/* 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 3 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, see <http://www.gnu.org/licenses/>.
 *
 */

#include "common/config-manager.h"
#include "common/file.h"
#include "common/md5.h"
#include "common/savefile.h"
#include "common/textconsole.h"

#include "graphics/thumbnail.h"
#include "graphics/surface.h"

#include "base/plugins.h"
#include "engines/advancedDetector.h"

#include "agi/agi.h"
#include "agi/preagi/preagi.h"
#include "agi/preagi/mickey.h"
#include "agi/preagi/troll.h"
#include "agi/preagi/winnie.h"

#include "agi/detection.h"

namespace Agi {

uint32 AgiBase::getGameID() const {
	return _gameDescription->gameID;
}

uint32 AgiBase::getFeatures() const {
	return _gameFeatures;
}

Common::Platform AgiBase::getPlatform() const {
	return _gameDescription->desc.platform;
}

Common::Language AgiBase::getLanguage() const {
	if (_gameDescription->desc.language != Common::UNK_LANG)
		return _gameDescription->desc.language;
	else if (ConfMan.hasKey("language"))
		return Common::parseLanguage(ConfMan.get("language"));
	else
		return Common::UNK_LANG;
}

bool AgiBase::isLanguageRTL() const {
	return getLanguage() == Common::HE_ISR;
}

uint16 AgiBase::getVersion() const {
	return _gameVersion;
}

uint16 AgiBase::getGameType() const {
	return _gameDescription->gameType;
}

const char *AgiBase::getGameMD5() const {
	return _gameDescription->desc.filesDescriptions[0].md5;
}

void AgiBase::initFeatures() {
	_gameFeatures = _gameDescription->features;
}

void AgiBase::setFeature(uint32 feature) {
	_gameFeatures |= feature;
}

void AgiBase::setVersion(uint16 version) {
	_gameVersion = version;
}

void AgiBase::initVersion() {
	_gameVersion = _gameDescription->version;
}

const char *AgiBase::getDiskName(uint16 id) {
	for (int i = 0; _gameDescription->desc.filesDescriptions[i].fileName != nullptr; i++)
		if (_gameDescription->desc.filesDescriptions[i].fileType == id)
			return _gameDescription->desc.filesDescriptions[i].fileName;

	return "";
}

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

} // End of namespace Agi


using namespace Agi;

class AgiMetaEngine : public AdvancedMetaEngine {
public:
	const char *getName() const override {
		return "agi";
	}

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

	bool hasFeature(MetaEngineFeature f) const override;
};

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

Common::Error AgiMetaEngine::createInstance(OSystem *syst, Engine **engine, const ADGameDescription *desc) const {
	const Agi::AGIGameDescription *gd = (const Agi::AGIGameDescription *)desc;

	switch (gd->gameType) {
	case Agi::GType_PreAGI:
		switch (gd->gameID) {
		case GID_MICKEY:
			*engine = new Agi::MickeyEngine(syst, gd);
			break;
		case GID_TROLL:
			*engine = new Agi::TrollEngine(syst, gd);
			break;
		case GID_WINNIE:
			*engine = new Agi::WinnieEngine(syst, gd);
			break;
		default:
			return Common::kUnsupportedGameidError;
		}
		break;
	case Agi::GType_V1:
	case Agi::GType_V2:
	case Agi::GType_V3:
		*engine = new Agi::AgiEngine(syst, gd);
		break;
	default:
		return Common::kUnsupportedGameidError;
	}

	return Common::kNoError;
}

SaveStateList AgiMetaEngine::listSaves(const char *target) const {
	const uint32 AGIflag = MKTAG('A', 'G', 'I', ':');
	Common::SaveFileManager *saveFileMan = g_system->getSavefileManager();
	Common::StringArray filenames;
	Common::String pattern = target;
	pattern += ".###";

	filenames = saveFileMan->listSavefiles(pattern);

	SaveStateList saveList;
	for (Common::StringArray::const_iterator file = filenames.begin(); file != filenames.end(); ++file) {
		// Obtain the last 3 digits of the filename, since they correspond to the save slot
		int slotNr = atoi(file->c_str() + file->size() - 3);

		if (slotNr >= 0 && slotNr <= 999) {
			Common::InSaveFile *in = saveFileMan->openForLoading(*file);
			if (in) {
				uint32 type = in->readUint32BE();
				char description[31];

				if (type == AGIflag) {
					uint16 descriptionPos = 0;

					in->read(description, 31);

