package org.simantics.acorn.internal;

import org.simantics.acorn.exception.IllegalAcornStateException;
import org.simantics.db.service.Bytes;
import org.simantics.db.service.ClusterUID;

public abstract class ClusterUpdateProcessorBase2 {

	final private byte[] bytes;
	private int pos = 0;
	final private int len;
	final private ClusterUID uid;
	
	public ClusterUpdateProcessorBase2(byte[] operations) {
		this.bytes = operations;
		this.len = Bytes.readLE4(bytes, 0) + 4; // whatta?
		int version = Bytes.readLE4(bytes, 4);
		assert(version == ClusterChange2.VERSION);
		long cuid1 = Bytes.readLE8(bytes, 8);
		long cuid2 = Bytes.readLE8(bytes, 16);
		pos = 24;
		uid = ClusterUID.make(cuid1, cuid2);
	}
	
	public ClusterUID getClusterUID() {
		return uid;
	}

	private void processSetImmutable(int op) {
		int value = bytes[pos++]&0xff;
		setImmutable(value > 0);
	}

	private void processUndoValue(int op) {
		Bytes.readLE4(bytes, pos);
		pos+=4;
	}

	public void process() throws IllegalAcornStateException {
		
		while(pos < len) {
		
			int op = bytes[pos++]&0xff;
			
			switch(op) {
			
			case ClusterChange2.SET_IMMUTABLE_OPERATION:
				processSetImmutable(op);
				break;
			case ClusterChange2.UNDO_VALUE_OPERATION:
				processUndoValue(op);
				break;
			default:
				throw new IllegalAcornStateException("Can not process cluster " + uid);
				
			}
		}
	}
	
	abstract void setImmutable(boolean value);
	
}