// MIT License

// Copyright (c) 2019 Erin Catto

// 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.

#include "settings.h"
#include "test.h"

class EdgeShapesCallback : public b2RayCastCallback
{
public:
	EdgeShapesCallback()
	{
		m_fixture = NULL;
	}

	float ReportFixture(b2Fixture* fixture, const b2Vec2& point,
						  const b2Vec2& normal, float fraction) override
	{
		m_fixture = fixture;
		m_point = point;
		m_normal = normal;

		return fraction;
	}

	b2Fixture* m_fixture;
	b2Vec2 m_point;
	b2Vec2 m_normal;
};

class EdgeShapes : public Test
{
public:

	enum
	{
		e_maxBodies = 256
	};

	EdgeShapes()
	{
		// Ground body
		{
			b2BodyDef bd;
			b2Body* ground = m_world->CreateBody(&bd);

			float x1 = -20.0f;
			float y1 = 2.0f * cosf(x1 / 10.0f * b2_pi);
			for (int32 i = 0; i < 80; ++i)
			{
				float x2 = x1 + 0.5f;
				float y2 = 2.0f * cosf(x2 / 10.0f * b2_pi);

				b2EdgeShape shape;
				shape.SetTwoSided(b2Vec2(x1, y1), b2Vec2(x2, y2));
				ground->CreateFixture(&shape, 0.0f);

				x1 = x2;
				y1 = y2;
			}
		}

		{
		b2Vec2 vertices[3];
		vertices[0].Set(-0.5f, 0.0f);
		vertices[1].Set(0.5f, 0.0f);
		vertices[2].Set(0.0f, 1.5f);
		m_polygons[0].Set(vertices, 3);
	}

		{
			b2Vec2 vertices[3];
			vertices[0].Set(-0.1f, 0.0f);
			vertices[1].Set(0.1f, 0.0f);
			vertices[2].Set(0.0f, 1.5f);
			m_polygons[1].Set(vertices, 3);
		}

		{
			float w = 1.0f;
			float b = w / (2.0f + b2Sqrt(2.0f));
			float s = b2Sqrt(2.0f) * b;

			b2Vec2 vertices[8];
			vertices[0].Set(0.5f * s, 0.0f);
			vertices[1].Set(0.5f * w, b);
			vertices[2].Set(0.5f * w, b + s);
			vertices[3].Set(0.5f * s, w);
			vertices[4].Set(-0.5f * s, w);
			vertices[5].Set(-0.5f * w, b + s);
			vertices[6].Set(-0.5f * w, b);
			vertices[7].Set(-0.5f * s, 0.0f);

			m_polygons[2].Set(vertices, 8);
		}

		{
			m_polygons[3].SetAsBox(0.5f, 0.5f);
		}

		{
			m_circle.m_radius = 0.5f;
		}

		m_bodyIndex = 0;
		memset(m_bodies, 0, sizeof(m_bodies));

		m_angle = 0.0f;
	}

	void Create(int32 index)
	{
		if (m_bodies[m_bodyIndex] != NULL)
		{
			m_world->DestroyBody(m_bodies[m_bodyIndex]);
			m_bodies[m_bodyIndex] = NULL;
		}

		b2BodyDef bd;

		float x = RandomFloat(-10.0f, 10.0f);
		float y = RandomFloat(10.0f, 20.0f);
		bd.position.Set(x, y);
		bd.angle = RandomFloat(-b2_pi, b2_pi);
		bd.type = b2_dynamicBody;

		if (index == 4)
		{
			bd.angularDamping = 0.02f;
		}

		m_bodies[m_bodyIndex] = m_world->CreateBody(&bd);

		if (index < 4)
		{
			b2FixtureDef fd;
			fd.shape = m_polygons + index;
			fd.friction = 0.3f;
			fd.density = 20.0f;
			m_bodies[m_bodyIndex]->CreateFixture(&fd);
		}
		else
		{
			b2FixtureDef fd;
			fd.shape = &m_circle;
			fd.friction = 0.3f;
			fd.density = 20.0f;
			m_bodies[m_bodyIndex]->CreateFixture(&fd);
		}

		m_bodyIndex = (m_bodyIndex + 1) % e_maxBodies;
	}

	void DestroyBody()
	{
		for (int32 i = 0; i < e_maxBodies; ++i)
		{
			if (m_bodies[i] != NULL)
			{
				m_world->DestroyBody(m_bodies[i]);
				m_bodies[i] = NULL;
				return;
			}
		}
	}

	void Keyboard(int key) override
	{
		switch (key)
		{
		case GLFW_KEY_1:
		case GLFW_KEY_2:
		case GLFW_KEY_3:
		case GLFW_KEY_4:
		case GLFW_KEY_5:
			Create(key - GLFW_KEY_1);
			break;

		case GLFW_KEY_D:
			DestroyBody();
			break;
		}
	}

	void Step(Settings& settings) override
	{
		bool advanceRay = settings.m_pause == 0 || settings.m_singleStep;

		Test::Step(settings);
		g_debugDraw.DrawString(5, m_textLine, "Press 1-5 to drop stuff");
		m_textLine += m_textIncrement;

		float L = 25.0f;
		b2Vec2 point1(0.0f, 10.0f);
		b2Vec2 d(L * cosf(m_angle), -L * b2Abs(sinf(m_angle)));
		b2Vec2 point2 = point1 + d;

		EdgeShapesCallback callback;

		m_world->RayCast(&callback, point1, point2);

		if (callback.m_fixture)
		{
			g_debugDraw.DrawPoint(callback.m_point, 5.0f, b2Color(0.4f, 0.9f, 0.4f));

			g_debugDraw.DrawSegment(point1, callback.m_point, b2Color(0.8f, 0.8f, 0.8f));

			b2Vec2 head = callback.m_point + 0.5f * callback.m_normal;
			g_debugDraw.DrawSegment(callback.m_point, head, b2Color(0.9f, 0.9f, 0.4f));
		}
		else
		{
			g_debugDraw.DrawSegment(point1, point2, b2Color(0.8f, 0.8f, 0.8f));
		}

		if (advanceRay)
		{
			m_angle += 0.25f * b2_pi / 180.0f;
		}
	}

	static Test* Create()
	{
		return new EdgeShapes;
	}

	int32 m_bodyIndex;
	b2Body* m_bodies[e_maxBodies];
	b2PolygonShape m_polygons[4];
	b2CircleShape m_circle;

	float m_angle;
};

static int testIndex = RegisterTest("Geometry", "Edge Shapes", EdgeShapes::Create);