events.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 MEDIASTATION_EVENTS_H
#define MEDIASTATION_EVENTS_H

#include "common/events.h"
#include "common/hash-ptr.h"
#include "common/ptr.h"
#include "common/str.h"
#include "common/queue.h"

#include "mediastation/mediascript/scriptconstants.h"
#include "mediastation/mediascript/scriptvalue.h"

namespace MediaStation {

enum EventClass {
    kEventClassInvalid = 0x00,
    kEventClassSystem = 0x01,
    kEventClassMouse = 0x02,
    kEventClassKeyboard = 0x04,
    kEventClassDisplay = 0x08,
    kEventClassTimerService = 0x10,
    kEventClassScriptTimer = 0x20,
    kEventClassActor = 0x40
};
const char *eventClassToStr(EventClass eventClass);

// This reimplementation doesn't use these values because
// there isn't the indirection of event handler classes. We
// just use the event class directly when deciding where to route an
// event. However, this is still included for completeness .
enum EventClassHandlerType {
    kNoEventClassHandler = 0x00,
    kStageDirectorEventClassHandler = 0x06,
    kDisplayUpdateEventClassHandler = 0x08,
    kTimerServiceClassHandler = 0x10,
    kActorEventClassHandler = 0x40,
};

struct Event {
    EventClass eventClass = kEventClassInvalid;
    EventType type = kEventTypeInvalid;

    Event(EventClass eventClass_, EventType eventType_)
        : eventClass(eventClass_), type(eventType_) {}
    virtual ~Event() {}
    virtual Event *clone() const = 0;
    virtual Common::String debugString() const;
};

struct DisplayEvent : public Event {
    uint disableScreenAutoUpdateToken = 0;

    DisplayEvent(EventType eventType_, uint token_)
        : Event(kEventClassDisplay, eventType_), disableScreenAutoUpdateToken(token_) {}
    Event *clone() const override { return new DisplayEvent(*this); }
    Common::String debugString() const override;
};

// This is an event queued to tell the timer service that a timer has expired. When this event is processed,
// an actual timer event will get sent to the actual timer event handler (actors and such).
class TimerEntry;
struct TimerServiceAlarmEvent : public Event {
    uint32 triggerTime = 0;
    TimerEntry *entry = nullptr;

    TimerServiceAlarmEvent(TimerEntry *entry_, uint32 triggerTime_)
        : Event(kEventClassTimerService, kTimerServiceAlarmEvent), triggerTime(triggerTime_), entry(entry_) {}
    Event *clone() const override { return new TimerServiceAlarmEvent(*this); }
    Common::String debugString() const override;
};

// This is actually sent to timer event handlers (actors and such).
struct TimerEvent : public Event {
    TimerEntry *entry = nullptr;

    TimerEvent(TimerEntry *entry_)
        : Event(kEventClassScriptTimer, kTimerScriptEvent), entry(entry_) {}
    Event *clone() const override { return new TimerEvent(*this); }
    Common::String debugString() const override;
};

struct ActorEvent : public Event {
    uint actorId = 0;
    ScriptValue arg;

    ActorEvent(uint16 actorId_, EventType eventType_)
        : Event(kEventClassActor, eventType_), actorId(actorId_) {}
    ActorEvent(uint16 actorId_, EventType eventType_, ScriptValue arg_)
        : Event(kEventClassActor, eventType_), actorId(actorId_), arg(arg_) {}
    Event *clone() const override { return new ActorEvent(*this); }
    Common::String debugString() const override;
};

struct ScreenBranchEvent : public ActorEvent {
    uint screenId = 0;
    bool disableScreenAutoUpdate = false;

    ScreenBranchEvent(uint16 actorId_, uint16 screenId_, bool disableScreenAutoUpdate_)
        : ActorEvent(actorId_, kScreenBranchEvent), screenId(screenId_), disableScreenAutoUpdate(disableScreenAutoUpdate_) {}
    Event *clone() const override { return new ScreenBranchEvent(*this); }
    Common::String debugString() const override;
};

struct MouseEvent : public Event {
    Common::Point position;

