//
// $Id: CssColumnWidth.java,v 1.4 2009-12-15 17:23:49 ylafon Exp $
// From Sijtsche de Jong (sy.de.jong@let.rug.nl)
//
// (c) COPYRIGHT 1995-2000  World Wide Web Consortium (MIT, INRIA, Keio University)
// Please first read the full copyright statement at
// http://www.w3.org/Consortium/Legal/copyright-software-19980720

package org.w3c.css.properties.css3;

import org.w3c.css.parser.CssStyle;
import org.w3c.css.properties.css1.CssProperty;
import org.w3c.css.util.ApplContext;
import org.w3c.css.util.InvalidParamException;
import org.w3c.css.values.CssExpression;
import org.w3c.css.values.CssIdent;
import org.w3c.css.values.CssLength;
import org.w3c.css.values.CssNumber;
import org.w3c.css.values.CssTypes;
import org.w3c.css.values.CssValue;

/**
 *  <P>
 *  <EM>Value:</EM> &lt;integer&gt; || auto <BR>
 *  <EM>Initial:</EM>auto<BR>
 *  <EM>Applies to:</EM>block-level elements<BR>
 *  <EM>Inherited:</EM>no<BR>
 *  <EM>Percentages:</EM>no<BR>
 *  <EM>Media:</EM>:visual
 *  <P>
 *  The 'column-width' property describes the optimal width of columns within the element.
 *  Depending on the value of 'column-width-policy', the actual column width may be
 *  larger than the specified one.
 */

public class CssColumnWidth extends CssProperty {

    CssValue width;

    static CssIdent auto;

    static {
	auto = new CssIdent("auto");
    }

    /**
     * Create a new CssColumnWidth
     */
    public CssColumnWidth() {
	// nothing to do
    }

    /**
     * Create a new CssColumnWidth
     *
     * @param expression The expression for this property
     * @exception InvalidParamException Incorrect value
     */
    public CssColumnWidth(ApplContext ac, CssExpression expression,
	    boolean check) throws InvalidParamException {

	setByUser();
	CssValue val = expression.getValue();
	Float value;

	switch (val.getType()) {
	case CssTypes.CSS_NUMBER:
	    val = ((CssNumber)val).getLength();
	    // if we didn't fall in the first trap, there is another one :)
	    throw new InvalidParamException("strictly-positive", 
					    expression.getValue(),
					    getPropertyName(), ac);
	case CssTypes.CSS_LENGTH:
	    value = (Float) ((CssLength)val).get();
	    if (value == null || value.floatValue() <= 0.0) {
		throw new InvalidParamException("strictly-positive", 
						expression.getValue(),
						getPropertyName(), ac);
	    }
	    width = val;
	    break;
	case CssTypes.CSS_IDENT:
	    if (inherit.equals(val)) {
		width = inherit;
		break;
	    } else if ( auto.equals(val)) {
		width = auto;
		break;
	    } 
	default:
	    throw new InvalidParamException("value", expression.getValue(),
					    getPropertyName(), ac);
	}
	expression.next();
    }

    public CssColumnWidth(ApplContext ac, CssExpression expression)
	    throws InvalidParamException {
	this(ac, expression, false);
    }

    /**
     * Add this property to the CssStyle
     *
     * @param style The CssStyle
     */
    public void addToStyle(ApplContext ac, CssStyle style) {
	if (((Css3Style) style).cssColumnWidth != null)
	    style.addRedefinitionWarning(ac, this);
	((Css3Style) style).cssColumnWidth = this;
    }

    /**
     * Get this property in the style.
     *
     * @param style The style where the property is
     * @param resolve if true, resolve the style to find this property
     */
    public CssProperty getPropertyInStyle(CssStyle style, boolean resolve) {
	if (resolve) {
	    return ((Css3Style) style).getColumnWidth();
	}
	else {
	    return ((Css3Style) style).cssColumnWidth;
	}
    }

    /**
     * Compares two properties for equality.
     *
     * @param value The other property.
     */
    public boolean equals(CssProperty property) {
	return (property instanceof CssColumnWidth &&
		width.equals(((CssColumnWidth) property).width));
    }

    /**
     * Returns the name of this property
     */
    public String getPropertyName() {
	return "column-width";
    }

    /**
     * Returns the value of this property
     */
    public Object get() {
	return width;
    }

    /**
     * Returns true if this property is "softly" inherited
     */
    public boolean isSoftlyInherited() {
	return width.equals(inherit);
    }

    /**
     * Returns a string representation of the object
     */
    public String toString() {
	return width.toString();
    }

    /**
     * Is the value of this property a default value
     * It is used by alle macro for the function <code>print</code>
     */
    public boolean isDefault() {
	return (width == auto);
    }

}
