/**
 * 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.nutch.util;

import java.io.IOException;

import org.junit.Assert;
import org.junit.Test;

/** Unit tests for GZIPUtils methods. */
public class TestGZIPUtils {

  /* a short, highly compressable, string */
  String SHORT_TEST_STRING = "aaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbcccccccccccccccc";

  /* a short, highly compressable, string */
  String LONGER_TEST_STRING = SHORT_TEST_STRING + SHORT_TEST_STRING
      + SHORT_TEST_STRING + SHORT_TEST_STRING + SHORT_TEST_STRING
      + SHORT_TEST_STRING + SHORT_TEST_STRING + SHORT_TEST_STRING
      + SHORT_TEST_STRING + SHORT_TEST_STRING + SHORT_TEST_STRING
      + SHORT_TEST_STRING;

  /* a snapshot of the nutch webpage */
  String WEBPAGE = "<!DOCTYPE html PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">\n"
      + "<html>\n"
      + "<head>\n"
      + "  <meta http-equiv=\"content-type\"\n"
      + " content=\"text/html; charset=ISO-8859-1\">\n"
      + "  <title>Nutch</title>\n"
      + "</head>\n"
      + "<body>\n"
      + "<h1\n"
      + " style=\"font-family: helvetica,arial,sans-serif; text-align: center; color: rgb(255, 153, 0);\"><a\n"
      + " href=\"http://www.nutch.org/\"><font style=\"color: rgb(255, 153, 0);\">Nutch</font></a><br>\n"
      + "<small>an open source web-search engine</small></h1>\n"
      + "<hr style=\"width: 100%; height: 1px;\" noshade=\"noshade\">\n"
      + "<table\n"
      + " style=\"width: 100%; text-align: left; margin-left: auto; margin-right: auto;\"\n"
      + " border=\"0\" cellspacing=\"0\" cellpadding=\"0\">\n"
      + "  <tbody>\n"
      + "    <tr>\n"
      + "      <td style=\"vertical-align: top; text-align: center;\"><a\n"
      + " href=\"http://sourceforge.net/project/showfiles.php?group_id=59548\">Download</a><br>\n"
      + "      </td>\n"
      + "      <td style=\"vertical-align: top; text-align: center;\"><a\n"
      + " href=\"tutorial.html\">Tutorial</a><br>\n"
      + "      </td>\n"
      + "      <td style=\"vertical-align: top; text-align: center;\"><a\n"
      + " href=\"http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/nutch/nutch/\">CVS</a><br>\n"
      + "      </td>\n"
      + "      <td style=\"vertical-align: top; text-align: center;\"><a\n"
      + " href=\"api/index.html\">Javadoc</a><br>\n"
      + "      </td>\n"
      + "      <td style=\"vertical-align: top; text-align: center;\"><a\n"
      + " href=\"http://sourceforge.net/tracker/?atid=491356&amp;group_id=59548&amp;func=browse\">Bugs</a><br>\n"
      + "      </td>\n"
      + "      <td style=\"vertical-align: top; text-align: center;\"><a\n"
      + " href=\"http://sourceforge.net/mail/?group_id=59548\">Lists</a></td>\n"
      + "      <td style=\"vertical-align: top; text-align: center;\"><a\n"
      + " href=\"policies.html\">Policies</a><br>\n"
      + "      </td>\n"
      + "    </tr>\n"
      + "  </tbody>\n"
      + "</table>\n"
      + "<hr style=\"width: 100%; height: 1px;\" noshade=\"noshade\">\n"
      + "<h2>Introduction</h2>\n"
      + "Nutch is a nascent effort to implement an open-source web search\n"
      + "engine. Web search is a basic requirement for internet navigation, yet\n"
      + "the number of web search engines is decreasing. Today's oligopoly could\n"
      + "soon be a monopoly, with a single company controlling nearly all web\n"
      + "search for its commercial gain. &nbsp;That would not be good for the\n"
      + "users of internet. &nbsp;Nutch aims to enable anyone to easily and\n"
      + "cost-effectively deploy a world-class web search engine.<br>\n"
      + "<br>\n"
      + "To succeed, the Nutch software must be able to:<br>\n"
      + "<ul>\n"
      + "  <li> crawl several billion pages per month</li>\n"
      + "  <li>maintain an index of these pages</li>\n"
      + "  <li>search that index up to 1000 times per second</li>\n"
      + "  <li>provide very high quality search results</li>\n"
      + "  <li>operate at minimal cost</li>\n"
      + "</ul>\n"
      + "<h2>Status</h2>\n"
      + "Currently we're just a handful of developers working part-time to put\n"
      + "together a demo. &nbsp;The demo is coded entirely in Java. &nbsp;However\n"
      + "persistent data is written in well-documented formats so that modules\n"
      + "may eventually be re-written in other languages (e.g., Perl, C++) as the\n"
      + "project progresses.<br>\n"
      + "<br>\n"
      + "<hr style=\"width: 100%; height: 1px;\" noshade=\"noshade\"> <a\n"
      + " href=\"http://sourceforge.net\"> </a>\n"
      + "<div style=\"text-align: center;\"><a href=\"http://sourceforge.net\"><img\n"
      + " src=\"http://sourceforge.net/sflogo.php?group_id=59548&amp;type=1\"\n"
      + " style=\"border: 0px solid ; width: 88px; height: 31px;\"\n"
      + " alt=\"SourceForge.net Logo\" title=\"\"></a></div>\n"
      + "</body>\n"
      + "</html>\n";

