using System;
using System.Drawing;
using System.Windows.Forms;
using System.Windows.Forms.DataVisualization.Charting;
using System.Diagnostics;
using System.Text;
using System.Linq;
using System.Net;
using System.Collections.Generic;

namespace Test_1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();

        }



        private void button1_Click(object sender, EventArgs e)
        {
            List<Capacities> _list = new List<Capacities>{
                new Capacities(DateTime.Parse("01/01/2013"), DateTime.Parse("01/01/2013 06:00"), 100),
                new Capacities(DateTime.Parse("01/01/2013 04:00"), DateTime.Parse("01/02/2013 00:00"), 120),
                new Capacities(DateTime.Parse("01/04/2013"), DateTime.Parse("01/04/2013 15:00"), 100),
                new Capacities(DateTime.Parse("01/04/2013 15:00"), DateTime.Parse("01/04/2013 18:00"), 150)
            };

            SortedSet<DateTime> splitdates = new SortedSet<DateTime>();
            foreach (var item in _list)
            {
                splitdates.Add(item.Period.Start);
                splitdates.Add(item.Period.End);
            }

            var list = splitdates.ToList();
            var ranges = new List<DateRange>();
            for (int i = 0; i < list.Count - 1; i++)
                ranges.Add(new DateRange() { Start = list[i], End = list[i + 1] });

            var result = from range in ranges
                         from c in _list
                         where c.Period.Intersect(range) != null
                         group c by range into r
                         select new Capacities(r.Key.Start, r.Key.End, r.Sum(a => a.Capacity));

            foreach (var item in result)
                Debug.WriteLine(item);

            /* Writes:
                01.01.2013 00:00:00 - 01.01.2013 04:00:00    100
                01.01.2013 04:00:00 - 01.01.2013 06:00:00    220
                01.01.2013 06:00:00 - 01.02.2013 00:00:00    120
                01.04.2013 00:00:00 - 01.04.2013 15:00:00    100
                01.04.2013 15:00:00 - 01.04.2013 18:00:00    150
             */
        }

        private bool IsSubrange(DateTime start1, DateTime end1, DateTime start2, DateTime end2)
        {
            return start1 <= start2 && end1 >= end2;
        }
    }

    public class DateRange : IEquatable<DateRange>
    {
        public DateTime Start { get; set; }
        public DateTime End { get; set; }

        public DateRange Intersect(DateRange d)
        {
            var s = (d.Start > this.Start) ? d.Start : this.Start; // Later Start
            var e = (d.End < this.End) ? d.End : this.End; // Earlier ending

            if (s < e)
                return new DateRange() { Start = s, End = e };
            else
                return null;
        }

        public bool Contains(DateTime d)
        {
            return d >= Start && d <= End;
        }

        public bool Equals(DateRange obj)
        {
            return Start.Equals(obj.Start) && End.Equals(obj.End);
        }
    }

    public class Capacities
    {
        public DateRange Period { get; set; }
        public int Capacity { get; set; }

        public Capacities()
        {
            Period = new DateRange();
        }

        public Capacities(DateTime start, DateTime end, int c)
            : this()
        {
            Period.Start = start;
            Period.End = end;
            Capacity = c;
        }

        public override string ToString()
        {
            return string.Format("{0} - {1} \t {2}", Period.Start, Period.End, Capacity);
        }
    }
}