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

/* contacts - growable -- shows how to use malloc and realloc to grow an array
 */

#define	NAME_LEN	100
#define	NUM_LEN		30

#define	INIT_CAP	4
#define	ADDN_AMT	2

struct contact
{
	char	name[NAME_LEN];
	char	phonenum[NUM_LEN];
};

void fill_entry(struct contact *);
void print_entry(struct contact *);
void list_contacts(struct contact *, int);
int find_contact(struct contact *, int);
int  add_to_list( struct contact **, int, int );
struct contact *expand_list( struct contact * , int *capacity );


int main()
{
	struct contact *contact_list ;	// will point to an array
	int	capacity = INIT_CAP;
	int	n_rows   = 0;
	char	choice[NAME_LEN];

	contact_list = malloc( INIT_CAP * sizeof( struct contact ) );

	while( 1 )
	{
		printf("add, find, list? ");
		fgets( choice, NAME_LEN, stdin);
		switch ( choice[0] )
		{
			case 'a':	capacity = add_to_list( &contact_list, n_rows, capacity);
					n_rows++;
					break;
			case 'f':	find_contact( contact_list, n_rows );
					break;
			case 'l':	list_contacts( contact_list, n_rows );
					break;
			case 'q':	return 0;
			default:	printf("unknown choice: \"%s\"\n", choice);
		}
	}
}

int add_to_list( struct contact **list_addr , int num_so_far, int capacity )
{
	struct contact *list = *list_addr;

	if ( num_so_far >= capacity ){
		list = expand_list( list, &capacity );
		*list_addr = list;
	}
	fill_entry(&list[num_so_far]);		// &alan is ADDRESS of the variable
	return capacity;
}

// expand the array and update by ref the capacity
// ret new list
struct contact *expand_list( struct contact *orig, int *cap_ptr)
{
	struct contact *new_list = realloc( orig, *cap_ptr + ADDN_AMT ) ;
	*cap_ptr += ADDN_AMT;
	return new_list;
}

// search list for a name
// linear search and stop at found or at end
// ret 1 if found, 0 if not

int find_contact( struct contact *contact_list, int n_rows )
{
	int	i;
	char	findme[NAME_LEN];

	printf("Find what name? ");
	scanf("%s", findme);

	for ( i = 0 ; i < n_rows ;  i++ )
	{
		if ( strcmp(contact_list[i].name , findme) == 0 )
		{
			print_entry( &contact_list[i] );
			return 1;
		}
	}
	return 0;
}

// iterate and print
void list_contacts( struct contact *contact_list, int n_rows )
{
	int	i;

	for ( i = 0 ; i < n_rows ; i++ )
		print_entry( &contact_list[i] );
}
	
void fill_entry( struct contact *cp )
{
	printf("name? ");
	scanf("%s", cp->name );
	printf("phone num? ");
	scanf("%s", cp->phonenum );
}
void print_entry( struct contact *cp )
{
	printf("name: %s\n", cp->name);
	printf("phone num: %s\n", cp->phonenum);
}