/* *****************************************************************************
 * decode/std/addin.c -- decode an add-in 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>

/**
 *	addin_set_data:
 *	Set handle data.
 *
 *	Will take basic add-in data, put it into the right interface format
 *	and store it.
 *
 *	@arg	handle				the handle.
 *	@arg	title				the addin title.
 *	@arg	title_size			the addin title size.
 *	@arg	internal_name		the addin internal name.
 *	@arg	internal_name_size	the addin internal name size.
 *	@arg	version				the version string.
 *	@arg	creation_time		the creation time.
 */

static void addin_set_data(g1m_t *handle,
	char *title, size_t title_size,
	char *internal_name, size_t internal_name_size,
	char *version, char *creation_time)
{
	/* useful vars */
	const int two = '0' + '0' * 10;
	const int four = two + '0' * 100 + '0' * 1000;

	/* put title */
	bzero(handle->title, 17);
	strncpy(handle->title, title, title_size);

	/* put internal name */
	bzero(handle->internal_name, 12);
	strncpy(handle->internal_name, internal_name, internal_name_size);

	/* put version */
#define v version
	handle->version = (g1m_version_t){
		.major = v[0] * 10 + v[1] - two,
		.minor = v[3] * 10 + v[4] - two,
		.revision = v[6] * 1000 + v[7] * 100 + v[8] * 10 + v[9] - four
	};
#undef v

	/* put time */
#define c creation_time
	struct tm created = {
		.tm_year = c[0] * 1000 + c[1] * 100 + c[2] * 10 + c[3] - four,
		.tm_mon = c[5] * 10 + c[6] - two,
		.tm_mday = c[7] * 10 + c[8] - two,
		.tm_hour = c[10] * 10 + c[11] - two,
		.tm_min = c[12] * 10 + c[13] - two
	};
	handle->creation_date = mktime(&created);
#undef c
}

/**
 *	g1m_decode_std_addin:
 *	Decodes a "normal" add-in (after Standard Header).
 *
 *	@arg	handle		the handle.
 *	@arg	buffer		the buffer to read from.
 *	@return				the error code (0 if ok).
 */

int g1m_decode_std_addin(g1m_t *handle, g1m_buffer_t *buffer,
	struct standard_header *std)
{
	int err = 0;
	(void)std;

	/* get the subheader */
	DREAD(hd, g1a_subheader)

	/* correct subheader endianess */
	hd.filesize = be32toh(hd.filesize);

	/* log info about the subheader */
	log_info("internal name is '%.8s'", hd.internal_name);
	log_info("title is '%.8s'", hd.title);
	log_info("estrips count is %" PRIu8, hd.estrips_count);
	log_info("version is %.10s", hd.version);
	log_info("creation date is %.14s", hd.creation_date);

	/* store data in the handle */
	addin_set_data(handle,
		(char*)hd.title, 8,
		(char*)hd.internal_name, 8,
		(char*)hd.version, (char*)hd.creation_date);

	/* allocate space for icon */
	handle->width = G1A_ICON_WIDTH;
	handle->height = G1A_ICON_HEIGHT;
	handle->pixels = alloc_pixels(G1A_ICON_WIDTH, G1A_ICON_HEIGHT);
	if (!handle->pixels) return (g1m_error_alloc);
	prepare_pixels(handle->pixels, G1A_ICON_WIDTH, G1A_ICON_HEIGHT)

	/* fill icon */
	g1m_decode_picture(handle->pixels, g1m_pictureformat_1bit_packed,
		hd.icon, G1A_ICON_WIDTH, G1A_ICON_HEIGHT);

	/* skip size */
	SKIP(hd.filesize - sizeof(struct standard_header)
		- sizeof(struct g1a_subheader))

	/* no errors */
	return (err);
}

/**
 *	g1m_decode_std_addin_cg:
 *	Decode fx-CG add-in (after Standard Header).
 *
 *	@arg	handle		the handle.
 *	@arg	buffer		the buffer to read from.
 *	@arg	std			the standard header.
 *	@return				the error code (0 if ok).
 */

int g1m_decode_std_addin_cg(g1m_t *handle, g1m_buffer_t *buffer,
	struct standard_header *std)
{
	int err = 0;
	/* get the subheader */
	DREAD(hd, addin_cp_subheader)

	/* correct subheader endianness */
	hd.checksum = be32toh(hd.checksum);
	hd.control = be32toh(hd.control);
	hd.filesize = be32toh(hd.filesize);

	/* control byte */
	size_t content_size = hd.filesize - 4
		- hd.magic[1] ? 0x7000 : 0x1000;
	if (hd.control != content_size) {
		log_fatal("control value is incorrect!");
		log_fatal("calculated %" PRIuSIZE ", expected %" PRIu32,
			content_size, hd.control);
		return (g1m_error_magic);
	}

	/* start making checksum */
	uint_fast32_t checksum =
		sizeof(struct standard_header) * 256
			- g1m_checksum32(std, sizeof(struct standard_header), 0)
		+ g1m_checksum32(&hd.magic, sizeof(struct addin_cp_subheader), 0);

	/* read subheader */
	if (hd.magic[1]) { /* is Prizm */
		DREAD(shd, g3a_subheader)

		checksum += g1m_checksum32(&shd, sizeof(struct g3a_subheader), 0);
		handle->pixels = alloc_pixels(G3A_ICON_WIDTH, G3A_ICON_HEIGHT);
		handle->width = G3A_ICON_WIDTH; handle->height = G3A_ICON_HEIGHT;
		if (!handle->pixels) return (g1m_error_alloc);
		prepare_pixels(handle->pixels, G3A_ICON_WIDTH, G3A_ICON_HEIGHT)

		g1m_decode_picture(handle->pixels, g1m_pictureformat_16bit,
			shd.unselected_icon_image, G3A_ICON_WIDTH, G3A_ICON_HEIGHT);
	} else { /* is C1A */
		DREAD(shd, c1a_subheader)

		checksum += g1m_checksum32(&shd, sizeof(struct c1a_subheader), 0);
		handle->pixels = alloc_pixels(C1A_ICON_WIDTH, C1A_ICON_HEIGHT);
		handle->width = C1A_ICON_WIDTH; handle->height = C1A_ICON_HEIGHT;
		if (!handle->pixels) return (g1m_error_alloc);
		prepare_pixels(handle->pixels, C1A_ICON_WIDTH, C1A_ICON_HEIGHT);

		g1m_decode_picture(handle->pixels, g1m_pictureformat_1bit_packed,
			shd.icon, C1A_ICON_WIDTH, C1A_ICON_HEIGHT);
	}

	/* skip content for now */
	if ((err = g1m_skip(buffer, content_size, &checksum)))
		goto fail;

	/* check the sum (yo!) */
	err = g1m_error_magic;
	if (checksum != hd.checksum) {
		log_fatal("Invalid checksum!");
		log_fatal("Header checksum is %" PRIu32
			", calculated checksum is %" PRIuFAST32,
			hd.checksum, checksum);
		goto fail;
	}

	/* log */
	log_info("title is '%.16s'", hd.title);
	log_info("internal name is '%.11s'", hd.internal_name);
	log_info("version is '%.10s'", hd.version);
	log_info("timestamp is '%.14s'", hd.stamp);

	/* store basic data in the handle */
	addin_set_data(handle,
		(char*)hd.title, 16,
		(char*)hd.internal_name, 12,
		(char*)hd.version, (char*)hd.stamp);

	/* no error */
	return (0);
fail:
	free(handle->pixels);
	return (err);
}