#include <QApplication>
#include <QDebug>
#include <QFrame>
#include <QVBoxLayout>
#include <QWidget>
#include <QTimer>
#include <QFont>
#include <QFontMetrics>

#include <Qt3DRender/QCamera>
#include <Qt3DRender/QCameraLens>
#include <Qt3DExtras/Qt3DWindow>
#include <Qt3DExtras/QOrbitCameraController>
#include <Qt3DExtras/QDiffuseSpecularMaterial>
#include <Qt3DRender/QBuffer>
#include <Qt3DRender/QAttribute>
#include <Qt3DRender/QGeometry>
#include <Qt3DRender/QGeometryRenderer>

Qt3DCore::QEntity* createTriangleMesh(bool isIndexed = false)
{
	auto lineMat = new Qt3DExtras::QDiffuseSpecularMaterial;
	lineMat->setDiffuse(QColor(Qt::red));

	auto geometry = new Qt3DRender::QGeometry;

	const quint32 elementSize = 3;
	const quint32 stride = elementSize * sizeof(float);

	auto vertexBuffer = new Qt3DRender::QBuffer(geometry);
	auto positionAttribute = new Qt3DRender::QAttribute;
	positionAttribute->setName(Qt3DRender::QAttribute::defaultPositionAttributeName());
	positionAttribute->setAttributeType(Qt3DRender::QAttribute::VertexAttribute);
	positionAttribute->setVertexBaseType(Qt3DRender::QAttribute::Float);
	positionAttribute->setVertexSize(3);
	positionAttribute->setByteStride(stride);
	positionAttribute->setBuffer(vertexBuffer);

	geometry->addAttribute(positionAttribute);

	float vertices[] = { 1,2,0, 0,0,0, 1,-2,0, 4,-2,0, 5,0,0, 4,2,0 };
	auto numVertices = (sizeof(vertices) / sizeof(vertices[0])) / 3;

	QByteArray vertexBufferData;
	vertexBufferData.resize(static_cast<int>(numVertices * stride));
	memcpy(vertexBufferData.data(), vertices, numVertices * stride);

	vertexBuffer->setData(vertexBufferData);
	positionAttribute->setCount(static_cast<uint>(numVertices));

	auto geometryRenderer = new Qt3DRender::QGeometryRenderer;
	// uncommenting the following line work around the bug
	//geometryRenderer->setVertexCount(numVertices);
	geometryRenderer->setRestartIndexValue(-1);
	geometryRenderer->setPrimitiveRestartEnabled(true);
	geometryRenderer->setPrimitiveType(Qt3DRender::QGeometryRenderer::Triangles);

	if (isIndexed) {
		auto indexBuffer = new Qt3DRender::QBuffer(geometry);
		auto indexAttribute = new Qt3DRender::QAttribute;
		indexAttribute->setAttributeType(Qt3DRender::QAttribute::IndexAttribute);
		indexAttribute->setVertexBaseType(Qt3DRender::QAttribute::UnsignedInt);
		indexAttribute->setVertexSize(1);
		indexAttribute->setByteStride(indexAttribute->vertexSize() * sizeof(uint32_t));
		indexAttribute->setBuffer(indexBuffer);

		geometry->addAttribute(indexAttribute);

		uint32_t indices[] = { 0, 1, 2, 3, 4, 5 };
		auto numIndices = sizeof(indices) / sizeof(indices[0]);

		QByteArray indexBufferData;
		indexBufferData.resize(static_cast<int>(numIndices * sizeof(uint32_t)));
		memcpy(indexBufferData.data(), indices, numIndices * sizeof(uint32_t));

		indexBuffer->setData(indexBufferData);
		indexAttribute->setCount(static_cast<uint>(numIndices));
	}

	geometryRenderer->setGeometry(geometry);

	auto meshEntity = new Qt3DCore::QEntity;
	meshEntity->addComponent(geometryRenderer);
	meshEntity->addComponent(lineMat);

	return meshEntity;
}

Qt3DCore::QEntity* createLineMesh(bool isIndexed = false)
{
	auto lineMat = new Qt3DExtras::QDiffuseSpecularMaterial;
	lineMat->setDiffuse(QColor(Qt::red));

