/*
 * #%L
 * Image processing operations for SciJava Ops.
 * %%
 * Copyright (C) 2014 - 2024 SciJava developers.
 * %%
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 *    this list of conditions and the following disclaimer.
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package org.scijava.ops.image.stats;

import java.util.NoSuchElementException;
import java.util.function.Function;

import net.imglib2.type.numeric.RealType;
import net.imglib2.util.Pair;
import net.imglib2.util.ValuePair;

import org.scijava.ops.spi.Op;

/**
 * Op to calculate the {@code stats.minMax}.
 *
 * @author Daniel Seebacher (University of Konstanz)
 * @author Christian Dietz (University of Konstanz)
 * @param <I> input type
 * @implNote op names='stats.minMax'
 */
public class IterableMinMax<I extends RealType<I>> implements
	Function<Iterable<I>, Pair<I, I>>
{

	/**
	 * TODO
	 *
	 * @param input the {@link Iterable} to compute over
	 * @return the minimum and maximum of the {@code input}, partitioned within a
	 *         {@link Pair}
	 */
	@Override
	public Pair<I, I> apply(final Iterable<I> input) {

		// set minVal to the largest possible value and maxVal to the smallest
		// possible.
		I minVal, maxVal;
		try {
			minVal = input.iterator().next().createVariable();
			minVal.setReal(minVal.getMaxValue());
			maxVal = minVal.createVariable();
			maxVal.setReal(maxVal.getMinValue());
		}
		catch (NoSuchElementException e) {
			throw new IllegalArgumentException(
				"Cannot determine minimum/maximum of an empty Iterator!");
		}

		for (final var in : input) {
			if (in.compareTo(minVal) < 0) minVal.set(in);
			if (in.compareTo(maxVal) > 0) maxVal.set(in);
		}
		return new ValuePair<>(minVal, maxVal);
	}

}
