/* 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 "base/plugins.h"

#include "common/archive.h"
#include "common/config-manager.h"
#include "common/fs.h"
#include "common/list.h"
#include "common/md5.h"
#include "common/savefile.h"
#include "common/system.h"
#include "common/translation.h"

#include "audio/mididrv.h"

#include "scumm/detection.h"
#include "scumm/detection_tables.h"
#include "scumm/he/intern_he.h"
#include "scumm/scumm_v0.h"
#include "scumm/scumm_v8.h"
#include "scumm/file.h"
#include "scumm/file_nes.h"
#include "scumm/resource.h"

#include "engines/metaengine.h"


namespace Scumm {

enum {
	// We only compute the MD5 of the first megabyte of our data files.
	kMD5FileSizeLimit = 1024 * 1024
};

#pragma mark -
#pragma mark --- Miscellaneous ---
#pragma mark -

static int compareMD5Table(const void *a, const void *b) {
	const char *key = (const char *)a;
	const MD5Table *elem = (const MD5Table *)b;
	return strcmp(key, elem->md5);
}

static const MD5Table *findInMD5Table(const char *md5) {
	uint32 arraySize = ARRAYSIZE(md5table) - 1;
	return (const MD5Table *)bsearch(md5, md5table, arraySize, sizeof(MD5Table), compareMD5Table);
}

Common::String ScummEngine::generateFilename(const int room) const {
	const int diskNumber = (room > 0) ? _res->_types[rtRoom][room]._roomno : 0;
	Common::String result;

	if (_game.version == 4) {
		if (room == 0 || room >= 900) {
			result = Common::String::format("%03d.lfl", room);
		} else {
			result = Common::String::format("disk%02d.lec", diskNumber);
		}
	} else {
		switch (_filenamePattern.genMethod) {
		case kGenDiskNum:
		case kGenDiskNumSteam:
			result = Common::String::format(_filenamePattern.pattern, diskNumber);
			break;

		case kGenRoomNum:
		case kGenRoomNumSteam:
			result = Common::String::format(_filenamePattern.pattern, room);
			break;

		case kGenUnchanged:
			result = _filenamePattern.pattern;
			break;

		default:
			error("generateFilename: Unsupported genMethod");
		}
	}

	return result;
}

Common::String ScummEngine_v60he::generateFilename(const int room) const {
	Common::String result;
	char id = 0;

	switch (_filenamePattern.genMethod) {
	case kGenHEMac:
	case kGenHEMacNoParens:
	case kGenHEPC:
		if (room < 0) {
			id = '0' - room;
		} else {
			const int diskNumber = (room > 0) ? _res->_types[rtRoom][room]._roomno : 0;
			id = diskNumber + '0';
		}

		if (_filenamePattern.genMethod == kGenHEPC) {
			result = Common::String::format("%s.he%c", _filenamePattern.pattern, id);
		} else {
			if (id == '3') { // Special case for cursors.
				// For mac they're stored in game binary.
				result = _filenamePattern.pattern;
			} else {
				if (_filenamePattern.genMethod == kGenHEMac)
					result = Common::String::format("%s (%c)", _filenamePattern.pattern, id);
				else
					result = Common::String::format("%s %c", _filenamePattern.pattern, id);
			}
		}

		break;

	default:
		// Fallback to parent method.
		return ScummEngine::generateFilename(room);
	}

	return result;
}

Common::String ScummEngine_v70he::generateFilename(const int room) const {
	Common::String result;
	char id = 0;

	Common::String bPattern = _filenamePattern.pattern;

	// Special cases for Blue's games, which share common (b) files.
	if (_game.id == GID_BIRTHDAYYELLOW || _game.id == GID_BIRTHDAYRED)
		bPattern = "Blue'sBirthday";
	else if (_game.id == GID_TREASUREHUNT)
		bPattern = "Blue'sTreasureHunt";

	switch (_filenamePattern.genMethod) {
	case kGenHEMac:
	case kGenHEMacNoParens:
	case kGenHEPC:
	case kGenHEIOS:
		if (_game.heversion >= 98 && room >= 0) {
			int disk = 0;
			if (_heV7DiskOffsets)
				disk = _heV7DiskOffsets[room];

			switch (disk) {
			case 2:
				id = 'b';
				result = bPattern + ".(b)";
				break;
			case 1:
				id = 'a';
				// Some of the newer HE games for iOS use the ".hea" suffix instead.
				if (_filenamePattern.genMethod == kGenHEIOS)
					result = Common::String::format("%s.hea", _filenamePattern.pattern);
				else
					result = Common::String::format("%s.(a)", _filenamePattern.pattern);
				break;
			default:
				id = '0';
				result = Common::String::format("%s.he0", _filenamePattern.pattern);
			}
		} else if (room < 0) {
			id = '0' - room;
		} else {
			id = (room == 0) ? '0' : '1';
		}

		if (_filenamePattern.genMethod == kGenHEPC || _filenamePattern.genMethod == kGenHEIOS) {
			if (id == '3' && _game.id == GID_MOONBASE) {
				result = Common::String::format("%s.u32", _filenamePattern.pattern);
				break;
			}

			// For HE >= 98, we already called snprintf above.
			if (_game.heversion < 98 || room < 0)
				result = Common::String::format("%s.he%c", _filenamePattern.pattern, id);
		} else {
			if (id == '3') { // Special case for cursors.
				// For mac they're stored in game binary.
				result = _filenamePattern.pattern;
			} else {
				Common::String pattern = id == 'b' ? bPattern : _filenamePattern.pattern;
				if (_filenamePattern.genMethod == kGenHEMac)
					result = Common::String::format("%s (%c)", pattern.c_str(), id);
				else
					result = Common::String::format("%s %c", pattern.c_str(), id);
			}
		}

		break;

	default:
		// Fallback to parent method.
		return ScummEngine_v60he::generateFilename(room);
	}

