/**
 * 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.activemq.openwire;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;

public abstract class DataFileGenerator extends org.junit.Assert {

   static final File MODULE_BASE_DIR;
   static final File CONTROL_DIR;
   static final File CLASS_FILE_DIR;

   static {
      MODULE_BASE_DIR = new File(System.getProperty("basedir", "."));
      CONTROL_DIR = new File(MODULE_BASE_DIR, "src/test/resources/openwire-control");
      CLASS_FILE_DIR = new File(MODULE_BASE_DIR, "src/test/java/org/apache/activemq/openwire");
   }

   public static void main(String[] args) throws Exception {
      generateControlFiles();
   }

   /**
    * @param srcdir
    * @return
    * @throws ClassNotFoundException
    * @throws InstantiationException
    * @throws IllegalAccessException
    */
   public static ArrayList<DataFileGenerator> getAllDataFileGenerators() throws Exception {
      // System.out.println("Looking for generators in : "+classFileDir);
      ArrayList<DataFileGenerator> l = new ArrayList<>();
      File[] files = CLASS_FILE_DIR.listFiles();
      for (int i = 0; files != null && i < files.length; i++) {
         File file = files[i];
         if (file.getName().endsWith("Data.java")) {
            String cn = file.getName();
            cn = cn.substring(0, cn.length() - ".java".length());
            Class<?> clazz = DataFileGenerator.class.getClassLoader().loadClass("org.apache.activemq.openwire." + cn);
            l.add((DataFileGenerator) clazz.newInstance());
         }
      }
      return l;
   }

   private static void generateControlFiles() throws Exception {
      ArrayList<DataFileGenerator> generators = getAllDataFileGenerators();
      for (DataFileGenerator element : generators) {
         try {
            // System.out.println("Processing: "+object.getClass());
            element.generateControlFile();
         } catch (Exception e) {
            // System.err.println("Error while processing:
            // "+object.getClass() + ". Reason: " + e);
         }
      }
   }

   public void generateControlFile() throws Exception {
      CONTROL_DIR.mkdirs();
      File dataFile = new File(CONTROL_DIR, getClass().getName() + ".bin");

      OpenWireFormat wf = new OpenWireFormat();
      wf.setCacheEnabled(false);
      wf.setStackTraceEnabled(false);
      wf.setVersion(1);

      FileOutputStream os = new FileOutputStream(dataFile);
      DataOutputStream ds = new DataOutputStream(os);
      wf.marshal(createObject(), ds);
      ds.close();
   }

   public InputStream generateInputStream() throws Exception {
      OpenWireFormat wf = new OpenWireFormat();
      wf.setCacheEnabled(false);
      wf.setStackTraceEnabled(false);
      wf.setVersion(1);

      ByteArrayOutputStream os = new ByteArrayOutputStream();
      DataOutputStream ds = new DataOutputStream(os);
      wf.marshal(createObject(), ds);
      ds.close();

      return new ByteArrayInputStream(os.toByteArray());
   }

   public static void assertAllControlFileAreEqual() throws Exception {
      ArrayList<DataFileGenerator> generators = getAllDataFileGenerators();
      for (DataFileGenerator element : generators) {
         // System.out.println("Processing: "+object.getClass());
         element.assertControlFileIsEqual();
      }
   }

   public void assertControlFileIsEqual() throws Exception {
      File dataFile = new File(CONTROL_DIR, getClass().getName() + ".bin");
      FileInputStream is1 = new FileInputStream(dataFile);
      int pos = 0;
      try {
         InputStream is2 = generateInputStream();
         int a = is1.read();
         int b = is2.read();
         pos++;
         assertEquals("Data does not match control file: " + dataFile + " at byte position " + pos, a, b);
         while (a >= 0 && b >= 0) {
            a = is1.read();
            b = is2.read();
            pos++;
            assertEquals(a, b);
         }
         is2.close();
      } finally {
         is1.close();
      }
   }

   protected abstract Object createObject() throws IOException;
}
