//
// $Id$
// 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.atsc;

import org.w3c.css.parser.CssStyle;
import org.w3c.css.properties.css.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.CssNumber;
import org.w3c.css.values.CssString;
import org.w3c.css.values.CssValue;

/**
 * <p/>
 * <EM>Value:</EM> &lt;integer&gt; || &lt;identifier&gt; ||
 * &lt;identifier&gt;  &lt;integer&gt; <BR>
 * <EM>Inherited:</EM>no<BR>
 * <EM>Percentages:</EM>no<BR>
 * <EM>Media:</EM>:visual
 * <p/>
 * This property is used to effect explicit directional navigation control by
 * associating specific styled elements with directional navigation events.
 */
public class ATSCNavUp extends CssProperty {

    CssValue navup;
    ApplContext ac;
    CssIdent auto = new CssIdent("auto");

    public ATSCNavUp() {
        // nothing to do
    }

    /**
     * Create a new ATSCNavUp
     *
     * @param expression The expression for this property
     * @throws InvalidParamException Values are incorrect
     */
    public ATSCNavUp(ApplContext ac, CssExpression expression, boolean check)
            throws InvalidParamException {

        if (check && expression.getCount() > 1) {
            throw new InvalidParamException("unrecognize", ac);
        }

        this.ac = ac;
        setByUser(); // tell this property is set by the user
        CssValue val = expression.getValue();

        if (val instanceof CssNumber) {
            navup = val;
            expression.next();
        } else if (val instanceof CssString) {
            navup = val;
            expression.next();
        } else if (val.equals(auto)) {
            navup = val;
            expression.next();
        } else {
            throw new InvalidParamException("value", val.toString(),
                    getPropertyName(), ac);
        }
    }

    public ATSCNavUp(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 (((ATSCStyle) style).navup != null)
            style.addRedefinitionWarning(ac, this);
        ((ATSCStyle) style).navup = 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 ((ATSCStyle) style).getNavUp();
        } else {
            return ((ATSCStyle) style).navup;
        }
    }

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

    /**
     * Returns the name of this property
     */
    public String getPropertyName() {
        return "atsc-nav-up";
    }

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

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

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

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

}