/*!
 * 12_cubes.cpp
 *
 * Copyright (c) 2015-2024, NADAL Jean-Baptiste. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301 USA
 *
 * @Author:  NADAL Jean-Baptiste
 * @Date: 13/03/2024
 *
 */

/*---------------------------------------------------------------------------*/

#include <external/catch.hpp>

#include "raytracing.h"

using namespace Raytracer;

/* ------------------------------------------------------------------------- */

class CubeTestIntersect
{
public:
    Tuple origin;
    Tuple direction;
    double t1;
    double t2;
};

/* ------------------------------------------------------------------------- */

class CubeTestNormal
{
public:
    Tuple point;
    Tuple normal;
};

/* ------------------------------------------------------------------------- */

SCENARIO("A Ray intersects a cube", "[features/cubes.feature]")
{
    // |        | origin            | direction        | t1 | t2 |
    // | +x     | point(5, 0.5, 0)  | vector(-1, 0, 0) | 4  | 6  |
    // | -x     | point(-5, 0.5, 0) | vector( 1, 0, 0) | 4  | 6  |
    // | +y     | point(0.5, 5, 0)  | vector( 0,-1, 0) | 4  | 6  |
    // | -y     | point(0.5, -5, 0) | vector( 0, 1, 0) | 4  | 6  |
    // | +z     | point(0.5, 0, 5)  | vector( 0, 0,-1) | 4  | 6  |
    // | -z     | point(0.5, 0, -5) | vector( 0, 0, 1) | 4  | 6  |
    // | inside | point(0, 0.5, 0)  | vector( 0, 0, 1) | -1 | -1 |
    CubeTestIntersect the_test[] = {
        { Tuple::Point(5.0,  0.5,  0.0), Tuple::Vector(-1,  0,  0),  4,  6},
        {Tuple::Point(-5.0,  0.5,  0.0),  Tuple::Vector(1,  0,  0),  4,  6},
        { Tuple::Point(0.5,  5.0,  0.0),  Tuple::Vector(0, -1,  0),  4,  6},
        { Tuple::Point(0.5, -5.0,  0.0),  Tuple::Vector(0,  1,  0),  4,  6},
        { Tuple::Point(0.5,  0.0,  5.0),  Tuple::Vector(0,  0, -1),  4,  6},
        { Tuple::Point(0.5,  0.0, -5.0),  Tuple::Vector(0,  0,  1),  4,  6},
        { Tuple::Point(0.0,  0.5,  0.0),  Tuple::Vector(0,  0,  1), -1, -1}
    };

    GIVEN("c <- cube()")
    {
        Cube c;
        AND_GIVEN("r <- ray(<origin>, <direction>)")
        {
            WHEN("xs <- local_intersect(c,r)")
            {
                for (int i = 0; i < 7; i++)
                {
                    Ray r(the_test[i].origin, the_test[i].direction);
                    Intersections xs = c.local_intersect(r);
                    THEN("xs.count = 2")
                    {
                        REQUIRE(xs.count() == 2);
                    }
                    AND_THEN("xs[0].t = <t1>")
                    {
                        REQUIRE(xs[0].distance_t() == the_test[i].t1);
                    }
                    AND_THEN("xs[1].t = <t2>")
                    {
                        REQUIRE(xs[1].distance_t() == the_test[i].t2);
                    }
                }
            }
        }
    }
}

/* ------------------------------------------------------------------------- */

SCENARIO("A Ray misses a cube", "[features/cubes.feature]")
{
    // | point            | direction                      |
    // | point(-2, 0, 0)  | vector(0.2673, 0.5345, 0.8018) |
    // | point(0, -2, 0)  | vector(0.8018, 0.2673, 0.5345) |
    // | point(0, 0, -2)  | vector(0.5345, 0.8018, 0.2673) |
    // | point(2, 0, 2)   | vector(0, 0, -1)               |
    // | point(0, 2, 2)   | vector(0, -1, 0)               |
    // | point(2, 2, 0)   | vector(-1, 0, 0)               |
    CubeTestIntersect the_test[] = {
        {Tuple::Point(-2,  0,  0), Tuple::Vector(0.2673, 0.5345, 0.8018), -1, -1},
        { Tuple::Point(0, -2,  0), Tuple::Vector(0.8018, 0.2673, 0.5345), -1, -1},
        { Tuple::Point(0,  0, -2), Tuple::Vector(0.5345, 0.8018, 0.2673), -1, -1},
        { Tuple::Point(2,  0,  2),      Tuple::Vector(0,      0,     -1), -1, -1},
        { Tuple::Point(0,  2,  2),      Tuple::Vector(0,     -1,      0), -1, -1},
        { Tuple::Point(2,  2,  0),     Tuple::Vector(-1,      0,      0), -1, -1}
    };
    GIVEN("c <- cube()")
    {
        Cube c;
        AND_GIVEN("r <- ray(<origin>, <direction>)")
        {
            WHEN("xs <- local_intersect(c,r)")
            {
                for (int i = 0; i < 6; i++)
                {
                    Ray r(the_test[i].origin, the_test[i].direction);
                    Intersections xs = c.local_intersect(r);
                    THEN("xs.count = 0")
                    {
                        REQUIRE(xs.count() == 0);
                    }
                }
            }
        }
    }
}

/* ------------------------------------------------------------------------- */

SCENARIO("The normal on the surface of a cube", "[features/cubes.feature]")
{
    // | origin                | normal            |
    // | point(1, 0.5, -0.8)   | vector(1, 0, 0)   |
    // | point(-1, -0.2, 0.9)  | vector(-1, 0, 0)  |
    // | point(-0.4, 1, -0.1)  | vector(0, 1, 0)   |
    // | point(0.3, -1, -0.7)  | vector(0, -1, 0)  |
    // | point(-0.6, 0.3, 1)   | vector(0, 0, 1)   |
    // | point(0.4, 0.4, -1)   | vector(0, 0, -1)  |
    // | point(1, 1, -1)       | vector(1, 0, 0)   |
    // | point(-1,-1, -1)      | vector(-1, 0, 0)  |
    CubeTestNormal the_test[] = {
        {   Tuple::Point(1,  0.5, -0.8),  Tuple::Vector(1,  0,  0)},
        {  Tuple::Point(-1, -0.2,  0.9), Tuple::Vector(-1,  0,  0)},
        {Tuple::Point(-0.4,    1, -0.1),  Tuple::Vector(0,  1,  0)},
        { Tuple::Point(0.3,   -1, -0.7),  Tuple::Vector(0, -1,  0)},
        {Tuple::Point(-0.6,  0.3,    1),  Tuple::Vector(0,  0,  1)},
        { Tuple::Point(0.4,  0.4,   -1),  Tuple::Vector(0,  0, -1)},
        {   Tuple::Point(1,    1,   -1),  Tuple::Vector(1,  0,  0)},
        {  Tuple::Point(-1,   -1,   -1), Tuple::Vector(-1,  0,  0)}
    };
    GIVEN("c <- cube()")
    {
        Cube c;
        AND_GIVEN("p <- <point>)")
        {
            WHEN("normal <- local_normal_at(p)")
            {
                for (int i = 0; i < 8; i++)
                {
                    Tuple p = the_test[i].point;
                    Tuple normal = c.local_normal_at(p);
                    THEN("normal = <normal>")
                    {
                        REQUIRE(normal == the_test[i].normal);
                    }
                }
            }
        }
    }
}