/*
 * JBoss, Home of Professional Open Source
 * Copyright 2011, Red Hat, Inc. and individual contributors
 * by the @authors tag. See the copyright.txt in the distribution for a
 * full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */

package org.mobicents.ss7.linkset.oam;

import javolution.xml.XMLFormat;
import javolution.xml.XMLSerializable;
import javolution.xml.stream.XMLStreamException;

import org.mobicents.protocols.ss7.scheduler.Scheduler;

/**
 * The instance of this class represents the signaling link over which SS7 signaling takes place. A link is in
 * {@link LinkState#UNAVAILABLE UNAVAILABLE} state and mode is {@link LinkMode#UNCONFIGURED UNCONFIGURED} by default.
 *
 * @author amit bhayani
 *
 */
public abstract class Link implements XMLSerializable {

    // Name of link can be max 10 characters
    protected static final int NAME_SIZE = 10;

    protected String linkName = null;

    protected int state = LinkState.UNAVAILABLE;
    protected int mode = LinkMode.UNCONFIGURED;

    protected Linkset linkSet;

    /**
     * Define attributes of xml
     */
    protected static final String LINK_NAME = "name";
    protected static final String LINK_STATE = "state";
    protected static final String LINK_MODE = "mode";

    protected static final boolean TRUE = true;
    protected static final boolean FALSE = false;

    protected Scheduler scheduler;

    public Link() {
    }

    public Link(String linkName) {
        this.linkName = linkName;
    }

    public Scheduler getScheduler() {
        return scheduler;
    }

    public void setScheduler(Scheduler scheduler) {
        this.scheduler = scheduler;
    }

    /**
     * Configure this link.
     *
     * @throws Exception
     */
    protected abstract void configure() throws Exception;

    /**
     * Get link name
     *
     * @return
     */
    public String getName() {
        return linkName;
    }

    /**
     * Get link state
     *
     * @return
     */
    public int getState() {
        return state;
    }

    /**
     * Set link state
     *
     * @param state
     */
    public void setState(int state) {
        this.state = state;
    }

    /**
     * Get link mode
     *
     * @return
     */
    public int getMode() {
        return mode;
    }

    /**
     * Set link mode
     *
     * @param mode
     */
    public void setMode(int mode) {
        this.mode = mode;
    }

    /**
     * Get the {@link Linkset} that this link belongs to
     *
     * @return
     */
    public Linkset getLinkSet() {
        return linkSet;
    }

    /**
     * Set the {@link Linkset}
     *
     * @param linkSet
     */
    public void setLinkSet(Linkset linkSet) {
        this.linkSet = linkSet;
    }

    /**
     * Operation
     */

    /**
     * Deactivate this link. If its not {@link LinkState#AVAILABLE AVAILABLE}, exception is thrown.
     */
    public abstract void deactivate() throws Exception;

    /**
     * Activate this link. If its already {@link LinkState#AVAILABLE AVAILABLE} exception is thrown
     *
     * @throws Exception
     */
    public abstract void activate() throws Exception;

    /**
     * Serialization code
     */
    protected static final XMLFormat<Link> LINK_XML = new XMLFormat<Link>(Link.class) {

        @Override
        public void read(javolution.xml.XMLFormat.InputElement xml, Link link) throws XMLStreamException {
            link.linkName = xml.getAttribute(LINK_NAME).toString();
            link.state = xml.getAttribute(LINK_STATE, LinkState.UNAVAILABLE);
            link.mode = xml.getAttribute(LINK_MODE, LinkMode.UNCONFIGURED);
        }

        @Override
        public void write(Link link, javolution.xml.XMLFormat.OutputElement xml) throws XMLStreamException {
            xml.setAttribute(LINK_NAME, link.linkName);
            xml.setAttribute(LINK_STATE, link.state);
            xml.setAttribute(LINK_MODE, link.mode);

        }
    };

    /**
     * Add the details of this link in passed {@link StringBuffer}. This is for printing the link state.
     *
     * @param sb Add the information in this buffer
     * @param leftPad number of spaces from left side
     * @param descPad number of spaces between each word
     */
    public abstract void print(StringBuffer sb, int leftPad, int descPad);

}