using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;

namespace Newtonsoft.Json
{
	/// <summary>
	/// Converts an <see cref="IPAddress"/> from and to JSON.
	/// </summary>
	[System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
	public class IPAddressConverter : JsonConverter
	{
		/// <summary>
		/// List of known types to use this converver.
		/// </summary>
		public static readonly Type[] KnownTypes =
		[
			typeof(IPAddress),
			typeof(IPAddress[]),
			typeof(List<IPAddress>),
			typeof(IEnumerable<IPAddress>)
		];

		/// <inheritdoc/>
		public override bool CanConvert(Type objectType)
			=> KnownTypes.Contains(objectType);

		/// <inheritdoc/>
		public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
		{
			if (reader.Value == null)
				return null;

			string str = (string)reader.Value;

			if (typeof(IPAddress) == objectType)
				return IPAddress.Parse(str);

			var ips = str.Split(';').Select(s => IPAddress.Parse(s));

			if (typeof(IPAddress[]) == objectType)
				return ips.ToArray();

			if (typeof(List<IPAddress>) == objectType)
				return ips.ToList();

			return ips;
		}

		/// <inheritdoc/>
		public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
		{
			string str = null;
			if (value == null)
			{
				writer.WriteValue(str);
				return;
			}

			if (value is IPAddress addr)
				str = addr.ToString();

			if (value is IPAddress[] addrArray)
				str = string.Join(";", addrArray.Select(ip => ip.ToString()));

			if (value is List<IPAddress> addrList)
				str = string.Join(";", addrList.Select(ip => ip.ToString()));

			if (value is IEnumerable<IPAddress> addrEnum)
				str = string.Join(";", addrEnum.Select(ip => ip.ToString()));

			writer.WriteValue(str);
		}
	}
}