/**
 * 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.shindig.gadgets.parse;

import org.apache.commons.io.IOUtils;
import org.apache.shindig.gadgets.GadgetException;
import org.apache.shindig.gadgets.parse.caja.CajaHtmlParser;
import org.apache.shindig.gadgets.parse.nekohtml.NekoHtmlParser;
import org.apache.shindig.gadgets.parse.nekohtml.NekoSimplifiedHtmlParser;

import org.w3c.dom.DOMImplementation;
import org.w3c.dom.bootstrap.DOMImplementationRegistry;

import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import java.io.File;
import java.io.FileInputStream;
import java.io.StringWriter;

/**
 * Benchmarks for HTML parsing and serialization
 */
public class ParseTreeSerializerBenchmark {
  private DOMImplementationRegistry registry = DOMImplementationRegistry.newInstance();
  private int numRuns;
  private String content;

  private GadgetHtmlParser cajaParser = new CajaHtmlParser(
      DOCUMENT_PROVIDER);

  private GadgetHtmlParser nekoParser = new NekoHtmlParser(
      DOCUMENT_PROVIDER);

  private GadgetHtmlParser nekoSimpleParser = new NekoSimplifiedHtmlParser(
      DOCUMENT_PROVIDER);

  
  private boolean warmup;

  private static final DOMImplementation DOCUMENT_PROVIDER =
      new ParseModule.DOMImplementationProvider().get();

  private ParseTreeSerializerBenchmark(String file, int numRuns) throws Exception {
    File inputFile = new File(file);
    if (!inputFile.exists() || !inputFile.canRead()) {
      System.err.println("Input file: " + file + " not found or can't be read.");
      System.exit(1);
    }
    content = new String(IOUtils.toByteArray(new FileInputStream(file)));

    this.numRuns = 10;
    warmup = true;
    //runCaja();
    runNeko();
    runNekoSimple();
    //Sleep to let JIT kick in
    Thread.sleep(10000L);
    this.numRuns = numRuns;
    warmup = false;
    //runCaja();
    runNeko();
    runNekoSimple();
  }

  private void runCaja() throws Exception {
    output("Caja-----------------");
    // Some warmup runs with wait. Enough iterations to trigger the JIT
    // Wait to allow it to swap execution paths etc...
    timeParseDom(cajaParser);
    timeParseDomSerialize(cajaParser);
  }

  private void runNeko() throws Exception {
    output("Neko-----------------");
    timeParseDom(nekoParser);
    timeParseDomSerialize(nekoParser);
  }

  private void runNekoSimple() throws Exception {
    output("NekoSimple-----------------");
    timeParseDom(nekoSimpleParser);
    timeParseDomSerialize(nekoSimpleParser);
  }

  private void output(String string) {
    if (!warmup) {
      System.out.println(string);
    }
  }

  private void timeParseDom(GadgetHtmlParser parser) throws GadgetException {
    long parseStart = System.currentTimeMillis();
    for (int i = 0; i < numRuns; ++i) {
      parser.parseDom(content);
    }
    long parseMillis = System.currentTimeMillis() - parseStart;

    output("Parsing W3C DOM [" + parseMillis + " ms total: " +
          ((double)parseMillis)/numRuns + "ms/run]");
  }

  private void timeParseDomSerialize(GadgetHtmlParser parser) throws GadgetException {
    org.w3c.dom.Document document = parser.parseDom(content);
    try {
      long parseStart = System.currentTimeMillis();
      for (int i = 0; i < numRuns; ++i) {
        HtmlSerializer.serialize(document);
      }
      long parseMillis = System.currentTimeMillis() - parseStart;

      output("Serializing [" + parseMillis + " ms total: " +
            ((double) parseMillis) / numRuns + "ms/run]");
    } catch (Exception e) {
      throw new GadgetException(GadgetException.Code.HTML_PARSE_ERROR, e);
    }

    try {
      // Create an "identity" transformer - copies input to output
      Transformer t = TransformerFactory.newInstance().newTransformer();
      t.setOutputProperty(OutputKeys.METHOD, "html");

      long parseStart = System.currentTimeMillis();
      for (int i = 0; i < numRuns; ++i) {
        StringWriter sw = new StringWriter((content.length() * 11) / 10);
        t.transform(new DOMSource(document), new StreamResult(sw));
        sw.toString();
      }
      long parseMillis = System.currentTimeMillis() - parseStart;

      output("Serializing DOM Transformer [" + parseMillis + " ms total: " +
            ((double) parseMillis) / numRuns + "ms/run]");
      
    } catch (Exception e) {
      throw new GadgetException(GadgetException.Code.HTML_PARSE_ERROR, e);
    }
  }

  public static void main(String[] args) {
    // Test can be run as standalone program to test out serialization and parsing
    // performance numbers, using Caja as a parser.
    if (args.length != 2) {
      System.err.println("Args: <input-file> <num-runs>");
      System.exit(1);
    }

    String fileArg = args[0];
    String runsArg = args[1];
    int numRuns = -1;
    try {
      numRuns = Integer.parseInt(runsArg);
    } catch (Exception e) {
      System.err.println("Invalid num-runs argument: " + runsArg + ", reason: " + e);
    }
    try {
      new ParseTreeSerializerBenchmark(fileArg, numRuns);
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
}