//     ____                _       __               
//    / __ )____  _____   | |     / /___ ___________
//   / __  / __ \/ ___/   | | /| / / __ `/ ___/ ___/
//  / /_/ / /_/ (__  )    | |/ |/ / /_/ / /  (__  ) 
// /_____/\____/____/     |__/|__/\__,_/_/  /____/  
//                                              
//       A futuristic real-time strategy game.
//          This file is part of Bos Wars.
//
/**@name util.cpp - General utilites. */
//
//      (c) Copyright 1998-2006 by Lutz Sammer and Jimmy Salmon
//
//      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; only version 2 of the License.
//
//      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, write to the Free Software
//      Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
//      02111-1307, USA.
//

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

#include "stratagus.h"
#include "util.h"

#ifdef USE_WIN32
#define WIN32_LEAN_AND_MEAN
#undef NOUSER
#include <windows.h>
#elif defined(HAVE_X)
#include <X11/Xlib.h>
#include <X11/Xatom.h>
#endif

/*----------------------------------------------------------------------------
--  Random
----------------------------------------------------------------------------*/

unsigned SyncRandSeed;               /// sync random seed value.

/**
**  Inititalize sync rand seed.
*/
void InitSyncRand(void)
{
	SyncRandSeed = 0x87654321;
}

/**
**  Synchronized random number.
**
**  @note This random value must be same on all machines in network game.
**  Very simple random generations, enough for us.
*/
int SyncRand(void)
{
	int val;

	val = SyncRandSeed >> 16;

	SyncRandSeed = SyncRandSeed * (0x12345678 * 4 + 1) + 1;

	return val;
}

/**
**  Synchronized random number.
**
**  @param max  Max value of random number to return
*/
int SyncRand(int max)
{
	return SyncRand() % max;
}


/*----------------------------------------------------------------------------
--  Math
----------------------------------------------------------------------------*/

/**
**  Compute a square root using ints
**
**  Uses John Halleck's method, see
**  http://www.cc.utah.edu/~nahaj/factoring/isqrt.legalize.c.html
**
**  @param num  Calculate the square root of this number
**
**  @return     The integer square root.
*/
long isqrt(long num)
{
	long squaredbit;
	long remainder;
	long root;

	if (num < 1) {
		return 0;
	}

	//
	//  Load the binary constant 01 00 00 ... 00, where the number
	//  of zero bits to the right of the single one bit
	//  is even, and the one bit is as far left as is consistant
	//  with that condition.)
	//
	//  This portable load replaces the loop that used to be
	//  here, and was donated by  legalize@xmission.com
	//
	squaredbit  = (long)((((unsigned long)~0L) >> 1) & ~(((unsigned long)~0L) >> 2));

	// Form bits of the answer.
	remainder = num;
	root = 0;
	while (squaredbit > 0) {
		if (remainder >= (squaredbit | root)) {
			remainder -= (squaredbit | root);
			root >>= 1;
			root |= squaredbit;
		} else {
			root >>= 1;
		}
		squaredbit >>= 2;
	}

	return root;
}


/*----------------------------------------------------------------------------
--  Strings
----------------------------------------------------------------------------*/

#if !defined(_MSC_VER) || _MSC_VER < 1400
unsigned int strcpy_s(char *dst, size_t dstsize, const char *src)
{
	if (dst == NULL || src == NULL) {
		return EINVAL;
	}
	if (strlen(src) >= dstsize) {
		return ERANGE;
	}
	strcpy(dst, src);
	return 0;
}

#ifndef HAVE_STRNLEN
size_t strnlen(const char *str, size_t strsize)
{
	size_t len = 0;
	while (len < strsize) {
		if (*str == '\0') {
			break;
		}
		++str;
		++len;
	}
	return len;
}
#endif

unsigned int strncpy_s(char *dst, size_t dstsize, const char *src, size_t count)
{
	if (dst == NULL || src == NULL || dstsize == 0) {
		return EINVAL;
	}

	size_t mincount;
	if (count == _TRUNCATE) {
	   mincount = strnlen(src, dstsize);
	} else {
	   mincount = strnlen(src, count);
	}
	if (mincount >= dstsize) {
		if (count != _TRUNCATE) {
			dst[0] = '\0';
			return EINVAL;
		} else {
			mincount = dstsize - 1;
		}
	}
	for (size_t i = 0; i < mincount; ++i) {
		*dst++ = *src++;
	}
	*dst = '\0';
	return 0;
}

