/*-
 * Copyright 2015 Diamond Light Source Ltd.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 */

package uk.ac.diamond.scisoft.analysis.processing.test.examples;

import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.util.Arrays;

import org.eclipse.dawnsci.analysis.api.processing.OperationData;
import org.eclipse.dawnsci.analysis.api.processing.OperationException;
import org.eclipse.dawnsci.analysis.api.processing.OperationRank;
import org.eclipse.dawnsci.analysis.api.processing.model.AbstractOperationModel;
import org.eclipse.dawnsci.analysis.dataset.operations.AbstractOperation;
import org.eclipse.dawnsci.analysis.dataset.slicer.SliceFromSeriesMetadata;
import org.eclipse.january.DatasetException;
import org.eclipse.january.IMonitor;
import org.eclipse.january.dataset.Dataset;
import org.eclipse.january.dataset.IDataset;
import org.eclipse.january.dataset.ILazyDataset;
import org.eclipse.january.dataset.LazyMaths;
import org.eclipse.january.dataset.Maths;

import uk.ac.diamond.scisoft.analysis.processing.operations.utils.ProcessingUtils;

public class ExampleExternalDataSubtractionOperation extends
		AbstractOperation<ExampleExternalDataModel, OperationData> {

	private PropertyChangeListener listener;
	private Dataset data;
	
	@Override
	public String getId() {
		return "uk.ac.diamond.scisoft.analysis.processing.test.examples.ExampleExternalDataSubtractionOperation";
	}

	@Override
	public OperationRank getInputRank() {
		return OperationRank.TWO;
	}

	@Override
	public OperationRank getOutputRank() {
		return OperationRank.TWO;
	}

	protected OperationData process(IDataset input, IMonitor monitor) throws OperationException {
		//will not be null
		SliceFromSeriesMetadata ssm = getSliceSeriesMetadata(input);
		
		if (data == null) {
			//lz also not null (Exception thrown if data not found)
			ILazyDataset lz = ProcessingUtils.getLazyDataset(this, model.getFilePath(), model.getDatasetName());

			int[] cdd = ssm.getCompatibleDataDimensions(lz.getShape());

			if (cdd == null) throw new OperationException(this, "Data not compatable");

			Dataset mean;
			try {
				mean = LazyMaths.mean(lz, cdd).squeeze();
			} catch (DatasetException e) {
				throw new OperationException(this, e);
			}

			if (!Arrays.equals(mean.getShape(), input.getShape())) throw new OperationException(this, "Data not compatable");
			data = mean;
		}
		
		Dataset out = Maths.subtract(input, data);
		
		return new OperationData(out);
	}
	
	@Override
	public void setModel(ExampleExternalDataModel model) {
		
		if (listener == null) {
			listener = new PropertyChangeListener() {
				
				@Override
				public void propertyChange(PropertyChangeEvent evt) {
					data = null;
				}
			};
		} else {
			((AbstractOperationModel)this.model).removePropertyChangeListener(listener);
		}
		
		super.setModel(model);
		((AbstractOperationModel)this.model).addPropertyChangeListener(listener);
	}
}