using System.Collections;

namespace Soul2.General.utils {
    public static class CollectionsUtils {
        /// <summary>
        /// 判断非空
        /// </summary>
        /// <param name="collection">集合对象</param>
        /// <returns>是否非空</returns>
        public static bool isNotEmpty(this IEnumerable collection) {
            return !isEmpty(collection);
        }

        /// <summary>
        /// 判断为空
        /// </summary>
        /// <param name="collection">集合对象</param>
        /// <returns>是否为空</returns>
        public static bool isEmpty(this IEnumerable collection) {
            if (collection == null) {
                return true;
            }
            foreach (var item in collection) {
                return false;
            }
            return true;
        }

        /// <summary>
        /// 去重
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="list"></param>
        /// <returns></returns>
        public static List<T> duplicateRemoval<T>(this List<T> list) {
            if (list.isNotEmpty()) {
                var set = new HashSet<T>(list);
                return new List<T>(set);
            } else {
                return list;
            }
        }

        public static HashSet<T> toSet<T>(this IEnumerable<T> collection) {
            return new HashSet<T>(collection);
        }
    }
}