/* FencedAtom.java
 * =========================================================================
 * This file is originally part of the JMathTeX Library - http://jmathtex.sourceforge.net
 * 
 * Copyright (C) 2004-2007 Universiteit Gent
 * Copyright (C) 2009 DENIZET Calixte
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or (at
 * your option) any later version.
 * 
 * This program 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
 * General Public License for more details.
 * 
 * A copy of the GNU General Public License can be found in the file
 * LICENSE.txt provided with the source distribution of this program (see
 * the META-INF directory in the source jar). This license can also be
 * found on the GNU website at http://www.gnu.org/licenses/gpl.html.
 * 
 * If you did not receive a copy of the GNU General Public License along
 * with this program, contact the lead developer, or write to the Free
 * Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 * 
 */

/* Modified by Calixte Denizet */

package org.scilab.forge.jlatexmath;

import java.util.List;

/**
 * An atom representing a base atom surrounded with delimiters that change their size
 * according to the height of the base.
 */
public class FencedAtom extends Atom {
    
    // parameters used in the TeX algorithm
    private static final int DELIMITER_FACTOR = 901;
    
    private static final float DELIMITER_SHORTFALL = 5f;

    // base atom
    private final Atom base;
    
    // delimiters
    private SymbolAtom left = null; 
    private SymbolAtom right = null;
    private final List<MiddleAtom> middle;
    
    /**
     * Creates a new FencedAtom from the given base and delimiters
     * 
     * @param base the base to be surrounded with delimiters
     * @param l the left delimiter
     * @param r the right delimiter
     */
    public FencedAtom(Atom base, SymbolAtom l, SymbolAtom r) {
	this(base, l, null, r);
    }
    
    public FencedAtom(Atom base, SymbolAtom l, List m, SymbolAtom r) {
	if (base == null)
	    this.base = new RowAtom(); // empty base
	else
	    this.base = base;
	if (l == null || !l.getName().equals("normaldot")) {
	    left = l;
	}
	if (r == null || !r.getName().equals("normaldot")) {
	    right = r;
	}
	middle =  m;
    }
    
    public int getLeftType() {
	return TeXConstants.TYPE_OPENING;
    }
    
    public int getRightType() {
	return TeXConstants.TYPE_CLOSING;
    }
    
    /**
    * Centers the given box with resprect to the given axis, by setting an appropriate
    * shift value.
    * 
    * @param box
    *           box to be vertically centered with respect to the axis
    */
    private static void center(Box box, float axis) {
	float h = box.getHeight(), total = h + box.getDepth();
	box.setShift(-(total / 2 - h) - axis);
    }
    
    public Box createBox(TeXEnvironment env) {
	TeXFont tf = env.getTeXFont();	
	Box content = base.createBox(env);
	float shortfall = DELIMITER_SHORTFALL * SpaceAtom.getFactor(TeXConstants.UNIT_POINT, env);
	float axis = tf.getAxisHeight(env.getStyle());
	float delta = Math.max(content.getHeight() - axis, content.getDepth() + axis);
	float minHeight = Math.max((delta / 500) * DELIMITER_FACTOR, 2 * delta - shortfall);
	
	// construct box
	HorizontalBox hBox = new HorizontalBox();

	if (middle != null) {
	    for (int i = 0; i < middle.size(); i++) {
		MiddleAtom at = middle.get(i);
		if (at.base instanceof SymbolAtom) {
		    Box b = DelimiterFactory.create(((SymbolAtom) at.base).getName(), env, minHeight);
		    center(b, axis);
		    at.box = b;
		}
	    }
	    if (middle.size() != 0) {
		content = base.createBox(env);
	    }
	}
	
	// left delimiter
	if (left != null) {
	    Box b = DelimiterFactory.create(left.getName(), env, minHeight);
	    center(b, axis);
	    hBox.add(b);
	}
	
	// glue between left delimiter and content (if not whitespace)
	if (!(base instanceof SpaceAtom)) {
	    hBox.add(Glue.get(TeXConstants.TYPE_OPENING, base.getLeftType(), env));
	}	

	// add content
	hBox.add(content);
	
	// glue between right delimiter and content (if not whitespace)
	if (!(base instanceof SpaceAtom)) {
	    hBox.add(Glue.get(base.getRightType(), TeXConstants.TYPE_CLOSING, env));
	}

	// right delimiter
	if (right != null) {
	    Box b = DelimiterFactory.create(right.getName(), env, minHeight);
	    center(b, axis);
	    hBox.add(b);
	}

	return hBox;
    }    
}
