/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * 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 2
 * of the License, or (at your option) 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, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 *
 * The Original Code is: all of this file.
 *
 * Contributor(s): none yet.
 *
 * ***** END GPL LICENSE BLOCK *****
 * Reorganised mar-01 nzc
 * Some really low-level file thingies.
 */

/** \file blender/blenlib/intern/storage.c
 *  \ingroup bli
 */

#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>

#include <sys/stat.h>

#if defined(__NetBSD__) || defined(__DragonFly__) || defined(__sun__) || defined(__sun)
   /* Other modern unix os's should probably use this also */
#  include <sys/statvfs.h>
#  define USE_STATFS_STATVFS
#elif (defined(__sparc) || defined(__sparc__)) && !defined(__FreeBSD__) && !defined(__linux__)
#  include <sys/statfs.h>
   /* 4 argument version (not common) */
#  define USE_STATFS_4ARGS
#endif

#if defined(__APPLE__) || defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__) || defined(__DragonFly__)
   /* For statfs */
#  include <sys/param.h>
#  include <sys/mount.h>
#endif

#if defined(__linux__) || defined(__hpux) || defined(__GNU__) || defined(__GLIBC__)
#  include <sys/vfs.h>
#endif

#include <fcntl.h>
#include <string.h>  /* strcpy etc.. */

#ifdef WIN32
#  include <io.h>
#  include <direct.h>
#  include "BLI_winstuff.h"
#  include "utfconv.h"
#else
#  include <sys/ioctl.h>
#  include <unistd.h>
#  include <pwd.h>
#endif

/* lib includes */
#include "MEM_guardedalloc.h"

#include "BLI_utildefines.h"
#include "BLI_linklist.h"
#include "BLI_string.h"
#include "BLI_fileops.h"
#include "BLI_fileops_types.h"
#include "BLI_path_util.h"

/**
 * Copies the current working directory into *dir (max size maxncpy), and
 * returns a pointer to same.
 *
 * \note can return NULL when the size is not big enough
 */
char *BLI_current_working_dir(char *dir, const size_t maxncpy)
{
	const char *pwd = getenv("PWD");
	if (pwd) {
		BLI_strncpy(dir, pwd, maxncpy);
		return dir;
	}

	return getcwd(dir, maxncpy);
}

/**
 * Returns the number of free bytes on the volume containing the specified pathname. */
/* Not actually used anywhere.
 */
double BLI_dir_free_space(const char *dir)
{
#ifdef WIN32
	DWORD sectorspc, bytesps, freec, clusters;
	char tmp[4];
	
	tmp[0] = '\\'; tmp[1] = 0; /* Just a failsafe */
	if (dir[0] == '/' || dir[0] == '\\') {
		tmp[0] = '\\';
		tmp[1] = 0;
	}
	else if (dir[1] == ':') {
		tmp[0] = dir[0];
		tmp[1] = ':';
		tmp[2] = '\\';
		tmp[3] = 0;
	}

	GetDiskFreeSpace(tmp, &sectorspc, &bytesps, &freec, &clusters);

	return (double) (freec * bytesps * sectorspc);
#else

#ifdef USE_STATFS_STATVFS
	struct statvfs disk;
#else
	struct statfs disk;
#endif

	char name[FILE_MAXDIR], *slash;
	int len = strlen(dir);
	
	if (len >= FILE_MAXDIR) /* path too long */
		return -1;
	
	strcpy(name, dir);

	if (len) {
		slash = strrchr(name, '/');
		if (slash) slash[1] = 0;
	}
	else {
		strcpy(name, "/");
	}

#if  defined(USE_STATFS_STATVFS)
	if (statvfs(name, &disk)) return -1;
#elif defined(USE_STATFS_4ARGS)
	if (statfs(name, &disk, sizeof(struct statfs), 0)) return -1;
#else
	if (statfs(name, &disk)) return -1;
#endif

	return ( ((double) disk.f_bsize) * ((double) disk.f_bfree));
#endif
}


/**
 * Returns the file size of an opened file descriptor.
 */
size_t BLI_file_descriptor_size(int file)
{
	struct stat st;
	if ((file < 0) || (fstat(file, &st) == -1))
		return -1;
	return st.st_size;
}

/**
 * Returns the size of a file.
 */
size_t BLI_file_size(const char *path)
{
	BLI_stat_t stats;
	if (BLI_stat(path, &stats) == -1)
		return -1;
	return stats.st_size;
}

