/* *****************************************************************************
 * usage/server/classical.c -- set up a classical protocol 7 server.
 * 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>
#include <string.h>

/* ************************************************************************** */
/*  Utilities                                                                 */
/* ************************************************************************** */
/* cookie structure */
typedef struct {
	p7_server_t *info;
	p7_filesystem_t *filesystems;
} p7_server_cookie_t;

/* macros */
#define gather_fs() \
	p7_filesystem_t *fs = find_filesystem(response.args[4], \
		cookie->filesystems); \
	if (!fs) return (p7_error_unknown);
#define gather_sdir() \
	const char *sdir = response.args[0]; \
	if (!sdir) sdir = fs->working_directory;

/**
 *	find_filesystem:
 *	Find a filesystem in a list.
 *
 *	@arg	name			the name of the filesystem to look for.
 *	@arg	filesystems		the filesystems list (with terminating entry)
 *	@return					the filesystem.
 */

static p7_filesystem_t *find_filesystem(const char *name,
	p7_filesystem_t *filesystems)
{
	while (filesystems->name) {
		if (!strcmp(name, filesystems->name))
			return (filesystems);
		filesystems++;
	}
	return (NULL);
}
/* ************************************************************************** */
/*  General callbacks                                                         */
/* ************************************************************************** */
/**
 *	send_server_info:
 *	Send the server information.
 *
 *	@arg	cookie		the cookie.
 *	@arg	handle		the libp7 handle.
 *	@return				the libp7 error.
 */

static int send_server_info(p7_server_cookie_t *cookie, p7_handle_t *handle)
{
	return (p7_seven_send_eack(handle, cookie->info));
}
/* ************************************************************************** */
/*  Backup-related callbacks                                                  */
/* ************************************************************************** */
/**
 *	backup_ram:
 *	Request a RAM image transfer.
 *
 *	@arg	cookie		the cookie.
 *	@arg	handle		the libp7 handle.
 *	@return				the libp7 error.
 */

static int backup_ram(p7_server_cookie_t *cookie, p7_handle_t *handle)
{
	p7_server_t *info = cookie->info;

	/* check that we have the RAM */
	if (!info->ram) return (p7_error_unknown);

	/* accept and roleswap */
	int err = p7_seven_send_ack(handle, 1);
	if (err) return (err);
	if (response.type != p7_seven_type_swp)
		return (p7_error_unknown);

	/* send the command */
	err = p7_seven_send_cmdbak_putram(handle);
	if (err) return (err);
	if (response.type == p7_seven_type_ack) {
		/* send the thing */
		err = p7_seven_send_data(handle, info->ram, info->ram_capacity,
			0, NULL);
		if (err) return (err);
	}

	/* re-swap roles */
	return (p7_seven_send_swp(handle));
}

/**
 *	backup_rom:
 *	Request a ROM image transfer.
 *
 *	@arg	cookie		the cookie.
 *	@arg	handle		the libp7 handle.
 *	@return				the libp7 error.
 */

static int backup_rom(p7_server_cookie_t *cookie, p7_handle_t *handle)
{
	p7_server_t *info = cookie->info;

	/* check that we have the ROM */
	if (!info->flash_rom) return (p7_error_unknown);

	/* accept and roleswap */
	int err = p7_seven_send_ack(handle, 1);
	if (err) return (err);
	if (response.type != p7_seven_type_swp)
		return (p7_error_unknown);

	/* send the command */
	err = p7_seven_send_cmdbak_putrom(handle);
	if (err) return (err);
	if (response.type == p7_seven_type_ack) {
		/* send the thing */
		err = p7_seven_send_data(handle, info->flash_rom,
			info->flash_rom_capacity, 0, NULL);
		if (err) return (err);
	}

	/* re-swap roles */
	return (p7_seven_send_swp(handle));
}

/**
 *	backup_boot:
 *	Request a bootcode transfer.
 *
 *	@arg	cookie		the cookie.
 *	@arg	handle		the libp7 handle.
 *	@return				the libp7 error.
 */

static int backup_boot(p7_server_cookie_t *cookie, p7_handle_t *handle)
{
	p7_server_t *info = cookie->info;

	/* check that we have the bootcode */
	if (!info->bootcode) return (p7_error_unknown);

	/* accept and roleswap */
	int err = p7_seven_send_ack(handle, 1);
	if (err) return (err);
	if (response.type != p7_seven_type_swp)
		return (p7_error_unknown);

	/* send the command */
	err = p7_seven_send_cmdbak_putboot(handle);
	if (err) return (err);
	if (response.type == p7_seven_type_ack) {
		/* send the thing */
		err = p7_seven_send_data(handle, info->bootcode, info->bootcode_size,
			0, NULL);
		if (err) return (err);
	}

