/* Program Name:  week3.c                            */
/* Program to keep track of names and phone numbers. */
/* Information is written to a disk file specified   */
/* with a command-line parameter.                    */

#include <conio.h>
#include <stdlib.h>
#include <stdio.h>
#include <time.h>
#include <string.h>

/*** defined constants ***/
#define YES   1
#define NO    0
#define REC_LENGTH  54

/*** variables ***/

struct record {
   char fname[15+1];              /* first name + NULL   */
   char lname[20+1];              /* last name + NULL    */
   char mname[10+1];              /* middle name + NULL  */
   char phone[9+1];               /* phone number + NULL */
} rec;

/*** function prototypes ***/

int  main(int argc, char *argv[]);
void display_usage(char *filename);
int  display_menu(void);
void get_data(FILE *fp, char *progname, char *filename);
void display_report(FILE *fp);
int  continue_function(void);
int  look_up( FILE *fp );

/* start of program */

int main(int argc, char *argv[])
{
    FILE *fp;
    int  cont = YES;

    if( argc < 2 )
    {
       display_usage("WEEK3");
       exit(1);
    }

    /* Open file. */
    if ((fp = fopen( argv[1], "a+")) == NULL)
    {
        fprintf( stderr, "%s(%d)—Error opening file %s",
                             argv[0],__LINE__, argv[1]);
        exit(1);
    }

    while( cont == YES )
    {
       switch( display_menu() )
       {
         case '1': get_data(fp, argv[0], argv[1]); /* Day 18*/
                   break;
         case '2': display_report(fp);
                   break;
         case '3': look_up(fp);
                   break;
         case '4': printf("\n\nThank you for using this program!");
                   cont = NO;
                   break;
         default:  printf("\n\nInvalid choice, Please select 1 to 4!");
                   break;
       }
    }
    fclose(fp);       /* close file */
    return(0);
}

/* display_menu() */

int display_menu(void)
{
    char ch, buf[20];

    printf( "\n");
    printf( "\n     MENU");
    printf( "\n   ========\n");
    printf( "\n1.  Enter names");
    printf( "\n2.  Print report");
    printf( "\n3.  Look up number");
    printf( "\n4.  Quit");
    printf( "\n\nEnter Selection ==> ");
    gets(buf);
    ch = *buf;
    return(ch);
}

/****************************************************
  Function:  get_data()
*****************************************************/

void get_data(FILE *fp, char *progname, char *filename)
{
   int cont = YES;

   while( cont == YES )
   {
      printf("\n\nPlease enter information: " );

      printf("\n\nEnter first name: ");
      gets(rec.fname);
      printf("\nEnter middle name: ");
      gets(rec.mname);
      printf("\nEnter last name: ");
      gets(rec.lname);
      printf("\nEnter phone in 123-4567 format: ");
      gets(rec.phone);

      if (fseek( fp, 0, SEEK_END ) == 0)
         if( fwrite(&rec, 1, sizeof(rec), fp) != sizeof(rec))
         {
         fprintf( stderr, "%s(%d) Error writing to file %s",
                          progname,__LINE__, filename);
         exit(2);
         }
      cont = continue_function();
   }
}

/********************************************************
Function:  display_report()                             
Purpose:   To print out the formatted names and numbers
           of people in the file.                              
*********************************************************/

void display_report(FILE *fp)
{
    time_t rtime;
    int num_of_recs = 0;

    time(&rtime);

    fprintf(stdout, "\n\nRun Time: %s", ctime( &rtime));
    fprintf(stdout, "\nPhone number report\n");

    if(fseek( fp, 0, SEEK_SET ) == 0)
    {
       fread(&rec, 1, sizeof(rec), fp);
       while(!feof(fp))
       {
          fprintf(stdout,"\n\t%s, %s %c %s", rec.lname,
                                  rec.fname, rec.mname[0],                                          
                                  rec.phone);
          num_of_recs++;
          fread(&rec, 1, sizeof(rec), fp);
       }
       fprintf(stdout, "\n\nTotal number of records: %d",                     
               num_of_recs);
       fprintf(stdout, "\n\n* * * End of Report * * *");
    }
    else
       fprintf( stderr, "\n\n*** ERROR WITH REPORT ***\n");
}

/************************************************** 
*  Function:  continue_function()
**************************************************/

int continue_function( void )
{
    char ch, buf[20];
    do
    {
     printf("\n\nDo you wish to enter another? (Y)es/(N)o ");
        gets(buf);
        ch = *buf;
    } while( strchr( "NnYy", ch) == NULL );

    if(ch == 'n' || ch == 'N')
        return(NO);
    else
        return(YES);
}

/**********************************************************
*  Function:  display_usage()
***********************************************************/

void display_usage( char *filename )
{
    printf("\n\nUSAGE: %s filename", filename );
    printf("\n\n   where filename is a file to store people\'s names");
    printf("\n     and phone numbers.\n\n");
}

/**********************************************
*  Function:  look_up()
*  Returns:   Number of names matched
*************************************************/

int look_up( FILE *fp )
{
    char tmp_lname[20+1];
    int  ctr = 0;

    fprintf(stdout, "\n\nPlease enter last name to be found: ");
    gets(tmp_lname);

    if( strlen(tmp_lname) != 0 )
    {
       if (fseek( fp, 0, SEEK_SET ) == 0)
       {
          fread(&rec, 1, sizeof(rec), fp);
          while( !feof(fp))
          {
             if( strcmp(rec.lname, tmp_lname) == 0 )                     
             /* if matched */
             {
                fprintf(stdout, "\n%s %s %s - %s", rec.fname,                                                        
                                               rec.mname,
                                               rec.lname,                                                        
                                               rec.phone);
                ctr++;
             }
             fread(&rec, 1, sizeof(rec), fp);
          }
       }
       fprintf( stdout, "\n\n%d names matched.", ctr );
    }
    else
    {
        fprintf( stdout, "\nNo name entered." );
    }
    return(ctr);
}