/**
 * Returns the st_mode from statting the specified path name, or 0 if it couldn't be statted
 * (most likely doesn't exist or no access).
 */
int BLI_exists(const char *name)
{
#if defined(WIN32) 
	BLI_stat_t st;
	wchar_t *tmp_16 = alloc_utf16_from_8(name, 1);
	int len, res;
	unsigned int old_error_mode;

	len = wcslen(tmp_16);
	/* in Windows #stat doesn't recognize dir ending on a slash
	 * so we remove it here */
	if (len > 3 && (tmp_16[len - 1] == L'\\' || tmp_16[len - 1] == L'/')) {
		tmp_16[len - 1] = '\0';
	}
	/* two special cases where the trailing slash is needed:
	 * 1. after the share part of a UNC path
	 * 2. after the C:\ when the path is the volume only
	 */
	if ((len >= 3) && (tmp_16[0] ==  L'\\') && (tmp_16[1] ==  L'\\')) {
		BLI_cleanup_unc_16(tmp_16);
	}

	if ((tmp_16[1] ==  L':') && (tmp_16[2] ==  L'\0')) {
		tmp_16[2] = L'\\';
		tmp_16[3] = L'\0';
	}


	/* change error mode so user does not get a "no disk in drive" popup
	 * when looking for a file on an empty CD/DVD drive */
	old_error_mode = SetErrorMode(SEM_FAILCRITICALERRORS | SEM_NOOPENFILEERRORBOX);

	res = BLI_wstat(tmp_16, &st);

	SetErrorMode(old_error_mode);

	free(tmp_16);
	if (res == -1) return(0);
#else
	struct stat st;
	BLI_assert(name);
	BLI_assert(!BLI_path_is_rel(name));
	if (stat(name, &st)) return(0);
#endif
	return(st.st_mode);
}


#ifdef WIN32
int BLI_stat(const char *path, BLI_stat_t *buffer)
{
	int r;
	UTF16_ENCODE(path);

	r = BLI_wstat(path_16, buffer);

	UTF16_UN_ENCODE(path);
	return r;
}

int BLI_wstat(const wchar_t *path, BLI_stat_t *buffer)
{
#if defined(_MSC_VER) || defined(__MINGW64__)
	return _wstat64(path, buffer);
#elif defined(__MINGW32__)
	return _wstati64(path, buffer);
#else
	return _wstat(path, buffer);
#endif
}
#else
int BLI_stat(const char *path, struct stat *buffer)
{
	return stat(path, buffer);
}
#endif

/**
 * Does the specified path point to a directory?
 * \note Would be better in fileops.c except that it needs stat.h so add here
 */
bool BLI_is_dir(const char *file)
{
	return S_ISDIR(BLI_exists(file));
}

/**
 * Does the specified path point to a non-directory?
 */
bool BLI_is_file(const char *path)
{
	const int mode = BLI_exists(path);
	return (mode && !S_ISDIR(mode));
}

/**
 * Reads the contents of a text file and returns the lines in a linked list.
 */
LinkNode *BLI_file_read_as_lines(const char *name)
{
	FILE *fp = BLI_fopen(name, "r");
	LinkNodePair lines = {NULL, NULL};
	char *buf;
	size_t size;

	if (!fp) return NULL;
		
	fseek(fp, 0, SEEK_END);
	size = (size_t)ftell(fp);
	fseek(fp, 0, SEEK_SET);

	if (UNLIKELY(size == (size_t)-1)) {
		fclose(fp);
		return NULL;
	}

	buf = MEM_mallocN(size, "file_as_lines");
	if (buf) {
		size_t i, last = 0;
		
		/*
		 * size = because on win32 reading
		 * all the bytes in the file will return
		 * less bytes because of crnl changes.
		 */
		size = fread(buf, 1, size, fp);
		for (i = 0; i <= size; i++) {
			if (i == size || buf[i] == '\n') {
				char *line = BLI_strdupn(&buf[last], i - last);

				BLI_linklist_append(&lines, line);
				/* faster to build singly-linked list in reverse order */
				/* alternatively, could process buffer in reverse order so
				 * list ends up right way round to start with */
				last = i + 1;
			}
		}
		
		MEM_freeN(buf);
	}
	
	fclose(fp);

	return lines.list;
}

/*
 * Frees memory from a previous call to BLI_file_read_as_lines.
 */
void BLI_file_free_lines(LinkNode *lines)
{
	BLI_linklist_freeN(lines);
}

/** is file1 older then file2 */
bool BLI_file_older(const char *file1, const char *file2)
{
#ifdef WIN32
#ifndef __MINGW32__
	struct _stat st1, st2;
#else
	struct _stati64 st1, st2;
#endif

	UTF16_ENCODE(file1);
	UTF16_ENCODE(file2);
	
#ifndef __MINGW32__
	if (_wstat(file1_16, &st1)) return false;
	if (_wstat(file2_16, &st2)) return false;
#else
	if (_wstati64(file1_16, &st1)) return false;
	if (_wstati64(file2_16, &st2)) return false;
#endif


	UTF16_UN_ENCODE(file2);
	UTF16_UN_ENCODE(file1);
#else
	struct stat st1, st2;

	if (stat(file1, &st1)) return false;
	if (stat(file2, &st2)) return false;
#endif
	return (st1.st_mtime < st2.st_mtime);
}