	return result;
}

// The following table includes all the index files, which are embedded in the
// main game executables in Steam versions.
static const SteamIndexFile steamIndexFiles[] = {
	{ GID_INDY3, Common::kPlatformWindows,   "%02d.LFL",      "00.LFL",        "Indiana Jones and the Last Crusade.exe",     162056,  6295 },
	{ GID_INDY3, Common::kPlatformMacintosh, "%02d.LFL",      "00.LFL",        "The Last Crusade",                           150368,  6295 },
	{ GID_INDY4, Common::kPlatformWindows,   "atlantis.%03d", "ATLANTIS.000",  "Indiana Jones and the Fate of Atlantis.exe", 224336, 12035 },
	{ GID_INDY4, Common::kPlatformMacintosh, "atlantis.%03d", "ATLANTIS.000",  "The Fate of Atlantis",                       260224, 12035 },
	{ GID_LOOM,  Common::kPlatformWindows,   "%03d.LFL",      "000.LFL",       "Loom.exe",                                   187248,  8307 },
	{ GID_LOOM,  Common::kPlatformMacintosh, "%03d.LFL",      "000.LFL",       "Loom",                                       170464,  8307 },
#ifdef ENABLE_SCUMM_7_8
	{ GID_DIG,   Common::kPlatformWindows,   "dig.la%d",      "DIG.LA0",       "The Dig.exe",                                340632, 16304 },
	{ GID_DIG,   Common::kPlatformMacintosh, "dig.la%d",      "DIG.LA0",       "The Dig",                                    339744, 16304 },
#endif
	{ 0,         Common::kPlatformUnknown,   nullptr,         nullptr,         nullptr,                                           0,     0 }
};

const SteamIndexFile *lookUpSteamIndexFile(Common::String pattern, Common::Platform platform) {
	for (const SteamIndexFile *indexFile = steamIndexFiles; indexFile->len; ++indexFile) {
		if (platform == indexFile->platform && pattern.equalsIgnoreCase(indexFile->pattern))
			return indexFile;
	}

	return nullptr;
}

static Common::String generateFilenameForDetection(const char *pattern, FilenameGenMethod genMethod, Common::Platform platform) {
	Common::String result;

	switch (genMethod) {
	case kGenDiskNum:
	case kGenRoomNum:
		result = Common::String::format(pattern, 0);
		break;

	case kGenDiskNumSteam:
	case kGenRoomNumSteam: {
		const SteamIndexFile *indexFile = lookUpSteamIndexFile(pattern, platform);
		if (!indexFile) {
			error("Unable to find Steam executable from detection pattern");
		} else {
			result = indexFile->executableName;
		}
		} break;

	case kGenHEPC:
	case kGenHEIOS:
		result = Common::String::format("%s.he0", pattern);
		break;

	case kGenHEMac:
		result = Common::String::format("%s (0)", pattern);
		break;

	case kGenHEMacNoParens:
		result = Common::String::format("%s 0", pattern);
		break;

	case kGenUnchanged:
		result = pattern;
		break;

	default:
		error("generateFilenameForDetection: Unsupported genMethod");
	}

	return result;
}

bool ScummEngine::isMacM68kIMuse() const {
	return _game.platform == Common::kPlatformMacintosh && (_game.id == GID_MONKEY2 || _game.id == GID_INDY4) && !(_game.features & GF_MAC_CONTAINER);
}

struct DetectorDesc {
	Common::FSNode node;
	Common::String md5;
	const MD5Table *md5Entry;	// Entry of the md5 table corresponding to this file, if any.
};

typedef Common::HashMap<Common::String, DetectorDesc, Common::IgnoreCase_Hash, Common::IgnoreCase_EqualTo> DescMap;

static bool testGame(const GameSettings *g, const DescMap &fileMD5Map, const Common::String &file);


// Search for a node with the given "name", inside fslist. Ignores case
// when performing the matching. The first match is returned, so if you
// search for "resource" and two nodes "RESOURE and "resource" are present,
// the first match is used.
static bool searchFSNode(const Common::FSList &fslist, const Common::String &name, Common::FSNode &result) {
	for (Common::FSList::const_iterator file = fslist.begin(); file != fslist.end(); ++file) {
		if (!scumm_stricmp(file->getName().c_str(), name.c_str())) {
			result = *file;
			return true;
		}
	}
	return false;
}

static BaseScummFile *openDiskImage(const Common::FSNode &node, const GameFilenamePattern *gfp) {
	Common::String disk1 = node.getName();
	BaseScummFile *diskImg;

	SearchMan.addDirectory("tmpDiskImgDir", node.getParent());

	if (disk1.hasSuffix(".prg")) { // NES
		diskImg = new ScummNESFile();
	} else { // C64 or Apple //gs
		// setup necessary game settings for disk image reader
		GameSettings gs;
		memset(&gs, 0, sizeof(GameSettings));
		gs.gameid = gfp->gameid;
		gs.id = (Common::String(gfp->gameid) == "maniac" ? GID_MANIAC : GID_ZAK);
		gs.platform = gfp->platform;
		if (strcmp(gfp->pattern, "maniacdemo.d64") == 0)
			gs.features |= GF_DEMO;

		// Determine second disk file name.
		Common::String disk2(disk1);
		for (Common::String::iterator it = disk2.begin(); it != disk2.end(); ++it) {
			// replace "xyz1.(d64|dsk)" by "xyz2.(d64|dsk)"
			if (*it == '1') {
				*it = '2';
				break;
			}
		}

		// Open image.
		diskImg = new ScummDiskImage(disk1.c_str(), disk2.c_str(), gs);
	}

	if (diskImg->open(disk1.c_str()) && diskImg->openSubFile("00.LFL")) {
		debug(0, "Success");
		return diskImg;
	}
	delete diskImg;
	return 0;
}

static void closeDiskImage(ScummDiskImage *img) {
	if (img)
		img->close();
	SearchMan.remove("tmpDiskImgDir");
}

/*
 * This function tries to detect if a speech file exists.
 * False doesn't necessarily mean there are no speech files.
 */
static bool detectSpeech(const Common::FSList &fslist, const GameSettings *gs) {
	if (gs->id == GID_MONKEY || gs->id == GID_MONKEY2) {
		// FM-TOWNS monkey and monkey2 games don't have speech but may have .sou files.
		if (gs->platform == Common::kPlatformFMTowns)
			return false;

		const char *const basenames[] = { gs->gameid, "monster", 0 };
		static const char *const extensions[] = { "sou",
#ifdef USE_FLAC
		 "sof",
#endif
#ifdef USE_VORBIS
		 "sog",
#endif
#ifdef USE_MAD
		 "so3",
#endif
		 0 };

		for (Common::FSList::const_iterator file = fslist.begin(); file != fslist.end(); ++file) {
			if (file->isDirectory())
				continue;

			for (int i = 0; basenames[i]; ++i) {
				Common::String basename = Common::String(basenames[i]) + ".";

				for (int j = 0; extensions[j]; ++j) {
					if ((basename + extensions[j]).equalsIgnoreCase(file->getName()))
						return true;
				}
			}
		}
	}
	return false;
}

