using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using AMWD.Common.MessagePack.Utilities;

namespace MessagePack.Formatters
{
	/// <summary>
	/// Serialization of an <see cref="IPAddress"/> list to and from <see cref="MessagePack"/>.
	/// </summary>
	[System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
	public class IPAddressListFormatter : IMessagePackFormatter<List<IPAddress>>
	{
		/// <inheritdoc/>
		public List<IPAddress> Deserialize(ref MessagePackReader reader, MessagePackSerializerOptions options)
		{
			if (reader.IsNil)
				return null;

			byte[] bytes = options.Resolver.GetFormatterWithVerify<byte[]>().Deserialize(ref reader, options);

			// skipping the length information
			int bytePos = sizeof(int);

			var list = new List<IPAddress>();
			while (bytePos < bytes.Length)
			{
				byte len = bytes.Skip(bytePos).First();
				bytePos++;

				byte[] buffer = bytes.Skip(bytePos).Take(len).ToArray();
				bytePos += len;

				list.Add(new IPAddress(buffer));
			}

			return list;
		}

		/// <inheritdoc/>
		public void Serialize(ref MessagePackWriter writer, List<IPAddress> value, MessagePackSerializerOptions options)
		{
			if (value == null)
			{
				writer.WriteNil();
				return;
			}

			var bytes = new List<byte>();

			int length = value.Count;
			byte[] buffer = BitConverter.GetBytes(length);
			NetworkHelper.SwapBigEndian(buffer);
			bytes.AddRange(buffer);

			foreach (var ip in value)
			{
				buffer = ip.GetAddressBytes();
				bytes.Add((byte)buffer.Length);
				bytes.AddRange(buffer);
			}

			options.Resolver.GetFormatterWithVerify<byte[]>().Serialize(ref writer, [.. bytes], options);
		}
	}
}