/**
*    Copyright (c) 2008 The Board of Trustees of The Leland Stanford Junior
*    University
* 
*    Licensed under the Apache License, Version 2.0 (the "License"); you may
*    not use this file except in compliance with the License. You may obtain
*    a copy of the License at
*
*         http://www.apache.org/licenses/LICENSE-2.0
*
*    Unless required by applicable law or agreed to in writing, software
*    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
*    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
*    License for the specific language governing permissions and limitations
*    under the License.
**/

package org.openflow.protocol.action;


import org.jboss.netty.buffer.ChannelBuffer;
import org.openflow.util.U16;

/**
 * The base class for all OpenFlow Actions.
 *
 * @author David Erickson (daviderickson@cs.stanford.edu) - Mar 11, 2010
 */
public class OFAction implements Cloneable {
    /**
     * Note the true minimum length for this header is 8 including a pad to 64
     * bit alignment, however as this base class is used for demuxing an
     * incoming Action, it is only necessary to read the first 4 bytes.  All
     * Actions extending this class are responsible for reading/writing the
     * first 8 bytes, including the pad if necessary.
     */
    public static int MINIMUM_LENGTH = 4;
    public static int OFFSET_LENGTH = 2;
    public static int OFFSET_TYPE = 0;

    protected OFActionType type;
    protected short length;

    /**
     * Get the length of this message
     *
     * @return
     */
    public short getLength() {
        return length;
    }

    /**
     * Get the length of this message, unsigned
     *
     * @return
     */
    public int getLengthU() {
        return U16.f(length);
    }

    /**
     * Set the length of this message
     *
     * @param length
     */
    public OFAction setLength(short length) {
        this.length = length;
        return this;
    }

    /**
     * Get the type of this message
     *
     * @return OFActionType enum
     */
    public OFActionType getType() {
        return this.type;
    }

    /**
     * Set the type of this message
     *
     * @param type
     */
    public void setType(OFActionType type) {
        this.type = type;
    }

    /**
     * Returns a summary of the message
     * @return "ofmsg=v=$version;t=$type:l=$len:xid=$xid"
     */
    public String toString() {
        return "ofaction" +
            ";t=" + this.getType() +
            ";l=" + this.getLength();
    }
    
    /**
     * Given the output from toString(), 
     * create a new OFAction
     * @param val
     * @return
     */
    public static OFAction fromString(String val) {
        String tokens[] = val.split(";");
        if (!tokens[0].equals("ofaction"))
            throw new IllegalArgumentException("expected 'ofaction' but got '" + 
                    tokens[0] + "'");
        String type_tokens[] = tokens[1].split("="); 
        String len_tokens[] = tokens[2].split("=");
        OFAction action = new OFAction();
        action.setLength(Short.valueOf(len_tokens[1]));
        action.setType(OFActionType.valueOf(type_tokens[1]));
        return action;
    }

    public void readFrom(ChannelBuffer data) {
        this.type = OFActionType.valueOf(data.readShort());
        this.length = data.readShort();
        // Note missing PAD, see MINIMUM_LENGTH comment for details
    }

    public void writeTo(ChannelBuffer data) {
        data.writeShort(type.getTypeValue());
        data.writeShort(length);
        // Note missing PAD, see MINIMUM_LENGTH comment for details
    }

    @Override
    public int hashCode() {
        final int prime = 347;
        int result = 1;
        result = prime * result + length;
        result = prime * result + ((type == null) ? 0 : type.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null) {
            return false;
        }
        if (!(obj instanceof OFAction)) {
            return false;
        }
        OFAction other = (OFAction) obj;
        if (length != other.length) {
            return false;
        }
        if (type == null) {
            if (other.type != null) {
                return false;
            }
        } else if (!type.equals(other.type)) {
            return false;
        }
        return true;
    }

    /* (non-Javadoc)
     * @see java.lang.Object#clone()
     */
    @Override
    public OFAction clone() throws CloneNotSupportedException {
        return (OFAction) super.clone();
    }
    
}