// The following function tries to detect the language for COMI and DIG.
static Common::Language detectLanguage(const Common::FSList &fslist, byte id) {
	// First try to detect Chinese translation.
	Common::FSNode fontFile;

	if (searchFSNode(fslist, "chinese_gb16x12.fnt", fontFile)) {
		debug(0, "Chinese detected");
		return Common::ZH_CNA;
	}

	// Now try to detect COMI and Dig by language files.
	if (id != GID_CMI && id != GID_DIG)
		return Common::UNK_LANG;

	// Check for LANGUAGE.BND (Dig) resp. LANGUAGE.TAB (CMI).
	// These are usually inside the "RESOURCE" subdirectory.
	// If found, we match based on the file size (should we
	// ever determine that this is insufficient, we can still
	// switch to MD5 based detection).
	const char *filename = (id == GID_CMI) ? "LANGUAGE.TAB" : "LANGUAGE.BND";
	Common::File tmp;
	Common::FSNode langFile;
	if (searchFSNode(fslist, filename, langFile))
		tmp.open(langFile);
	if (!tmp.isOpen()) {
		// Try loading in RESOURCE sub dir.
		Common::FSNode resDir;
		Common::FSList tmpList;
		if (searchFSNode(fslist, "RESOURCE", resDir)
			&& resDir.isDirectory()
			&& resDir.getChildren(tmpList, Common::FSNode::kListFilesOnly)
			&& searchFSNode(tmpList, filename, langFile)) {
			tmp.open(langFile);
		}
		// The Steam version of Dig has the LANGUAGE.BND in the DIG sub dir.
		if (!tmp.isOpen()
			&& id == GID_DIG
			&& searchFSNode(fslist, "DIG", resDir)
			&& resDir.isDirectory()
			&& resDir.getChildren(tmpList, Common::FSNode::kListFilesOnly)
			&& searchFSNode(tmpList, filename, langFile)) {
			tmp.open(langFile);
		}
	}
	if (tmp.isOpen()) {
		uint size = tmp.size();
		if (id == GID_CMI) {
			switch (size) {
			case 439080:	// 2daf3db71d23d99d19fc9a544fcf6431
				return Common::EN_ANY;
			case 322602:	// caba99f4f5a0b69963e5a4d69e6f90af
				return Common::ZH_TWN;
			case 493252:	// 5d59594b24f3f1332e7d7e17455ed533
				return Common::DE_DEU;
			case 461746:	// 35bbe0e4d573b318b7b2092c331fd1fa
				return Common::FR_FRA;
			case 443439:	// 4689d013f67aabd7c35f4fd7c4b4ad69
				return Common::IT_ITA;
			case 398613:	// d1f5750d142d34c4c8f1f330a1278709
				return Common::KO_KOR;
			case 440586:	// 5a1d0f4fa00917bdbfe035a72a6bba9d
				return Common::PT_BRA;
			case 454457:	// 0e5f450ec474a30254c0e36291fb4ebd
			case 394083:	// ad684ca14c2b4bf4c21a81c1dbed49bc
				return Common::RU_RUS;
			case 449787:	// 64f3fe479d45b52902cf88145c41d172
				return Common::ES_ESP;
			default:
				break;
			}
		} else { // The DIG
			switch (size) {
			case 248627:	// 1fd585ac849d57305878c77b2f6c74ff
				return Common::DE_DEU;
			case 257460:	// 04cf6a6ba6f57e517bc40eb81862cfb0
				return Common::FR_FRA;
			case 231402:	// 93d13fcede954c78e65435592182a4db
				return Common::IT_ITA;
			case 228772:	// 5d9ad90d3a88ea012d25d61791895ebe
				return Common::PT_BRA;
			case 229884:	// d890074bc15c6135868403e73c5f4f36
				return Common::ES_ESP;
			case 223107:	// 64f3fe479d45b52902cf88145c41d172
				return Common::JA_JPN;
			case 180730:	// 424fdd60822722cdc75356d921dad9bf
				return Common::ZH_TWN;
			default:
				break;
			}
		}
	}

	return Common::UNK_LANG;
}


static void computeGameSettingsFromMD5(const Common::FSList &fslist, const GameFilenamePattern *gfp, const MD5Table *md5Entry, DetectorResult &dr) {
	dr.language = md5Entry->language;
	dr.extra = md5Entry->extra;

	// Compute the precise game settings using gameVariantsTable.
	for (const GameSettings *g = gameVariantsTable; g->gameid; ++g) {
		if (g->gameid[0] == 0 || !scumm_stricmp(md5Entry->gameid, g->gameid)) {
			// The gameid either matches, or is empty. The latter indicates
			// a generic entry, currently used for some generic HE settings.
			if (g->variant == 0 || !scumm_stricmp(md5Entry->variant, g->variant)) {
				// Perfect match found, use it and stop the loop.
				dr.game = *g;
				dr.game.gameid = md5Entry->gameid;

				// Set the platform value. The value from the MD5 record has
				// highest priority; if missing (i.e. set to unknown) we try
				// to use that from the filename pattern record instead.
				if (md5Entry->platform != Common::kPlatformUnknown) {
					dr.game.platform = md5Entry->platform;
				} else if (gfp->platform != Common::kPlatformUnknown) {
					dr.game.platform = gfp->platform;
				}

				// HACK: Special case to distinguish the V1 demo from the full version
				// (since they have identical MD5).
				if (dr.game.id == GID_MANIAC && !strcmp(gfp->pattern, "%02d.MAN")) {
					dr.extra = "V1 Demo";
					dr.game.features = GF_DEMO;
				}

				// HACK: Try to detect languages for translated games.
				if (dr.language == UNK_LANG) {
					dr.language = detectLanguage(fslist, dr.game.id);
				}

