#include <stdio.h>
#include <conio.h>
#include "valid.c"struct purch_detail
{
  char item_desc[20];
  int unit_price;
  int qty;
};

  void display();
  void entryData();
  void readFile();
  void getName(char *str);
  void getWriteFileName(char *);
  void getReadFileName(char *);
  void getzeroInteger(char *_chr, int *_value);

  int count=0;
  int total_price=0;
  int total_amt=0;
  char option;
  char filename [14];
  FILE *fp;
  struct purch_detail *pd_ptr, *tmptr;

  void main()
  {
      clrscr();
      pd_ptr = (struct purch_detail *) malloc(sizeof(struct purch_detail) * 10);
      tmptr = pd_ptr;

    printf("\nDo you want to create the data file type 'y' for yes and 'n' for no.");
    scanf("%c", &option);
    fflush(NULL);

      if( option == 'y' || option == 'Y')
      {    printf("\nYou can generate bill of maximum 10 item.\n");
       getWriteFileName(filename);
       display();
      }
      elseif( option == 'n' || option == 'N')
       {   getReadFileName(filename);
       readFile();
       }


      getch();
  }

  void entryData()
  {
     while(1)
     {
      printf("\nEnter item name : ");
      getName(tmptr->item_desc);

      getPosInteger("Enter unit price of the item : ", &tmptr->unit_price);
      getzeroInteger("Enter no of qty purchased : ", &tmptr->qty);

      if(tmptr->qty == 0)
        break;

      count ++;
      if (count >= 10)
         break;
     /* if ( count % 2 == 0)
       if ( (pd_ptr = (struct purch_detail *) realloc(pd_ptr, sizeof(struct purch_detail) * 2)) == NULL)
       {  printf("Realloc failed. No enough memory available.");
          break;
       }
       */

      tmptr++;
     }
  }

  void display()
  {
     tmptr = pd_ptr;

     fprintf(fp,"\nItem                 Unit Price Quantity  Total Price ");
     fprintf(fp,"\n______________________________________________________");

     printf("\nItem                 Unit Price Quantity  Total Price ");
     printf("\n______________________________________________________");
     while(1)
     {
    total_price = tmptr->unit_price * tmptr->qty ;
    fprintf(fp, "\n%-20s      %4d    %4d     %5d", tmptr->item_desc, tmptr->unit_price, tmptr->qty, total_price);
    printf("\n%-20s      %4d    %4d     %5d", tmptr->item_desc, tmptr->unit_price, tmptr->qty, total_price);
    //printf("");
    total_amt += total_price;

    count--;
       if ( count <= 0)
        break;
      tmptr++;
     }

     fprintf(fp, "\n______________________________________________________");
     fprintf(fp, "\n\t\t\t    Total Amount : %5d", total_amt);
     printf("\n______________________________________________________");
     printf("\n\t\t\t    Total Amount : %5d", total_amt);
  }

   void getWriteFileName(char *fname)
   {
     printf("Enter Output File name maxium 14 character : ");
     scanf("%s", fname);

     if( ( fp = fopen(fname, "wt") ) == NULL  )
     {  fclose(fp);
    printf("\nInvalid file name entered.");
     }
     else
    entryData();
  }

   void getReadFileName(char *fname)
   {
     printf("Enter Input File name maxium 14 character : ");
     scanf("%s", fname);

     if( ( fp = fopen(fname, "r+t") ) == NULL  )
     {  fclose(fp);
    printf("\nInvalid file name entered.");
     }
   }

   void readFile()
   {
     char chr;
     while( feof(fp) == 0)
     {
     chr = getc(fp);
     printf("%c",chr);
     }
   }
    void getName(char *str)
    {
    int count1=0;
    char *getstr;
    char readch='\0';
    int errorflag = 0;

       fflush(NULL);
       getstr = str;

       while(1)
       {
        scanf("%c", &readch);
        if( readch == '\n')
           break;

        *getstr = readch;

        count1++;
        getstr++;
        if( count1 >= 20 )
          break;
       }
       fflush(NULL);

       if(errorflag)
          getName(str);

       *getstr='\0';
    }

 void getzeroInteger(char *_chr, int *_value)
 {
   float tempval =1;
   int _ival=0;

    printf("\n%s", _chr);
    _scaint = scanf("%f", &tempval);
    fflush(NULL);


   if ( _scaint != 0 )
   {
     _ival = tempval;

     if ( tempval < 0 )
     {
      printf("%s", "\nYou should enter value greater then or equal to zero. Enter the value again...");
      getzeroInteger(_chr, _value);
     }

     elseif ( _ival != tempval)
     {
      printf("%s", "\nError(decimal value). It will be truncated the digit after the percision. Enter integer number only.");
      getzeroInteger(_chr, _value);
     }
     elseif( ! ( (tempval >= -32768 ) && (tempval <= 32767 )  ) )
     {
      printf("%s", "\nError out of range entry. You should enter integer value in the range of -32768 to 327678 only.");
      getzeroInteger(_chr, _value);
     }
     else
     {
      *_value = (int) tempval;
     }

  }
  else
     {
    printf("\n%s","Error in entry. Enter integers only.");
    getzeroInteger(_chr, _value);
     }
 }

    /***************************   Input  *******************************


    Do you want to create the data file type 'y' for yes and 'n' for no.y


    You can generate bill of maximum 10 item.
    Enter Output File name maxium 14 character : output.txt

    Enter item name : soap

    Enter unit price of the item : 12

    Enter no of qty purchased : 3

    ***********************************************************************/
/********************************   OutPut ******************************

    Item                 Unit Price Quantity  Total Price
    ______________________________________________________
    soap                        15       3        45
    Coco Cola                   35       5       175
    Cadbury                     40       3       120
    ______________________________________________________
                    Total Amount :   340

    ************************************************************************/