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

namespace YTWL.Common
{
    /// <summary>
    /// 时间跨度表达式
    /// 只支持 ‘数字’，‘*’，‘-’，‘,’，‘ ’
    /// </summary>
    public class CronExpression
    {
        private const string EnableChar = "0123456789,*- ";
        public CronExpression(string cron)
        {
            if (cron.Any(m => !EnableChar.Contains(m)))
            {
                throw new FormatException("Cron表达式包含不支持的字符:{0}".FormatExt(cron));
            }
            #region 初始化

            if (Seconds == null)
            {
                Seconds = new List<int>();
            }
            if (Minutes == null)
            {
                Minutes = new List<int>();
            }
            if (Hours == null)
            {
                Hours = new List<int>();
            }
            if (DaysOfMonth == null)
            {
                DaysOfMonth = new List<int>();
            }
            if (Months == null)
            {
                Months = new List<int>();
            }
            if (DaysOfWeek == null)
            {
                DaysOfWeek = new List<int>();
            }
            if (Years == null)
            {
                Years = new List<int>();
            }
            #endregion

            int exprOn = (int)CronFieldIndex.Second;
            string[] exprsTok = cron.Trim().Split(new char[] { ' ', '\t', '\r', '\n' }, StringSplitOptions.RemoveEmptyEntries);


            foreach (string exprTok in exprsTok)
            {
                string expr = exprTok.Trim();

                if (expr.Length == 0)
                {
                    continue;
                }
                string[] vTok = expr.Split(',');
                foreach (string v in vTok)
                {
                    var v1 = v.TrimAll();
                    Add2List((CronFieldIndex)exprOn, v1);
                    exprOn++;
                }

            }
        }
        private void Add2List(CronFieldIndex index, string value)
        {

            switch (index)
            {
                case CronFieldIndex.Second:
                    if (value == "*")
                    {
                        60.For(n => Seconds.Add(n));
                    }
                    else if (value.Contains('-'))
                    {
                        var values = value.Split('-').Select(m => m.ToInt32()).ToArray();
                        (values[1] - values[0] + 1).For(m => Seconds.Add(values[0] + m));
                    }
                    else
                    {
                        Seconds.Add(value.ToInt32());
                    }
                    break;
                case CronFieldIndex.Minute:
                    if (value == "*")
                    {
                        60.For(n => Minutes.Add(n));
                    }
                    else if (value.Contains('-'))
                    {
                        var values = value.Split('-').Select(m => m.ToInt32()).ToArray();
                        (values[1] - values[0] + 1).For(m => Minutes.Add(values[0] + m));
                    }
                    else
                    {
                        Minutes.Add(value.ToInt32());
                    }
                    break;
                case CronFieldIndex.Hour:
                    if (value == "*")
                    {
                        24.For(n => Hours.Add(n));
                    }
                    else if (value.Contains('-'))
                    {
                        var values = value.Split('-').Select(m => m.ToInt32()).ToArray();
                        (values[1] - values[0] + 1).For(m => Hours.Add(values[0] + m));
                    }
                    else
                    {
                        Hours.Add(value.ToInt32());
                    }
                    break;
                case CronFieldIndex.DayOfMonth:
                    if (value == "*")
                    {
                        31.For(n => DaysOfMonth.Add(n + 1));
                    }
                    else if (value.Contains('-'))
                    {
                        var values = value.Split('-').Select(m => m.ToInt32()).ToArray();
                        (values[1] - values[0] + 1).For(m => DaysOfMonth.Add(values[0] + m));
                    }
                    else
                    {
                        DaysOfMonth.Add(value.ToInt32());
                    }
                    break;
                case CronFieldIndex.Month:
                    if (value == "*")
                    {
                        12.For(n => Months.Add(n + 1));
                    }
                    else if (value.Contains('-'))
                    {
                        var values = value.Split('-').Select(m => m.ToInt32()).ToArray();
                        (values[1] - values[0] + 1).For(m => Months.Add(values[0] + m));
                    }
                    else
                    {
                        Months.Add(value.ToInt32());
                    }
                    break;
                case CronFieldIndex.DayOfWeek:
                    if (value == "*")
                    {
                        7.For(n => DaysOfWeek.Add(n + 1));
                    }
                    else if (value.Contains('-'))
                    {
                        var values = value.Split('-').Select(m => m.ToInt32()).ToArray();
                        (values[1] - values[0] + 1).For(m => DaysOfWeek.Add(values[0] + m));
                    }
                    else
                    {
                        DaysOfWeek.Add(value.ToInt32());
                    }
                    break;
                case CronFieldIndex.Year:
                    if (value == "*")
                    {
                        Years.Add(DateTime.Now.Year);
                    }
                    else if (value.Contains('-'))
                    {
                        var values = value.Split('-').Select(m => m.ToInt32()).ToArray();
                        (values[1] - values[0] + 1).For(m => Years.Add(values[0] + m));
                    }
                    else
                    {
                        Years.Add(value.ToInt32());
                    }
                    break;
                default:
                    throw new AggregateException("输入参数错误");
            }
        }

        private List<int> Seconds { get; set; }
        private List<int> Minutes { get; set; }
        private List<int> Hours { get; set; }
        private List<int> DaysOfMonth { get; set; }
        private List<int> Months { get; set; }
        private List<int> DaysOfWeek { get; set; }
        private List<int> Years { get; set; }
        public bool TimeInCron(DateTime time)
        {
            //1.秒
            //2.分
            //3.小时
            //4.日
            //5.月
            //6.星期几
            //7.年
            return Seconds.Contains(time.Second)
                && Minutes.Contains(time.Minute)
                && Hours.Contains(time.Hour)
                && DaysOfMonth.Contains(time.Day)
                && DaysOfWeek.Contains((int)time.DayOfWeek)
                && Months.Contains(time.Month)
                && (!Years.Any() || Years.Contains(time.Year));
        }
    }
    public enum CronFieldIndex
    {
        /// <summary> 秒    0-59    , - * / </summary>
        Second,
        /// <summary> 分    0-59    , - * / </summary>
        Minute,
        /// <summary> 小时    0-23    , - * / </summary>
        Hour,
        /// <summary> 日    1-31    , - * ? / L W C </summary>
        DayOfMonth,
        /// <summary> 月    1-12     , - * / </summary>
        Month,
        /// <summary> 周几    1-7     , - * ? / L C # </summary>
        DayOfWeek,
        /// <summary> 年 (可选字段)    空 或1970-2099    , - * / </summary>
        Year
    }
}