//	Spludlow Software
//	Copyright © Samuel P. Ludlow 2020 All Rights Reserved
//	Distributed under the terms of the GNU General Public License version 3
//	Distributed WITHOUT ANY WARRANTY; without implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE
//	https://www.spludlow.co.uk/LICENCE.TXT
//	The Spludlow logo is a registered trademark of Samuel P. Ludlow and may not be used without permission
//	v1.14

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

using System.IO;

namespace Spludlow.Net
{
	public class IPWhoIsRange
	{
		public Dictionary<uint, uint> IpRanges = new Dictionary<uint, uint>();  //	start, end IP

		private string StoreDirectory = Spludlow.Config.ProgramData + @"\Data\IPWhoIsRange";

		public IPWhoIsRange()
		{
			if (Directory.Exists(this.StoreDirectory) == false)
				Directory.CreateDirectory(this.StoreDirectory);

			foreach (string filename in Directory.GetFiles(this.StoreDirectory, "*.txt"))
			{
				uint[] range = ParseRangeFilename(filename);

				this.IpRanges.Add(range[0], range[1]);
			}
		}

		public static uint[] ParseRangeFilename(string filename)
		{
			filename = Path.GetFileNameWithoutExtension(filename);

			string[] parts = filename.Split(new char[] { '-' });

			if (parts.Length != 2)
				throw new ApplicationException("IPWhoIsRange, ParseRangeFilename; did not split into 2 parts: " + filename);

			return new uint[] { Spludlow.Net.IP.IPAddressToInt(parts[0].Trim()), Spludlow.Net.IP.IPAddressToInt(parts[1].Trim()) };
		}

		public string WhoIsQuery(string ipv4Address)
		{
			uint ip = Spludlow.Net.IP.IPAddressToInt(ipv4Address);

			uint[] starts;
			lock (this.IpRanges)
			{
				starts = this.IpRanges.Keys.ToArray();
			}

			foreach (uint start in starts)
			{
				uint end = this.IpRanges[start];

				if (ip >= start && ip <= end)
				{
					string existingFilename = this.StoreDirectory + @"\" + Spludlow.Net.IP.IntToIPAddress(start) + "-" + Spludlow.Net.IP.IntToIPAddress(end) + ".txt";
					if (File.Exists(existingFilename) == false)
						throw new ApplicationException("IPWhoIsRange, ParseRangeFilename; did not find file: " + existingFilename);

					return File.ReadAllText(existingFilename);
				}
			}

			string whoIsText = Spludlow.Net.IpWhoIs.WhoIs(ipv4Address);

			string[] range = SplitINetNum(whoIsText);

			string filename = this.StoreDirectory + @"\" + range[0] + "-" + range[1] + ".txt";

			uint rangeStart = Spludlow.Net.IP.IPAddressToInt(range[0]);

			lock (this.IpRanges)
			{
				if (this.IpRanges.ContainsKey(rangeStart) == false) //	Not added elsewhere
				{
					File.WriteAllText(filename, whoIsText);
					this.IpRanges.Add(rangeStart, Spludlow.Net.IP.IPAddressToInt(range[1]));
				}
			}

			return whoIsText;
		}

		public string CountryCode(string ipv4Address)
		{
			string whoIsText = WhoIsQuery(ipv4Address);

			Dictionary<string, List<string>> whoIs = Spludlow.Net.IpWhoIs.Parse(whoIsText);

			string code = "";

			if (whoIs.ContainsKey("country") == true && whoIs["country"].Count > 0)
			{
				code = whoIs["country"][whoIs["country"].Count - 1];
				code = code.ToUpper();
				if (code.StartsWith("EU") == true)
					code = "EU";
			}

			return code;
		}

		public static string[] SplitINetNum(string whoIsText)
		{
			Dictionary<string, List<string>> whois = Spludlow.Net.IpWhoIs.Parse(whoIsText);

			if (whois.ContainsKey("inetnum") == false || whois["inetnum"].Count == 0)
				throw new ApplicationException("Did not find inetnum in whois");

			string range = whois["inetnum"][whois["inetnum"].Count - 1];

			string[] parts;

			if (range.Contains("/") == true)
			{
				parts = Spludlow.Net.IP.IPRangeFromCIDR(range);
			}
			else
			{
				parts = range.Split(new char[] { '-' });
				parts[0] = parts[0].Trim();
				parts[1] = parts[1].Trim();
			}

			if (parts.Length != 2)
				throw new ApplicationException("inetnum did not split into 2 parts in whois: " + range);

			return new string[] { parts[0], parts[1] };
		}
	}
}