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 * #%L
 * Image processing operations for SciJava Ops.
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 * Copyright (C) 2014 - 2024 SciJava developers.
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package org.scijava.ops.image.image.histogram;

import java.util.function.BiFunction;
import java.util.function.Function;

import net.imglib2.histogram.Histogram1d;
import net.imglib2.histogram.Real1dBinMapper;
import net.imglib2.type.numeric.RealType;
import net.imglib2.util.Pair;

import org.scijava.ops.spi.OpDependency;
import org.scijava.ops.spi.Nullable;

/**
 * @author Martin Horn (University of Konstanz)
 * @author Christian Dietz (University of Konstanz)
 * @implNote op names='image.histogram'
 */
public class HistogramCreate<T extends RealType<T>> implements
	BiFunction<Iterable<T>, Integer, Histogram1d<T>>
{

	public static final int DEFAULT_NUM_BINS = 256;

	@OpDependency(name = "stats.minMax")
	private Function<Iterable<T>, Pair<T, T>> minMaxFunc;

	/**
	 * TODO
	 *
	 * @param input the iterable to feed into the {@link Histogram1d}
	 * @param numBins the number of bins in the resulting {@link Histogram1d}
	 * @return a histogram
	 */
	@Override
	public Histogram1d<T> apply(final Iterable<T> input,
		@Nullable Integer numBins)
	{
		if (numBins == null) numBins = DEFAULT_NUM_BINS;

		final var res = minMaxFunc.apply(input);

		final var histogram1d = new Histogram1d<T>(new Real1dBinMapper<T>(
			res.getA().getRealDouble(), res.getB().getRealDouble(), numBins, false));

		histogram1d.countData(input);

		return histogram1d;
	}

}