unsigned int strcat_s(char *dst, size_t dstsize, const char *src)
{
	if (dst == NULL || src == NULL) {
		return EINVAL;
	}
	char *enddst = dst;
	size_t count = dstsize;
	while (count > 0 && *enddst != '\0') {
		++enddst;
		count--;
	}
	if (count == 0) {
		return EINVAL;
	}
	if (strlen(src) >= count ) {
		return ERANGE;
	}
	strcpy(enddst, src);
	return 0;
}

int sprintf_s(char *dest, size_t destSize, const char *format, ...)
{
	va_list args;
	int ret;

	if (dest == NULL || format == NULL) {
		errno = EINVAL;
		return -1;
	}

	va_start(args, format);
	ret = vsnprintf(dest, destSize, format, args);
	va_end(args);

	if (ret < 0 || (size_t)ret >= destSize) {
		dest[0] = '\0';
		errno = EINVAL;
		ret = -1;
	}

	return ret;
}
#endif

/**
**  String duplicate/concatenate (two arguments)
**
**  @param l  Left string
**  @param r  Right string
**
**  @return   Allocated combined string (must be freed).
*/
char *strdcat(const char *l, const char *r)
{
	int len = strlen(l) + strlen(r) + 1;
	char *res = new char[len];

	if (res) {
		strcpy_s(res, len, l);
		strcat_s(res, len, r);
	}
	return res;
}

/**
**  String duplicate/concatenate (three arguments)
**
**  @param l  Left string
**  @param m  Middle string
**  @param r  Right string
**
**  @return   Allocated combined string (must be freeded).
*/
char *strdcat3(const char *l, const char *m, const char *r)
{
	int len = strlen(l) + strlen(m) + strlen(r) + 1;
	char *res = new char[len];

	if (res) {
		strcpy_s(res, len, l);
		strcat_s(res, len, m);
		strcat_s(res, len, r);
	}
	return res;
}

#if !defined(HAVE_STRCASESTR)
/**
**  Case insensitive version of strstr
**
**  @param a  String to search in
**  @param b  Substring to search for
**
**  @return   Pointer to first occurence of b or NULL if not found.
*/
char *strcasestr(const char *a, const char *b)
{
	int x;

	if (!a || !*a || !b || !*b || strlen(a) < strlen(b)) {
		return NULL;
	}

	x = 0;
	while (*a) {
		if (a[x] && (tolower(a[x]) == tolower(b[x]))) {
			++x;
		} else if (b[x]) {
			++a;
			x = 0;
		} else {
			return (char *)a;
		}
	}

	return NULL;
}
#endif // !HAVE_STRCASESTR


/*----------------------------------------------------------------------------
--  Getopt
----------------------------------------------------------------------------*/

/**
**  Standard implementation of getopt(3).
**
**  One extension: If the first character of the optionsstring is a ':'
**  the error return for 'argument required' is a ':' not a '?'.
**  This makes it easier to differentiate between an 'illegal option' and
**  an 'argument required' error.
*/

#if defined(_MSC_VER)

#include <io.h>
#include <string.h>

int opterr = 1;
int optind = 1;
int optopt;
char *optarg;

static void getopt_err(char *argv0, char *str, char opt)
{
	if (opterr) {
		char errbuf[2];
		char *x;

		errbuf[0] = opt;
		errbuf[1] = '\n';

		while ((x = strchr(argv0, '/'))) {
			argv0 = x + 1;
		}

		write(2, argv0, strlen(argv0));
		write(2, str, strlen(str));
		write(2, errbuf, 2);
	}
}

int getopt(int argc, char *const *argv, const char *opts)
{
	static int sp = 1;
	register int c;
	register const char *cp;

	optarg = NULL;

