#include "core.h"

int fd_open( const char *filename, int flags )
{
	int ret;

	ret = open( filename, flags );

	return ret;
}


int fd_close( int fd )
{
	int ret;

	ret = close( fd );

	return ret;
}


int fd_seek( int fd, off_t offset, int whence )
{
	int ret = 0;
	off_t off_new=0;

	off_new = lseek( fd, offset, whence );
	if ( errno != 0)
	{
		printf("!Cannot seek %s\n", strerror(errno));
		errno = 0; //why i need to reset it?
		return -1;
	}
	ret = off_new;

	return ret;
}


off_t fd_pos( int fd )
{
	off_t cur = 0;
	cur = lseek( fd, 0, SEEK_CUR );
	return cur;
}


off_t fd_set_pos( int fd, off_t offset )
{
	off_t ret;

	ret = lseek( fd, offset, SEEK_SET );

	return ret;
}


off_t fd_size( int fd )
{
	off_t ret;
	off_t old;

	old = lseek( fd, 0, FD_SEEK_CUR );
	ret = lseek( fd, 0, FD_SEEK_END );
	lseek( fd, old, FD_SEEK_SET );

	return ret;
}


ssize_t fd_read( int fd, void *buf, size_t count )
{
	ssize_t ret;
	
	ret = read( fd, buf, count );

	return ret;
}


ssize_t fd_write( int fd, void *buf, size_t count )
{
	ssize_t ret;

	ret = write( fd, buf, count );
	if ( errno != 0)
	{
		printf("Cannot write %s\n", strerror(errno));
		errno = 0;
	}

	return ret;
}


file_t *file_init()
{
	file_t *ret = NULL;

	ret = (file_t *)malloc( sizeof(file_t) );
	memset( ret, 0, sizeof(file_t) );

	ret->flags = FD_RO; //di we really need that?

	return ret;
}


int file_open_fn( file_t *ft, const char *filename, int flags )
{
	int ret = 0;
	int fd;

	//check if file is allready initialized or opened
	if (ft->fd > 0)
	{
		printf("Trying to open file but file descriptor allready set\n");
		return -1;
	}

	if (ft->filename != NULL)
	{
		printf("Trying open file, bus structure allready have filename\n");
		return -1;
	}

	fd = fd_open( filename, flags );
	if ( fd < 1 )
	{
		printf("Couldnt open %s\n", filename);
		return -1;
	}

	ft->fd = fd;
	ft->flags = flags;

	uint8_t fn_sz = strlen( filename );
	char *fn = (char *)malloc( fn_sz );
	memcpy( fn, filename, fn_sz );
	ft->filename = fn;


	/* set current file cursor postion and file size */
	ft->size = fd_size( fd );    /* if it RO mode - could be important */
	ft->position = fd_pos( fd ); /* file cursor position could be bigger 
	                                then file size*/
	ft->blk_size = DEFAULT_BLK_SIZE;

	return ret;
}


int file_seek( file_t *ft, off_t offset )
{
	int ret = 0;
	off_t new_off=0;

	
	ret = fd_seek( ft->fd, offset, FD_SEEK_CUR );
	if (ret >= 0) 
	{
		new_off = fd_pos( ft->fd );
		if (new_off > ft->size)
		{
			fd_seek( ft->fd, ft->size, FD_SEEK_SET );
			new_off = fd_pos( ft->fd );
		}
		ft->position = new_off;
		ft->offset = offset;
		if ( offset != new_off )
		{
			printf("Offset set to %zd requested %zd\n", new_off, offset);
		}
	} else
	{
		printf("Cannot set offset\n");
		ret = -1;
	}

	return ret;
}


int file_seekp( file_t *ft, off_t offset )
{
	int ret = 0;
	off_t new_off = 0;

	ret = fd_seek( ft->fd, offset, FD_SEEK_SET );
	ft->offset = fd_seek( ft->fd, 0, FD_SEEK_CUR ); //cul be errors?
	
	return ret;
}


int file_pos( file_t *ft )
{
	int ret = 0;
	long pos = fd_pos( ft->fd );
	if (pos < 0)
	{
		printf("Cannot get file cursor position\n");
		ret = -1;
	}

	ft->position = pos;
	ret = pos;

	return ret;
}


int file_size( file_t *ft )
{
	int ret = 0;
	off_t size;

	size = fd_size( ft->fd );
	if (size < 0)
	{
		printf("Cannot get file size\n");
		return -1;
	}
	ft->size = size;
	ret = size;

	return ret;
}


int file_resize( file_t *ft, size_t size )
{
	int ret = 0;
	off_t cur_pos;
	off_t cur_size;
	off_t resize;
	uint8_t *buf;