					// Security-check, if saveDescription has a terminating NUL
					while (description[descriptionPos]) {
						descriptionPos++;
						if (descriptionPos >= sizeof(description))
							break;
					}
					if (descriptionPos >= sizeof(description)) {
						strcpy(description, "[broken saved game]");
					}
				} else {
					strcpy(description, "[not an AGI saved game]");
				}

				delete in;

				saveList.push_back(SaveStateDescriptor(this, slotNr, description));
			}
		}
	}

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

void AgiMetaEngine::removeSaveState(const char *target, int slot) const {
	Common::String fileName = Common::String::format("%s.%03d", target, slot);
	g_system->getSavefileManager()->removeSavefile(fileName);
}

int AgiMetaEngine::getMaximumSaveSlot() const { return 999; }

SaveStateDescriptor AgiMetaEngine::querySaveMetaInfos(const char *target, int slotNr) const {
	const uint32 AGIflag = MKTAG('A', 'G', 'I', ':');
	Common::String fileName = Common::String::format("%s.%03d", target, slotNr);

	Common::InSaveFile *in = g_system->getSavefileManager()->openForLoading(fileName);

	if (in) {
		if (in->readUint32BE() != AGIflag) {
			delete in;
			return SaveStateDescriptor();
		}

		char description[31];
		uint16 descriptionPos = 0;

		in->read(description, 31);

		while (description[descriptionPos]) {
			descriptionPos++;
			if (descriptionPos >= sizeof(description))
				break;
		}
		if (descriptionPos >= sizeof(description)) {
			// broken description, ignore it
			delete in;

			SaveStateDescriptor descriptor(this, slotNr, "[broken saved game]");
			return descriptor;
		}

		SaveStateDescriptor descriptor(this, slotNr, description);

		char saveVersion = in->readByte();
		if (saveVersion >= 4) {
			Graphics::Surface *thumbnail;
			if (!Graphics::loadThumbnail(*in, thumbnail)) {
				delete in;
				return SaveStateDescriptor();
			}

			descriptor.setThumbnail(thumbnail);

			uint32 saveDate = in->readUint32BE();
			uint16 saveTime = in->readUint16BE();
			if (saveVersion >= 9) {
				in->readByte(); // skip over seconds of saveTime (not needed here)
			}
			if (saveVersion >= 6) {
				uint32 playTime = in->readUint32BE();
				descriptor.setPlayTime(playTime * 1000);
			}

			int day = (saveDate >> 24) & 0xFF;
			int month = (saveDate >> 16) & 0xFF;
			int year = saveDate & 0xFFFF;

			descriptor.setSaveDate(year, month, day);

			int hour = (saveTime >> 8) & 0xFF;
			int minutes = saveTime & 0xFF;

			descriptor.setSaveTime(hour, minutes);
		}

		delete in;

		return descriptor;

	} else {
		SaveStateDescriptor emptySave;
		// Do not allow save slot 0 (used for auto-saving) to be overwritten.
		if (slotNr == 0) {
			emptySave.setAutosave(true);
			emptySave.setWriteProtectedFlag(true);
		} else {
			emptySave.setWriteProtectedFlag(false);
		}
		return emptySave;
	}
}

#if PLUGIN_ENABLED_DYNAMIC(AGI)
	REGISTER_PLUGIN_DYNAMIC(AGI, PLUGIN_TYPE_ENGINE, AgiMetaEngine);
#else
	REGISTER_PLUGIN_STATIC(AGI, PLUGIN_TYPE_ENGINE, AgiMetaEngine);
#endif

namespace Agi {

bool AgiBase::canLoadGameStateCurrently() {
	if (!(getGameType() == GType_PreAGI)) {
		if (getFlag(VM_FLAG_MENUS_ACCESSIBLE)) {
			if (!_noSaveLoadAllowed) {
				if (!cycleInnerLoopIsActive()) {
					// We can't allow to restore a game, while inner loop is active
					// For example Mixed Up Mother Goose has an endless loop for user name input
					// Which means even if we abort the inner loop, the game would keep on calling
					// GetString() until something is entered. And this would of course also happen
					// right after restoring a saved game.
					return true;
				}
			}
		}
	}
	return false;
}

bool AgiBase::canSaveGameStateCurrently() {
	if (getGameID() == GID_BC) // Technically in Black Cauldron we may save anytime
		return true;

	if (!(getGameType() == GType_PreAGI)) {
		if (getFlag(VM_FLAG_MENUS_ACCESSIBLE)) {
			if (!_noSaveLoadAllowed) {
				if (!cycleInnerLoopIsActive()) {
					if (promptIsEnabled()) {
						return true;
					}
				}
			}
		}
	}
	return false;
}

int AgiEngine::agiDetectGame() {
	int ec = errOK;

	assert(_gameDescription != nullptr);

	if (getVersion() <= 0x2001) {
		_loader = new AgiLoader_v1(this);
	} else if (getVersion() <= 0x2999) {
		_loader = new AgiLoader_v2(this);
	} else {
		_loader = new AgiLoader_v3(this);
	}
	ec = _loader->detectGame();

	return ec;
}

} // End of namespace Agi
