/** General purpose helper functions.
 *
 * @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
 * @copyright 2017, Institute for Automation of Complex Power Systems, EONERC
 * @license GNU General Public License (version 3)
 *
 * VILLASnode
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *********************************************************************************/

#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <stdarg.h>
#include <string.h>
#include <unistd.h>
#include <math.h>
#include <pthread.h>
#include <fcntl.h>
#include <ctype.h>

#include "config.h"
#include "utils.h"

void print_copyright()
{
	printf("VILLASnode %s (built on %s %s)\n",
		BLU(BUILDID), MAG(__DATE__), MAG(__TIME__));
	printf(" Copyright 2014-2017, Institute for Automation of Complex Power Systems, EONERC\n");
	printf(" Steffen Vogel <StVogel@eonerc.rwth-aachen.de>\n");
}

int version_parse(const char *s, struct version *v)
{
	return sscanf(s, "%u.%u", &v->major, &v->minor) != 2;
}

int version_cmp(struct version *a, struct version *b) {
	int major = a->major - b->major;
	int minor = a->minor - b->minor;

	return major ? major : minor;
}

double box_muller(float m, float s)
{
	double x1, x2, y1;
	static double y2;
	static int use_last = 0;

	if (use_last) {		/* use value from previous call */
		y1 = y2;
		use_last = 0;
	}
	else {
		double w;
		do {
			x1 = 2.0 * randf() - 1.0;
			x2 = 2.0 * randf() - 1.0;
			w = x1*x1 + x2*x2;
		} while (w >= 1.0);

		w = sqrt(-2.0 * log(w) / w);
		y1 = x1 * w;
		y2 = x2 * w;
		use_last = 1;
	}

	return m + y1 * s;
}

double randf()
{
	return (double) random() / RAND_MAX;
}

void die()
{
	int zero = 0;
	log_outdent(&zero);
	abort();
}

char * strcatf(char **dest, const char *fmt, ...)
{
	va_list ap;
	va_start(ap, fmt);
	vstrcatf(dest, fmt, ap);
	va_end(ap);

	return *dest;
}

char * vstrcatf(char **dest, const char *fmt, va_list ap)
{
	char *tmp;
	int n = *dest ? strlen(*dest) : 0;
	int i = vasprintf(&tmp, fmt, ap);

	*dest = (char *)(realloc(*dest, n + i + 1));
	if (*dest != NULL)
		strncpy(*dest+n, tmp, i + 1);

	free(tmp);

	return *dest;
}

void cpuset_to_integer(cpu_set_t *cset, uintmax_t *set)
{
	*set = 0;
	for (int i = 0; i < MIN(sizeof(*set) * 8, CPU_SETSIZE); i++) {
		if (CPU_ISSET(i, cset))
			*set |= 1ULL << i;
	}
}

void cpuset_from_integer(uintmax_t set, cpu_set_t *cset)
{
	CPU_ZERO(cset);
	for (int i = 0; i < MIN(sizeof(set) * 8, CPU_SETSIZE); i++) {
		if (set & (1L << i))
			CPU_SET(i, cset);
	}
}

/* From: https://github.com/mmalecki/util-linux/blob/master/lib/cpuset.c */
static const char *nexttoken(const char *q,  int sep)
{
	if (q)
		q = strchr(q, sep);
	if (q)
		q++;
	return q;
}

int cpulist_parse(const char *str, cpu_set_t *set, int fail)
{
	const char *p, *q;
	int r = 0;

	q = str;
	CPU_ZERO(set);

	while (p = q, q = nexttoken(q, ','), p) {
		unsigned int a;	/* beginning of range */
		unsigned int b;	/* end of range */
		unsigned int s;	/* stride */
		const char *c1, *c2;
		char c;

		if ((r = sscanf(p, "%u%c", &a, &c)) < 1)
			return 1;
		b = a;
		s = 1;

