//	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;
using System.Data;

namespace Spludlow.Drawing
{
	public class Unicode
	{
		private static string CacheName = "Spludlow.Drawing.UnicodeBlocks";

		private static string UnicodeBlocksFilename = Spludlow.Config.ProgramData + @"\Data\UnicodeBlocks.txt";

		public static DataTable BlocksTable()
		{
			DataTable table = (DataTable)Spludlow.Caching.Get(CacheName);

			if (table == null)
			{
				if (File.Exists(UnicodeBlocksFilename) == false)
				{
					table = CreateBlocksTable();
					Spludlow.Data.TextTable.Write(UnicodeBlocksFilename, table);
				}
				else
				{
					table = Spludlow.Data.TextTable.ReadFile(UnicodeBlocksFilename);
				}
				Spludlow.Caching.Set(CacheName, table);
			}

			if (table.DataSet != null)
				table.DataSet.Tables.Remove(table);

			return table;
		}

		public static DataTable CreateBlocksTable()
		{
			string url = "http://www.unicode.org/Public/UCD/latest/ucd/Blocks.txt";

			DataTable table = Spludlow.Data.TextTable.ReadText(new string[]
			{
				"StartCode	EndCode	BlockName	HexRange",
				"Int32*		Int32	String		String",
			});
			
			string text = Spludlow.Net.Http.GetText(url, Encoding.UTF8);

			using (StringReader reader = new StringReader(text))
			{
				string line;
				while ((line = reader.ReadLine()) != null)
				{
					line = line.Trim();
					if (line.Length == 0 || line.StartsWith("#") == true)
						continue;

					int index;

					index = line.IndexOf(";");

					string range = line.Substring(0, index).Trim();
					string name = line.Substring(index + 1).Trim();

					string[] rangeParts = Spludlow.Text.Split(range, '.', true);

					int start = Int32.Parse(rangeParts[0], System.Globalization.NumberStyles.HexNumber);
					int end = Int32.Parse(rangeParts[1], System.Globalization.NumberStyles.HexNumber);

					table.Rows.Add(start, end, name, range);
				}
			}
			
			return table;
		}
	}
}