// This Source Code is in the Public Domain per: http://unlicense.org
package org.litesoft.GWT.eventbus.client.nonpublic;

import org.litesoft.GWT.eventbus.client.*;
import org.litesoft.commonfoundation.base.*;

public class TimerNode {
    private TimerNode mPrev = null;
    private TimerNode mNext = null;
    private long mFireWhen;
    private int mClientIdNumber;
    private EventPackage mParcel;

    public TimerNode( int pFireInMilliSecs, int pClientIdNumber, EventPackage pPackage ) {
        long now = MillisecTimeSource.INSTANCE.now();
        mFireWhen = now + pFireInMilliSecs;
        mClientIdNumber = pClientIdNumber;
        if ( null == (mParcel = pPackage) ) {
            throw new IllegalArgumentException( "Parcel may not be null" );
        }
    }

    public long getFireWhen() {
        return mFireWhen;
    }

    public int getClientIdNumber() {
        return mClientIdNumber;
    }

    public EventPackage getParcel() {
        return mParcel;
    }

    public boolean isBefore( TimerNode pTimerNode ) {
        return (pTimerNode != null) && (this.mFireWhen < pTimerNode.mFireWhen);
    }

    /**
     * Remove 'this' from LinkList
     *
     * @return mNext
     */
    public TimerNode remove() {
        // x - this - y
        TimerNode rv = this.mNext;
        if ( this.mPrev != null ) {
            mPrev.mNext = this.mNext;
        }
        if ( this.mNext != null ) {
            mNext.mPrev = this.mPrev;
        }
        mPrev = mNext = null;
        // x - y
        return rv;
    }

    /**
     * Insert 'pNewTimerNode' before 'this' in the LinkList
     *
     * @param pNewTimerNode may NOT have its links set
     *
     * @return pNewTimerNode
     */
    public TimerNode insertBeforeMe( TimerNode pNewTimerNode ) {
        // x - this - y
        if ( chk( pNewTimerNode ) ) {
            pNewTimerNode.mNext = this;
            pNewTimerNode.mPrev = this.mPrev;
            if ( this.mPrev != null ) {
                this.mPrev.mNext = pNewTimerNode;
            }
            this.mPrev = pNewTimerNode;
        }
        // x - pNewTimerNode - this - y
        return pNewTimerNode;
    }

    /**
     * Insert 'pNewTimerNode' after 'this' in the LinkList
     *
     * @param pNewTimerNode may NOT have its links set
     */
    public void insertAfterMe( TimerNode pNewTimerNode ) {
        // x - this - y
        if ( chk( pNewTimerNode ) ) {
            pNewTimerNode.mNext = this.mNext;
            if ( this.mNext != null ) {
                this.mNext.mPrev = pNewTimerNode;
            }
            this.mNext = pNewTimerNode;
            pNewTimerNode.mPrev = this;
        }
        // x - this - pNewTimerNode - y
    }

    private boolean chk( TimerNode pNewTimerNode ) {
        if ( pNewTimerNode == null ) {
            return false;
        }
        if ( (pNewTimerNode.mPrev != null) || (pNewTimerNode.mNext != null) ) {
            throw new IllegalArgumentException( "NewTimerNode has non-Null links" );
        }
        return true;
    }

    /**
     * @return the New Head
     */
    public static TimerNode addTo( TimerNode pCurrentHead, TimerNode pNewTimerNode ) {
        if ( pNewTimerNode == null ) {
            return pCurrentHead;
        }
        if ( pCurrentHead == null ) {
            return pNewTimerNode;
        }
        if ( pNewTimerNode.isBefore( pCurrentHead ) ) {
            return pCurrentHead.insertBeforeMe( pNewTimerNode );
        }
        TimerNode cur = pCurrentHead;
        while ( cur.mNext != null ) {
            cur = cur.mNext;
            if ( pNewTimerNode.isBefore( cur ) ) {
                cur.insertBeforeMe( pNewTimerNode );
                return pCurrentHead;
            }
        }
        cur.insertAfterMe( pNewTimerNode );
        return pCurrentHead;
    }
}