using System;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace FlexJobApi.Core
{
    /// <summary>
    /// 字符串工具
    /// </summary>
    public static class StringUtils
    {
        /// <summary>
        /// 校验字符串为空
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static bool IsNull([NotNullWhen(false)] this string str)
        {
            return string.IsNullOrWhiteSpace(str) || str == "undefined";
        }

        /// <summary>
        /// 校验字段不为空
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static bool IsNotNull([NotNullWhen(true)] this string str)
        {
            return !str.IsNull();
        }

        /// <summary>
        /// 获取复数英文名
        /// </summary>
        /// <param name="singularName"></param>
        /// <returns></returns>
        public static string GetPluralizedName(this string singularName)
        {
            if (singularName.EndsWith("s") || singularName.EndsWith("x") || singularName.EndsWith("z") ||
                singularName.EndsWith("ch") || singularName.EndsWith("sh"))
            {
                return singularName + "es";
            }
            else if (singularName.EndsWith("y") && !"aeiou".Contains(singularName[singularName.Length - 2]))
            {
                return singularName.Substring(0, singularName.Length - 1) + "ies";
            }
            else
            {
                return singularName + "s";
            }
        }
    }
}