	/* re-swap roles */
	return (p7_seven_send_swp(handle));
}
/* ************************************************************************** */
/*  Storage-related callbacks                                                 */
/* ************************************************************************** */
/**
 *	create_directory:
 *	Create a directory.
 *
 *	@arg	cookie		the cookie.
 *	@arg	handle		the libp7 handle.
 *	@return				the libp7 error.
 */

static int create_directory(p7_server_cookie_t *cookie, p7_handle_t *handle)
{
	gather_fs()
	gather_sdir()

	/* create the directory */
	if (!fs->create_directory || !sdir)
		return (p7_error_unknown);
	int err = (*fs->create_directory)(fs->cookie, sdir);
	if (err) return (err);

	/* send ack */
	return (p7_seven_send_ack(handle, 1));
}

/**
 *	delete_directory:
 *	Delete a directory.
 *
 *	@arg	cookie		the cookie.
 *	@arg	handle		the libp7 handle.
 *	@return				the libp7 error.
 */

static int delete_directory(p7_server_cookie_t *cookie, p7_handle_t *handle)
{
	gather_fs()
	gather_sdir()

	/* delete the directory */
	if (!fs->delete_directory || !sdir)
		return (p7_error_unknown);
	int err = (*fs->delete_directory)(fs->cookie, sdir);
	if (err) return (err);

	/* send ack */
	return (p7_seven_send_ack(handle, 1));
}

/**
 *	rename_directory:
 *	Rename a directory.
 *
 *	@arg	cookie		the cookie.
 *	@arg	handle		the libp7 handle.
 *	@return				the libp7 error.
 */

static int rename_directory(p7_server_cookie_t *cookie, p7_handle_t *handle)
{
	gather_fs()
	gather_sdir()

	/* rename the directory */
	if (!fs->rename_directory || !sdir || !response.args[1])
		return (p7_error_unknown);
	int err = (*fs->rename_directory)(fs->cookie, sdir, response.args[1]);
	if (err) return (err);

	/* send ack */
	return (p7_seven_send_ack(handle, 1));
}

/**
 *	change_working_directory:
 *	Change the current working directory.
 *
 *	@arg	cookie		the cookie.
 *	@arg	handle		the libp7 handle.
 *	@return				the libp7 error.
 */

static int change_working_directory(p7_server_cookie_t *cookie,
	p7_handle_t *handle)
{
	gather_fs()

	/* check and change working directory */
	log_info("Changing directory to \"%s\"", response.args[0]);
	if (!response.args[0])
		fs->working_directory = NULL;
	else if (fs->directory_exists
	 && (*fs->directory_exists)(fs->cookie, response.args[0])) {
		log_info("Directory does not exist, not changing!");
		return (p7_error_unknown);
	} else {
		fs->working_directory = fs->_wd;
		strncpy(fs->_wd, response.args[0], 256);
		fs->_wd[256] = 0;
	}

	/* success! */
	return (p7_seven_send_ack(handle, 1));
}
/* ************************************************************************** */
/*  Main function                                                             */
/* ************************************************************************** */
/**
 *	p7_serve:
 *	Initialize a server.
 *
 *	@arg	handle		the libp7 handle.
 *	@arg	info		the server information.
 *	@arg	callbacks	the server callbacks.
 *	@return				the error code.
 */

int p7_serve(p7_handle_t *handle, p7_server_t *info,
	p7_filesystem_t *filesystems)
{
	/* make cookie and commands */
	p7_server_cookie_t cookie = {
		.info = info,
		.filesystems = filesystems};
	p7_server_callback_t callbacks[256] = {
		/* main commands */
		[p7_seven_cmdsys_getinfo] = (p7_server_callback_t)send_server_info,

		/* backup commands */
		[p7_seven_cmdbak_reqram]  = (p7_server_callback_t)backup_ram,
		[p7_seven_cmdbak_reqrom]  = (p7_server_callback_t)backup_rom,
		[p7_seven_cmdbak_reqboot] = (p7_server_callback_t)backup_boot,

		/* storage-related commands */
		[p7_seven_cmdfls_mkdir] = (p7_server_callback_t)create_directory,
		[p7_seven_cmdfls_rmdir] = (p7_server_callback_t)delete_directory,
		[p7_seven_cmdfls_mvdir] = (p7_server_callback_t)rename_directory,
		[p7_seven_cmdfls_cwd] = (p7_server_callback_t)change_working_directory,
	};

	/* serve! */
	return (p7_serve_directly(handle, callbacks, (void*)&cookie));
}