				// HACK: Detect between 68k and PPC versions.
				if (dr.game.platform == Common::kPlatformMacintosh && dr.game.version >= 5 && dr.game.heversion == 0 && strstr(gfp->pattern, "Data"))
					dr.game.features |= GF_MAC_CONTAINER;

				break;
			}
		}
	}
}

static void composeFileHashMap(DescMap &fileMD5Map, const Common::FSList &fslist, int depth, const char *const *globs) {
	if (depth <= 0)
		return;

	if (fslist.empty())
		return;

	for (Common::FSList::const_iterator file = fslist.begin(); file != fslist.end(); ++file) {
		if (!file->isDirectory()) {
			DetectorDesc d;
			d.node = *file;
			d.md5Entry = 0;
			fileMD5Map[file->getName()] = d;
		} else {
			if (!globs)
				continue;

			bool matched = false;
			for (const char *const *glob = globs; *glob; glob++)
				if (file->getName().matchString(*glob, true)) {
					matched = true;
					break;
				}

			if (!matched)
				continue;

			Common::FSList files;
			if (file->getChildren(files, Common::FSNode::kListAll)) {
				composeFileHashMap(fileMD5Map, files, depth - 1, globs);
			}
		}
	}
}

static void detectGames(const Common::FSList &fslist, Common::List<DetectorResult> &results, const char *gameid) {
	DescMap fileMD5Map;
	DetectorResult dr;

	// Dive one level down since mac indy3/loom have their files split into directories. See Bug #1438631.
	// Dive two levels down for Mac Steam games.
	composeFileHashMap(fileMD5Map, fslist, 3, directoryGlobs);

	// Iterate over all filename patterns.
	for (const GameFilenamePattern *gfp = gameFilenamesTable; gfp->gameid; ++gfp) {
		// If a gameid was specified, we only try to detect that specific game,
		// so we can just skip over everything with a differing gameid.
		if (gameid && scumm_stricmp(gameid, gfp->gameid))
			continue;

		// Generate the detectname corresponding to the gfp. If the file doesn't
		// exist in the directory we are looking at, we can skip to the next
		// one immediately.
		Common::String file(generateFilenameForDetection(gfp->pattern, gfp->genMethod, gfp->platform));
		if (!fileMD5Map.contains(file))
			continue;

		// Reset the DetectorResult variable.
		dr.fp.pattern = gfp->pattern;
		dr.fp.genMethod = gfp->genMethod;
		dr.game.gameid = 0;
		dr.language = gfp->language;
		dr.md5.clear();
		dr.extra = 0;

		//  ____            _     _
		// |  _ \ __ _ _ __| |_  / |
		// | |_) / _` | '__| __| | |
		// |  __/ (_| | |  | |_  | |
		// |_|   \__,_|_|   \__| |_|
		//
		// PART 1: Trying to find an exact match using MD5.
		//
		//
		// Background: We found a valid detection file. Check if its MD5
		// checksum occurs in our MD5 table. If it does, try to use that
		// to find an exact match.
		//
		// We only do that if the MD5 hadn't already been computed (since
		// we may look at some detection files multiple times).
		DetectorDesc &d = fileMD5Map[file];
		if (d.md5.empty()) {
			Common::SeekableReadStream *tmp = 0;
			bool isDiskImg = (file.hasSuffix(".d64") || file.hasSuffix(".dsk") || file.hasSuffix(".prg"));

			if (isDiskImg) {
				tmp = openDiskImage(d.node, gfp);

				debug(2, "Falling back to disk-based detection");
			} else {
				tmp = d.node.createReadStream();
			}

			Common::String md5str;
			if (tmp)
				md5str = computeStreamMD5AsString(*tmp, kMD5FileSizeLimit);
			if (!md5str.empty()) {

				d.md5 = md5str;
				d.md5Entry = findInMD5Table(md5str.c_str());

				dr.md5 = d.md5;

				if (d.md5Entry) {
					// Exact match found. Compute the precise game settings.
					computeGameSettingsFromMD5(fslist, gfp, d.md5Entry, dr);

					// Print some debug info.
					int filesize = tmp->size();
					debug(1, "SCUMM detector found matching file '%s' with MD5 %s, size %d\n",
						file.c_str(), md5str.c_str(), filesize);

					// Sanity check: We *should* have found a matching gameid/variant at this point.
					// If not, we may have #ifdef'ed the entry out in our detection_tables.h, because we
					// don't have the required stuff compiled in, or there's a bug in our data tables.
					if (dr.game.gameid != 0)
						// Add it to the list of detected games.
						results.push_back(dr);
				}
			}

			if (isDiskImg)
				closeDiskImage((ScummDiskImage *)tmp);
			delete tmp;
		}

		// If an exact match for this file has already been found, don't bother
		// looking at it anymore.
		if (d.md5Entry)
			continue;

		// Prevent executables being detected as Steam variant. If we don't
		// know the md5, then it's just the regular executable. Otherwise we
		// will most likely fail on trying to read the index from the executable.
		// Fixes bug #10290.
		if (gfp->genMethod == kGenRoomNumSteam || gfp->genMethod == kGenDiskNumSteam)
			continue;

		//  ____            _     ____
		// |  _ \ __ _ _ __| |_  |___ \ *
		// | |_) / _` | '__| __|   __) |
		// |  __/ (_| | |  | |_   / __/
		// |_|   \__,_|_|   \__| |_____|
		//
		// PART 2: Fuzzy matching for files with unknown MD5.
		//
		//
		// We loop over the game variants matching the gameid associated to
		// the gfp record. We then try to decide for each whether it could be
		// appropriate or not.
		dr.md5 = d.md5;
		for (const GameSettings *g = gameVariantsTable; g->gameid; ++g) {
			// Skip over entries with a different gameid.
			if (g->gameid[0] == 0 || scumm_stricmp(gfp->gameid, g->gameid))
				continue;

			dr.game = *g;
			dr.extra = g->variant; // FIXME: We (ab)use 'variant' for the 'extra' description for now.

			if (gfp->platform != Common::kPlatformUnknown)
				dr.game.platform = gfp->platform;


			// If a variant has been specified, use that!
			if (gfp->variant) {
				if (!scumm_stricmp(gfp->variant, g->variant)) {
					// Perfect match found.
					results.push_back(dr);
					break;
				}
				continue;
			}

