/*
    * junixsocket
    *
    * Copyright 2009-2026 Christian Kohlschütter
    *
    * Licensed 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.newsclub.net.unix;
  
  import java.io.Closeable;
  import java.io.FileDescriptor;
  import java.io.IOException;
  import java.net.SocketException;
  import java.nio.ByteBuffer;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  final class AncillaryDataSupport implements Closeable {
    private static final ByteBuffer EMPTY_BUFFER = ByteBuffer.allocate(0);
    private static final FileDescriptor[] NO_FILE_DESCRIPTORS = new FileDescriptor[0];
  
    private static final int MIN_ANCBUF_LEN = NativeUnixSocket.isLoaded() ? NativeUnixSocket
        .ancillaryBufMinLen() : 0;
  
    private final Map<FileDescriptor, Integer> openReceivedFileDescriptors = Collections
        .synchronizedMap(new HashMap<>());
  
    private final List<FileDescriptor[]> receivedFileDescriptors = Collections.synchronizedList(
        new ArrayList<>());
  
    // referenced from native code
    private ByteBuffer ancillaryReceiveBuffer = EMPTY_BUFFER;
  
    // referenced from native code
    int[] pendingFileDescriptors = null;
  
    private int[] tipcErrorInfo = null;
  
    private int[] tipcDestName = null;
  
    // referenced from native code
    void setTipcErrorInfo(int errorCode, int dataLength) {
      if (errorCode == 0 && dataLength == 0) {
        tipcErrorInfo = null;
      } else {
        tipcErrorInfo = new int[] {errorCode, dataLength};
      }
    }
  
    int[] getTIPCErrorInfo() {
      int[] info = tipcErrorInfo;
      tipcErrorInfo = null;
      return info;
    }
  
    void setTipcDestName(int a, int b, int c) {
      if (a == 0 && b == 0 && c == 0) {
        this.tipcDestName = null;
      } else {
        this.tipcDestName = new int[] {a, b, c};
      }
    }
  
    int[] getTIPCDestName() {
      int[] addr = tipcDestName;
      tipcDestName = null;
      return addr;
    }
  
    int getAncillaryReceiveBufferSize() {
      return ancillaryReceiveBuffer.capacity();
    }
  
    void setAncillaryReceiveBufferSize(int size) {
      if (size == ancillaryReceiveBuffer.capacity()) {
        return;
      } else if (size <= 0) {
        this.ancillaryReceiveBuffer = EMPTY_BUFFER;
      } else {
        setAncillaryReceiveBufferSize0(Math.max(256, Math.min(MIN_ANCBUF_LEN, size)));
      }
    }
  
    void setAncillaryReceiveBufferSize0(int size) {
      this.ancillaryReceiveBuffer = ByteBuffer.allocateDirect(size);
    }
 
   public void ensureAncillaryReceiveBufferSize(int minSize) {
     if (minSize <= 0) {
       return;
     }
     if (ancillaryReceiveBuffer.capacity() < minSize) {
       setAncillaryReceiveBufferSize(minSize);
     }
   }
 
   // called from native code
   void receiveFileDescriptors(int[] fds) throws IOException {
     if (fds == null || fds.length == 0) {
       return;
     }
     final int fdsLength = fds.length;
     FileDescriptor[] descriptors = new FileDescriptor[fdsLength];
     for (int i = 0; i < fdsLength; i++) {
       final FileDescriptor fdesc = new FileDescriptor();
       NativeUnixSocket.initFD(fdesc, fds[i]);
       descriptors[i] = fdesc;
 
       openReceivedFileDescriptors.put(fdesc, fds[i]);
 
       final Closeable cleanup = new Closeable() {
 
         @Override
         public void close() throws IOException {
           openReceivedFileDescriptors.remove(fdesc);
         }
       };
 
       try {
         NativeUnixSocket.attachCloseable(fdesc, cleanup);
       } catch (SocketException e) {
         // ignore (cannot attach)
       }
     }
 
     this.receivedFileDescriptors.add(descriptors);
   }
 
   void clearReceivedFileDescriptors() {
     receivedFileDescriptors.clear();
   }
 
   FileDescriptor[] getReceivedFileDescriptors() {
     if (receivedFileDescriptors.isEmpty()) {
       return NO_FILE_DESCRIPTORS;
     }
     List<FileDescriptor[]> copy = new ArrayList<>(receivedFileDescriptors);
     if (copy.isEmpty()) {
       return NO_FILE_DESCRIPTORS;
     }
     receivedFileDescriptors.removeAll(copy);
     int count = 0;
     for (FileDescriptor[] fds : copy) {
       count += fds.length;
     }
     if (count == 0) {
       return NO_FILE_DESCRIPTORS;
     }
     FileDescriptor[] oneArray = new FileDescriptor[count];
     int offset = 0;
     for (FileDescriptor[] fds : copy) {
       System.arraycopy(fds, 0, oneArray, offset, fds.length);
       offset += fds.length;
     }
     return oneArray;
   }
 
   void setOutboundFileDescriptors(int[] fds) {
     this.pendingFileDescriptors = (fds == null || fds.length == 0) ? null : fds;
   }
 
   boolean hasOutboundFileDescriptors() {
     return this.pendingFileDescriptors != null;
   }
 
   void setOutboundFileDescriptors(FileDescriptor... fdescs) throws IOException {
     final int[] fds;
     if (fdescs == null || fdescs.length == 0) {
       fds = null;
     } else {
       final int numFdescs = fdescs.length;
       fds = new int[numFdescs];
       for (int i = 0; i < numFdescs; i++) {
         FileDescriptor fdesc = fdescs[i];
         fds[i] = NativeUnixSocket.getFD(fdesc);
       }
     }
     this.setOutboundFileDescriptors(fds);
   }
 
   @Override
   public void close() {
     synchronized (openReceivedFileDescriptors) {
       for (FileDescriptor desc : openReceivedFileDescriptors.keySet()) {
         if (desc.valid()) {
           try {
             NativeUnixSocket.close(desc);
           } catch (Exception e) {
             // ignore
           }
         }
       }
     }
   }
 }