//---------------------------------------------------------------------------
// Generowanie kodow kreskowych ITF-14
// www.algorytm.org
// (c)2007 Tomasz Lubinski
//---------------------------------------------------------------------------

#include <vcl.h>
#pragma hdrstop

#include "Unit1.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"

char codeI25sign[10] = {
      '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'
      };
      
char codeI25bars[10][5] = {
     {'N', 'N', 'W', 'W', 'N'},
     {'W', 'N', 'N', 'N', 'W'},
     {'N', 'W', 'N', 'N', 'W'},
     {'W', 'W', 'N', 'N', 'N'},
     {'N', 'N', 'W', 'N', 'W'},
     {'W', 'N', 'W', 'N', 'N'},
     {'N', 'W', 'W', 'N', 'N'},
     {'N', 'N', 'N', 'W', 'W'},
     {'W', 'N', 'N', 'W', 'N'},
     {'N', 'W', 'N', 'W', 'N'}
     };

char start[4] = {
        1, 0, 1, 0
        };

char stop[4] = {
        1, 1, 0, 1
        };
        

TForm1 *Form1;
int curentPos;

// returns letter value for check digit
int getLetterValue(char ch)
{
        for (int i=0; i<10; i++)
                if (codeI25sign[i] == ch)
                        return i;

        return 0;
}

// return check digit
int checkDigit(char *txt)
{
        int sum = 3 * getLetterValue(txt[0]) +
                  1 * getLetterValue(txt[1]) +
                  3 * getLetterValue(txt[2]) +
                  1 * getLetterValue(txt[3]) +
                  3 * getLetterValue(txt[4]) +
                  1 * getLetterValue(txt[5]) +
                  3 * getLetterValue(txt[6]) +
                  1 * getLetterValue(txt[7]) +
                  3 * getLetterValue(txt[8]) +
                  1 * getLetterValue(txt[9]) +
                  3 * getLetterValue(txt[10]) +
                  1 * getLetterValue(txt[11]) +
                  3 * getLetterValue(txt[12]);

        sum %= 10;
        sum = 10 - sum;
        sum %= 10;

        return sum;
}

// returns 1 if letter is correct, 0 otherwise
int checkLetter(char ch)
{
        for (int i=0; i<10; i++)
                if (codeI25sign[i] == ch)
                        return 1;

        return 0;
}

// reurns 1 if given EAN-14 is correct, 0 otherwise
int check(char *txt)
{
        if (strlen(txt) != 14)
           return 0;

        for (unsigned int i=0; i<strlen(txt); i++)
                if (checkLetter(txt[i]) == 0)
                        return 0;

        if (checkDigit(txt) != getLetterValue(txt[13]))
                return 0;

        return 1;
}

void drawSignBars(char bars[], int count)
{
        Form1->Image1->Canvas->Brush->Color = clBlack;

        //print bars
        for (int i=0; i<count; i++)
        {
                if (bars[i] == 1)
                        Form1->Image1->Canvas->Rectangle(curentPos + 20, 10, curentPos + 22, 100);

                curentPos += 2;
        }
}

void drawSignBars(char bars[], char spaces[])
{
        Form1->Image1->Canvas->Brush->Color = clBlack;

        //print bars
        for (int i=0; i<5; i++)
        {
                if (bars[i] == 'W') // wide bar
                {
                        Form1->Image1->Canvas->Rectangle(curentPos + 20, 10, curentPos + 24, 100);
                        curentPos += 4;
                }
                else               // narrow bar
                {
                        Form1->Image1->Canvas->Rectangle(curentPos + 20, 10, curentPos + 22, 100);
                        curentPos += 2;
                }

                if (spaces[i] == 'W') // wide space
                {
                        curentPos += 4;
                }
                else               // narrow space
                {
                        curentPos += 2;
                }
       }
}


void drawBars(char *txt)
{
        int odd, even;

        curentPos = 0;
        Form1->Image1->Canvas->Brush->Color = clWhite;
        Form1->Image1->Canvas->Rectangle(0, 0, 257, 121);

        //print start character
        drawSignBars(start, 4);

        //print characters
        for (unsigned int i=0; i<strlen(txt); i+=2)
        {
                odd = getLetterValue(txt[i]);
                even = getLetterValue(txt[i+1]);
                drawSignBars(codeI25bars[odd], codeI25bars[even]);

        }

        //print stop character
        drawSignBars(stop, 4);

        //Draw text
        Form1->Image1->Canvas->Font->Size = 10;
        Form1->Image1->Canvas->Brush->Color = clWhite;
        Form1->Image1->Canvas->Font->Color = clBlack;
        Form1->Image1->Canvas->TextOut(curentPos/2 + 20 - strlen(txt)*3, 100, txt);        
}

//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
        : TForm(Owner)
{
}
//---------------------------------------------------------------------------


void __fastcall TForm1::Button1Click(TObject *Sender)
{
        if (check(Kod->Text.c_str()) == 0)
        {
                ShowMessage("Incorrect text");
                return;
        }

        drawBars(Kod->Text.c_str());
}
//---------------------------------------------------------------------------