#include "fileutil.h"

#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/statvfs.h>
#include <errno.h>
#include <stdlib.h>
#include <assert.h>
#include <string.h>

int file_isReadable(char *file)
{
	int fd = open( file, O_RDONLY );
	if ( fd < 0 ) return FALSE;
	close( fd );
	return TRUE;
}

int file_isWritable(char *file)
{
	int fd = open( file, O_WRONLY );
	if ( fd >= 0 ) {
		close( fd );
		return TRUE;
	}
	fd = open( file, O_WRONLY | O_CREAT, 0600 );
	if ( fd < 0 ) return FALSE;
	close( fd );
	unlink( file );
	return TRUE;
}

int mkdir_p(const char* path)
{
	assert( path != NULL );
	if ( *path == '\0' ) return TRUE;
	char buffer[strlen( path ) + 1];
	strcpy( buffer, path );
	char *current = buffer;
	char *slash;
	while ( (slash = strchr( current, '/' )) != NULL ) {
		*slash = '\0';
		if ( *buffer != '\0' && mkdir( buffer, 0750 ) != 0 && errno != EEXIST ) return FALSE;
		*slash = '/';
		current = slash + 1;
	}
	if ( mkdir( buffer, 0750 ) != 0 && errno != EEXIST ) return FALSE;
	return TRUE;
}

int file_alloc(int fd, uint64_t offset, uint64_t size)
{
	if ( fallocate( fd, 0, offset, size ) == 0 ) return TRUE; // fast way
	if ( posix_fallocate( fd, offset, size ) == 0 ) return TRUE; // slow way
	if ( lseek( fd, offset + size - 1, SEEK_SET ) != offset ) return FALSE; // dumb way
	if ( write( fd, "", 1 ) != 1 ) return FALSE;
	return TRUE;
}

uint64_t file_freeDiskSpace(const char * const path)
{
	struct statvfs fiData;
	if ( (statvfs( path, &fiData )) < 0 ) {
		return 0;
	}
	return ((uint64_t)fiData.f_bavail * (uint64_t)fiData.f_bsize);
}

time_t file_lastModification(const char * const file)
{
	struct stat st;
	if ( stat( file, &st ) != 0 ) return 0;
	return st.st_mtime;
}