using System;
using ln.types.btree;
using ln.types.net;
namespace skyspot.ip
{
    public class IPPool<T> where T : IComparable
    {
        public IPv4 FirstIP { get; set; }
        public IPv4 LastIP { get; set; }

        public IPv4 NextIP { get; set;}

        BTree<IPv4, T> forward = new BTree<IPv4, T>();
        BTree<T, IPv4> reverse = new BTree<T, IPv4>();

        public IPPool()
        {
        }

        public T FindForward(IPv4 ip)
        {
            lock (this)
            {
                return forward[ip];
            }
        }
        public IPv4 FindReverse(T lookup)
        {
            lock (this)
            {
                return reverse[lookup];
            }
        }

        public void Assign(IPv4 ip, T assigned)
        {
            lock (this)
            {
                if (forward.ContainsKey(ip) || reverse.ContainsKey(assigned))
                    throw new ArgumentException("<ip> or <assigend> already in pool");
                forward.Add(ip, assigned);
                reverse.Add(assigned, ip);
            }
        }
        public void Remove(IPv4 ip)
        {
            lock (this)
            {
                if (forward.ContainsKey(ip))
                {
                    reverse.Remove(forward[ip]);
                    forward.Remove(ip);
                }
            }
        }
        public void RemoveAssigned(T assigned)
        {
            lock (this)
            {
                if (reverse.ContainsKey(assigned))
                {
                    forward.Remove(reverse[assigned]);
                    reverse.Remove(assigned);
                }
            }
        }

        public IPv4 Allocate(T assigned)
        {
            if (reverse.ContainsKey(assigned))
                return reverse[assigned];

        }

    }
}