/*
 * #%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.geom.geom2d;

import java.util.List;
import java.util.function.Function;

import org.scijava.ops.image.geom.GeomUtils;
import net.imglib2.RealLocalizable;
import net.imglib2.roi.geom.real.Polygon2D;
import net.imglib2.util.Pair;
import net.imglib2.util.ValuePair;

import org.scijava.ops.spi.OpDependency;

/**
 * Maximum Feret of a polygon.
 *
 * @author Tim-Oliver Buchholz, University of Konstanz
 * @implNote op names='geom.maximumFeret'
 */
public class DefaultMaximumFeret implements
	Function<Polygon2D, Pair<RealLocalizable, RealLocalizable>>
{

	@OpDependency(name = "geom.convexHull")
	private Function<Polygon2D, Polygon2D> function;

	/**
	 * TODO
	 *
	 * @param input
	 * @return the maximum feret of the input polygon, stored as a {@link Pair}
	 */
	@Override
	public Pair<RealLocalizable, RealLocalizable> apply(Polygon2D input) {
		final List<? extends RealLocalizable> points = GeomUtils.vertices(function
			.apply(input));

        var distance = Double.NEGATIVE_INFINITY;
        var p0 = points.get(0);
        var p1 = points.get(0);
		for (var i = 0; i < points.size(); i++) {
			for (var j = i + 2; j < points.size(); j++) {
				final var tmpP0 = points.get(i);
				final var tmpP1 = points.get(j);

				final var tmp = Math.sqrt(Math.pow(tmpP0.getDoublePosition(0) - tmpP1
					.getDoublePosition(0), 2) + Math.pow(tmpP0.getDoublePosition(1) -
						tmpP1.getDoublePosition(1), 2));

				if (tmp > distance) {
					distance = tmp;
					p0 = tmpP0;
					p1 = tmpP1;
				}
			}
		}

		return new ValuePair<>(p0, p1);
	}

}
