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

namespace BS.Shared.Core
{
    public static class DateTimeUtils
    {
        public static AnzahlMonate GetTotalMonths(DateTime start, DateTime end)
        {
            int restTageStart = 0;
            int restTageEnd = 0;

            DateTime startDt = start;
            DateTime endDt = end;

            if (startDt.Day > 1)
            {
                var endMonat = new DateTime(startDt.Year, startDt.Month, 1).AddMonths(1).AddDays(-1);

                if (endDt < endMonat)
                {
                    endMonat = endDt;
                }
                restTageStart = endMonat.Subtract(startDt).Days + 1;
                startDt = endMonat.AddDays(1);
            }
            if (startDt <= endDt && endDt.AddDays(1).Day != 1)
            {
                var startMonat = new DateTime(endDt.Year, endDt.Month, 1);

                restTageEnd += endDt.Subtract(startMonat).Days + 1;

                endDt = startMonat;
            }

            int fullMonths = 0;
            while (startDt < endDt)
            {
                fullMonths++;
                startDt = startDt.AddMonths(1);
            }

            decimal monthsTotal = fullMonths;


            if (restTageStart != 0)
            {
                monthsTotal += restTageStart / (decimal)DateTime.DaysInMonth(start.Date.Year, start.Date.Month);

            }
            if (restTageEnd != 0)
            {
                monthsTotal += restTageEnd / (decimal)DateTime.DaysInMonth(end.Date.Year, end.Date.Month);

            }

            var am = new AnzahlMonate();
            am.GanzeMonate = fullMonths;
            am.RestTageAnfang = restTageStart;
            am.RestTageEnde = restTageEnd;
            am.AnzahlMonateGesamt = monthsTotal;

            return am;
        }
        
    }

    public class AnzahlMonate
    {
        public decimal AnzahlMonateGesamt { get; set; }
        public int GanzeMonate { get; set; }
        public decimal RestTageAnfang { get; set; }
        public decimal RestTageEnde { get; set; }
    }
}