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 *       copyright notice, this list of conditions and the following
 *       disclaimer in the documentation and/or other materials provided
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package com.android.incallui;

import android.os.Bundle;
import com.android.incallui.InCallPresenter.InCallDetailsListener;
import com.google.common.base.Preconditions;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.List;

import org.codeaurora.QtiVideoCallConstants;

/**
 * This class listens to incoming events from the {@class InCallDetailsListener}.
 * When call details change, this class is notified and we parse the extras from the details to
 * figure out if session modification cause has been sent when a call upgrades/downgrades and
 * notify the {@class InCallMessageController} to display the indication on UI.
 */
public class SessionModificationCauseNotifier implements InCallDetailsListener{

    private final List<InCallSessionModificationCauseListener> mSessionModificationCauseListeners
            = new CopyOnWriteArrayList<>();

    private static SessionModificationCauseNotifier sSessionModificationCauseNotifier;

    /**
     * Returns a singleton instance of {@class SessionModificationCauseNotifier}
     */
    public static synchronized SessionModificationCauseNotifier getInstance() {
        if (sSessionModificationCauseNotifier == null) {
            sSessionModificationCauseNotifier = new SessionModificationCauseNotifier();
        }
        return sSessionModificationCauseNotifier;
    }

    /**
     * Adds a new session modification cause listener. Users interested in this cause
     * should add a listener of type {@class InCallSessionModificationCauseListener}
     */
    public void addListener(InCallSessionModificationCauseListener listener) {
        Preconditions.checkNotNull(listener);
        mSessionModificationCauseListeners.add(listener);
    }

    /**
     * Removes an existing session modification cause listener. Users listening to any cause
     * changes when not interested any more can de-register an existing listener of type
     * {@class InCallSessionModificationCauseListener}
     */
    public void removeListener(InCallSessionModificationCauseListener listener) {
        if (listener != null) {
            mSessionModificationCauseListeners.remove(listener);
        } else {
            Log.e(this, "Can't remove null listener");
        }
    }

    /**
     * Private constructor. Must use getInstance() to get this singleton.
     */
    private SessionModificationCauseNotifier() {
    }

    /**
     * Overrides onDetailsChanged method of {@class InCallDetailsListener}. We are
     * notified when call details change and extract the session modification cause from the
     * extras, detect if the cause has changed and notify all registered listeners.
     */
    @Override
    public void onDetailsChanged(Call call, android.telecom.Call.Details details) {
        Log.d(this, "onDetailsChanged: - call: " + call + "details: " + details);
        final Bundle extras =  (call != null && details != null) ? details.getExtras() : null;
        final int sessionModificationCause = (extras != null) ? extras.getInt(
                QtiVideoCallConstants.SESSION_MODIFICATION_CAUSE_EXTRA_KEY,
                QtiVideoCallConstants.CAUSE_CODE_UNSPECIFIED) :
                QtiVideoCallConstants.CAUSE_CODE_UNSPECIFIED;

        if (sessionModificationCause != QtiVideoCallConstants.CAUSE_CODE_UNSPECIFIED) {
            Preconditions.checkNotNull(mSessionModificationCauseListeners);
            for (InCallSessionModificationCauseListener listener :
                    mSessionModificationCauseListeners) {
                listener.onSessionModificationCauseChanged(call, sessionModificationCause);
            }
        }
    }
}