//Kod kreskowy EAN-8
//(c) 2019 by Tomasz Lubinski
//www.algorytm.org

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Drawing.Imaging;

namespace Barcodes.EAN8
{
    public partial class Form1 : Form
    {
        private readonly int[,] right = {
            {1, 1, 1, 0, 0, 1, 0},
            {1, 1, 0, 0, 1, 1, 0},
            {1, 1, 0, 1, 1, 0, 0},
            {1, 0, 0, 0, 0, 1, 0},
            {1, 0, 1, 1, 1, 0, 0},
            {1, 0, 0, 1, 1, 1, 0},
            {1, 0, 1, 0, 0, 0, 0},
            {1, 0, 0, 0, 1, 0, 0},
            {1, 0, 0, 1, 0, 0, 0},
            {1, 1, 1, 0, 1, 0, 0}
        };

        private readonly int[,] left = {
            {0, 0, 0, 1, 1, 0, 1},
            {0, 0, 1, 1, 0, 0, 1},
            {0, 0, 1, 0, 0, 1, 1},
            {0, 1, 1, 1, 1, 0, 1},
            {0, 1, 0, 0, 0, 1, 1},
            {0, 1, 1, 0, 0, 0, 1},
            {0, 1, 0, 1, 1, 1, 1},
            {0, 1, 1, 1, 0, 1, 1},
            {0, 1, 1, 0, 1, 1, 1},
            {0, 0, 0, 1, 0, 1, 1}
        };

        /// <summary>
        /// Zainicjuj
        /// </summary>
        public Form1()
        {
            InitializeComponent();
            pictureBox.Image = new Bitmap(pictureBox.Width, pictureBox.Height, PixelFormat.Format24bppRgb);
            System.Drawing.SolidBrush whiteBrush = new System.Drawing.SolidBrush(System.Drawing.Color.White);
            System.Drawing.Graphics graphics = Graphics.FromImage(pictureBox.Image);
            graphics.FillRectangle(whiteBrush, new Rectangle(0, 0, pictureBox.Width, pictureBox.Height));
            pictureBox.Refresh();
            whiteBrush.Dispose();
            graphics.Dispose();
        }


        /// <summary>
        /// Generuj kod kreskowy EAN-8
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void Generate_Click(object sender, EventArgs e)
        {
            //Zainicjuj narzedzia do rysowania
            System.Drawing.SolidBrush whiteBrush = new System.Drawing.SolidBrush(System.Drawing.Color.White);
            System.Drawing.SolidBrush blackBrush = new System.Drawing.SolidBrush(System.Drawing.Color.Black);
            System.Drawing.Graphics graphics = Graphics.FromImage(pictureBox.Image);
            Font drawFont = new Font("Arial", 10);

            //Wyczysc obszar rysowania
            graphics.FillRectangle(whiteBrush, new Rectangle(0, 0, pictureBox.Width, pictureBox.Height));

            string code = Code.Text.Trim();
            if (checkCode(code) == false)
            {
                MessageBox.Show("Nieprawidłowy kod EAN-8!", "Bład", MessageBoxButtons.OK, MessageBoxIcon.Error);
                return;
            }

            //Wygeneruj i narysuj kod
            int[] bars = generateBars(code);
            int length;
            for (int i = 0; i < bars.Length; i++)
            {
                if ((i >= 0 && i <= 2) ||
                (i >= 31 && i <= 35) ||
                (i >= 64 && i <= 66))
                {
                    //Paski ochronne sa dluzsze
                    length = 100;
                }
                else
                {
                    //Paski kodujace cyfry sa krotsze
                    length = 90;
                }
                if (bars[i] == 1)
                {
                    graphics.FillRectangle(blackBrush, i * 2 + 40, 10, 2, length);
                }
            }

            //Wypisz cyfry pod kodem
            for (int i = 0; i < 4; i++)
            {
                graphics.DrawString(code.Substring(i, 1), drawFont, blackBrush, i * 14 + 47, 102);
            }
            for (int i = 4; i < 8; i++)
            {
                graphics.DrawString(code.Substring(i, 1), drawFont, blackBrush, i * 14 + 57, 102);
            }

            //Odswiez
            pictureBox.Refresh();

            //Zwolinij zasoby
            whiteBrush.Dispose();
            blackBrush.Dispose();
            graphics.Dispose();
        }

        /// <summary>
        /// Sprawdz EAN-8
        /// </summary>
        /// <param name="code"></param>
        /// <returns>true jezeli prawidlowy, false w przeciwnym razie</returns>
        private bool checkCode(string code)
        {
            //Sprawdz dlugosc
            if (code.Length != 8)
            {
                return false;
            }

            //Sprawdz czy podano tylko cyfry
            int[] values = new int[8];
            for (int i = 0; i < 8; i++)
            {
                if (int.TryParse(code.Substring(i, 1), out values[i]) == false)
                    return false;
            }

            //Sprawdz sume kontrolna
            int sum = 3 * values[0] +
                      1 * values[1] +
                      3 * values[2] +
                      1 * values[3] +
                      3 * values[4] +
                      1 * values[5] +
                      3 * values[6];
            sum %= 10;
            sum = 10 - sum;
            sum %= 10;
            if (sum != values[7])
            {
                return false;
            }

            return true;
        }

        /// <summary>
        /// Generuje kod kreskowy
        /// </summary>
        /// <param name="code">kod EAN-8</param>
        /// <returns>kod kreskowy - 1 pasek czarny, 0 - pasek bialy</returns>
        private int[] generateBars(string code)
        {
            int[] bars = new int[67];

            int[] EAN8 = new int[8];
            for (int i = 0; i < 8; i++)
            {
                int.TryParse(code.Substring(i, 1), out EAN8[i]);
            }

            bars[0] = 1;
            bars[1] = 0;
            bars[2] = 1;

            for (int i = 0; i < 4; i++)
            {
                for (int j = 0; j < 7; j++)
                {
                    bars[i * 7 + 3 + j] = left[EAN8[i], j];
                }
            }

            bars[31] = 0;
            bars[32] = 1;
            bars[33] = 0;
            bars[34] = 1;
            bars[35] = 0;

            for (int i = 4; i < 8; i++)
            {
                for (int j = 0; j < 7; j++)
                {
                    bars[(i - 4) * 7 + 36 + j] = right[EAN8[i], j];
                }
            }

            bars[64] = 1;
            bars[65] = 0;
            bars[66] = 1;

            return bars;
        }
    }
}