  @Test
  public void testZipUnzip() {
    byte[] testBytes = SHORT_TEST_STRING.getBytes();
    testZipUnzip(testBytes);
    testBytes = LONGER_TEST_STRING.getBytes();
    testZipUnzip(testBytes);
    testBytes = WEBPAGE.getBytes();
    testZipUnzip(testBytes);
  }

  @Test
  public void testZipUnzipBestEffort() {
    byte[] testBytes = SHORT_TEST_STRING.getBytes();
    testZipUnzipBestEffort(testBytes);
    testBytes = LONGER_TEST_STRING.getBytes();
    testZipUnzipBestEffort(testBytes);
    testBytes = WEBPAGE.getBytes();
    testZipUnzipBestEffort(testBytes);
  }

  public void testTruncation() {
    byte[] testBytes = SHORT_TEST_STRING.getBytes();
    testTruncation(testBytes);
    testBytes = LONGER_TEST_STRING.getBytes();
    testTruncation(testBytes);
    testBytes = WEBPAGE.getBytes();
    testTruncation(testBytes);
  }

  @Test
  public void testLimit() {
    byte[] testBytes = SHORT_TEST_STRING.getBytes();
    testLimit(testBytes);
    testBytes = LONGER_TEST_STRING.getBytes();
    testLimit(testBytes);
    testBytes = WEBPAGE.getBytes();
    testLimit(testBytes);
  }

  // helpers

  public void testZipUnzip(byte[] origBytes) {
    byte[] compressedBytes = GZIPUtils.zip(origBytes);

    Assert.assertTrue("compressed array is not smaller!",
        compressedBytes.length < origBytes.length);

    byte[] uncompressedBytes = null;
    try {
      uncompressedBytes = GZIPUtils.unzip(compressedBytes);
    } catch (IOException e) {
      e.printStackTrace();
      Assert.assertTrue("caught exception '" + e + "' during unzip()", false);
    }
    Assert.assertTrue("uncompressedBytes is wrong size",
        uncompressedBytes.length == origBytes.length);

    for (int i = 0; i < origBytes.length; i++)
      if (origBytes[i] != uncompressedBytes[i])
        Assert.assertTrue("uncompressedBytes does not match origBytes", false);
  }

  public void testZipUnzipBestEffort(byte[] origBytes) {
    byte[] compressedBytes = GZIPUtils.zip(origBytes);

    Assert.assertTrue("compressed array is not smaller!",
        compressedBytes.length < origBytes.length);

    byte[] uncompressedBytes = GZIPUtils.unzipBestEffort(compressedBytes);
    Assert.assertTrue("uncompressedBytes is wrong size",
        uncompressedBytes.length == origBytes.length);

    for (int i = 0; i < origBytes.length; i++)
      if (origBytes[i] != uncompressedBytes[i])
        Assert.assertTrue("uncompressedBytes does not match origBytes", false);
  }

  public void testTruncation(byte[] origBytes) {
    byte[] compressedBytes = GZIPUtils.zip(origBytes);

    System.out.println("original data has len " + origBytes.length);
    System.out.println("compressed data has len " + compressedBytes.length);

    for (int i = compressedBytes.length; i >= 0; i--) {

      byte[] truncCompressed = new byte[i];

      for (int j = 0; j < i; j++)
        truncCompressed[j] = compressedBytes[j];

      byte[] trunc = GZIPUtils.unzipBestEffort(truncCompressed);

      if (trunc == null) {
        System.out.println("truncated to len " + i + ", trunc is null");
      } else {
        System.out.println("truncated to len " + i + ", trunc.length=  "
            + trunc.length);

        for (int j = 0; j < trunc.length; j++)
          if (trunc[j] != origBytes[j])
            Assert.assertTrue("truncated/uncompressed array differs at pos "
                + j + " (compressed data had been truncated to len " + i + ")",
                false);
      }
    }
  }

  public void testLimit(byte[] origBytes) {
    byte[] compressedBytes = GZIPUtils.zip(origBytes);

    Assert.assertTrue("compressed array is not smaller!",
        compressedBytes.length < origBytes.length);

    for (int i = 0; i < origBytes.length; i++) {

      byte[] uncompressedBytes = GZIPUtils.unzipBestEffort(compressedBytes, i);

      Assert.assertTrue("uncompressedBytes is wrong size",
          uncompressedBytes.length == i);

      for (int j = 0; j < i; j++)
        if (origBytes[j] != uncompressedBytes[j])
          Assert
              .assertTrue("uncompressedBytes does not match origBytes", false);
    }
  }

}
