/* BipolarReferenceMontageGenerator.java created 2007-11-29
 *
 */

package org.signalml.domain.montage.generators;

import java.util.ArrayList;
import java.util.List;

import org.signalml.app.model.components.validation.ValidationErrors;
import org.signalml.domain.montage.system.ChannelType;
import org.signalml.domain.montage.Montage;
import org.signalml.domain.montage.MontageException;
import org.signalml.domain.montage.SourceChannel;
import org.signalml.domain.montage.SourceMontage;
import org.signalml.domain.montage.system.ChannelFunction;

import org.springframework.validation.Errors;

/**
 * This class represents the generator for a bipolar montage.
 * In bipolar montage each channel (i.e., waveform) represents the difference
 * between two adjacent electrodes. The entire montage consists of a series
 * of these channels.
 * For example, the channel "Fp1-F3" represents the difference in voltage
 * between the Fp1 electrode and the F3 electrode. The next channel in the montage,
 * "F3-C3," represents the voltage difference between F3 and C3, and so on through
 * the entire array of electrodes.
 * (source: {@code http://en.wikipedia.org/wiki/Electroencephalography})
 *
 * It generates montage of that type from given "raw" montage and checks
 * if {@link SourceMontage montages} are valid bipolar montages.
 *
 * @author Michal Dobaczewski © 2007-2008 CC Otwarte Systemy Komputerowe Sp. z o.o.
 */
public class BipolarReferenceMontageGenerator extends AbstractMontageGenerator {

	private static final long serialVersionUID = 1L;

	/**
	 * An array of pairs of channels (channels {@link Channel functions})
	 * that will be used to create montage channels.
	 * Each pair is used to create one {@link MontageChannel montage channel}.
	 * First element as primary channel, second as reference.
	 */
	protected transient String[][] channelPairs;

	/**
	 * Constructor. Creates a generator for an bipolar reference montage
	 * based on <i>refChannels</i> array
	 * @param channelPairs an array of pairs of {@link Channel channels}
	 * (channels functions) that will be used to create montage channels.
	 * Each pair is used to create one {@link MontageChannel montage channel}.
	 * First element as primary channel, second as reference.
	 */
	public BipolarReferenceMontageGenerator(String[][] channelPairs) {
		if (channelPairs == null || channelPairs.length == 0) {
			throw new NullPointerException("Definition cannot be null or empty");
		}
		this.channelPairs = channelPairs;
	}

	/**
	 * Creates a bipolar montage from the given montage.
	 * @param montage the montage to be used
	 * @throws MontageException if two channels have the same function
	 * (in the given montage) or there is no channel with some function
	 */
	@Override
	public void createMontage(Montage montage) throws MontageException {

		List<SourceChannel> primaryChannels = new ArrayList<SourceChannel>();
		List<SourceChannel> referenceChannels = new ArrayList<SourceChannel>();
		for (int i = 0; i < channelPairs.length; i++) {
			String channelName = channelPairs[i][0];
			SourceChannel sourceChannel = montage.getSourceChannelByLabel(channelName);
			if (sourceChannel == null) {
				throw new MontageException("Cannot find primary channel " + channelName);
			}
			primaryChannels.add(sourceChannel);

			channelName = channelPairs[i][1];
			sourceChannel = montage.getSourceChannelByLabel(channelName);
			if (sourceChannel == null) {
				throw new MontageException("Cannot find reference channel " + channelName);
			}
			referenceChannels.add(sourceChannel);
		}

		String token = "-1";

		boolean oldMajorChange = montage.isMajorChange();

		try {

			montage.setMajorChange(true);

			montage.reset();

			int index;
			for (int i=0; i<primaryChannels.size(); i++) {
				int primaryChannelIndex = primaryChannels.get(i).getChannel();
				int referenceChannelIndex = referenceChannels.get(i).getChannel();
				index = montage.addMontageChannel(primaryChannelIndex);
				montage.setReference(index, referenceChannelIndex, token);
				montage.setMontageChannelLabelAt(index, montage.getSourceChannelLabelAt(primaryChannelIndex) + "-" + montage.getSourceChannelLabelAt(referenceChannelIndex));
			}

			int size = montage.getSourceChannelCount();

			for (int i=0; i<size; i++) {
				SourceChannel sourceChannel = montage.getSourceChannelAt(i);
				if (sourceChannel.getFunction() != ChannelFunction.EEG
						|| (sourceChannel.getFunction() == ChannelFunction.EEG
							&& !sourceChannel.isChannelType(ChannelType.PRIMARY))) {
					index = montage.addMontageChannel(i);
				}
			}

		} finally {
			montage.setMajorChange(oldMajorChange);
		}

		montage.setMontageGenerator(this);
		montage.setChanged(false);

	}

	/**
	 * Checks if the montage is a valid bipolar montage.
	 * @param sourceMontage the montage to be checked
	 * @param errors Errors object used to report errors
	 * @return true if the montage is a valid bipolar montage, false otherwise
	 */
	@Override
	public boolean validateSourceMontage(SourceMontage sourceMontage, ValidationErrors errors) {

		boolean ok = true;

		for (int i=0; i<channelPairs.length; i++) {

			for (int j = 0; j < 2; j++) {
				SourceChannel sourceChannel = sourceMontage.getSourceChannelByLabel(channelPairs[i][j]);
				if (sourceChannel == null) {
					onNotFound(channelPairs[i][j], errors);
					ok = false;
				}
			}

		}

		return ok;

	}

}