/* memo: program to record personal memos and display them in
 * the terminal. Memos saved in conf/all_memos.txt */

#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>

#define MAX_MEMOS 100 //max number of memos
#define MAX_T 100     //max length of title
#define MAX_B 3000    //max length of body
#define D '#'

struct memo {
	char title[MAX_T];
	char body[MAX_B];
}; 
struct memo memos[MAX_MEMOS];


FILE *all_memos;  


int main(int argc, char *argv[])
{
	int read_t_b_between_d(FILE*, char*, char*, char);
	void print_titles_to_screen(int);
	int print_n_take_opts(int);
	void print_memo_to_screen(int);
	void clear();
	int compose_memo(int);
	void save_memos(FILE*, int);
	int delete_memo(FILE*, int, int);
	int read_memos(FILE*);
	int m_count; // memo count, total number of memos
	int selected;
/* check if conf directory exists. if not, create it. */
	struct stat st = {0};
	if (stat("conf", &st) == -1){
		mkdir("conf", 0700);
	}
/* create conf/all_memos.txt in case it does not already exist */
	char *command_1 = "touch conf/all_memos.txt";
	system(command_1);
	m_count = read_memos(all_memos);
	if (m_count == 0){
		clear();
		printf("\n\n\tMemo Wizard\n\n\tCreate your first memo.\n");
		m_count = compose_memo(m_count);
		save_memos(all_memos, m_count);
		clear();
	}
	while((selected = print_n_take_opts(m_count))){  
		 if (selected == m_count + 1){
			clear();
			m_count = compose_memo(m_count);
			save_memos(all_memos, m_count);
			clear();
		}else if (selected > 0 && selected <= m_count)  
			print_memo_to_screen(selected);
		 else if (selected * -1 > 0 && selected * -1 <= m_count){  
			selected *= -1;
			m_count = delete_memo(all_memos, selected, m_count);
			read_memos(all_memos);
		 }else
			;
		
	}
	clear();
	printf("\nHave a nice day!\n\n");
	return 0;
}
/* read_t_b_between_d: function to read the title and the body from all_memos.txt. title and body 
 * saved between demarker d, which is '#' */
int read_t_b_between_d(FILE *am, char *t, char *b, char d)
{ 
	char c;
	while ((c = getc(am)) != d && c != EOF)
		;
	if (c == EOF)
		return -1;
	while ((c = getc(am)) != d && c != EOF)
		*t++ = c;
	if (c == EOF)
		return -1;
	*t = '\0';
	while ((c = getc(am)) != d && c != EOF)
		;
	if (c == EOF)
		return -1;
	while ((c = getc(am)) != d && c != EOF)
		*b++ = c;
	if (c == EOF)
		return -1;
	*b = '\0';
	return 0;	
}

void print_titles_to_screen(int i)
{  
	printf("\n\n\tMemo Wizard\n\n\t");
	for (int k = 0; i > 0; i--, k++){  
		printf("%d. %s  ", k+1, memos[k].title);
		if (((k+1) % 4) == 0)
			printf("\n\t");
	}
}
/* save memos from struct to all_memos.txt, n = number of memos */
void save_memos(FILE *am, int n){  
	am = fopen("conf/all_memos.txt", "w");
	for (int i = 0; i < n; i++)
		fprintf(am, "#%s# #%s#\n\n", memos[i].title, memos[i].body);		
	fclose(am);
}

void clear(){
	system("clear");
}
/* compose memo saving it to the correct array member and returning the new number of memos */
int compose_memo(int n){  
		int j = 0;
		printf("\n\tTitle: ");
		while ((memos[n].title[j++] = getchar()) != '\n')
			;
		--j;
		memos[n].title[j] = '\0';
		j = 0;
		printf("\n\n\tCompose memo ['|' to end]\n\n\t");
		while ((memos[n].body[j++] = getchar()) != '|')
			;
		--j;
		memos[n].body[j] = '\0';
		++n;
		return n;
}

int print_n_take_opts(int mc){
	void clear();
	int s; //selection
	clear();
	print_titles_to_screen(mc);
	printf("\n\n\tEnter a memo number to view it. To compose a new memo,\n"
			   "\tenter the next consecutive number. To delete a memo, enter\n"
    		   "\tits number preceded by a minus sign. ['0' to exit] ");
	scanf("%d", &s);
	getchar();
	return s;
}

void print_memo_to_screen(int s){
	--s; 
	clear();
	printf("\n\n\t%s\n\n\t%s\n\n\tPress enter to return to main menu ", memos[s].title, memos[s].body);
	getchar();
}

/* delete_memo: to delete a memo, *am = all_memos, number of memo to delete md, and the total number of 
 * memos = n */
int delete_memo(FILE *am, int md, int n){
	am = fopen("conf/all_memos.txt", "w");
	for (int i = 0; i < n; i++){  
	     if (i == md-1)
			;
		else
			fprintf(am, "#%s# #%s#\n\n", memos[i].title, memos[i].body);		
	}
	fclose(am);
	return --n;
}

int read_memos(FILE *am){  
	 am = fopen("conf/all_memos.txt", "r");
	int i = 0;
	while ((read_t_b_between_d(am, memos[i].title, memos[i].body, D) != -1))
		++i;
	fclose(am);
	return i;
}