/* 
 * Simple "US money" type -- definitions of functions declared in
 * simple-us-money.h.
 */

#include "simple-us-money.h"

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

/* helper functions */
static long money_to_cents(us_money_t m);
static us_money_t cents_to_money(long n);

/* functions defined in .h */

void print_money(FILE * f, us_money_t m) {
	if (m.is_negative) {
		fputc('-', f);
	}
	fputc('$', f);
	fprintf(f, "%ld.%02d", m.dollars, m.cents);
}

bool input_money(FILE * f, us_money_t *m) {
	long dollars;
	int cents;
	char ch;
	if (fscanf(f, "%ld.%d%c", &dollars, &cents, &ch) == 3) {
		ungetc(ch, f);
		if (!isspace(ch)) {
			return false;
		}
		if ((cents < 0) || (cents > 99)) {
			return false;
		}
		m->is_negative = (dollars < 0);
		m->dollars = labs(dollars);
		m->cents = cents;
		return true;
	}
	return false;
}

us_money_t add_money(us_money_t m1, us_money_t m2) {
	long n1 = money_to_cents(m1);
	long n2 = money_to_cents(m2);
	return cents_to_money(n1 + n2);
}

us_money_t subtract_money(us_money_t m1, us_money_t m2) {
	long n1 = money_to_cents(m1);
	long n2 = money_to_cents(m2);
	return cents_to_money(n1 - n2);
}

us_money_t multiply_money(us_money_t m1, double d) {
	long n1 = money_to_cents(m1);
	return cents_to_money(round(n1 * d));
}

static long money_to_cents(us_money_t m) {
	long n = m.dollars*100 + m.cents;
	if (m.is_negative) 
		return -n;
	else
		return n;
}

static us_money_t cents_to_money(long n) {
	us_money_t tempm = {
		(n < 0) ? true : false,
		labs(n) / 100,
		labs(n) % 100
	};
	return tempm;
}