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

namespace Impeltech.EDS.Helper
{
    public class DateHelper
    {

        public static DateTime DatesReportingYear()
        {
            DateTime year;
            DateTime last;
            DatesReportingRange(DateTime.Now, out year, out last);


            return year;
        }

        public static DateTime DatesReportingLast()
        {
            DateTime year;
            DateTime last;
            DatesReportingRange(DateTime.Now, out year, out last);


            return last;
        }


        public static void DatesReportingRange(DateTime date, out DateTime year, out DateTime last)
        {

            var oldDate = date;
            if (date.Month != 4)
            {
                date = date.AddMonths(-1);
            }

            last = GetPreviosDate(date);
            year = GetPreviosDateByYear(last);
            if (oldDate.Month == 4)
            {
                last = year;

            }
            else
            {


                if (last.Month == year.Month && year.Day == last.Day)
                {

                    DatesReportingRange(last, out year, out last);
                }
            }

        }

        /// <summary>
        /// Интервал в который попадает дата
        /// </summary>
        /// <param name="date"></param>
        /// <param name="from"></param>
        /// <param name="to"></param>
        public static void DateRange(DateTime date, out DateTime from, out DateTime to)
        {

            from = GetPreviosDate(date);
            to = GetNextDate(date);
        }

        public static DateTime MinDateCopy(DateTime date)
        {

            DateTime currentFrom;
            DateTime currentTo;
            DatesReportingRange(date, out currentFrom, out currentTo);


            return currentTo;
        }

        public static DateTime GetNextDate(DateTime start)
        {

            return GetNextDate(start, DateTime.MaxValue);
        }



        /// <summary>
        /// Ближайшая дата начала
        /// </summary>
        /// <param name="start"></param>
        /// <param name="Max"></param>
        /// <returns></returns>
        public static DateTime GetNextDate(DateTime start, DateTime Max)
        {
            var list = new List<DateTime>() {

                GetNextDateByYear(start, 31, 03),
                GetNextDateByYear(start, 30, 06),
                GetNextDateByYear(start, 30, 09),
                GetNextDateByYear(start, 31, 12)
            };

            var date = list.OrderBy(c => c).FirstOrDefault();
            if (date < Max)
            {


                return date;
            }
            else
            {

                return Max.AddDays(1);
            }
        }



        /// <summary>
        /// Ближайшая дата начала
        /// </summary>
        /// <param name="start"></param>
        /// <param name="Max"></param>
        /// <returns></returns>
        public static DateTime GetPreviosDate(DateTime start)
        {
            var list = new List<DateTime>() {

                GetPreviosByYear(start, 31, 03),
                GetPreviosByYear(start, 30, 06),
                GetPreviosByYear(start, 30, 09),
                GetPreviosByYear(start, 31, 12)
            };

            var date = list.OrderByDescending(c => c).FirstOrDefault();
            return date;
        }

        public static List<DateTime> GetLastQuarts()
        {
            var list = new List<DateTime>() {

                GetPreviosByYear(DateTime.Today, 31, 03),
                GetPreviosByYear(DateTime.Today, 30, 06),
                GetPreviosByYear(DateTime.Today, 30, 09),
                GetPreviosByYear(DateTime.Today, 31, 12)
            };

            return list.OrderBy(c => c).ToList();
        }

        private static DateTime GetPreviosDateByYear(DateTime date)
        {

            return new DateTime(date.Year - 1, 12, 31);
        }

        /// <summary>
        /// Ближайшая дата
        /// </summary>
        /// <param name="date">От </param>
        /// <param name="Month">месяй   </param>
        /// <param name="Day">день</param>
        /// <returns></returns>
        private static DateTime GetNextDateByYear(DateTime date, int Day, int Month)
        {

            var nextDate = new DateTime(date.Year, Month, Day);

            if (nextDate <= date)
            {

                return nextDate.AddYears(1).AddDays(1);
            }
            else
            {

                return nextDate.AddDays(1);
            }
        }




        /// <summary>
        /// Ближайшая дата прошедшая
        /// </summary>
        /// <param name="date">От </param>
        /// <param name="Month">месяй   </param>
        /// <param name="Day">день</param>
        /// <returns></returns>
        private static DateTime GetPreviosByYear(DateTime date, int Day, int Month)
        {

            var curDate = new DateTime(date.Year, Month, Day);

            if (date <= curDate)
            {

                return curDate.AddYears(-1);
            }
            else
            {

                return curDate;
            }
        }

        public static int GetDaysInYear(DateTime date)
        {

            var start = new DateTime(date.Year, 1, 1);
            var end = start.AddYears(1);

            return (int)(end - start).TotalDays;
        }
    }
}