    MouseEvent(EventType eventType_, const Common::Point &position_)
        : Event(kEventClassMouse, eventType_), position(position_) {}
    Event *clone() const override { return new MouseEvent(*this); }
    Common::String debugString() const override;
};

enum SpecialCharCodes {
    kBackspaceCharCode = 0x08,
    kLeftArrowCharCode = 0x100,
    kRightArrowCharCode = 0x101,
    kUpArrowCharCode = 0x102,
    kDownArrowCharCode = 0x103,
    kCursorCharCode = 0x104,
};

struct KeyboardEvent : public Event {
    Common::KeyState state;

    KeyboardEvent(EventType eventType_, Common::KeyState state_)
        : Event(kEventClassKeyboard, eventType_), state(state_) {}
    Event *clone() const override { return new KeyboardEvent(*this); }
    Common::String debugString() const override;

    // Scripts and text actors use a 16-bit field for their char codes,
    // which also encapsulates non-text keys like backspace and arrow keys.
    // This converts the platform-independent ScummVM keystate into what scripts
    // want. See MAC_App::doKeyDownEvent in the 68k disassembly.
    uint16 getMediaStationCharCode() const;
};

enum PreDisplaySyncState {
    kPreDisplaySyncForceScreenUpdate = 0,
    kPreDisplaySyncNoScreenUpdateRequested = 1,
    kPreDisplaySyncStateBlockScreenUpdate = 2
};

// Interface for clients that need to update during the pre-display sync phase.
// Only stream movie actors seem to actually use this.
class PreDisplaySyncClient {
public:
    virtual ~PreDisplaySyncClient() {}
    virtual PreDisplaySyncState preDisplaySync() = 0;

    void registerForSyncCalls();
    void unregisterForSyncCalls();
};

// The main event loop. In the original, much of the functionality lived in a separate
// EventLoopSupport class (implemented by MAC_App or WIN_App), but in ScummVM there
// is no need for that extra indirection.
class EventLoop {
public:
    void run();
    void queueEvent(const Event &event);

    void registerForPreDisplaySyncCalls(PreDisplaySyncClient *client);
    void unregisterForPreDisplaySyncCalls(PreDisplaySyncClient *client);

private:
    Common::Queue<Common::ScopedPtr<Event>> _incomingQueue;
    Common::Queue<Common::ScopedPtr<Event>> _dispatchQueue;
    Common::Event _queuedSystemEvent;
    Common::HashMap<PreDisplaySyncClient *, PreDisplaySyncClient *> _preDisplaySyncClients;

    void dispatchImtEvents();
    PreDisplaySyncState preDisplaySync();
    void updateDisplay();

    // The original had a separate EventDispatcher, but things are much simpler by not using
    // the polymorphism that required this intermediate class.
    void dispatchImtEvent(const Event &event);
};

class TimerEventReceiver {
public:
    virtual ~TimerEventReceiver() {};

    uint32 currentReceiverTime();
    virtual void timerEvent(const TimerEvent &event) = 0;
};

class TimerEntry {
public:
    TimerEntry() = default;
    TimerEntry(TimerEventReceiver *receiver) : _receiver(receiver) {}
    ~TimerEntry();

    void setDuration(uint32 duration) { _duration = duration; }
    uint32 calculateFirstExpirationTime(uint32 currentTime);
    uint32 calculateNextExpirationTime(uint32 currentTime);
    uint32 deltaTimeAtExpiration() const;
    uint32 expirationTime() const { return _expirationTime; }
    bool shouldReschedule() const { return _shouldRepeat; }
    TimerEventReceiver *getReceiver() const { return _receiver; }

    bool operator==(const TimerEntry &other) const;
    bool operator<(const TimerEntry &other) const;
    bool operator>(const TimerEntry &other) const;

private:
    TimerEventReceiver *_receiver = nullptr;
    uint32 _expirationTime = 0;
    uint32 _actualExpirationTime = 0;
    uint32 _duration = 0;
    bool _shouldRepeat = false;
};

class TimerService {
public:
    // This is called to actually dispatch a timer event to the event receiver.
    void handleEvent(const TimerServiceAlarmEvent &event);

    void startTimer(TimerEntry &entry, uint32 duration);
    void startTimer(TimerEntry &entry, double duration);
    void stopTimer(TimerEntry &entry);
    void queueExpiredTimerEvents();

private:
    Common::HashMap<TimerEntry *, TimerEntry *> _timers;

    void rescheduleTimerEntry(TimerEntry &entry);
};

} // End of namespace MediaStation

#endif