/*
 * $Id$
 *
 * 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 com.wxxr.nirvana.json;

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

import junit.framework.Assert;

import org.apache.commons.io.IOUtils;
import org.apache.commons.lang3.StringUtils;

/**
 * Utility methods for test classes
 */
public class TestUtils {
    /**
     * A regex pattern for recognizing blocks of whitespace characters.
     */
    private static final Pattern WHITESPACE_BLOCK = Pattern.compile("\\s+");

    /**
     * normalizes a string so that strings generated on different platforms can
     * be compared. any group of one or more space, tab, \r, and \n characters
     * are converted to a single space character
     * 
     * @param obj
     *            the object to be normalized. normalize will perform its
     *            operation on obj.toString().trim() ;
     * @param appendSpace
     * @return the normalized string
     */
    public static String normalize(Object obj, boolean appendSpace) {
        Matcher matcher = WHITESPACE_BLOCK.matcher(StringUtils.trim(obj.toString()));
        /*
        FIXME: appendSpace has been always ignored, uncommenting the following line will cause dozen of test fails
        if (appendSpace) {
            return matcher.replaceAll(" ");
        }
        */
        return matcher.replaceAll("");
    }

    public static String normalize(URL url) throws Exception {
        return normalize(readContent(url), true);
    }

    /**
     * Attempt to verify the contents of text against the contents of the URL
     * specified. Performs a trim on both ends
     * 
     * @param url
     *            the HTML snippet that we want to validate against
     * @throws Exception
     *             if the validation failed
     */
    public static boolean compare(URL url, String text) throws Exception {
        /**
         * compare the trimmed values of each buffer and make sure they're
         * equivalent. however, let's make sure to normalize the strings first
         * to account for line termination differences between platforms.
         */
        String writerString = TestUtils.normalize(text, true);
        String bufferString = TestUtils.normalize(readContent(url), true);

        return bufferString.equals(writerString);
    }

    public static void assertEquals(URL source, String text) throws Exception {
        String writerString = TestUtils.normalize(text, true);
        String bufferString = TestUtils.normalize(readContent(source), true);
        Assert.assertEquals(bufferString,writerString);
    }

    public static String readContent(URL url) throws Exception {
        if (url == null)
            throw new Exception("unable to verify a null URL");

        return IOUtils.toString(url.openStream());
    }
}
