/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 */

#include "glk/frotz/detection.h"
#include "glk/frotz/detection_tables.h"
#include "glk/frotz/quetzal.h"
#include "common/debug.h"
#include "common/file.h"
#include "common/md5.h"
#include "common/translation.h"

namespace Glk {
namespace Frotz {

void FrotzMetaEngine::getSupportedGames(PlainGameList &games) {
	for (const PlainGameDescriptor *pd = FROTZ_GAME_LIST; pd->gameId; ++pd)
		games.push_back(*pd);
}

PlainGameDescriptor FrotzMetaEngine::findGame(const char *gameId) {
	for (const PlainGameDescriptor *pd = FROTZ_GAME_LIST; pd->gameId; ++pd) {
		if (!strcmp(gameId, pd->gameId))
			return *pd;
	}

	return PlainGameDescriptor();;
}

bool FrotzMetaEngine::detectGames(const Common::FSList &fslist, DetectedGames &gameList) {
	const char *const EXTENSIONS[11] = { ".z1", ".z2", ".z3", ".z4", ".z5", ".z6", ".z7", ".z8", ".zblorb", ".dat", ".zip" };

	// Loop through the files of the folder
	for (Common::FSList::const_iterator file = fslist.begin(); file != fslist.end(); ++file) {
		// Check for a recognised filename
		if (file->isDirectory())
			continue;
		Common::String filename = file->getName();
		bool hasExt = false;
		for (int idx = 0; idx < 11 && !hasExt; ++idx)
			hasExt = filename.hasSuffixIgnoreCase(EXTENSIONS[idx]);
		if (!hasExt)
			continue;

		// Open up the file and calculate the md5
		Common::File gameFile;
		if (!gameFile.open(*file))
			continue;
		Common::String md5 = Common::computeStreamMD5AsString(gameFile, 5000);
		size_t filesize = gameFile.size();
		char serial[7] = "unkown";
		if (!filename.hasSuffixIgnoreCase(".zblorb")) {
			gameFile.seek(18);
			gameFile.read(&serial[0], 6);
		}
		gameFile.close();

		// Check for known games. Note that there has been some variation in exact filesizes
		// for Infocom games due to padding at the end of files. So we match on md5s for the
		// first 5Kb, and only worry about filesize for more recent Blorb based Zcode games
		const FrotzGameDescription *p = FROTZ_GAMES;
		while (p->_gameId && p->_md5 && (md5 != p->_md5 ||
				(filesize != p->_filesize && filename.hasSuffix(".zblorb"))))
			++p;

		DetectedGame gd;
		if (!p->_gameId) {
			// Generic .dat/.zip files don't get reported as matches unless they have a known md5
			if (filename.hasSuffixIgnoreCase(".dat") || filename.hasSuffixIgnoreCase(".zip"))
				continue;

			if (gDebugLevel > 0) {
				// Print an entry suitable for putting into the detection_tables.h, using the
				// name of the parent folder the game is in as the presumed game Id
				Common::String folderName = file->getParent().getName();
				if (folderName.hasSuffix("\\"))
					folderName.deleteLastChar();
				Common::String fname = filename;
				const char *dot = strchr(fname.c_str(), '.');
				if (dot)
					fname = Common::String(fname.c_str(), dot);

				debug("ENTRY0(\"%s\", \"%s-%s\", \"%s\", %u),",
					folderName.c_str(), fname.c_str(), serial, md5.c_str(), (uint)filesize);
			}
			const PlainGameDescriptor &desc = FROTZ_GAME_LIST[0];
			gd = DetectedGame(desc.gameId, desc.description, Common::UNK_LANG, Common::kPlatformUnknown);
		} else {
			PlainGameDescriptor gameDesc = findGame(p->_gameId);
			gd = DetectedGame(p->_gameId, gameDesc.description, p->_language, Common::kPlatformUnknown, p->_extra);
			gd.setGUIOptions(p->_guiOptions);
		}

		gd.addExtraEntry("filename", filename);
		gameList.push_back(gd);
	}

	return !gameList.empty();
}

bool FrotzMetaEngine::readSavegameHeader(Common::SeekableReadStream *stream, Glk::SavegameHeader &header) {
	stream->seek(0);
	if (stream->readUint32BE() != ID_FORM)
		return false;
	stream->readUint32BE();
	if (stream->readUint32BE() != ID_IFZS)
		return false;

	header._interpType = INTERPRETER_FROTZ;
	header._saveName = _("Unnamed savegame");

	while (stream->pos() < stream->size()) {
		uint type = stream->readUint32BE();
		size_t len = stream->readUint32BE();

		if (type == ID_ANNO) {
			// Read savegame name from the annotation chunk
			char *buffer = new char[len + 1];
			stream->read(buffer, len);
			buffer[len] = '\0';
			header._saveName = Common::String(buffer);
			break;

		} else {
			if (len & 1)
				// Length must be even
				++len;
			stream->skip(len);
		}
	}

	stream->seek(0);
	return true;
}

} // End of namespace Frotz
} // End of namespace Glk