#include <stdio.h>
#include <stdlib.h>

#define MAX 1000 /* max number of records */
#define ENTRY 32 /* max number of chars for name, surname and phone */

#define ONE 49
#define TWO 50
#define THREE 51
#define FOUR 52
#define FIVE 53
#define SIX 54
#define SEVEN 55
#define EIGHT 56    /* define ASCII values for numbers 1-8 */

void addRecord();
void delRecord();
int findFree();
void findRecord();
void listPeople();
void save();
void eraseAll();
void menu();
void showHelp();
void showRecord();
int freeSpace();

struct data 
{
       char name[ENTRY];
       char surname[ENTRY];
       char phone[ENTRY];
};

struct data People[MAX];

int main()
{
    
    /* Error checking for reading and creating the database file */
    
    FILE *fp;
        
    if ( (fp=fopen("phonebook.dat" , "r")) == NULL)
    {
         if( (fp=fopen("phonebook.dat" , "w")) == NULL ) 
         {
             puts( "Can not create the file! The program will exit\n" );
             system( "PAUSE" );
             exit(0);
         } /* if */
         
         save();
         
         fclose( fp );
    } /* if */
         
    fp=fopen("phonebook.dat" , "r");
         
    fread(People , sizeof People , 1 , fp);
   
    if (ferror(fp))
    {
            puts("An error occurred while reading file! The program will exit\n");
            system( "PAUSE" );
            fclose(fp);
            exit(0);
    } /* if */           
    
    
    
    
    puts( "**************************" );
    puts( "Phonebook 1.0 Beta by Ivan" );
    puts( "korhner5@neobee.net" );
    puts( "**************************\n\n" );
    
    showHelp();
       
    while (1)
    {
          rewind( stdin );   /* clears the STDIN */
          menu();
    } /* while */
    
} /* main */

void addRecord()
{
     int position;
     position = findFree();  /* find index of a free space in the array */
     
     if( position == -1 )    /* if there is not any space say that to user */
     {
         puts( "The list is full!" );
         return;
     } /* if */
     
     rewind(stdin);     /* clears the STDIN */
         
     puts( "Please enter name:" );
     fgets( People[position].name, ENTRY, stdin );
               
     rewind( stdin );     /* clears the STDIN */
     
     if( strlen( People[position].name ) <= 1 ) return;     /* if the user entered nothing, return */
     
     if ( strlen( People[position].name ) < ENTRY )     /* if the user entered a name with chars < ENTRY, then delete the newline char */ 
     {
          People[position].name[strlen( People[position].name ) - 1] = '\0';
     } /* if */
     
     while( strlen( People[position].surname ) <= 1 )
     {
            puts( "Please enter surname:" );
            fgets( People[position].surname, ENTRY, stdin );
     } /* while */       
     
     rewind( stdin );     /* clears the STDIN */
     
     if ( strlen( People[position].surname ) < ENTRY ) 
     {
          People[position].surname[strlen( People[position].surname ) - 1] = '\0';
     } /* if */
     
      while( strlen( People[position].phone ) <= 1 )
     {
            puts( "Please enter phone number:" );
            fgets( People[position].phone, ENTRY, stdin );
     } /* while */      
          
     rewind( stdin );     /* clears the STDIN */
     
     if ( strlen( People[position].phone ) < ENTRY ) 
     {
          People[position].phone[strlen( People[position].phone ) - 1] = '\0';
     } /* if */
    
     
} /* addRecord */

void delRecord()
{
     char name[ENTRY ];
     char surname[ENTRY];
     
     int i;
     
     rewind( stdin );    /* clears the STDIN */
     
     puts( "Please enter name you want to delete: " );
     fgets( name, ENTRY, stdin );
     
     puts( "Please enter surname you want to delete: " );
     fgets( surname, ENTRY, stdin );
     
     for( i=0; i<MAX; i++ )     /* check for the name and surname the user entered */
     {
          if( strcmp( People[i].name, name ) == 0 )
          {
              if ( strcmp( People[i].surname, surname ) == 0 ) *People[i].name = '\0';     /* when found deleted it */
              puts( "Deleted!\n" );
          } /* if */
     } /* for */
     
