//========= Copyright Valve Corporation, All rights reserved. ============//
//
// Purpose:
//
//=============================================================================//

#ifndef TIMEDEVENTMGR_H
#define TIMEDEVENTMGR_H
#ifdef _WIN32
#pragma once
#endif

#include "utlpriorityqueue.h"

//
//
// These classes provide fast timed event callbacks. To use them, make a
// CTimedEventMgr and put CEventRegister objects in your objects that want the
// timed events.
//
//

class CTimedEventMgr;

abstract_class IEventRegisterCallback {
   public:
    virtual void FireEvent() = 0;
};

class CEventRegister {
    friend bool TimedEventMgr_LessFunc(CEventRegister *const &a,
                                       CEventRegister *const &b);
    friend class CTimedEventMgr;

   public:
    CEventRegister();
    ~CEventRegister();

    // Call this before ever calling SetUpdateInterval().
    void Init(CTimedEventMgr *pMgr, IEventRegisterCallback *pCallback);

    // Use these to start and stop getting updates.
    void SetUpdateInterval(float interval);
    void StopUpdates();

    inline bool IsRegistered() const { return m_bRegistered; }

   private:
    void Reregister();  // After having an event processed, this is called to
                        // have it register for the next one.
    void Term();

   private:
    CTimedEventMgr *m_pEventMgr;
    float m_flNextEventTime;
    float m_flUpdateInterval;
    IEventRegisterCallback *m_pCallback;
    bool m_bRegistered;
};

class CTimedEventMgr {
    friend class CEventRegister;

   public:
    CTimedEventMgr();

    // Call this each frame to fire events.
    void FireEvents();

   private:
    // Things used by CEventRegister.
    void RegisterForNextEvent(CEventRegister *pEvent);
    void RemoveEvent(CEventRegister *pEvent);

   private:
    // Events, sorted by the time at which they will fire.
    CUtlPriorityQueue<CEventRegister *> m_Events;
};

#endif  // TIMEDEVENTMGR_H