/*
 *
 *  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.
 *
 */

package org.apache.flex.compiler.internal.css;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.antlr.runtime.TokenStream;
import org.antlr.runtime.tree.CommonTree;

/**
 * Implementation for number CSS property values. The number can also have a
 * unit string. For example: <code>12px; 12em; 12%</code>
 */
public class CSSNumberPropertyValue extends CSSPropertyValue
{
    /**
     * Match a signed real number.
     * 
     * <pre>
     * +100
     * -3.14
     * .25
     * 10.00
     * </pre>
     */
    private static final Pattern PATTERN = Pattern.compile(
            "[\\+\\-]?((\\d+(\\.\\d+)?)|(\\.\\d+))");

    protected CSSNumberPropertyValue(final String numberWithUnit,
                                     final CommonTree tree,
                                     final TokenStream tokenStream)
    {
        super(tree, tokenStream, CSSModelTreeType.PROPERTY_VALUE);
        assert numberWithUnit != null : "Number can't be null.";

        final Matcher matcher = PATTERN.matcher(numberWithUnit);
        if (matcher.find())
        {
            this.number = Float.parseFloat(matcher.group());
            this.unit = numberWithUnit.substring(matcher.end());
        }
        else
        {
            this.number = null;
            this.unit = null;
        }
        this.raw = numberWithUnit;
    }

    private final String raw;
    private final Number number;
    private final String unit;

    /**
     * @return The number value.
     */
    public Number getNumber()
    {
        return number;
    }

    /**
     * @return Unit for the number; Or {@code null} if this number doesn't have
     * a unit.
     */
    public String getUnit()
    {
        return unit;
    }

    @Override
    public String toString()
    {
        return raw;
    }
}