/*
    * Copyright 2020 The Netty Project
    *
    * The Netty Project 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:
    *
    *   https://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 io.netty.handler.codec.quic;
  
  import io.netty.buffer.ByteBuf;
  import io.netty.buffer.ByteBufUtil;
  import io.netty.buffer.Unpooled;
  import io.netty.util.internal.EmptyArrays;
  
  import java.net.SocketAddress;
  import java.nio.ByteBuffer;
  import java.util.Objects;
  
  /**
   * A {@link QuicConnectionAddress} that can be used to connect too.
   */
  public final class QuicConnectionAddress extends SocketAddress {
  
      static final QuicConnectionAddress NULL_LEN = new QuicConnectionAddress(EmptyArrays.EMPTY_BYTES);
  
      /**
       * Special {@link QuicConnectionAddress} that should be used when the connection address should be generated
       * and chosen on the fly.
       */
      public static final QuicConnectionAddress EPHEMERAL = new QuicConnectionAddress(null, false);
  
      private final String toStr;
  
      private final ByteBuffer connId;
  
      /**
       * Create a new instance
       *
       * @param connId the connection id to use.
       */
      public QuicConnectionAddress(byte[] connId) {
          this(ByteBuffer.wrap(connId.clone()), true);
      }
  
      /**
       * Create a new instance
       *
       * @param connId the connection id to use.
       */
      public QuicConnectionAddress(ByteBuffer connId) {
          this(connId.duplicate(), true);
      }
  
      private QuicConnectionAddress(ByteBuffer connId, boolean validate) {
          Quic.ensureAvailability();
          if (validate && connId.remaining() > Quiche.QUICHE_MAX_CONN_ID_LEN) {
              throw new IllegalArgumentException("Connection ID can only be of max length "
                      + Quiche.QUICHE_MAX_CONN_ID_LEN);
          }
          if (connId == null) {
              this.connId = null;
              toStr = "QuicConnectionAddress{EPHEMERAL}";
          } else {
              this.connId = connId.asReadOnlyBuffer().duplicate();
              ByteBuf buffer = Unpooled.wrappedBuffer(connId);
              try {
                  toStr = "QuicConnectionAddress{" +
                          "connId=" + ByteBufUtil.hexDump(buffer) + '}';
              } finally {
                  buffer.release();
              }
          }
      }
  
      @Override
      public String toString() {
          return toStr;
      }
  
      @Override
      public int hashCode() {
          if (this == EPHEMERAL) {
              return System.identityHashCode(EPHEMERAL);
          }
          return Objects.hash(connId);
      }
  
      @Override
      public boolean equals(Object obj) {
          if (!(obj instanceof QuicConnectionAddress)) {
              return false;
         }
         QuicConnectionAddress address = (QuicConnectionAddress) obj;
         if (obj == this) {
             return true;
         }
         return connId.equals(address.connId);
     }
 
     ByteBuffer id() {
         if (connId == null) {
             return ByteBuffer.allocate(0);
         }
         return connId.duplicate();
     }
 
     /**
      * Return a random generated {@link QuicConnectionAddress} of a given length
      * that can be used to connect a {@link QuicChannel}
      *
      * @param length    the length of the {@link QuicConnectionAddress} to generate.
      * @return          the generated address.
      */
     public static QuicConnectionAddress random(int length) {
         return new QuicConnectionAddress(QuicConnectionIdGenerator.randomGenerator().newId(length));
     }
 
     /**
      * Return a random generated {@link QuicConnectionAddress} of maximum size
      * that can be used to connect a {@link QuicChannel}
      *
      * @return the generated address.
      */
     public static QuicConnectionAddress random() {
         return random(Quiche.QUICHE_MAX_CONN_ID_LEN);
     }
 }