	auto geometry = new Qt3DRender::QGeometry;
	auto vertexBuffer = new Qt3DRender::QBuffer(geometry);
	auto indexBuffer = new Qt3DRender::QBuffer(geometry);

	const quint32 elementSize = 3;
	const quint32 stride = elementSize * sizeof(float);

	auto positionAttribute = new Qt3DRender::QAttribute;
	positionAttribute->setName(Qt3DRender::QAttribute::defaultPositionAttributeName());
	positionAttribute->setAttributeType(Qt3DRender::QAttribute::VertexAttribute);
	positionAttribute->setVertexBaseType(Qt3DRender::QAttribute::Float);
	positionAttribute->setVertexSize(3);
	positionAttribute->setByteStride(stride);
	positionAttribute->setBuffer(vertexBuffer);

	geometry->addAttribute(positionAttribute);

	float vertices[] = { 0,0,0, 1,0,0, 0,0,0, 0,1,0, 0,0,0, 0,0,1 };
	auto numVertices = (sizeof(vertices) / sizeof(vertices[0])) / 3;

	QByteArray vertexBufferData;
	vertexBufferData.resize(static_cast<int>(numVertices * stride));
	memcpy(vertexBufferData.data(), vertices, numVertices * stride);

	vertexBuffer->setData(vertexBufferData);
	positionAttribute->setCount(static_cast<uint>(numVertices));

	auto geometryRenderer = new Qt3DRender::QGeometryRenderer;
	// uncommenting the following line work around the bug
	//geometryRenderer->setVertexCount(numVertices);
	geometryRenderer->setRestartIndexValue(-1);
	geometryRenderer->setPrimitiveRestartEnabled(true);
	geometryRenderer->setPrimitiveType(Qt3DRender::QGeometryRenderer::Lines);

	if (isIndexed) {
		auto indexAttribute = new Qt3DRender::QAttribute;
		indexAttribute->setAttributeType(Qt3DRender::QAttribute::IndexAttribute);
		indexAttribute->setVertexBaseType(Qt3DRender::QAttribute::UnsignedInt);
		indexAttribute->setVertexSize(1);
		indexAttribute->setByteStride(indexAttribute->vertexSize() * sizeof(uint32_t));
		indexAttribute->setBuffer(indexBuffer);

		geometry->addAttribute(indexAttribute);

		uint32_t indices[] = { 0, 1, 2, 3, 4, 5 };
		auto numIndices = sizeof(indices) / sizeof(indices[0]);

		QByteArray indexBufferData;
		indexBufferData.resize(static_cast<int>(numIndices * sizeof(uint32_t)));
		memcpy(indexBufferData.data(), indices, numIndices * sizeof(uint32_t));

		indexBuffer->setData(indexBufferData);
		indexAttribute->setCount(static_cast<uint>(numIndices));
	}

	geometryRenderer->setGeometry(geometry);

	auto meshEntity = new Qt3DCore::QEntity;
	meshEntity->addComponent(geometryRenderer);
	meshEntity->addComponent(lineMat);

	return meshEntity;
}

int main(int argc, char* argv[])
{
	QApplication a(argc, argv);

	auto view = new Qt3DExtras::Qt3DWindow();

	auto rootEntity = new Qt3DCore::QEntity();
	view->setRootEntity(rootEntity);

	auto camera = view->camera();
	camera->lens()->setPerspectiveProjection(45.0f, 1., 0.1f, 10000.0f);
	camera->setPosition(QVector3D(0, 0, 5));
	camera->setUpVector(QVector3D(0, 1, 0));
	camera->setViewCenter(QVector3D(0, 0, 0));

	auto camController = new Qt3DExtras::QOrbitCameraController(rootEntity);
	camController->setCamera(camera);

	bool showBug = true;
	auto lines = createLineMesh(!showBug);
	lines->setParent(rootEntity);
	auto triangles = createTriangleMesh(!showBug);
	triangles->setParent(rootEntity);

	auto container = QWidget::createWindowContainer(view);
	QFrame frame;
	frame.setLayout(new QVBoxLayout);
	frame.layout()->addWidget(container);
	frame.resize(QSize(400, 300));

	QTimer::singleShot(100, [&]() {
		camera->viewAll();
	});

	frame.show();
	return a.exec();
}