/*******************************************************************************
 * Copyright (c) 2007 Oracle Corporation.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    Oracle - initial API and implementation
 *    
 ********************************************************************************/

package org.eclipse.jst.jsf.taglibprocessing.attributevalues;

/**
 * Meta-data processing type representing an length attribute value runtime type.
 * Does not support min and max values from MD.  Length must be positive.
 * that implements IValidValues, IDefaultValue, IValidELValues.
 */
public class LengthType extends IntegerType {	
	private static final String INVALID_LENGTH = Messages.LengthType_invalid_integer;
	/**
	 * Type coercion according to JSP 2.0 spec: JSP.1.14.2.1 Conversions from String values
	 * Allows a percentage.
	 * @see org.eclipse.jst.jsf.metadataprocessors.features.IValidValues#isValidValue(java.lang.String)
	 **/
	public boolean isValidValue(String value) {	
		//FIXME:  this is not right... px, em, etc. are also valid... and spaces between # and units are not
		//see http://www.w3.org/TR/html401/types.html#h-6.6
		if (value == null) return true;
		String aValue = stripPercentIfPresent(value);		
		try {
			int anInt = Integer.valueOf(aValue).intValue();
			if (anInt < 0)
				addNewValidationMessage(INVALID_LENGTH);
			
			return getValidationMessages().isEmpty();
		} catch (NumberFormatException e) {
			addNewValidationMessage(INVALID_LENGTH);
			return false;
		}

	}
	//will strip '%' if at end of string.  If string is only '%', then will return empty which will be invalid.
	private String stripPercentIfPresent(String value) {
		//"%" is allowed at end
		if (value.length() > 0
			&& value.lastIndexOf('%') == value.length() - 1)
				return value.replaceFirst("%",""); //$NON-NLS-1$ //$NON-NLS-2$
		
		return value;
	}

}