} /* delRecord */
     

int findFree()     /* find free index of the array and return it */
{
    int i;
    for(i=0; i<MAX; i++) 
    {
         if( !*People[i].name )
         {
             return i;
             break;
         } /* if */
             
    } /* for */
    return -1;     /* if list is full return -1 */
} /* findFree */

void findRecord()
{
     int i;
     char input[30];
     
     rewind( stdin );     /* clears the STDIN */
     
     puts( "Enter what you want to search: " );
     gets( input );
     
     if( strlen( input ) == 0 )
     {
         rewind( stdin );
         return;
     } /* if */
     
     for( i=0; i<MAX; i++)     /* check for user input in names, surnames, and phones */
     {
          if( (strcmp( People[i].name, input ) == 0) || (strcmp( People[i].surname, input ) == 0) || (strcmp( People[i].phone, input ) == 0)  ) 
          {
              showRecord(i);
          } /* if */
     } /* for */
     
} /* findRecord */
     
void listPeople()     /* list all the records */
{
     int i;
     for( i=0; i<MAX; i++ )
     {
          if( *People[i].name )     /* do not show empy records */
          {
              showRecord(i);
          } /* if */
     } /* for */ 
} /* listPeople */
     
void menu()
{
     char sel;
     
     puts( "Enter your choice ( 8 for help ):" );
     
     sel = fgetc( stdin );     /* read a char from STDIN */
     
     rewind( stdin );     /* clears the STDIN */
          
     if( sel<ONE || sel>EIGHT )     /* check if user entered a number between 1 and 8 */
     {
         puts( "Please enter a number between 1 and 8!\n" );
         return;
     } /* if */
     
     switch (sel)
     {
            case ONE:
                 save();
                 break;
                 
            case TWO:
                 eraseAll();
                 break;
                 
            case THREE:
                 addRecord();
                 break;
                                  
            case FOUR:
                 delRecord();
                 break;
                 
            case FIVE:
                 findRecord();
                 break;
                 
            case SIX:
                 listPeople();
                 printf( "\n--------------------------\n" );
                 printf( "Free space = %4d     %3d%% \n", freeSpace(), (100 * freeSpace()) / MAX );
                 printf( "Used space = %4d     %3d%% \n", MAX - freeSpace(), 100 - ((100 * freeSpace()) / MAX) );
                 printf( "--------------------------\n\n" );
                 break;
                 
            case SEVEN:
                 exit(0);
                 
            case EIGHT:
                 showHelp();
                 break;
                 
            default:     
                 puts( "Please enter a number between 1 and 8!\n" );
                 break;               
     } /* switch */       
} /* menu */

void save()
{
    FILE *fp;

    if ( (fp=fopen("phonebook.dat" , "w")) == NULL)
    {     /* handle file errors */
      printf("cannot open file\n");
      return;
    } /* if */
    
    fwrite(People , sizeof People , 1 , fp);    /* main instruction that writes the array */
    
    if (ferror(fp))     /* check for file errors */
    {
         printf("An error occurred while writing file.\n");
         fclose(fp);
         return;
    } /* if */
    
    fclose(fp);
    
    puts("File has been saved!\n");
} /* save */

void eraseAll()     /* erase all records( only names ) */
{
     int i;
     
     for( i=0; i<MAX; i++)
     {
          *People[i].name = '\0';     /* clears every name */
     } /* for */
     
     puts( "All records have been deleted!\n" );
} /* eraseAll */
        
void showHelp()
{
     puts( "Save...........................1\n" );
     puts( "Reset..........................2\n" );
     puts( "Add new entry..................3\n" );
     puts( "Delete an entry................4\n" );
     puts( "Find...........................5\n" );
     puts( "List the file, view free space.6\n" );
     puts( "Exit...........................7\n" );

} /* showHelp */

void showRecord(int index)     /* prints the name, surname and phone of the People[index] */
{
     printf("\nName:        %s\n", People[index].name );
     printf("Surname:     %s\n", People[index].surname );
     printf("Phone:       %s\n\n", People[index].phone );
} /* showRecord */

int freeSpace()     /* calulates free space of the array */
{
     int i;
     int count = 0;
     
     for( i=0; i<MAX; i++)
     {
          if( !*People[i].name ) count++;
     } /* for */
     
     return count;
     
} /* freeSpace */