//	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;
using System.Drawing;

namespace Spludlow.Drawing
{
	public class BarCode128 : IBarCode
	{
		private class LookupDictionaries
		{
			public LookupDictionaries()
			{
				this.ValueWeights = new Dictionary<int, string>();

				this.CharacterValue = new Dictionary<string, Dictionary<string, int>>();

				foreach (string code in new string[] { "A", "B", "C" })
					this.CharacterValue.Add(code, new Dictionary<string, int>());
			}

			public Dictionary<int, string> ValueWeights;

			public Dictionary<string, Dictionary<string, int>> CharacterValue;
		}

		private LookupDictionaries Lookup;

		private string CodeSet;

		private string CacheKey = "Spludlow.BarCode128";

		public BarCode128()
		{
			this.CodeSet = "B";
			this.Load();
		}

		public BarCode128(string codeSet)
		{
			this.CodeSet = codeSet;
			this.Load();
		}

		private void Load()
		{
			this.Lookup = (LookupDictionaries)Spludlow.Caching.Get(this.CacheKey);

			if (this.Lookup == null)
			{
				this.Lookup = new LookupDictionaries();

				string fileName = Spludlow.Config.ProgramData + @"\Data\BarCode128.txt";

				if (System.IO.File.Exists(fileName) == false)
					throw new ApplicationException("BarCode128 Data File not there.\t" + fileName);

				DataTable table = Spludlow.Data.TextTable.ReadFile(fileName);

				foreach (DataRow row in table.Rows)
				{
					int value = (int)row["Value"];
					string weights = (string)row["Weights"];

					this.Lookup.ValueWeights.Add(value, weights);

					foreach (string code in new string[] { "A", "B", "C" })
					{
						string character = (string)row[code];
						this.Lookup.CharacterValue[code].Add(character, value);
					}
				}

				Spludlow.Caching.Set(this.CacheKey, this.Lookup);
			}
		}

		public bool[][] Encode(string data)
		{
			return new bool[][] { this.EncodeBars(data) };
		}

		public bool[] EncodeBars(string data)
		{
			int[] values = this.EncodeValues(data);

			List<bool> result = new List<bool>();
			
			foreach (int value in values)
				result.AddRange(this.EncodeValue(value));
			
			return result.ToArray();
		}

		private int[] EncodeValues(string data)
		{
			int[] values;

			if (this.CodeSet == "C")
			{
				if (data.Length % 2 != 0)
					data = "0" + data;

				values = new int[(data.Length / 2) + 3];

				for (int index = 0; index < data.Length; index += 2)
					values[1 + index / 2] = this.FindValue(new string(new char[] { data[index], data[index + 1] }));
			}
			else
			{
				values = new int[data.Length + 3];

				for (int index = 0; index < data.Length; ++index)
				{
					string character = data[index].ToString();
					values[index + 1] = this.FindValue(character);
				}
			}

			values[0] = this.FindValue("START " + this.CodeSet);

			values[values.Length - 2] = this.CheckSum(values);
			values[values.Length - 1] = this.FindValue("STOP");

			return values;
		}

		private bool[] EncodeValue(int value)
		{
			string weights = this.Lookup.ValueWeights[value];
			
			List<bool> result = new List<bool>();

			bool on = true;

			foreach (char weightChar in weights)
			{
				int weight = Int32.Parse(weightChar.ToString());

				for (int index = 0; index < weight; ++index)
					result.Add(on);

				on = !on;
			}

			return result.ToArray();
		}

		private int FindValue(string data)
		{
			if (this.Lookup.CharacterValue[this.CodeSet].ContainsKey(data) == false)
				throw new ApplicationException("BarCode128; character not Found: '" + data + "', codeset:" + this.CodeSet);

			return this.Lookup.CharacterValue[this.CodeSet][data];
		}

		private int CheckSum(int[] values)
		{
			int checkLength = values.Length - 2;

			int total = 0;

			for (int index = 0; index < checkLength; ++index)
			{
				int value = values[index];

				if (index == 0)
					total += value;
				else
					total += value * index;
			}

			return total % 103;
		}

	}
}