			// HACK: Perhaps it is some modified translation?
			dr.language = detectLanguage(fslist, g->id);

			// Detect if there are speech files in this unknown game.
			if (detectSpeech(fslist, g)) {
				if (strchr(dr.game.guioptions, GUIO_NOSPEECH[0]) != NULL) {
					if (g->id == GID_MONKEY || g->id == GID_MONKEY2)
						// TODO: This may need to be updated if something important gets added
						// in the top detection table for these game ids.
						dr.game.guioptions = GUIO0();
					else
						warning("FIXME: fix NOSPEECH fallback");
				}
			}

			// Add the game/variant to the candidates list if it is consistent
			// with the file(s) we are seeing.
			if (testGame(g, fileMD5Map, file))
				results.push_back(dr);
		}
	}
}

static bool testGame(const GameSettings *g, const DescMap &fileMD5Map, const Common::String &file) {
	const DetectorDesc &d = fileMD5Map[file];

	// At this point, we know that the gameid matches, but no variant
	// was specified, yet there are multiple ones. So we try our best
	// to distinguish between the variants.
	// To do this, we take a close look at the detection file and
	// try to filter out some cases.

	Common::File tmp;
	if (!tmp.open(d.node)) {
		warning("SCUMM testGame: failed to open '%s' for read access", d.node.getPath().c_str());
		return false;
	}

	if (file == "maniac1.d64" || file == "maniac1.dsk" || file == "zak1.d64") {
		// TODO
	} else if (file == "00.LFL") {
		// Used in V1, V2, V3 games.
		if (g->version > 3)
			return false;

		// Read a few bytes to narrow down the game.
		byte buf[6];
		tmp.read(buf, 6);

		if (buf[0] == 0xbc && buf[1] == 0xb9) {
			// The NES version of MM.
			if (g->id == GID_MANIAC && g->platform == Common::kPlatformNES) {
				// Perfect match.
				return true;
			}
		} else if ((buf[0] == 0xCE && buf[1] == 0xF5) || // PC
			(buf[0] == 0xCD && buf[1] == 0xFE)) {    // Commodore 64
			// Could be V0 or V1.
			// Candidates: maniac classic, zak classic.

			if (g->version >= 2)
				return false;

			// Zak has 58.LFL, Maniac doesn't.
			const bool has58LFL = fileMD5Map.contains("58.LFL");
			if (g->id == GID_MANIAC && !has58LFL) {
			} else if (g->id == GID_ZAK && has58LFL) {
			} else
				return false;
		} else if (buf[0] == 0xFF && buf[1] == 0xFE) {
			// GF_OLD_BUNDLE: could be V2 or old V3.
			// Note that GF_OLD_BUNDLE is true if and only if GF_OLD256 is false.
			// Candidates: maniac enhanced, zak enhanced, indy3ega, loom.

			if ((g->version != 2 && g->version != 3)  || (g->features & GF_OLD256))
				return false;

			/* We distinguish the games by the presence/absence of
			   certain files. In the following, '+' means the file
			   present, '-' means the file is absent.

			   maniac:    -58.LFL, -84.LFL,-86.LFL, -98.LFL

			   zak:       +58.LFL, -84.LFL,-86.LFL, -98.LFL
			   zakdemo:   +58.LFL, -84.LFL,-86.LFL, -98.LFL

			   loom:      +58.LFL, -84.LFL,+86.LFL, -98.LFL
			   loomdemo:  -58.LFL, +84.LFL,-86.LFL, -98.LFL

			   indy3:     +58.LFL, +84.LFL,+86.LFL, +98.LFL
			   indy3demo: -58.LFL, +84.LFL,-86.LFL, +98.LFL
			*/
			const bool has58LFL = fileMD5Map.contains("58.LFL");
			const bool has84LFL = fileMD5Map.contains("84.LFL");
			const bool has86LFL = fileMD5Map.contains("86.LFL");
			const bool has98LFL = fileMD5Map.contains("98.LFL");

			if (g->id == GID_INDY3         && has98LFL && has84LFL) {
			} else if (g->id == GID_ZAK    && !has98LFL && !has86LFL && !has84LFL && has58LFL) {
			} else if (g->id == GID_MANIAC && !has98LFL && !has86LFL && !has84LFL && !has58LFL) {
			} else if (g->id == GID_LOOM   && !has98LFL && (has86LFL != has84LFL)) {
			} else
				return false;
		} else if (buf[4] == '0' && buf[5] == 'R') {
			// Newer V3 game.
			// Candidates: indy3, indy3Towns, zakTowns, loomTowns.

			if (g->version != 3 || !(g->features & GF_OLD256))
				return false;

			/*
			Considering that we know about *all* TOWNS versions, and
			know their MD5s, we could simply rely on this and if we find
			something which has an unknown MD5, assume that it is an (so
			far unknown) version of Indy3. However, there are also fan
			translations of the TOWNS versions, so we can't do that.

			But we could at least look at the resource headers to distinguish
			TOWNS versions from regular games:

			Indy3:
			_numGlobalObjects 1000
			_numRooms 99
			_numCostumes 129
			_numScripts 139
			_numSounds 84

			Indy3Towns, ZakTowns, ZakLoom demo:
			_numGlobalObjects 1000
			_numRooms 99
			_numCostumes 199
			_numScripts 199
			_numSounds 199

			Assuming that all the town variants look like the latter, we can
			do the check like this:
			  if (numScripts == 139)
				assume Indy3
			  else if (numScripts == 199)
				assume towns game
			  else
				unknown, do not accept it
			*/

			// We now try to exclude various possibilities by the presence of certain
			// LFL files. Note that we only exclude something based on the *presence*
			// of a LFL file here; compared to checking for the absence of files, this
			// has the advantage that we are less likely to accidentally exclude demos
			// (which, after all, are usually missing many LFL files present in the
			// full version of the game).

