/******************************************************************************/
/* SlunkCrypt, by LoRd_MuldeR <MuldeR2@GMX.de>                                */
/* This work has been released under the CC0 1.0 Universal license!           */
/******************************************************************************/

#ifdef _WIN32
#	define WIN32_LEAN_AND_MEAN 1
#	define _CRT_SECURE_NO_WARNINGS 1
#else
#	define _GNU_SOURCE 1
#endif

/* Internal */
#include <slunkcrypt.h>
#include "utils.h"

/* CRT */
#include <sys/stat.h>
#include <sys/types.h>
#include <signal.h>

/* Platform support */
#ifdef _WIN32
#	include <Windows.h>
#	include <io.h>
#	include <fcntl.h>
#	define STAT_T struct _stati64
#	define FSTAT(X,Y) _fstati64((X),(Y))
#	define FILENO(X) _fileno((X))
#	define S_IFMT  _S_IFMT
#	define S_IFDIR _S_IFDIR
#	define S_IFIFO _S_IFIFO
#	ifndef _O_U8TEXT
#		define _O_U8TEXT 0x40000
#	endif
#else
#	if defined(__USE_LARGEFILE64) && (__USE_LARGEFILE64)
#		define STAT_T struct stat64
#		define FSTAT(X,Y) fstat64((X),(Y))
#	else
#		define STAT_T struct stat
#		define FSTAT(X,Y) fstat((X),(Y))
#	endif
#	define FILENO(X) fileno((X))
#endif

// ==========================================================================
// Terminal initialization
// ==========================================================================

#ifdef _WIN32
#ifdef _DLL
#define _acmdln GetCommandLineA()
#define _wcmdln GetCommandLineW()
#else
extern char    *const _acmdln;
extern wchar_t *const _wcmdln;
#endif
static void clear_cmdline_args(char *const acmdln, wchar_t *const wcmdln)
{
	if (acmdln && acmdln[0U])
	{
		const size_t len = strlen(acmdln);
		slunkcrypt_bzero(acmdln, len * sizeof(char));
		if (len > 5U) strcpy(acmdln, "slunk");
	}
	if (wcmdln && wcmdln[0U])
	{
		const size_t len = wcslen(wcmdln);
		slunkcrypt_bzero(wcmdln, len * sizeof(wchar_t));
		if (len > 5U) wcscpy(wcmdln, L"slunk");
	}
}
#endif

void init_terminal(void)
{
#ifdef _WIN32
	SetErrorMode(SEM_FAILCRITICALERRORS | SEM_NOGPFAULTERRORBOX);
	_setmode(_fileno(stdout), _O_BINARY);
	_setmode(_fileno(stdin),  _O_BINARY);
	_setmode(_fileno(stderr), _O_U8TEXT);
	clear_cmdline_args(_acmdln, _wcmdln);
#endif
}

// ==========================================================================
// Signal handling
// ==========================================================================

void setup_signal_handler(const int signo, signal_handler_t* const handler)
{
#ifdef _WIN32
	signal(signo, handler);
#else
	struct sigaction act;
	act.sa_handler = handler;
	sigemptyset(&act.sa_mask);
	act.sa_flags = 0;
	sigaction(signo, &act, NULL);
#endif
}

// ==========================================================================
// Character set conversion
// ==========================================================================

char* CHR_to_utf8(const CHR*const input)
{
#ifdef _WIN32
	char* buffer;
	DWORD buffer_size = 0U, result = 0U;

	buffer_size = WideCharToMultiByte(CP_UTF8, 0, input, -1, NULL, 0, NULL, NULL);
	if (buffer_size < 1U)
	{
		return NULL;
	}

	buffer = (char*)malloc(sizeof(char) * buffer_size);
	if (!buffer)
	{
		return NULL;
	}

	result = WideCharToMultiByte(CP_UTF8, 0, input, -1, (LPSTR)buffer, buffer_size, NULL, NULL);
	if ((result > 0U) && (result <= buffer_size))
	{
		return buffer;
	}

	free(buffer);
	return NULL;
#else
	return strdup(input);
#endif
}

// ==========================================================================
// Byte-order support
// ==========================================================================

#if defined(__BYTE_ORDER) && defined(__BIG_ENDIAN) && (__BYTE_ORDER == __BIG_ENDIAN)
#	define BIG_ENDIAN_BYTE_ORDER 1
#elif defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) && (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
#	define BIG_ENDIAN_BYTE_ORDER 1
#else
#	define BIG_ENDIAN_BYTE_ORDER 0
#endif

uint64_t swap_bytes_u64(const uint64_t value)
{
#if BIG_ENDIAN_BYTE_ORDER
	return
		(((value) >> 56) & 0x00000000000000FF) | (((value) >> 40) & 0x000000000000FF00) |
		(((value) >> 24) & 0x0000000000FF0000) | (((value) >>  8) & 0x00000000FF000000) |
		(((value) <<  8) & 0x000000FF00000000) | (((value) << 24) & 0x0000FF0000000000) |
		(((value) << 40) & 0x00FF000000000000) | (((value) << 56) & 0xFF00000000000000);
#else
	return value; /*nothing to do*/
#endif
}

// ==========================================================================
// File functions
// ==========================================================================

uint64_t get_file_size(FILE* const file)
{
	STAT_T stat;
	if (FSTAT(FILENO(file), &stat) == 0)
	{
		const uint16_t file_type = stat.st_mode & S_IFMT;
		if ((file_type != S_IFDIR) && (file_type != S_IFIFO))
		{
			const int64_t ssize = stat.st_size;
			return (ssize >= 0) ? ((uint64_t)ssize) : 0U;
		}
		return 0U;
	}
	return UINT64_MAX;
}

const CHR* get_file_name(const CHR* path)
{
	const CHR* ptr;
	while ((ptr = STRRCHR(path, T('/'))))
	{
		path = ptr + 1U;
	}
	while ((ptr = STRRCHR(path, T('\\'))))
	{
		path = ptr + 1U;
	}
	return path;
}

// ==========================================================================
// Math functions
// ==========================================================================

uint64_t round_down(const uint64_t value, const uint64_t base)
{
	const uint64_t modulus = value % base;
	return modulus ? (value - modulus) : value;
}