metaengine.h

/* 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/>.
 *
 */

#ifndef ENGINES_METAENGINE_H
#define ENGINES_METAENGINE_H

#include "common/scummsys.h"
#include "common/error.h"
#include "common/array.h"
#include "common/debug-channels.h"

#include "engines/achievements.h"
#include "engines/game.h"
#include "engines/savestate.h"

#include "base/plugins.h"

class Engine;
class OSystem;

namespace Common {
class Keymap;
class FSList;
class OutSaveFile;
class String;

typedef SeekableReadStream InSaveFile;
}

namespace Graphics {
struct Surface;
}

namespace GUI {
class GuiObject;
class OptionsContainerWidget;
}

struct ExtraGuiOption {
    const char *label;         
    const char *tooltip;       
    const char *configOption;  
    bool defaultState;         
    byte groupId;        
    byte groupLeaderId;  
};

typedef Common::Array<ExtraGuiOption> ExtraGuiOptions;

enum { kSavegameFilePattern = -99 };

#define EXTENDED_SAVE_VERSION 4

struct ExtendedSavegameHeader {
    char id[6];                   
    uint8 version;                
    Common::String saveName;      
    Common::String description;   
    uint32 date;                  
    uint16 time;                  
    uint32 playtime;              
    Graphics::Surface *thumbnail; 
    bool isAutosave;              
    ExtendedSavegameHeader() {
        memset(id, 0, 6);
        version = 0;
        date = 0;
        time = 0;
        playtime = 0;
        thumbnail = nullptr;
        isAutosave = false;
    }
};

class MetaEngineDetection : public PluginObject {
protected:
    static Common::String escapeString(const char *string);

public:
    static const char GAME_NOT_IMPLEMENTED[];

    virtual ~MetaEngineDetection() {}

    virtual const char *getName() const override = 0;

    virtual const char *getEngineName() const = 0;

    virtual const char *getOriginalCopyright() const = 0;

    virtual PlainGameList getSupportedGames() const = 0;

    virtual PlainGameDescriptor findGame(const char *gameId) const = 0;

    virtual Common::Error identifyGame(DetectedGame &game, const void **descriptor) = 0;

    virtual DetectedGames detectGames(const Common::FSList &fslist, uint32 skipADFlags = 0, bool skipIncomplete = false) = 0;

    virtual uint getMD5Bytes() const = 0;

    virtual int getGameVariantCount() const {
        return -1;
    }

    virtual void dumpDetectionEntries() const = 0;

    virtual const DebugChannelDef *getDebugChannels() const {
        return NULL;
    }
};

class MetaEngine : public PluginObject {
protected:
    virtual void getSavegameThumbnail(Graphics::Surface &thumb);

    int findEmptySaveSlot(const char *target);

    virtual const ExtraGuiOptions getExtraGuiOptions(const Common::String &target) const {
        return ExtraGuiOptions();
    }

public:
    virtual ~MetaEngine() {}

    virtual const char *getName() const override = 0;

    virtual Common::Error createInstance(OSystem *syst, Engine **engine, const DetectedGame &gameDescriptor, const void *meDescriptor) = 0;

    virtual void deleteInstance(Engine *engine, const DetectedGame &gameDescriptor, const void *meDescriptor);

    virtual SaveStateList listSaves(const char *target) const;

    SaveStateList listSaves(const char *target, bool saveMode) const;

    virtual int getAutosaveSlot() const {
        return 0;
    }

    virtual int getMaximumSaveSlot() const {
        // For games using the new save format, assume 99 slots by default
        return hasFeature(kSavesUseExtendedFormat) ? 99 : 0;
    }

    virtual bool removeSaveState(const char *target, int slot) const;

    virtual SaveStateDescriptor querySaveMetaInfos(const char *target, int slot) const;

    virtual Common::String getSavegameFile(int saveGameIdx, const char *target = nullptr) const;

    Common::String getSavegameFilePattern(const char *target = nullptr) const {
        return getSavegameFile(kSavegameFilePattern, target);
    }

    virtual Common::Array<Common::Keymap *> initKeymaps(const char *target) const;

    virtual void registerDefaultSettings(const Common::String &target) const;

    virtual GUI::OptionsContainerWidget *buildEngineOptionsWidget(GUI::GuiObject *boss, const Common::String &name, const Common::String &target) const;

    enum MetaEngineFeature {
        kSupportsListSaves,

        kSupportsLoadingDuringStartup,

        kSupportsDeleteSave,

        kSavesSupportMetaInfo,

        kSavesSupportThumbnail,

        kSavesSupportCreationDate,

        kSavesSupportPlayTime,

        kSimpleSavesNames,

        kSavesUseExtendedFormat
    };

    virtual Common::AchievementsPlatform getAchievementsPlatform(const Common::String &target) const;

    virtual const Common::AchievementsInfo getAchievementsInfo(const Common::String &target) const;

    virtual const Common::AchievementDescriptionList* getAchievementDescriptionList() const {
        return nullptr;
    }

    virtual bool hasFeature(MetaEngineFeature f) const;

    void appendExtendedSave(Common::OutSaveFile *saveFile, uint32 playtime, Common::String desc, bool isAutosave);

    void appendExtendedSaveToStream(Common::WriteStream *saveFile, uint32 playtime, Common::String desc, bool isAutosave, uint32 offset = 0);

    bool copySaveFileToFreeSlot(const char *target, int slot);

    static void parseSavegameHeader(ExtendedSavegameHeader *header, SaveStateDescriptor *desc);
    static void fillDummyHeader(ExtendedSavegameHeader *header);

    static void decodeSavegameDate(const ExtendedSavegameHeader *header, uint16 &outYear, uint8 &outMonth, uint8 &outDay);

    static void decodeSavegameTime(const ExtendedSavegameHeader *header, uint8 &outHour, uint8 &outMinute);

    WARN_UNUSED_RESULT static bool readSavegameHeader(Common::InSaveFile *in, ExtendedSavegameHeader *header, bool skipThumbnail = true);
};

class EngineManager : public Common::Singleton<EngineManager> {
public:
    DetectionResults detectGames(const Common::FSList &fslist, uint32 skipADFlags = 0, bool skipIncomplete = false);

    const Plugin *findDetectionPlugin(const Common::String &engineId) const;

    const PluginList &getPlugins(const PluginType fetchPluginType) const;

    QualifiedGameDescriptor findTarget(const Common::String &target) const;

    QualifiedGameList findGamesMatching(const Common::String &engineId, const Common::String &gameId) const;

    Common::String createTargetForGame(const DetectedGame &game);

    void upgradeTargetIfNecessary(const Common::String &target) const;

    Common::String generateUniqueDomain(const Common::String &gameId);

private:
    QualifiedGameList findGameInLoadedPlugins(const Common::String &gameId) const;

    void upgradeTargetForEngineId(const Common::String &target) const;
};

#define EngineMan EngineManager::instance()

#endif