using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;

namespace IwbZero.ToolCommon.StringModel
{
    public static class ListHelper
    {
        /// <summary>
        /// 自定义Distinct扩展方法
        /// </summary>
        /// <typeparam name="T">要去重的对象类</typeparam>
        /// <typeparam name="TC">自定义去重的字段类型</typeparam>
        /// <param name="source">要去重的对象</param>
        /// <param name="getField">获取自定义去重字段的委托</param>
        /// <returns></returns>
        public static IEnumerable<T> IwbDistinct<T, TC>(this IEnumerable<T> source, Func<T, TC> getField)
        {
            return source.Distinct(new Compare<T, TC>(getField));
        }

        /// <summary>
        /// 合并字典
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="first">字典1</param>
        /// <param name="second">字典2</param>
        /// <param name="isCover">字典2是否覆盖字典1，默认 true</param>
        /// <returns></returns>
        public static Dictionary<string, T> MergeDictionary<T>(this Dictionary<string, T> first, Dictionary<string, T> second ,bool isCover= true)
        {
            if (first == null) first = new Dictionary<string, T>();
            if (second == null) return first;

            foreach (string key in second.Keys)
            {
                if (first.ContainsKey(key))
                {
                    if (isCover)
                    {
                        first[key] = second[key];
                    }
                }
                else
                {
                    first.Add(key, second[key]);
                }

            }
            return first;
        }
        /// <summary>
        /// 合并字典
        /// </summary>
        /// <param name="first">字典1</param>
        /// <param name="second">字典2</param>
        /// <param name="isCover">字典2是否覆盖字典1，默认 true</param>
        /// <returns></returns>
        public static Hashtable MergeHashtable(this Hashtable first, Hashtable second ,bool isCover= true)
        {
            if (first == null) first = new Hashtable();
            if (second == null) return first;

            foreach (string key in second.Keys)
            {
                if (first.ContainsKey(key))
                {
                    if (isCover)
                    {
                        first[key] = second[key];
                    }
                }
                else
                {
                    first.Add(key, second[key]);
                }

            }
            return first;
        }
    }

    public class Compare<T, TC> : IEqualityComparer<T>
    {
        private Func<T, TC> GetField { get; }

        public Compare(Func<T, TC> getField)
        {
            GetField = getField;
        }

        public bool Equals(T x, T y)
        {
            return EqualityComparer<TC>.Default.Equals(GetField(x), GetField(y));
        }

        public int GetHashCode(T obj)
        {
            return EqualityComparer<TC>.Default.GetHashCode(GetField(obj));
        }
    }
}