using System;
using System.ComponentModel;
using System.Windows;
using System.Windows.Data;
using System.Windows.Markup;

namespace TeamAAS.Localization
{
    /// <summary>
    /// XAML 标记扩展（共享版，供 Core / FlowEngine / 插件等程序集使用）：
    /// 支持 {loc:Translate '保存配置'}，语言切换时自动刷新。
    /// 主程序 TeamAAS.exe 内的 TeamAAS.Localization.TranslateExtension 与本类等价，
    /// 两者查询同一个 GlobalLocalizationManager 单例。
    /// </summary>
    [MarkupExtensionReturnType(typeof(BindingExpression))]
    public class TranslateExtension : MarkupExtension
    {
        /// <summary>要翻译的原文（中文）</summary>
        [ConstructorArgument("key")]
        public string Key { get; set; }

        /// <summary>可选的上下文（用于消歧义）</summary>
        public string Context { get; set; }

        public TranslateExtension()
        {
        }

        public TranslateExtension(string key)
        {
            Key = key;
        }

        public override object ProvideValue(IServiceProvider serviceProvider)
        {
            if (string.IsNullOrWhiteSpace(Key))
                return "[未设置翻译Key]";

            if (DesignerProperties.GetIsInDesignMode(new DependencyObject()))
                return Key;

            var proxy = new SharedTranslationProxy(Key, Context);
            var binding = new Binding("Value")
            {
                Source = proxy,
                Mode = BindingMode.OneWay,
            };

            if (serviceProvider.GetService(typeof(IProvideValueTarget)) is IProvideValueTarget target
                && target.TargetObject is DependencyObject
                && target.TargetProperty is DependencyProperty)
            {
                return binding.ProvideValue(serviceProvider);
            }

            return proxy.Value;
        }
    }

    /// <summary>
    /// 翻译代理：监听语言切换事件，自动更新翻译
    /// </summary>
    internal class SharedTranslationProxy : INotifyPropertyChanged
    {
        private readonly string _key;
        private readonly string _context;

        public SharedTranslationProxy(string key, string context = null)
        {
            _key = key;
            _context = context;
            GlobalLocalizationManager.Instance.LanguageChanged += OnLanguageChanged;
        }

        public string Value => GlobalLocalizationManager.Instance.Translate(_key, _context);

        private void OnLanguageChanged(object sender, EventArgs e)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Value)));
        }

        public event PropertyChangedEventHandler PropertyChanged;
    }
}