	if (sp == 1) {
		if (optind >= argc || argv[optind][0] != '-' || argv[optind][1] == '\0') {
			return EOF;
		} else if (!strcmp(argv[optind], "--")) {
			optind++;
			return EOF;
		}
	}
	optopt = c = argv[optind][sp];
	if (c == ':' || (cp = strchr(opts, c)) == NULL) {
		getopt_err(argv[0], ": illegal option -", (char)c);
		cp = "xx"; /* make the next if false */
		c = '?';
	}
	if (*++cp == ':') {
		if (argv[optind][++sp] != '\0') {
			optarg = &argv[optind++][sp];
		} else if (++optind < argc) {
			optarg = argv[optind++];
		} else {
			getopt_err(argv[0], ": option requires an argument -", (char)c);
			c = (*opts == ':') ? ':' : '?';
		}
		sp = 1;
	} else if (argv[optind][++sp] == '\0') {
		optind++;
		sp = 1;
	}
	return c;
}

#endif /* _MSC_VER */


/*----------------------------------------------------------------------------
--  Clipboard
----------------------------------------------------------------------------*/

/**
** Paste text from the clipboard
*/
int GetClipboard(std::string &str)
{
#if defined(USE_WIN32) || defined(HAVE_X)
	int i;
	unsigned char *clipboard;
#ifdef USE_WIN32
	HGLOBAL handle;
#elif defined(HAVE_X)
	Display *display;
	Window window;
	Atom rettype;
	unsigned long nitem;
	unsigned long dummy;
	int retform;
	XEvent event;
#endif

#ifdef USE_WIN32
	if (!IsClipboardFormatAvailable(CF_TEXT) || !OpenClipboard(NULL)) {
		return -1;
	}
	handle = GetClipboardData(CF_TEXT);
	if (!handle) {
		CloseClipboard();
		return -1;
	}
	clipboard = (unsigned char *)GlobalLock(handle);
	if (!clipboard) {
		CloseClipboard();
		return -1;
	}
#elif defined(HAVE_X)
	if (!(display = XOpenDisplay(NULL))) {
		return -1;
	}

	// Creates a non maped temporary X window to hold the selection
	if (!(window = XCreateSimpleWindow(display,
			DefaultRootWindow(display), 0, 0, 1, 1, 0, 0, 0))) {
		XCloseDisplay(display);
		return -1;
	}

	XConvertSelection(display, XA_PRIMARY, XA_STRING, XA_STRING,
		window, CurrentTime);

	XNextEvent(display, &event);

	if (event.type != SelectionNotify ||
			event.xselection.property != XA_STRING) {
		return -1;
	}

	XGetWindowProperty(display, window, XA_STRING, 0, 1024, False,
		XA_STRING, &rettype, &retform, &nitem, &dummy, &clipboard);

	XDestroyWindow(display, window);
	XCloseDisplay(display);

	if (rettype != XA_STRING || retform != 8) {
		if (clipboard != NULL) {
			XFree(clipboard);
		}
		clipboard = NULL;
	}

	if (clipboard == NULL) {
		return -1;
	}
#endif
	// Only allow ascii characters
	for (i = 0; clipboard[i] != '\0'; ++i) {
		if (clipboard[i] < 32 || clipboard[i] > 126) {
			return -1;
		}
	}
	str = (char *)clipboard;
#ifdef USE_WIN32
	GlobalUnlock(handle);
	CloseClipboard();
#elif defined(HAVE_X)
	if (clipboard != NULL) {
		XFree(clipboard);
	}
#endif
	return 0;
#else
	return -1;
#endif
}


/*----------------------------------------------------------------------------
--  UTF8
----------------------------------------------------------------------------*/

int UTF8GetPrev(const std::string &text, int curpos)
{
	--curpos;
	if (curpos < 0) {
		return curpos;
	}
	while (curpos >= 0) {
		if ((text[curpos] & 0xC0) != 0x80) {
			return curpos;
		}
		--curpos;
	}
	if (curpos < 0) {
		fprintf(stderr, "Invalid UTF8.\n");
	}
	return 0;
}

int UTF8GetNext(const std::string &text, int curpos)
{
	if (curpos == (int)text.size()) {
		return curpos + 1;
	}
	char c = text[curpos];
	if (!(c & 0x80)) {
		return curpos + 1;
	}
	if ((c & 0xE0) == 0xC0) {
		return curpos + 2;
	}
	if ((c & 0xF0) == 0xE0) {
		return curpos + 3;
	}
	fprintf(stderr, "Invalid UTF8.\n");
	return text.size();
}