/*
 * 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.proton.plug.util;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.UnpooledByteBufAllocator;

public class ByteUtil {

   public static void debugFrame(String message, ByteBuf byteIn) {
      int location = byteIn.readerIndex();
      // debugging
      byte[] frame = new byte[byteIn.writerIndex()];
      byteIn.readBytes(frame);

      try {
         System.out.println(message + "\n" + ByteUtil.formatGroup(ByteUtil.bytesToHex(frame), 8, 16));
      }
      catch (Exception e) {
         e.printStackTrace();
      }

      byteIn.readerIndex(location);
   }

   public static String formatGroup(String str, int groupSize, int lineBreak) {
      StringBuffer buffer = new StringBuffer();

      int line = 1;
      buffer.append("/*  1 */ \"");
      for (int i = 0; i < str.length(); i += groupSize) {
         buffer.append(str.substring(i, i + Math.min(str.length() - i, groupSize)));

         if ((i + groupSize) % lineBreak == 0) {
            buffer.append("\" +\n/* ");
            line++;
            if (line < 10) {
               buffer.append(" ");
            }
            buffer.append(Integer.toString(line) + " */ \"");
         }
         else if ((i + groupSize) % groupSize == 0 && str.length() - i > groupSize) {
            buffer.append("\" + \"");
         }
      }

      buffer.append("\";");

      return buffer.toString();

   }

   protected static final char[] hexArray = "0123456789ABCDEF".toCharArray();

   public static String bytesToHex(byte[] bytes) {
      char[] hexChars = new char[bytes.length * 2];
      for (int j = 0; j < bytes.length; j++) {
         int v = bytes[j] & 0xFF;
         hexChars[j * 2] = hexArray[v >>> 4];
         hexChars[j * 2 + 1] = hexArray[v & 0x0F];
      }
      return new String(hexChars);
   }

   public static byte[] hexStringToByteArray(String s) {
      int len = s.length();
      byte[] data = new byte[len / 2];
      for (int i = 0; i < len; i += 2) {
         data[i / 2] = (byte) ((Character.digit(s.charAt(i), 16) << 4) + Character.digit(s.charAt(i + 1), 16));
      }
      return data;
   }

   public static byte[] longToBytes(long x) {
      ByteBuf buffer = UnpooledByteBufAllocator.DEFAULT.heapBuffer(8, 8);
      buffer.writeLong(x);
      return buffer.array();
   }

   public static String maxString(String value, int size) {
      if (value.length() < size) {
         return value;
      }
      else {
         return value.substring(0, size / 2) + " ... " + value.substring(value.length() - size / 2);
      }
   }

   public static String bytesToHex(byte[] bytes, int groupSize) {
      char[] hexChars = new char[bytes.length * 2 + numberOfGroups(bytes, groupSize)];
      int outPos = 0;
      for (int j = 0; j < bytes.length; j++) {
         if (j > 0 && j % groupSize == 0) {
            hexChars[outPos++] = ' ';
         }
         int v = bytes[j] & 0xFF;
         hexChars[outPos++] = hexArray[v >>> 4];
         hexChars[outPos++] = hexArray[v & 0x0F];
      }
      return new String(hexChars);
   }

   private static int numberOfGroups(byte[] bytes, int groupSize) {
      int groups = bytes.length / groupSize;

      if (bytes.length % groupSize == 0) {
         groups--;
      }

      return groups;
   }

}
