// This is Free Software under GNU Affero General Public License v >= 3.0
// without warranty, see README.md and license for details.
//
// SPDX-License-Identifier: AGPL-3.0-or-later
// License-Filename: LICENSES/AGPL-3.0.txt
//
// Copyright (C) 2018 by via donau
//   – Österreichische Wasserstraßen-Gesellschaft mbH
// Software engineering by Intevation GmbH
//
// Author(s):
//  * Sascha L. Teichmann <sascha.teichmann@intevation.de>

package mesh

import (
	"math"
	"testing"
)

func TestIntersection(t *testing.T) {

	table := []struct {
		a          [4]float64
		b          [4]float64
		intersects bool
		x, y       float64
	}{
		{[4]float64{-1, -1, 1, 1}, [4]float64{-1, 1, 1, -1}, true, 0, 0},
		{[4]float64{0, 0, 1, 1}, [4]float64{0, 1, 1, 0}, true, 0.5, 0.5},
		{[4]float64{0, 0, 1, 0}, [4]float64{0, 1, 1, 1}, false, 0, 0},
	}

	for _, e := range table {
		p1 := NewPlane2D(e.a[0], e.a[1], e.a[2], e.a[3])
		p2 := NewPlane2D(e.b[0], e.b[1], e.b[2], e.b[3])
		x, y, intersects := p1.Intersection(p2)
		if intersects != e.intersects {
			t.Fatalf("Have %t want %t\n", intersects, e.intersects)
		}
		if e.intersects {
			if math.Abs(e.x-x) > epsPlane || math.Abs(e.y-y) > epsPlane {
				t.Fatalf("Have (%f, %f)t want (%f, %f)\n", x, y, e.x, e.y)
			}
		}
	}
}