/* *****************************************************************************
 * encode/mcs.c -- encode an MCS file.
 * Copyright (C) 2017 Thomas "Cakeisalie5" Touhey <thomas@touhey.fr>
 *
 * This file is part of libg1m.
 * libg1m 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.
 *
 * libg1m 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 libg1m; if not, see <http://www.gnu.org/licenses/>.
 * ************************************************************************** */
#include <libg1m/internals.h>
#define FUNCS(name) g1m_announce_mcs_##name, g1m_encode_mcs_##name

/* ************************************************************************** */
/*  Correspondances                                                           */
/* ************************************************************************** */
/* Types */
typedef int (*announce_t)(const g1m_mcsfile_t*, size_t*);
typedef int (*encode_t)(const g1m_mcsfile_t*, g1m_buffer_t *buffer);
struct corresp {
	/* 'identification' */
	g1m_mcstype_t types;

	/* functions */
	announce_t announce;
	encode_t encode;
};

/* All correspondances */
static const struct corresp encodings[] = {
	{g1m_mcstype_list | g1m_mcstype_matrix, FUNCS(cells)},
	{g1m_mcstype_program,                   FUNCS(program)},
	{g1m_mcstype_alpha,                     FUNCS(var)},

	/* sentinel */
	{0, NULL, NULL}
};
/* ************************************************************************** */
/*  Default functions                                                         */
/* ************************************************************************** */
/**
 *	default_announce:
 *	Announce a file with no type.
 *
 *	@arg	handle		the file handle.
 *	@arg	sz			the size to contribute to.
 *	@return				the error code (0 if ok).
 */

static int default_announce(const g1m_mcsfile_t *handle, size_t *sz)
{
	*sz += handle->g1m_mcsfile_head.g1m_mcshead_size;
	return (0);
}

/**
 *	default_encode:
 *	'Encode' a file with no type.
 *
 *	@arg	handle		the file handle.
 *	@arg	buffer		the buffer to write to.
 *	@return				the error code (0 if ok).
 */

static int default_encode(const g1m_mcsfile_t *handle, g1m_buffer_t *buffer)
{
	WRITE(handle->g1m_mcsfile_content,
		handle->g1m_mcsfile_head.g1m_mcshead_size)
	return (0);
}

/* default correspondance */
static struct corresp default_corresp = { 0, default_announce, default_encode};
/* ************************************************************************** */
/*  Main function                                                             */
/* ************************************************************************** */
/**
 *	g1m_encode_mcsfile:
 *	Encode an MCS file.
 *
 *	@arg	handle		the file handle.
 *	@arg	buffer		the buffer to which to encode it.
 *	@return				the error that occured (0 if ok).
 */

int g1m_encode_mcsfile(g1m_mcsfile_t *handle, g1m_buffer_t *buffer)
{
	int err;

	/* find the announcement and encoding function */
	const struct corresp *c = encodings - 1;
	if (!c->types) c = &default_corresp;
	else {
		while ((++c)->encode) {
			if (c->types && !(c->types & handle->g1m_mcsfile_head
			  .g1m_mcshead_type))
				continue;
			break;
		} if (!c->encode) return (g1m_error_op);
	}

	/* announce if necessary */
	if (buffer->g1m_buffer_announce) {
		size_t size = 0;
		if ((err = (*c->announce)(handle, &size))
		 || (err = (*buffer->g1m_buffer_announce)(buffer->g1m_buffer_cookie,
		  size)))
			return (err);
	}

	/* encode */
	if (buffer->g1m_buffer_write) {
		err = (*c->encode)(handle, buffer);
		if (err && buffer->g1m_buffer_unannounce) {
			(*buffer->g1m_buffer_unannounce)(buffer->g1m_buffer_cookie);
			return (err);
		}
	}

	/* everything went well! */
	return (0);
}