//	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.Data;
using System.Drawing;

namespace Spludlow.Drawing
{
	/// <summary>
	/// Delivery Point Suffix (DPS), a checksum character, and a stop character. The DPS is a two-character code ranging from 1A to 9T, with codes 9U to 9Z being accepted as default codes when no DPS has been allocated
	/// </summary>
	public class RM4SCC : IBarCode
	{
		private static DataTable Data;
		private static DataTable CheckSums;		//	change to use dictionaries !!!!!!!!!!!!!!!!!!!!!!!!!!!!

		private static string CacheKey = "Spludlow.RM4SCC";

		static RM4SCC()
		{
			DataSet dataSet = (DataSet)Spludlow.Caching.Get(CacheKey);

			if (dataSet == null)
			{
				dataSet = new DataSet();
				DataTable table;

				table = Spludlow.Data.TextTable.ReadFile(Spludlow.Config.ProgramData + @"\Data\BarCodeRM4SCC.txt");
				table.TableName = "Data";
				dataSet.Tables.Add(table);

				table = Spludlow.Data.TextTable.ReadFile(Spludlow.Config.ProgramData + @"\Data\BarCodeRM4SCCchecksum.txt");
				table.TableName = "CheckSums";
				dataSet.Tables.Add(table);

				Spludlow.Caching.Set(CacheKey, dataSet);
			}

			Data = dataSet.Tables["Data"];
			CheckSums = dataSet.Tables["CheckSums"];
		}

		public RM4SCC()
		{

		}

		public string EncodeData(string data)
		{
			data = PreparePostCode(data);	//	Aloow passing of DPS

			StringBuilder result = new StringBuilder();

			foreach (char character in data)
			{
				DataRow row = Data.Rows.Find(character.ToString());

				if (row == null)
					throw new ApplicationException("BarCodeRM4SCC Encode character not found:\t" + character.ToString());

				result.Append((string)row[1]);
			}

			return result.ToString();
		}

		public bool[][] Encode(string data)
		{
			data = this.EncodeData(data);

			bool[][] result = new bool[3][];
			for (int row = 0; row < 3; ++row)
				result[row] = new bool[data.Length * 2 + 1];

			for (int index = 0; index < data.Length; ++index)
			{
				int targetIndex = index * 2 + 1;

				switch (data[index])
				{
					case 'T':
						result[0][targetIndex] = true;
						result[1][targetIndex] = true;
						//result[2][targetIndex] = false;
						break;

					case 'B':
						//result[0][targetIndex] = false;
						result[1][targetIndex] = true;
						result[2][targetIndex] = true;
						break;

					case 'L':
						result[0][targetIndex] = true;
						result[1][targetIndex] = true;
						result[2][targetIndex] = true;
						break;

					case 'S':
						//result[0][targetIndex] = false;
						result[1][targetIndex] = true;
						//result[2][targetIndex] = false;
						break;

					default:
						throw new ApplicationException("RM4SCC Encode Unknown character: " + data[index].ToString());
				}
			}

			return result;
		}

		public static string PreparePostCode(string postcode)
		{
			return PreparePostCode(postcode, "9Z");
		}

		public static string PreparePostCode(string postcode, string dps)
		{
			StringBuilder result = new StringBuilder(postcode.ToUpper());
			result.Replace(" ", "");
			result.Append(dps);

			string postCodeAndDps = result.ToString();
			
			result.Length = 0;

			result.Append("(");
			result.Append(postCodeAndDps);
			result.Append(CheckSum(postCodeAndDps));
			result.Append(")");

			return result.ToString();
		}

		private static string CheckSum(string checkString)
		{
			int rowTotal = 0;
			int columnTotal = 0;

			foreach (char ch in checkString)
			{
				bool found = false;

				foreach (DataRow row in CheckSums.Rows)
				{
					for (int colIndex = 1; colIndex < CheckSums.Columns.Count; ++colIndex)
					{
						if (ch == ((string)row[colIndex])[0])
						{
							rowTotal += (int)row["Row"];
							columnTotal += Int32.Parse(row.Table.Columns[colIndex].ColumnName);

							found = true;
							break;
						}

					}
					if (found == true)
						break;
				}

				if (found == false)
					throw new ApplicationException("BarCodeRM4SCC Could not find CheckSum:\t" + ch.ToString() + "\t" + checkString);
			}

			int rowRemainder = rowTotal % 6;
			int columnRemainder = columnTotal % 6;

			DataRow checkRow = CheckSums.Rows.Find(rowRemainder.ToString());

			return (string)checkRow[columnRemainder.ToString()];
		}
	}
}