using System;
using System.Collections.Generic;
using System.Linq;
using LocalizationTool.Services;

namespace LocalizationTool.ViewModels
{
    /// <summary>新增语言窗口：从语言目录选择，排除已存在的语言。</summary>
    public class AddLanguageViewModel : ViewModelBase
    {
        private LanguageEntry _selected;

        public List<LanguageEntry> Languages { get; }

        public LanguageEntry Selected
        {
            get => _selected;
            set => Set(ref _selected, value);
        }

        public bool CanConfirm => Selected != null;

        /// <summary>请求关闭窗口（true = 确认）。</summary>
        public event Action<bool> RequestClose;

        public RelayCommand ConfirmCommand { get; }
        public RelayCommand CancelCommand { get; }

        public AddLanguageViewModel(IEnumerable<string> existingCodes)
        {
            var existing = new HashSet<string>(
                (existingCodes ?? Enumerable.Empty<string>()).Select(c => c.Trim()),
                System.StringComparer.OrdinalIgnoreCase);

            Languages = LanguageCatalog.All
                .Where(e => !existing.Contains(e.Code))
                .ToList();

            Selected = Languages.FirstOrDefault();

            ConfirmCommand = new RelayCommand(() =>
            {
                if (CanConfirm) RequestClose?.Invoke(true);
            });
            CancelCommand = new RelayCommand(() => RequestClose?.Invoke(false));
        }
    }
}