/*
 * 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.pdfbox.pdmodel.interactive.form;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import org.apache.pdfbox.cos.COSString;
import org.apache.pdfbox.pdfparser.PDFStreamParser;
import org.apache.pdfbox.pdmodel.interactive.annotation.PDAnnotationWidget;

/**
 * Utility class for form-related tests.
 */
public class TestUtils
{
    /**
     * Extract strings from a PDF field's normal appearance stream.
     *
     * @param field the PDF field
     * @return list of strings found in the appearance stream
     * @throws IOException if an error occurs while parsing the stream
     */
    public static List<String> getStringsFromStream(PDField field) throws IOException
    {
    	PDAnnotationWidget widget = field.getWidgets().get(0);
    	PDFStreamParser parser = new PDFStreamParser(widget.getNormalAppearanceStream());
    	
    	Object token = parser.parseNextToken();
    	
    	List<String> stringValues = new ArrayList<String>();
    	
    	while (token != null)
    	{
    		if (token instanceof COSString)
    		{
    			// TODO: improve the string output to better match
    			// trimming as Acrobat adds spaces to strings
    			// where we don't
    			stringValues.add(((COSString) token).getString().trim());
    		}
    		token = parser.parseNextToken();
    	}
    	return stringValues;   	
    }
}
