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

#include "curly.h"
#include "functies.h"
#include "mt19937ar.h"
#include "worker.h"

real fact(real z) {
	real r = 1.0;

	while(z > 1.0 && !isinf(r)) {
		r *= z;
		z -= 1.0;
	}

	// if(z != 1.0) r *= correctiefactor;

	return r;
}

real invfact(real z) {
	real r = 1.0;

	if(!finite(z))
		return 0.0/0.0;

	while(z > r + 0.99999) {
		r += 1.0;
		z /= r;
	}
	if(z > 1.0) r += (z - 1.0) / r;

	return r;
}

real upow(real x, u64 e) {
	if(!e)
		return 1.0;
	if(e&1)
		return x * upow(x, e - 1);
	else
		return x = upow(x, e >> 1), x * x;
}

real spow(real x, s64 e) {
	return e < 0 ? 1.0 / upow(x, -e) : upow(x, e);
}

u64 dice(int m, int n) {
	u64 r = 0;

	if(n < 0 || m < 0)
		return ~0;

	if(n == 0 || m == 0)
		return 0;

	if(n > 65536)
		return 2*dice(m, n/2-1) + dice(m, 2+n%2);

	do
		r += mt_genrand32_bounded(0, m) + 1;
	while(--n > 0);

	return r;
}

real realdice(int m, int n) {
	u64 r = dice(m, n);
	return r == ~0 ? 0.0/0.0 : (real)r;
}

real gcd(real m, real n) {
	if(m < 0.0)
		m = -m;
	if(n < 0.0)
		n = -n;

	return n > 0.0 ? gcd(n, fmod(m, n)) : m;
}

real lcm(real m, real n) {
	if(m < 0.0)
		m = -m;
	if(n < 0.0)
		n = -m;

	return m * n / gcd(m, n);
}

bool isint(real x) {
	if(!finite(x))
		return false;

	if(fabs(floor(x) - x) < 1e-14
	|| fabs(ceil(x) - x) < 1.0e-14L)
		return true;

	return false;
}

bool isnoemer(real x, real n) {
	if(fabs(floor(x * n) - x * n) < n * 1.0e-14L
	|| fabs(ceil(x * n) - x * n) < n * 1.0e-14L)
		return true;

	return false;
}

/* Zoals geript uit util-linux (misc/ddate.c) van Druel the Chaotic. */

void makeday(int imonth, int iday, int iyear, struct disc_time *funkychickens) {
	static const int cal[12] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
	int dayspast = 0;

	/* basic range checks */
	if (imonth < 1 || imonth > 12) {
		funkychickens->season = -1;
		return;
	}
	if (iday < 1 || iday > cal[imonth-1]) {
		if (!(imonth == 2 && iday == 29 && iyear%4 == 0 &&
				(iyear%100 != 0 || iyear%400 == 0))) {
			funkychickens->season = -1;
			return;
		}
	}

	imonth--;
	funkychickens->year = iyear + 1166;
	while(imonth > 0)
		dayspast += cal[--imonth];

	funkychickens->day = dayspast+iday-1;
	funkychickens->season = 0;

	if((funkychickens->year % 4) == 2) {
			if (funkychickens->day==59 && iday==29)
				funkychickens->day = -1;
	}
	funkychickens->yday = funkychickens->day;

	while(funkychickens->day >= 73) {
		funkychickens->season++;
		funkychickens->day -= 73;
	}

	return;
}

static bool grepvaluta(splitline_t *l) {
	real *koers;

	koers = splitbuf_userdata(l);
	*koers = strtor(l->buf, NULL);

	return true;
}

real wisselkoers(const char *valuta) {
	splitbuf_t b, *q;
	real koers;

	q = qnew();
	qprintf(q, "http://download.finance.yahoo.com/d/quotes.csv?s=EUR");
	url_encode(q, valuta);
	qprintf(q, "=X&f=l1");
	splitbuf_finish(q);

	splitbuf_init(&b);
	b.keepempty = false;
	b.keepdelim = false;
	b.hook = grepvaluta;
	b.userdata = &koers;

	url_fetch(&b, splitline(q)->buf);

	splitbuf_clean(&b);

	return 1.0/koers;
}