using Avalonia.Data;
using Avalonia.Data.Converters;
using Avalonia.Markup.Xaml;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Cowain.Base.Converters;

/// <summary>
/// 通用ID到对象属性值转换器
/// 支持通过ID从集合中查找对象，并返回该对象的指定属性值
/// </summary>
public class MultiIdToPropertyConverter : MarkupExtension, IMultiValueConverter
{
    public object? Convert(IList<object?> values, Type targetType, object? parameter, CultureInfo culture)
    {
        try
        {
            // 参数说明：values[0]=ID值, values[1]=集合对象, values[2]=目标属性名（可选）
            if (values.Count < 2 || values[0] is null || values[1] is null)
                return BindingOperations.DoNothing;

            object? id = values[0];
            object? collection = values[1];
            string targetProperty = (values.Count >= 3 && values[2] is string s && !string.IsNullOrEmpty(s))
                ? s
                : "Name"; // 默认属性名为 "Name"

            // 从集合中查找项
            object? item = (id is not null && collection is not null) ? FindItemById(collection, id) : null;
            if (item is null) return "Null";

            var propertyInfo = item.GetType().GetProperty(targetProperty);
            return propertyInfo?.GetValue(item) ?? "Null";
        }
        catch
        {
            return BindingOperations.DoNothing;
        }
    }

    private object? FindItemById(object collection, object id)
    {
        switch (collection)
        {
            case IDictionary dict:
                return id is not null && dict.Contains(id) ? dict[id] : null;
            case IEnumerable enumerable:
                foreach (var item in enumerable)
                {
                    var itemId = item?.GetType().GetProperty("Id")?.GetValue(item);
                    if (itemId is not null && itemId.Equals(id))
                        return item;
                }
                break;
        }
        return null;
    }
    public override object ProvideValue(IServiceProvider serviceProvider) => this;
}