSelected, value);
        }

        /// <summary>
        /// 获取底层会话对象
        /// </summary>
        public ChatSession Session => _session;

        /// <summary>
        /// 更新显示信息（当会话变化时调用）
        /// </summary>
        public void Refresh()
        {
            OnPropertyChanged(nameof(Title));
            OnPropertyChanged(nameof(UpdatedAt));
            OnPropertyChanged(nameof(MessageCount));
        }
    }
}