/*
 * Copyright 2006, Haiku.
 * Distributed under the terms of the MIT License.
 *
 * Authors:
 *              Stephan Aßmus <superstippi@gmx.de>
 */

#include "Observable.h"

#include <stdio.h>
#include <typeinfo>

#include <OS.h>

#include "Observer.h"

// constructor
Observable::Observable()
        : fObservers(2),
          fSuspended(0),
          fPendingNotifications(false)
{
}

// destructor
Observable::~Observable()
{
        if (fObservers.CountItems() > 0) {
                char message[256];
                Observer* o = (Observer*)fObservers.ItemAt(0);
                sprintf(message, "Observable::~Observable() - %" B_PRId32
                                                 " observers still watching, first: %s\n",
                                                 fObservers.CountItems(), typeid(*o).name());
                debugger(message);
        }
}

// AddObserver
bool
Observable::AddObserver(Observer* observer)
{
        if (observer && !fObservers.HasItem((void*)observer)) {
                return fObservers.AddItem((void*)observer);
        }
        return false;
}

// RemoveObserver
bool
Observable::RemoveObserver(Observer* observer)
{
        return fObservers.RemoveItem((void*)observer);
}

// CountObservers
int32
Observable::CountObservers() const
{
        return fObservers.CountItems();
}

// ObserverAtFast
Observer*
Observable::ObserverAtFast(int32 index) const
{
        return (Observer*)fObservers.ItemAtFast(index);
}

// #pragma mark -

// Notify
void
Observable::Notify() const
{
        if (!fSuspended) {
                BList observers(fObservers);
                int32 count = observers.CountItems();
                for (int32 i = 0; i < count; i++)
                        ((Observer*)observers.ItemAtFast(i))->ObjectChanged(this);
                fPendingNotifications = false;
        } else {
                fPendingNotifications = true;
        }
}

// SuspendNotifications
void
Observable::SuspendNotifications(bool suspend)
{
        if (suspend)
                fSuspended++;
        else
                fSuspended--;

        if (fSuspended < 0) {
                fprintf(stderr, "Observable::SuspendNotifications(false) - "
                                                "error: suspend level below zero!\n");
                fSuspended = 0;
        }

        if (!fSuspended && fPendingNotifications)
                Notify();
}