			// No version of Indy3 has 05.LFL but MM, Loom and Zak all have it.
			if (g->id == GID_INDY3 && fileMD5Map.contains("05.LFL"))
				return false;

			// All versions of Indy3 have 93.LFL, but no other game does.
			if (g->id != GID_INDY3 && fileMD5Map.contains("93.LFL"))
				return false;

			// No version of Loom has 48.LFL.
			if (g->id == GID_LOOM && fileMD5Map.contains("48.LFL"))
				return false;

			// No version of Zak has 60.LFL, but most (non-demo) versions of Indy3 have it.
			if (g->id == GID_ZAK && fileMD5Map.contains("60.LFL"))
				return false;

			// All versions of Indy3 and ZakTOWNS have 98.LFL, but no other game does.
			if (g->id == GID_LOOM && g->platform != Common::kPlatformPCEngine && fileMD5Map.contains("98.LFL"))
				return false;


		} else {
			// TODO: Unknown file header, deal with it. Maybe an unencrypted
			// variant...
			// Anyway, we don't know how to deal with the file, so we
			// just skip it.
		}
	} else if (file == "000.LFL") {
		// Used in V4.
		// Candidates: monkeyEGA, pass, monkeyVGA, loomcd.

		if (g->version != 4)
			return false;

		/*
		For all of them, we have:
		_numGlobalObjects 1000
		_numRooms 99
		_numCostumes 199
		_numScripts 199
		_numSounds 199

		Any good ideas to distinguish those? Maybe by the presence/absence
		of some files?
		At least PASS and the monkeyEGA demo differ by 903.LFL missing.
		And the count of DISK??.LEC files differ depending on what version
		you have (4 or 8 floppy versions).
		loomcd of course shipped on only one "disc".

		pass: 000.LFL, 901.LFL, 902.LFL, 904.LFL, disk01.lec
		monkeyEGA:  000.LFL, 901-904.LFL, DISK01-09.LEC
		monkeyEGA DEMO: 000.LFL, 901.LFL, 902.LFL, 904.LFL, disk01.lec
		monkeyVGA: 000.LFL, 901-904.LFL, DISK01-04.LEC
		loomcd: 000.LFL, 901-904.LFL, DISK01.LEC
		*/

		const bool has903LFL = fileMD5Map.contains("903.LFL");
		const bool hasDisk02 = fileMD5Map.contains("DISK02.LEC");

		// There is not much we can do based on the presence/absence
		// of files. Only that if 903.LFL is present, it can't be PASS;
		// and if DISK02.LEC is present, it can't be LoomCD.
		if (g->id == GID_PASS              && !has903LFL && !hasDisk02) {
		} else if (g->id == GID_LOOM       &&  has903LFL && !hasDisk02) {
		} else if (g->id == GID_MONKEY_VGA) {
		} else if (g->id == GID_MONKEY_EGA) {
		} else
			return false;
	} else {
		// Must be a V5+ game.
		if (g->version < 5)
			return false;

		// At this point the gameid is determined, but not necessarily
		// the variant!

		// TODO: Add code that handles this, at least for the non-HE games.
		// Not sure how realistic it is to correctly detect HE game
		// variants, would require me to look at a sufficiently large
		// sample collection of HE games (assuming I had the time :).

		// TODO: For Mac versions in container file, we can sometimes
		// distinguish the demo from the regular version by looking
		// at the content of the container file and then looking for
		// the *.000 file in there.
	}

	return true;
}


} // End of namespace Scumm

#pragma mark -
#pragma mark --- Plugin code ---
#pragma mark -


using namespace Scumm;

class ScummMetaEngine : public MetaEngine {
public:
	const char *getEngineId() const override {
		return "scumm";
	}

	const char *getName() const override;
	const char *getOriginalCopyright() const override;

	bool hasFeature(MetaEngineFeature f) const override;
	PlainGameList getSupportedGames() const override;
	PlainGameDescriptor findGame(const char *gameid) const override;
	DetectedGames detectGames(const Common::FSList &fslist) const override;

	Common::Error createInstance(OSystem *syst, Engine **engine) const override;

	SaveStateList listSaves(const char *target) const override;
	int getMaximumSaveSlot() const override;
	void removeSaveState(const char *target, int slot) const override;
	SaveStateDescriptor querySaveMetaInfos(const char *target, int slot) const override;
	const ExtraGuiOptions getExtraGuiOptions(const Common::String &target) const override;
};

bool ScummMetaEngine::hasFeature(MetaEngineFeature f) const {
	return
		(f == kSupportsListSaves) ||
		(f == kSupportsLoadingDuringStartup) ||
		(f == kSupportsDeleteSave) ||
		(f == kSavesSupportMetaInfo) ||
		(f == kSavesSupportThumbnail) ||
		(f == kSavesSupportCreationDate) ||
		(f == kSavesSupportPlayTime) ||
		(f == kSimpleSavesNames);
}

bool ScummEngine::hasFeature(EngineFeature f) const {
	return
		(f == kSupportsReturnToLauncher) ||
		(f == kSupportsLoadingDuringRuntime) ||
		(f == kSupportsSavingDuringRuntime) ||
		(f == kSupportsSubtitleOptions);
}

PlainGameList ScummMetaEngine::getSupportedGames() const {
	return PlainGameList(gameDescriptions);
}

PlainGameDescriptor ScummMetaEngine::findGame(const char *gameid) const {
	return Engines::findGameID(gameid, gameDescriptions, obsoleteGameIDsTable);
}

static Common::String generatePreferredTarget(const DetectorResult &x) {
	Common::String res(x.game.gameid);

	if (x.game.preferredTag) {
		res = res + "-" + x.game.preferredTag;
	}

	if (x.game.features & GF_DEMO) {
		res = res + "-demo";
	}

	// Append the platform, if a non-standard one has been specified.
	if (x.game.platform != Common::kPlatformDOS && x.game.platform != Common::kPlatformUnknown) {
		// HACK: For CoMI, it's pointless to encode the fact that it's for Windows.
		if (x.game.id != GID_CMI)
			res = res + "-" + Common::getPlatformAbbrev(x.game.platform);
	}

	// Append the language, if a non-standard one has been specified.
	if (x.language != Common::EN_ANY && x.language != Common::UNK_LANG) {
		res = res + "-" + Common::getLanguageCode(x.language);
	}

	return res;
}

DetectedGames ScummMetaEngine::detectGames(const Common::FSList &fslist) const {
	DetectedGames detectedGames;
	Common::List<DetectorResult> results;
	::detectGames(fslist, results, 0);

	for (Common::List<DetectorResult>::iterator
	          x = results.begin(); x != results.end(); ++x) {
		const PlainGameDescriptor *g = findPlainGameDescriptor(x->game.gameid, gameDescriptions);
		assert(g);

