/* NetHalt - Library functions
 * Copyright (C) 2008 Daniel Collins <solemnwarning@solemnwarning.net>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *	* Redistributions of source code must retain the above copyright
 *	  notice, this list of conditions and the following disclaimer.
 *
 *	* Redistributions in binary form must reproduce the above copyright
 *	  notice, this list of conditions and the following disclaimer in the
 *	  documentation and/or other materials provided with the distribution.
 *
 *	* Neither the name of the author nor the names of its contributors may
 *	  be used to endorse or promote products derived from this software
 *	  without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <stdarg.h>
#include <stdio.h>

#include "lib.h"

/* Parse a time in the HH:MM[:SS] format
 * If the supplied string is not a valid time, -1 will be returned.
*/
int parse_time(char const *tstr) {
	int hours, mins, secs = 0;
	
	if(!isdigit(tstr[0]) || (!isdigit(tstr[1]) && tstr[1] != ':')) {
		return -1;
	}
	
	hours = atoi(tstr);
	tstr += (tstr[1] == ':' ? 2 : 3);
	
	if(!isdigit(tstr[0]) || (!isdigit(tstr[1]) && tstr[1] != ':')) {
		return -1;
	}
	
	mins = atoi(tstr);
	tstr += (tstr[1] == ':' ? 2 : 3);
	
	if(isdigit(tstr[0])) {
		secs = atoi(tstr);
	}
	
	if(hours > 23 || mins > 59 || secs > 59) {
		return -1;
	}
	
	return (3600*hours) + (60*mins) + secs;
}

/* Convert a windows error number to an error message */
char const *w32_error(DWORD errnum) {
	static char buf[1024] = {'\0'};
	
	FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM, NULL, errnum, 0, buf, 1023, NULL);
	buf[strcspn(buf, "\r\n")] = '\0';
	return buf;	
}

/* Compare two strings, ignoring case
 * Returns zero if the strings don't match, 1 otherwise.
*/
int ncase_eq(char const *str1, char const *str2) {
	size_t pos = 0;
	
	while(tolower(str1[pos]) == tolower(str2[pos])) {
		if(str1[pos] == '\0') {
			return 1;
		}
		
		pos++;
	}
	
	return 0;
}

/* Allocate and zero memory, or die */
void *allocate(size_t size) {
	void *ptr = malloc(size);
	
	if(!ptr) {
		die("Failed to malloc() %u bytes", size);
	}
	
	memset(ptr, '\0', size);
	return ptr;
}

/* Check if a year is a leap-year
 * Returns 1 if the supplied year is a leap-year, zero otherwise.
*/
int is_leapyear(int year) {
	if((year % 400) == 0) return 1;
	if((year % 100) == 0) return 0;
	if((year % 4) == 0) return 1;
	
	return 0;
}

/* Return the number of days in a month
 * Month should be 0-11
*/
int month_days(int year, int month) {
	int mdays[2][12] = {
		{31,28,31,30,31,30,31,31,30,31,30,31},
		{31,29,31,30,31,30,31,31,30,31,30,31}
	};
	
	return mdays[is_leapyear(year)][month];
}

/* Convert a time in seconds to a string
 * THIS IS NOT THREADSAFE
*/
char *fmt_time(int n) {
	static char buf[32];
	int days, hours, mins, secs;
	
	days = n / 86400;
	hours = (n % 86400) / 3600;
	mins = (n % 3600) / 60;
	secs = n % 60;
	
	if(days == 0) {
		strcpy(buf, "");
	}else if(days == 1) {
		strcpy(buf, "1 day, ");
	}else{
		sprintf(buf, "%d days, ", days);
	}
	
	if(hours > 0) {
		sprintf(buf+strlen(buf), "%d:%02d:%02d", hours, mins, secs);
	}else{
		sprintf(buf+strlen(buf), "%d:%02d", mins, secs);
	}
	
	return buf;
}