/*************************************************************************/
/*  test_gradient.h                                                      */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                      https://godotengine.org                          */
/*************************************************************************/
/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md).   */
/*                                                                       */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the       */
/* "Software"), to deal in the Software without restriction, including   */
/* without limitation the rights to use, copy, modify, merge, publish,   */
/* distribute, sublicense, and/or sell copies of the Software, and to    */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions:                                             */
/*                                                                       */
/* The above copyright notice and this permission notice shall be        */
/* included in all copies or substantial portions of the Software.       */
/*                                                                       */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
/*************************************************************************/

#ifndef TEST_GRADIENT_H
#define TEST_GRADIENT_H

#include "core/math/color.h"
#include "core/object/class_db.h"
#include "scene/resources/gradient.h"

#include "thirdparty/doctest/doctest.h"

namespace TestGradient {

TEST_CASE("[Gradient] Default gradient") {
	// Black-white gradient.
	Ref<Gradient> gradient = memnew(Gradient);

	CHECK_MESSAGE(
			gradient->get_points_count() == 2,
			"Default gradient should contain the expected number of points.");

	CHECK_MESSAGE(
			gradient->get_color_at_offset(0.0).is_equal_approx(Color(0, 0, 0)),
			"Default gradient should return the expected interpolated value at offset 0.0.");
	CHECK_MESSAGE(
			gradient->get_color_at_offset(0.4).is_equal_approx(Color(0.4, 0.4, 0.4)),
			"Default gradient should return the expected interpolated value at offset 0.4.");
	CHECK_MESSAGE(
			gradient->get_color_at_offset(0.8).is_equal_approx(Color(0.8, 0.8, 0.8)),
			"Default gradient should return the expected interpolated value at offset 0.8.");
	CHECK_MESSAGE(
			gradient->get_color_at_offset(1.0).is_equal_approx(Color(1, 1, 1)),
			"Default gradient should return the expected interpolated value at offset 1.0.");

	// Out of bounds checks.
	CHECK_MESSAGE(
			gradient->get_color_at_offset(-1.0).is_equal_approx(Color(0, 0, 0)),
			"Default gradient should return the expected interpolated value at offset -1.0.");
	CHECK_MESSAGE(
			gradient->get_color_at_offset(1234.0).is_equal_approx(Color(1, 1, 1)),
			"Default gradient should return the expected interpolated value at offset 1234.0.");
}

TEST_CASE("[Gradient] Custom gradient (points specified in order)") {
	// Red-yellow-green gradient (with overbright green).
	Ref<Gradient> gradient = memnew(Gradient);
	Vector<Gradient::Point> points;
	points.push_back({ 0.0, Color(1, 0, 0) });
	points.push_back({ 0.5, Color(1, 1, 0) });
	points.push_back({ 1.0, Color(0, 2, 0) });
	gradient->set_points(points);

	CHECK_MESSAGE(
			gradient->get_points_count() == 3,
			"Custom gradient should contain the expected number of points.");

	CHECK_MESSAGE(
			gradient->get_color_at_offset(0.0).is_equal_approx(Color(1, 0, 0)),
			"Custom gradient should return the expected interpolated value at offset 0.0.");
	CHECK_MESSAGE(
			gradient->get_color_at_offset(0.25).is_equal_approx(Color(1, 0.5, 0)),
			"Custom gradient should return the expected interpolated value at offset 0.25.");
	CHECK_MESSAGE(
			gradient->get_color_at_offset(0.5).is_equal_approx(Color(1, 1, 0)),
			"Custom gradient should return the expected interpolated value at offset 0.5.");
	CHECK_MESSAGE(
			gradient->get_color_at_offset(0.75).is_equal_approx(Color(0.5, 1.5, 0)),
			"Custom gradient should return the expected interpolated value at offset 0.75.");
	CHECK_MESSAGE(
			gradient->get_color_at_offset(1.0).is_equal_approx(Color(0, 2, 0)),
			"Custom gradient should return the expected interpolated value at offset 1.0.");

	gradient->remove_point(1);
	CHECK_MESSAGE(
			gradient->get_points_count() == 2,
			"Custom gradient should contain the expected number of points after removing one point.");
	CHECK_MESSAGE(
			gradient->get_color_at_offset(0.5).is_equal_approx(Color(0.5, 1, 0)),
			"Custom gradient should return the expected interpolated value at offset 0.5 after removing point at index 1.");
}

TEST_CASE("[Gradient] Custom gradient (points specified out-of-order)") {
	// HSL rainbow with points specified out of order.
	// These should be sorted automatically when adding points.
	Ref<Gradient> gradient = memnew(Gradient);
	Vector<Gradient::Point> points;
	points.push_back({ 0.2, Color(1, 0, 0) });
	points.push_back({ 0.0, Color(1, 1, 0) });
	points.push_back({ 0.8, Color(0, 1, 0) });
	points.push_back({ 0.4, Color(0, 1, 1) });
	points.push_back({ 1.0, Color(0, 0, 1) });
	points.push_back({ 0.6, Color(1, 0, 1) });
	gradient->set_points(points);

	CHECK_MESSAGE(
			gradient->get_points_count() == 6,
			"Custom out-of-order gradient should contain the expected number of points.");

	CHECK_MESSAGE(
			gradient->get_color_at_offset(0.0).is_equal_approx(Color(1, 1, 0)),
			"Custom out-of-order gradient should return the expected interpolated value at offset 0.0.");
	CHECK_MESSAGE(
			gradient->get_color_at_offset(0.3).is_equal_approx(Color(0.5, 0.5, 0.5)),
			"Custom out-of-order gradient should return the expected interpolated value at offset 0.3.");
	CHECK_MESSAGE(
			gradient->get_color_at_offset(0.6).is_equal_approx(Color(1, 0, 1)),
			"Custom out-of-order gradient should return the expected interpolated value at offset 0.6.");
	CHECK_MESSAGE(
			gradient->get_color_at_offset(1.0).is_equal_approx(Color(0, 0, 1)),
			"Custom out-of-order gradient should return the expected interpolated value at offset 1.0.");

	gradient->remove_point(0);
	CHECK_MESSAGE(
			gradient->get_points_count() == 5,
			"Custom out-of-order gradient should contain the expected number of points after removing one point.");
	// The color will be clamped to the nearest point (which is at offset 0.2).
	CHECK_MESSAGE(
			gradient->get_color_at_offset(0.1).is_equal_approx(Color(1, 0, 0)),
			"Custom out-of-order gradient should return the expected interpolated value at offset 0.1 after removing point at index 0.");
}
} // namespace TestGradient

#endif // TEST_GRADIENT_H