		DetectedGame game = DetectedGame(getEngineId(), x->game.gameid, g->description, x->language, x->game.platform, x->extra);

		// Compute and set the preferred target name for this game.
		// Based on generateComplexID() in advancedDetector.cpp.
		game.preferredTarget = generatePreferredTarget(*x);

		game.setGUIOptions(x->game.guioptions + MidiDriver::musicType2GUIO(x->game.midi));
		game.appendGUIOptions(getGameGUIOptionsDescriptionLanguage(x->language));

		detectedGames.push_back(game);
	}

	return detectedGames;
}

/**
 * Create a ScummEngine instance, based on the given detector data.
 *
 * This is heavily based on our MD5 detection scheme.
 */
Common::Error ScummMetaEngine::createInstance(OSystem *syst, Engine **engine) const {
	assert(syst);
	assert(engine);
	const char *gameid = ConfMan.get("gameid").c_str();

	// We start by checking whether the specified game ID is obsolete.
	// If that is the case, we automatically upgrade the target to use
	// the correct new game ID (and platform, if specified).
	Engines::upgradeTargetIfNecessary(obsoleteGameIDsTable);

	// Fetch the list of files in the current directory.
	Common::FSList fslist;
	Common::FSNode dir(ConfMan.get("path"));
	if (!dir.isDirectory())
		return Common::kPathNotDirectory;
	if (!dir.getChildren(fslist, Common::FSNode::kListAll))
		return Common::kNoGameDataFoundError;

	// Invoke the detector, but fixed to the specified gameid.
	Common::List<DetectorResult> results;
	::detectGames(fslist, results, gameid);

	// Unable to locate game data.
	if (results.empty())
		return Common::kNoGameDataFoundError;

	// No unique match found. If a platform override is present, try to
	// narrow down the list a bit more.
	if (results.size() > 1 && ConfMan.hasKey("platform")) {
		Common::Platform platform = Common::parsePlatform(ConfMan.get("platform"));
		Common::List<DetectorResult> tmp;

		// Copy only those candidates which match the platform setting.
		for (Common::List<DetectorResult>::iterator
		          x = results.begin(); x != results.end(); ++x) {
			if (x->game.platform == platform) {
				tmp.push_back(*x);
			}
		}

		// If we narrowed it down too much, print a warning, else use the list
		// we just computed as new candidates list.
		if (tmp.empty()) {
			warning("Engine_SCUMM_create: Game data inconsistent with platform override");
		} else {
			results = tmp;
		}
	}

	// Still no unique match found -> print a warning.
	if (results.size() > 1)
		warning("Engine_SCUMM_create: No unique game candidate found, using first one");

	// Simply use the first match.
	DetectorResult res(*(results.begin()));
	debug(1, "Using gameid %s, variant %s, extra %s", res.game.gameid, res.game.variant, res.extra);
	debug(1, "  SCUMM version %d, HE version %d", res.game.version, res.game.heversion);

	// Print the MD5 of the game; either verbose using printf, in case of an
	// unknown MD5, or with a medium debug level in case of a known MD5 (for
	// debugging purposes).
	if (!findInMD5Table(res.md5.c_str())) {
		Common::String md5Warning;

		md5Warning = _("Your game version appears to be unknown. If this is *NOT* a fan-modified\n"
		               "version (in particular, not a fan-made translation), please, report the\n"
		               "following data to the ScummVM team along with the name of the game you tried\n"
		               "to add and its version, language, etc.:\n");

		md5Warning += Common::String::format("  SCUMM gameid '%s', file '%s', MD5 '%s'\n\n",
				res.game.gameid,
				generateFilenameForDetection(res.fp.pattern, res.fp.genMethod, res.game.platform).c_str(),
				res.md5.c_str());

		g_system->logMessage(LogMessageType::kWarning, md5Warning.c_str());
	} else {
		debug(1, "Using MD5 '%s'", res.md5.c_str());
	}

	// We don't support the "Lite" version off puttzoo iOS because it contains
	// the full game.
	if (!strcmp(res.game.gameid, "puttzoo") && !strcmp(res.extra, "Lite")) {
		GUIErrorMessage(_("The Lite version of Putt-Putt Saves the Zoo iOS is not supported to avoid piracy.\n"
		                  "The full version is available for purchase from the iTunes Store."));
		return Common::kUnsupportedGameidError;
	}

	// We don't support yet the
	// the full game.
	if (!strcmp(res.game.gameid, "pajama2") && !strcmp(res.extra, "Russobit")) {
		GUIErrorMessage(_("The Russian version of Pajama Sam 2 is not supported yet due to incomplete code."));
		return Common::kUnsupportedGameidError;
	}

	// If the GUI options were updated, we catch this here and update them in the users config
	// file transparently.
	Common::updateGameGUIOptions(res.game.guioptions, getGameGUIOptionsDescriptionLanguage(res.language));

	// Check for a user override of the platform. We allow the user to override
	// the platform, to make it possible to add games which are not yet in
	// our MD5 database but require a specific platform setting.
	// TODO: Do we really still need/want the platform override?
	if (ConfMan.hasKey("platform"))
		res.game.platform = Common::parsePlatform(ConfMan.get("platform"));

	// Language override.
	if (ConfMan.hasKey("language"))
		res.language = Common::parseLanguage(ConfMan.get("language"));

