/*
 * SIP Communicator, the OpenSource Java VoIP and Instant Messaging client.
 *
 * Distributable under LGPL license.
 * See terms of license at gnu.org.
 */
package net.java.sip.communicator.service.protocol;

import java.util.*;

import net.java.sip.communicator.service.protocol.event.*;
import net.java.sip.communicator.util.*;


/**
 * A represenation of a Call. The Call class must obly be created by users (i.e.
 * telephony protocols) of the PhoneUIService such as a SIP protocol
 * implemenation. Extensions of this class might have names like SipCall
 * or H323Call or AnyOtherTelephonyProtocolCall
 *
 * @author Emil Ivov
 */
public abstract class Call
{
    private static final Logger logger
        = Logger.getLogger(Call.class);
    /**
     * An identifier uniquely representing the call.
     */
    private String callID = null;

    /**
     * A list of all listeners currently registered for
     * <tt>CallChangeEvent</tt>s
     */
    private Vector callListeners = new Vector();

    /**
     * A reference to the ProtocolProviderService instance that created us.
     */
    private ProtocolProviderService protocolProvider = null;

    /**
     * Creates a new Call instance.
     *
     * @param sourceProvider the proto provider that created us.
     */
    protected Call(ProtocolProviderService sourceProvider)
    {
        //create the uid
        this.callID = String.valueOf( System.currentTimeMillis())
                    + String.valueOf(super.hashCode());

        this.protocolProvider = sourceProvider;
    }

    /**
     * Returns the id of the specified Call.
     * @return a String uniquely identifying the call.
     */
    public String getCallID()
    {
        return callID;
    }

    /**
     * Compares the specified object with this call and returns true if it the
     * specified object is an instance of a Call object and if the
     * extending telephony protocol considers the calls represented by both
     * objects to be the same.
     *
     * @param obj the call to compare this one with.
     * @return true in case both objects are pertaining to the same call and
     * false otherwise.
     */
    public boolean equals(Object obj)
    {
        if(obj == null
           || !(obj instanceof Call))
            return false;
        if (obj == this
           || ((Call)obj).getCallID().equals( getCallID() ))
            return true;

        return false;
    }

    /**
     * Returns a hash code value for this call.
     *
     * @return  a hash code value for this call.
     */
    public int hashCode()
    {
        return getCallID().hashCode();
    }

    /**
     * Returns an iterator over all call participants.
     * @return an Iterator over all participants currently involved in the call.
     */
    public abstract Iterator getCallParticipants();

    /**
     * Returns the number of participants currently associated with this call.
     * @return an <tt>int</tt> indicating the number of participants currently
     * associated with this call.
     */
    public abstract int getCallParticipantsCount();

    /**
     * Adds a call change listener to this call so that it could receive events
     * on new call participants, theme changes and others.
     *
     * @param listener the listener to register
     */
    public void addCallChangeListener(CallChangeListener listener)
    {
        synchronized(callListeners)
        {
            if(!callListeners.contains(listener))
                this.callListeners.add(listener);
        }
    }

    /**
     * Removes <tt>listener</tt> to this call so that it won't receive further
     * <tt>CallChangeEvent</tt>s.
     * @param listener the listener to register
     */
    public void removeCallChangeListener(CallChangeListener listener)
    {
        synchronized(callListeners)
        {
            this.callListeners.remove(listener);
        }
    }

    /**
     * Returns a reference to the <tt>ProtocolProviderService</tt> instance
     * that created this call.
     * @return a reference to the <tt>ProtocolProviderService</tt> instance that
     * created this call.
     */
    public ProtocolProviderService getProtocolProvider()
    {
        return this.protocolProvider;
    }

    /**
     * Creates a <tt>CallParticipantEvent</tt> with
     * <tt>sourceCallParticipant</tt> and <tt>eventID</tt> and dispatches it on
     * all currently registered listeners.
     *
     * @param sourceCallParticipant the source <tt>CallParticipant</tt> for the
     * newly created event.
     * @param eventID the ID of the event to create (see CPE member ints)
     */
    protected void fireCallParticipantEvent(CallParticipant sourceCallParticipant,
                                            int             eventID)
    {
        CallParticipantEvent cpEvent = new CallParticipantEvent(
            sourceCallParticipant, this, eventID);

        logger.debug("Dispatching a CallParticipant event to "
                     + callListeners.size()
                     +" listeners. event is: " + cpEvent.toString());

        Iterator listeners = null;
        synchronized(callListeners)
        {
           listeners = new ArrayList(callListeners).iterator();
        }

        while(listeners.hasNext())
        {
            CallChangeListener listener = (CallChangeListener)listeners.next();

            if(eventID == CallParticipantEvent.CALL_PARTICIPANT_ADDED)
                listener.callParticipantAdded(cpEvent);
            else if (eventID == CallParticipantEvent.CALL_PARTICIPANT_REMVOVED)
                listener.callParticipantRemoved(cpEvent);

        }
    }

    /**
     * Returns a string textually representing this Call.
     *
     * @return  a string representation of the object.
     */
    public String toString()
    {
        return "Call: id=" + getCallID() + " participants="
                           + getCallParticipantsCount();
    }

    /**
     * Creates a <tt>CallChangeEvent</tt> with this class as
     * <tt>sourceCall</tt>,  and the specified <tt>eventID</tt> and old and new
     * values and  dispatches it on all currently registered listeners.
     *
     * @param type the type of the event to create (see CallChangeEvent member
     * ints)
     * @param oldValue the value of the call property that changed, before the
     * event had occurred.
     * @param newValue the value of the call property that changed, after the
     * event has occurred.
     */
    protected void fireCallChangeEvent( String type,
                                        Object oldValue,
                                        Object newValue)
    {
        CallChangeEvent ccEvent = new CallChangeEvent(
            this, type, oldValue, newValue);

        logger.debug("Dispatching a CallChange event to "
                     + callListeners.size()
                     +" listeners. event is: " + ccEvent.toString());

        Iterator listeners = null;
        synchronized(callListeners)
        {
            listeners = new ArrayList(callListeners).iterator();
        }

        while(listeners.hasNext())
        {
            CallChangeListener listener = (CallChangeListener)listeners.next();

            if(type.equals(CallChangeEvent.CALL_STATE_CHANGE))
                listener.callStateChanged(ccEvent);
        }
    }

    /**
     * Returns the state that this call is currently in.
     *
     * @return a reference to the <tt>CallState</tt> instance that the call is
     * currently in.
     */
    public abstract CallState getCallState();
}