		c1 = nexttoken(p, '-');
		c2 = nexttoken(p, ',');
		if (c1 != NULL && (c2 == NULL || c1 < c2)) {
			if ((r = sscanf(c1, "%u%c", &b, &c)) < 1)
				return 1;
			c1 = nexttoken(c1, ':');
			if (c1 != NULL && (c2 == NULL || c1 < c2)) {
				if ((r = sscanf(c1, "%u%c", &s, &c)) < 1)
					return 1;
				if (s == 0)
					return 1;
			}
		}

		if (!(a <= b))
			return 1;
		while (a <= b) {
			if (fail && (a >= CPU_SETSIZE))
				return 2;
			CPU_SET(a, set);
			a += s;
		}
	}

	if (r == 2)
		return 1;

	return 0;
}

char *cpulist_create(char *str, size_t len, cpu_set_t *set)
{
	size_t i;
	char *ptr = str;
	int entry_made = 0;

	for (i = 0; i < CPU_SETSIZE; i++) {
		if (CPU_ISSET(i, set)) {
			int rlen;
			size_t j, run = 0;
			entry_made = 1;
			for (j = i + 1; j < CPU_SETSIZE; j++) {
				if (CPU_ISSET(j, set))
					run++;
				else
					break;
			}
			if (!run)
				rlen = snprintf(ptr, len, "%zd,", i);
			else if (run == 1) {
				rlen = snprintf(ptr, len, "%zd,%zd,", i, i + 1);
				i++;
			} else {
				rlen = snprintf(ptr, len, "%zd-%zd,", i, i + run);
				i += run;
			}
			if (rlen < 0 || (size_t) rlen + 1 > len)
				return NULL;
			ptr += rlen;
			if (rlen > 0 && len > (size_t) rlen)
				len -= rlen;
			else
				len = 0;
		}
	}
	ptr -= entry_made;
	*ptr = '\0';

	return str;
}

void * alloc(size_t bytes)
{
	void *p = malloc(bytes);
	if (!p)
		error("Failed to allocate memory");

	memset(p, 0, bytes);

	return p;
}

void * memdup(const void *src, size_t bytes)
{
	void *dst = alloc(bytes);

	memcpy(dst, src, bytes);

	return dst;
}

ssize_t read_random(char *buf, size_t len)
{
	int fd;
	ssize_t bytes, total;

	fd = open("/dev/urandom", O_RDONLY);
	if (fd < 0)
		return -1;

	bytes = 0;
	total = 0;
	while (total < len) {
		bytes = read(fd, buf + total, len - total);
		if (bytes < 0)
			break;

		total += bytes;
	}

	close(fd);

	return bytes;
}

void rdtsc_sleep(uint64_t nanosecs, uint64_t start)
{
	uint64_t cycles;

	/** @todo Replace the hard coded CPU clock frequency */
	cycles = (double) nanosecs / (1e9 / 3392389000);

	if (start == 0)
		start = rdtsc();

	do {
		__asm__("nop");
	} while (rdtsc() - start < cycles);
}

/* Setup exit handler */
void signals_init(void (*cb)(int signal, siginfo_t *sinfo, void *ctx))
{
	info("Initialize signals");

	struct sigaction sa_quit = {
		.sa_flags = SA_SIGINFO,
		.sa_sigaction = cb
	};

	sigemptyset(&sa_quit.sa_mask);
	sigaction(SIGINT, &sa_quit, NULL);
	sigaction(SIGTERM, &sa_quit, NULL);

	struct sigaction sa_chld = {
		.sa_flags = 0,
		.sa_handler = SIG_IGN
	};

	sigaction(SIGCHLD, &sa_chld, NULL);
}

pid_t spawn(const char* name, char *const argv[])
{
	pid_t pid;

	pid = fork();
	switch (pid) {
		case -1: return -1;
		case 0:  return execvp(name, (char * const*) argv);
	}

	return pid;
}