	// V3 FM-TOWNS games *always* should use the corresponding music driver,
	// anything else makes no sense for them.
	// TODO: Maybe allow the null driver, too?
	if (res.game.platform == Common::kPlatformFMTowns && res.game.version == 3)
		res.game.midi = MDT_TOWNS;
	// Finally, we have massaged the GameDescriptor to our satisfaction, and can
	// instantiate the appropriate game engine. Hooray!
	switch (res.game.version) {
	case 0:
		*engine = new ScummEngine_v0(syst, res);
		break;
	case 1:
	case 2:
		*engine = new ScummEngine_v2(syst, res);
		break;
	case 3:
		if (res.game.features & GF_OLD256)
			*engine = new ScummEngine_v3(syst, res);
		else
			*engine = new ScummEngine_v3old(syst, res);
		break;
	case 4:
		*engine = new ScummEngine_v4(syst, res);
		break;
	case 5:
		*engine = new ScummEngine_v5(syst, res);
		break;
	case 6:
		switch (res.game.heversion) {
#ifdef ENABLE_HE
		case 200:
			*engine = new ScummEngine_vCUPhe(syst, res);
			break;
		case 101:
		case 100:
			*engine = new ScummEngine_v100he(syst, res);
			break;
		case 99:
			*engine = new ScummEngine_v99he(syst, res);
			break;
		case 98:
		case 95:
		case 90:
			*engine = new ScummEngine_v90he(syst, res);
			break;
		case 85:
		case 80:
			*engine = new ScummEngine_v80he(syst, res);
			break;
		case 74:
		case 73:
		case 72:
			*engine = new ScummEngine_v72he(syst, res);
			break;
		case 71:
			*engine = new ScummEngine_v71he(syst, res);
			break;
#endif
		case 70:
			*engine = new ScummEngine_v70he(syst, res);
			break;
		case 62:
		case 61:
		case 60:
			*engine = new ScummEngine_v60he(syst, res);
			break;
		default:
			*engine = new ScummEngine_v6(syst, res);
		}
		break;
#ifdef ENABLE_SCUMM_7_8
	case 7:
		*engine = new ScummEngine_v7(syst, res);
		break;
	case 8:
		*engine = new ScummEngine_v8(syst, res);
		break;
#endif
	default:
		error("Engine_SCUMM_create(): Unknown version of game engine");
	}

	return Common::kNoError;
}

const char *ScummMetaEngine::getName() const {
	return "SCUMM ["

#if defined(ENABLE_SCUMM_7_8) && defined(ENABLE_HE)
		"all games"
#else

		"v0-v6 games"

#if defined(ENABLE_SCUMM_7_8)
		", v7 & v8 games"
#endif
#if defined(ENABLE_HE)
		", HE71+ games"
#endif

#endif
		"]";
}

const char *ScummMetaEngine::getOriginalCopyright() const {
	return "LucasArts SCUMM Games (C) LucasArts\n"
	       "Humongous SCUMM Games (C) Humongous";
}

namespace Scumm {
bool getSavegameName(Common::InSaveFile *in, Common::String &desc, int heversion);
} // End of namespace Scumm

int ScummMetaEngine::getMaximumSaveSlot() const { return 99; }

SaveStateList ScummMetaEngine::listSaves(const char *target) const {
	Common::SaveFileManager *saveFileMan = g_system->getSavefileManager();
	Common::StringArray filenames;
	Common::String saveDesc;
	Common::String pattern = target;
	pattern += ".s##";

	filenames = saveFileMan->listSavefiles(pattern);

	SaveStateList saveList;
	for (Common::StringArray::const_iterator file = filenames.begin(); file != filenames.end(); ++file) {
		// Obtain the last 2 digits of the filename, since they correspond to the save slot.
		int slotNum = atoi(file->c_str() + file->size() - 2);

		if (slotNum >= 0 && slotNum <= 99) {
			Common::InSaveFile *in = saveFileMan->openForLoading(*file);
			if (in) {
				Scumm::getSavegameName(in, saveDesc, 0);	// FIXME: heversion?!?
				saveList.push_back(SaveStateDescriptor(slotNum, saveDesc));
				delete in;
			}
		}
	}

	// Sort saves based on slot number.
	Common::sort(saveList.begin(), saveList.end(), SaveStateDescriptorSlotComparator());
	return saveList;
}

void ScummMetaEngine::removeSaveState(const char *target, int slot) const {
	Common::String filename = ScummEngine::makeSavegameName(target, slot, false);
	g_system->getSavefileManager()->removeSavefile(filename);
}

SaveStateDescriptor ScummMetaEngine::querySaveMetaInfos(const char *target, int slot) const {
	Common::String saveDesc;
	Graphics::Surface *thumbnail = nullptr;
	SaveStateMetaInfos infos;
	memset(&infos, 0, sizeof(infos));
	SaveStateMetaInfos *infoPtr = &infos;

	// FIXME: heversion?!?
	if (!ScummEngine::querySaveMetaInfos(target, slot, 0, saveDesc, thumbnail, infoPtr)) {
		return SaveStateDescriptor();
	}

	SaveStateDescriptor desc(slot, saveDesc);

	// Do not allow save slot 0 (used for auto-saving) to be deleted or
	// overwritten.
	if (slot == 0) {
		desc.setWriteProtectedFlag(true);
		desc.setDeletableFlag(false);
	}

	desc.setThumbnail(thumbnail);

	if (infoPtr) {
		int day = (infos.date >> 24) & 0xFF;
		int month = (infos.date >> 16) & 0xFF;
		int year = infos.date & 0xFFFF;

		desc.setSaveDate(year, month, day);

		int hour = (infos.time >> 8) & 0xFF;
		int minutes = infos.time & 0xFF;

		desc.setSaveTime(hour, minutes);
		desc.setPlayTime(infos.playtime * 1000);
	}

	return desc;
}

static const ExtraGuiOption comiObjectLabelsOption = {
	_s("Show Object Line"),
	_s("Show the names of objects at the bottom of the screen"),
	"object_labels",
	true
};

static const ExtraGuiOption mmnesObjectLabelsOption = {
	_s("Use NES Classic Palette"),
	_s("Use a more neutral color palette that closely emulates the NES Classic"),
	"mm_nes_classic_palette",
	false
};

const ExtraGuiOptions ScummMetaEngine::getExtraGuiOptions(const Common::String &target) const {
	ExtraGuiOptions options;
	if (target.empty() || ConfMan.get("gameid", target) == "comi") {
		options.push_back(comiObjectLabelsOption);
	}
	if (target.empty() || Common::parsePlatform(ConfMan.get("platform", target)) == Common::kPlatformNES) {
		options.push_back(mmnesObjectLabelsOption);
	}
	return options;
}

#if PLUGIN_ENABLED_DYNAMIC(SCUMM)
	REGISTER_PLUGIN_DYNAMIC(SCUMM, PLUGIN_TYPE_ENGINE, ScummMetaEngine);
#else
	REGISTER_PLUGIN_STATIC(SCUMM, PLUGIN_TYPE_ENGINE, ScummMetaEngine);
#endif