	cur_pos = fd_pos( ft->fd );
	cur_size = fd_size( ft->fd );
	if (cur_size < 0)
	{
		return -1;
	}
	buf = (uint8_t *)malloc( size );
	memset( buf, 0, size );
	fd_seek( ft->fd, cur_size, FD_SEEK_SET );
	resize = fd_write( ft->fd, buf, size );
	fd_seek( ft->fd, cur_pos, FD_SEEK_SET );

	ret = resize;

	return ret;
}


int file_open( file_t *ft, const char *filename, int flags, int mode )
{
	int ret = 0;
	printf("Not implemented\n");
	ret = -1;
	return ret;
}


int file_read_blk( file_t *ft, uint8_t *buf, int sz )
{
	int ret = 0;

	if ( ft->fd < 0 )
		return -1;

	file_pos( ft );
	int read_sz = sz;
	if (read_sz > ft->blk_size)
	{	
		read_sz = ft->blk_size;
	}
	ret = fd_read( ft->fd, buf, read_sz );
	fd_set_pos( ft->fd, ft->position ); //chck err?

	if ( ret < 0)
	{
		printf("Error while reading from file\n");
	}

	return ret;
}


int file_read( file_t *ft, uint8_t *buf, size_t count )
{
	int ret = 0;

	ret = fd_read( ft->fd, buf, count );
	if ( ret < 0 )
	{
		printf("Cannot read\n");
	} else if ( ret < count )
	{
		printf("Requestd %zu readed %d\n", count, ret);
	}

	return ret;
}


int file_write_blk( file_t *ft, uint8_t *buf, int sz )
{
	int ret = 0;
	unsigned int write_sz;

	file_pos( ft );
	if ( ft->position + ft->blk_size <= ft->size )
	{
		write_sz = ft->blk_size;
	} else
	{
		write_sz = ft->size - ft->position; //when pos 0 ans size 1 then will write 1 byte
	}

	if (write_sz > sz)
	{
		write_sz = sz;
	}

	ret = fd_write( ft->fd, buf, write_sz );
	if ( ret < 0 )
	{
		printf("Error while writing block to file\n");
	}
	fd_set_pos( ft->fd, ft->position );

	

	return ret;
}


int file_write( file_t *ft, uint8_t *buf, size_t count )
{
	int ret = 0;

	ret = fd_write( ft->fd, buf, count );
	if ( ret < 0 )
	{
		printf("Cannot write\n");
	} else if ( ret < count )
	{
		printf("Requested %zu written %d\n", count, ret);
	}

	return ret;
}


int file_s_mode( file_t *ft, int mode )
{
	int ret = 0;

	if ( ft == NULL)
		return -1;

	ft->mode = mode;

	return ret;
}

int file_s_bufs( file_t *ft, unsigned int size )
{
	int ret = 0;

	ft->blk_size = size;

	return ret;
}


int file_close( file_t *ft )
{
	int ret = 0;

	if ( ft->fd < 1 )
	{
		printf("File descriptor <1\n");
		return -1;
	}

	if ( ft->filename == NULL )
	{
		printf("File name is empty\n");
		return -1;
	} else {
		free(ft->filename);
		ft->filename = NULL;
	}
	
	fd_close( ft->fd );
	memset( ft, 0, sizeof(file_t) );
	ft->fd = -1;

	return ret;
}


uint8_t **dir_list( char *path)
{
	uint8_t **ret = NULL, **new_ptr;
	int cnt=0;
	DIR *dp;
	struct dirent *ep;
	int str_sz = 0;

	/* lets use libc example. they know what they are doing */
	dp = opendir( path );
	if ( dp != NULL )
	{
		while ( (ep = readdir( dp )) != NULL )
		{
			//count one more in da list
			cnt += 1;
			//lets alloc pointer on pointer where we put pointer
			new_ptr = (uint8_t **)realloc( ret, sizeof(uint8_t*)*(cnt) );
			if ( new_ptr == NULL )
				goto failed_realloc;
			ret = new_ptr;
			str_sz = strlen(ep->d_name);
			ret[cnt-1] = (uint8_t *)malloc( str_sz+1 );
			memcpy( ret[cnt-1], ep->d_name, str_sz );
			ret[cnt-1][str_sz] = 0;
		}
		closedir( dp );
		dp = NULL;
	} else
	{
		perror("Couldnt list directory files");
		*ret = NULL;
	}

	//add NULL element at the end
	new_ptr = (uint8_t **)realloc( ret, sizeof(uint8_t*)*(cnt+1) );
	if ( new_ptr == NULL )
		goto failed_add_entry;
	ret = new_ptr;
	ret[cnt] = NULL;

	return ret;

failed_realloc:
	closedir( dp );
failed_add_entry:
	//forgot to free ret
	return NULL;
}