/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 */

/* $Id$ */

package org.apache.fop.render.afp.modca.goca;

import org.apache.fop.render.afp.tools.BinaryUtils;

/**
 * A base class encapsulating the structure of coordinate based GOCA objects
 */
public abstract class AbstractGraphicsCoord extends AbstractPreparedAFPObject {

    /** array of x/y coordinates */
    protected int[] coords = null;

    /**
     * @param coords the x/y coordinates for this object
     */
    public AbstractGraphicsCoord(int[] coords) {
        this.coords = coords;
        prepareData();
    }
               
    /**
     * @param x the x coordinate for this object
     * @param y the y coordinate for this object
     */
    public AbstractGraphicsCoord(int x, int y) {
        this(new int[] {x, y});
    }

    /**
     * @param x1 the x1 coordinate for this object
     * @param y1 the y1 coordinate for this object
     * @param x2 the x2 coordinate for this object
     * @param y2 the y2 coordinate for this object
     */
    public AbstractGraphicsCoord(int x1, int y1, int x2, int y2) {
        this(new int[] {x1, y1, x2, y2});
    }

    /**
     * @return the order code to use
     */
    protected abstract byte getOrderCode();

    /**
     * @return the length of this order code
     * (typically this is the same as the coordinate length)
     */
    protected int getLength() {
        return this.coords.length * 2;
    }

    /**
     * Creates a newly created and initialized byte data
     * @return a newly created and initialized byte data
     */
    protected byte[] createData() {
        int len = getLength();
        byte[] data = new byte[len + 2];
        data[0] = getOrderCode(); // ORDER CODE
        data[1] = (byte)len; // LENGTH
        return data;
    }

    /**
     * {@inheritDoc}
     */
    protected void prepareData() {
        super.data = createData();
        int fromIndex = data.length - getLength();
        addCoords(data, fromIndex);
    }

    /**
     * Adds the coordinates to the structured field data
     * @param data the structured field data
     * @param fromIndex the start index
     */
    protected void addCoords(byte[] data, int fromIndex) {
        // X/Y POS
        for (int i = 0; i < coords.length; i++, fromIndex += 2) {
            byte[] coord = BinaryUtils.convert(coords[i], 2);
            data[fromIndex] = coord[0];
            data[fromIndex + 1] = coord[1];            
        }
    }
    
    /**
     * @return the short name of this GOCA object
     */
    protected String getName() {
        String className = getClass().getName();
        return className.substring(className.lastIndexOf(".") + 1);
    }

    /**
     * {@inheritDoc}
     */
    public String toString() {
        String coordsStr = "";
        for (int i = 0; i < coords.length; i++) {
            coordsStr += (i % 2 == 0) ? "x" : "y";
            coordsStr += (i / 2) + "=" + coords[i] + ",";                   
        }
        coordsStr = coordsStr.substring(0, coordsStr.length() - 1);
        return getName() + "(" + coordsStr + ")";
    }        
}