using System;
using System.Collections.Generic;
using System.Text;
using System.Net;

namespace SDP
{
    /// <summary>
    /// This class describes a range of addresses.
    /// </summary>
    public class AddressRange
    {
        private IPAddress address;
        /// <summary>
        /// Gets the value of the starting adress.
        /// </summary>
        public IPAddress Address
        {
            get { return this.address; }
        }

        private uint numberOfAddresses;
        /// <summary>
        /// Gets the number of ports in the range.
        /// </summary>
        public uint NumberOfAddresses
        {
            get { return this.numberOfAddresses; }
        }

        private byte ttl;
        /// <summary>
        /// Gets the Time To Live value.
        /// </summary>
        public byte TTL
        {
            get { return this.ttl; }
        }

        /// <summary>
        /// Instantiates a new AddressRange.
        /// </summary>
        /// <param name="address">The unicast starting address. The default number of addresses is one, so this
        /// range is effectively one address.</param>
        public AddressRange(IPAddress address) : this(address, 1) { }

        /// <summary>
        /// Instantiates a new AddressRange.
        /// </summary>
        /// <param name="address">The multiciast starting address.</param>
        /// <param name="ttl">The Time to Live.</param>
        public AddressRange(IPAddress address, byte ttl) : this(address, 1, ttl) { }

        /// <summary>
        /// Instantiates a new AddressRange.
        /// </summary>
        /// <param name="address">The multicast hierarchial starting address.</param>
        /// <param name="numberOfAddresses">The number of addresses in the range. This value must
        /// be greater than or equal to one.</param>
        /// <param name="ttl">The Time to Live.</param>
        public AddressRange(IPAddress address, uint numberOfAddresses, byte ttl)
        {
            if (address == null) throw new ArgumentNullException("address");
            if (numberOfAddresses < 1) throw new ArgumentException("Number of addresses must be greater than or equal to one.");

            this.ttl = ttl;
            this.address = address;
            this.numberOfAddresses = numberOfAddresses;
        }

        /// <summary>
        /// Converts an AddressRange to its string representation.
        /// </summary>
        /// <returns>A string.</returns>
        public override string ToString()
        {
            string s = this.address.ToString();
            if (this.ttl == 0) return s;
            s = s + "/" + ttl.ToString();
            if (this.numberOfAddresses == 1) return s;
            s = s + "/" + numberOfAddresses;
            return s;
        }
    }
}