package org.kne.cloud.network;

import java.lang.foreign.Arena;
import java.lang.foreign.MemorySegment;
import java.lang.foreign.MemorySegment.Scope;
import java.lang.ref.PhantomReference;
import java.lang.ref.Reference;
import java.lang.ref.ReferenceQueue;
import java.nio.ByteBuffer;
import java.util.concurrent.atomic.AtomicLong;
import java.util.concurrent.atomic.AtomicReference;
import java.util.concurrent.locks.ReentrantLock;

public class DirectBufferedArena implements Arena{
	private static long blockSize=1024*1024L;
	private volatile PreAlloc buffer;
	public static long getBlockSize() {
		return blockSize;
	}



	public static void setBlockSize(long blockSizex) {
		blockSize = blockSizex;
	}



	
	private class PreAlloc{
		private MemorySegment segment;
		private AtomicLong pos=new AtomicLong(0);
		private AtomicLong refs=new AtomicLong(0);
		public MemorySegment getSegment() {
			return segment;
		}
		public AtomicLong getPos() {
			return pos;
		}
		public PreAlloc(MemorySegment segment) {
			super();
			this.segment = segment;
		}
		public long byteSize() {
			return segment.byteSize();
		}
		public AtomicLong getRefs() {
			return refs;
		}
		
	}
	
	private void allocateNew(long blockSize2) {
		MemorySegment raw=MemorySegment.ofArray(ByteBufferAllocator.allocateUninitializedArray((int) blockSize2));
		buffer=new PreAlloc(raw);
			
	}


	public DirectBufferedArena() {
		super();
		allocateNew(blockSize);
	}

	@Override
	public MemorySegment allocate(long byteSize, long byteAlignment) {
		if(byteSize>blockSize)
			throw new IndexOutOfBoundsException("byteSize can't large than buffer block");
		long pos;
		PreAlloc bufferx;
		 do{
			 bufferx=this.buffer;
		 pos=bufferx.getPos().getAndAdd(byteSize);
		if(pos+byteSize>bufferx.byteSize()) {
			allocateNew(blockSize);
		}else {
			break;
		}
		}while(true);
		 bufferx.getRefs().incrementAndGet();
		MemorySegment sliced=bufferx.getSegment().asSlice(pos, byteSize);
			return sliced;
		
	}

	@Override
	public Scope scope() {
		return null;
	}

	@Override
	public void close() {
	}
	public static DirectBufferedArena ofBuffered() {
		return new DirectBufferedArena();
	}
	
}