using System.Collections.Generic;

namespace DTS.Common.Utils
{
    public class IPRange
    {
        /// <summary>
        /// ip range, or a start and a stop
        /// </summary>
        public IPAddressIntForm RangeStart { get; set; }
        public IPAddressIntForm RangeEnd { get; set; }
        public IPRange(IPAddressIntForm start, IPAddressIntForm end)
        {
            RangeStart = start;
            RangeEnd = end;
        }
    }
    /// <summary>
    /// just structure for ips broken into bytes
    /// </summary>
    public class IPAddressIntForm
    {
        public int ByteOne { get; }
        public int ByteTwo { get; }
        public int ByteThree { get; }
        public int ByteFour { get; }

        public IPAddressIntForm(int b1, int b2, int b3, int b4)
        {
            ByteOne = b1;
            ByteTwo = b2;
            ByteThree = b3;
            ByteFour = b4;
        }
        public override string ToString()
        {
            return $"{ByteOne}.{ByteTwo}.{ByteThree}.{ByteFour}";
        }
        public static bool TryParse(string input, out IPAddressIntForm output)
        {
            var tokens = input.Split('.');
            if (4 != tokens.Length)
            {
                output = null;
                return false;
            }
            if (int.TryParse(tokens[0], out int one)
                && int.TryParse(tokens[1], out int two)
                && int.TryParse(tokens[2], out int three)
                && int.TryParse(tokens[3], out int four))
            {
                output = new IPAddressIntForm(one, two, three, four);
                return true;
            }
            else
            {
                output = null;
                return false;
            }
        }
        internal class IPComparer : IComparer<IPAddressIntForm>
        {
            public int Compare(IPAddressIntForm x, IPAddressIntForm y)
            {
                if (x == y) { return 0; }
                if (null == x) { return -1; }
                if (null == y) { return 1; }
                var ret = x.ByteOne.CompareTo(y.ByteOne);
                if (ret != 0) { return ret; }
                ret = x.ByteTwo.CompareTo(y.ByteTwo);
                if (ret != 0) { return ret; }
                ret = x.ByteThree.CompareTo(y.ByteThree);
                if (ret != 0) { return ret; }
                ret = x.ByteFour.CompareTo(y.ByteFour);
                if (ret != 0) { return ret; }
                return 0;
            }
            
        }
        /// <summary>
        /// gets all ips between a start and an end
        /// </summary>
        /// <param name="start"></param>
        /// <param name="end"></param>
        /// <returns></returns>
        public static string[] GetAllIPs(IPAddressIntForm a, IPAddressIntForm b)
        {
            var list = new List<string>();

            var comparer = new IPComparer();
            IPAddressIntForm start = a;
            IPAddressIntForm end = b;
            if (comparer.Compare(a, b) > 0) { start = b; end = a; }

            for( var firstByte = start.ByteOne; firstByte <= end.ByteOne; firstByte ++)
            {
                for( var secondByte = start.ByteTwo; secondByte <= end.ByteTwo; secondByte ++)
                {
                    for ( var thirdByte = start.ByteThree; thirdByte <= end.ByteThree; thirdByte ++)
                    {
                        for ( var fourthByte = start.ByteFour; fourthByte <= end.ByteFour; fourthByte ++)
                        {
                            list.Add($"{firstByte}.{secondByte}.{thirdByte}.{fourthByte}");
                        }
                    }
                }
            }
            return list.ToArray();
        }
    }
}