using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Runtime.Loader;

namespace Wood.Util
{
    public class ReflectionHelper
    {
        private static ConcurrentDictionary<string, object> dictCache = new ConcurrentDictionary<string, object>();

        #region 得到类里面的属性集合
        /// <summary>
        /// 得到类里面的属性集合
        /// </summary>
        /// <param name="type"></param>
        /// <param name="columns"></param>
        /// <returns></returns>
        public static PropertyInfo[]? GetProperties(Type type, string[]? columns = null)
        {
            if(string.IsNullOrEmpty(type.FullName))
                return null;
            PropertyInfo[]? properties = null;
            if (dictCache.ContainsKey(type.FullName))
            {
                properties = dictCache[type.FullName] as PropertyInfo[];
            }
            else
            {
                properties = type.GetProperties();
                dictCache.TryAdd(type.FullName, properties);
            }

            if (columns != null && columns.Length > 0)
            {
                //  按columns顺序返回属性
                var columnPropertyList = new List<PropertyInfo>();
                foreach (var column in columns)
                {
                    var columnProperty = properties?.Where(p => p.Name == column).FirstOrDefault();
                    if (columnProperty != null)
                    {
                        columnPropertyList.Add(columnProperty);
                    }
                }
                return columnPropertyList.ToArray();
            }
            else
            {
                return properties;
            }
        }
		#endregion
	}
}