#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <stdlib.h>
#define NAME_SIZE  20
#define STRSZ  6
#define MAX_FRIENDS 4

typedef struct {
	char name[NAME_SIZE];
	char birthday[STRSZ];
} friend_t;

typedef struct s {
	struct s *next_record;
	friend_t friend;
}record_t;
record_t *friends_start =NULL, *friends_last = NULL;

int read_friend_record(friend_t *friend);
int store_friend_record(const friend_t friend);
friend_t next_friend(const int first);
int friend_name(const friend_t friend, const char name[]);
int save_friend_file(const char file_name[]);
int string_read(const char prompt[], char string[], const int size);
int find_friend(friend_t *friend, char myfriend_name[]);
void print_friend_record(const friend_t friend);
void print_all_friend(void);

int main()
{

friend_t friend;
	char myfriend_name[NAME_SIZE];
	char filename[NAME_SIZE];
	FILE *out;


	 	 while(read_friend_record(&friend)) {
	 if(store_friend_record(friend))
			printf("\n Record on '%s' stored ", friend.name);
		else
			printf("\n\a  Failed to store '%s' ", friend.name);
	}

			printf("\n\n Enter name of file to save friend records ");
	scanf("%s", filename);
	out = fopen(filename, "wb");
	if(out==NULL)
		printf("\n Cannot open file for output");
		if(save_friend_file(filename))
			printf("\n Record on '%s' saved ", friend.name);
		else
			printf("\n\a  Failed to save '%s' \n", friend.name);

	fclose(out);

				while(string_read("\n\nFind friend name?", myfriend_name, NAME_SIZE)) {
			if(find_friend(&friend, myfriend_name))
				printf("\n  '%s' data found", myfriend_name);
			else
				printf("\n  '%s' data not found", myfriend_name);
		}

			print_all_friend();

return 0;
}

int read_friend_record(friend_t *friend)
{
	printf("\n\nEnter record on next friend \n");
	if(string_read("friend name?", (*friend).name, NAME_SIZE))
		if(string_read("friend birthday?", (*friend).birthday, STRSZ))
			return 1;
		return 0;
		}

			int store_friend_record(const friend_t friend)
		{
			int num_of_friends = 0;
			friend_t friends[MAX_FRIENDS];
			record_t *new_record;


			if((new_record = (record_t*) calloc(sizeof(record_t), 1)) != NULL)
			{
				if(friends_start==NULL)
					friends_start = new_record;
				else
					friends_last->next_record = new_record;
				friends_last = new_record;
				new_record->next_record = NULL;
			}
			else
			{
				printf("\n\a creation of new friend record failed \n ");
				return 0;
			};

			new_record->friend = friend;
			return 1;
		}

		friend_t next_friend(const int first)
		{
			record_t *friends = NULL;
			friend_t friend = {""};

			if(first)
				friends = friends_start;
			if(friends != NULL)
			{

				friend = friends->friend;
			     friends = friends->next_record;
			}
			return friend;
		}

		int friend_name(const friend_t friend, const char name[])
		{
			return(!strcmp(friend.name, name));
		}

		int save_friend_file(const char file_name[])
		{
			FILE *out;
			friend_t friend;

			printf("\n\nSave friend records to file'%s' ", file_name);
			if((out = fopen(file_name, "wb"))==NULL)
				printf("\nUnable to open friend records file");

			friend = next_friend(1);
			while(!friend_name(friend, "")) {
				fwrite(&friend, sizeof(MAX_FRIENDS), 1, out);
				friend = next_friend(0);
			}
			fclose(out);
			return 1;
		}

		int string_read(const char prompt[], char string[], const int size)
		{
			int index = 0, ch;

			printf("%s", prompt);
			while(((ch=getchar()) !='\n') && (ch!=EOF)) {
				if(isprint(ch) && (index<size-1))
				   string[index++] = (char) ch;
				string[index] = '\0';
			}
				return index;
			}

			int find_friend(friend_t *friend, char myfriend_name[])
			{
				*friend = next_friend(1);
				while(!friend_name(*friend, "")) {

					if(friend_name(*friend, myfriend_name))
						return 1;
					*friend = next_friend(0);
			}
				return 0;
			}

			void print_friend_record(const friend_t friend)
			{
				printf("\n %-*s  %-*s ", NAME_SIZE, friend.name, STRSZ, friend.birthday);
			}

			void print_all_friend(void)
			{
				friend_t friend;

				printf("\n\n All friends record\n %-*s  %-*s ", NAME_SIZE, friend.name, STRSZ, friend.birthday);

				friend = next_friend(1);
				while(!friend_name(friend, ""))
				{
					print_friend_record(friend);
					friend = next_friend(0);\
				}
			}