/* *****************************************************************************
 * storage/getfreemem.c -- get the amount of free memory on the calculator.
 * Copyright (C) 2016-2017 Thomas "Cakeisalie5" Touhey <thomas@touhey.fr>
 *
 * This file is part of libp7.
 * libp7 is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 3.0 of the License,
 * or (at your option) any later version.
 *
 * libp7 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with libp7; if not, see <http://www.gnu.org/licenses/>.
 * ************************************************************************** */
#include <libp7/internals.h>

/**
 *	p7_getfreemem:
 *	Request a device's capacity.
 *
 *	@arg	handle		the libp7 handle.
 *	@arg	devname		the device name.
 *	@arg	capacity	pointer to the capacity to fill.
 *	@return				if there was an error.
 */

int p7_getfreemem(p7_handle_t *handle, const char *devname,
	p7uint_t *capacity)
{
	int err;
	/* make checks */
	chk_handle(handle);
	chk_active(handle);

	/* send command packet */
	log_info("sending capacity transmit request");
	if ((err = p7_send_cmdfls_reqcapacity(handle, devname))) {
		log_fatal("couldn't send request/didn't receive answer");
		return (err);
	}

	/* check response packet */
	if (response.type == p7_pt_error
	 && response.code == p7_err_other) {
		log_fatal("filesystem probably doesn't exist");
		return (p7_error_unsupported_device);
	} else if (response.type != p7_pt_ack) {
		log_fatal("didn't receive ack or known error...");
		return (p7_error_unknown);
	}

	/* swap roles */
	log_info("sending roleswap");
	if ((err = p7_send_roleswp(handle))) {
		log_fatal("couldn't swap roles");
		return (err);
	} else if (response.type != p7_pt_cmd || response.code != 0x4C
	 || !response.args[4]) {
		log_fatal("didn't receive expected command");
		return (p7_error_unknown);
	}

	/* decode thingy */
	*capacity = response.filesize;

	/* ack and check for the roleswap */
	log_info("return ack and wait for roleswp");
	if ((err = p7_send_ack(handle, 1))) {
		log_fatal("unable to send ack.");
		return (err);
	} else if (response.type != p7_pt_roleswp)
		return (p7_error_unknown);

	/* no error! */
	return (0);
}