#include "mesh_viewer.h"

#include <tgmath.h>
#include <QOpenGLShader>
#include <QOpenGLDebugLogger>
#include <QtGlobal>


MeshViewer::MeshViewer(QWidget *parent) : QOpenGLWidget(parent) {
	setMouseTracking(true);
	setFocus();
}


QSize MeshViewer::sizeHint() const {
	return QSize(640, 480);
}


void MeshViewer::initializeGL() {
	QOpenGLFunctions *glf = context()->functions();
#ifdef QT_DEBUG
	QOpenGLDebugLogger *logger = new QOpenGLDebugLogger(this);
	if (!logger->initialize()) {
		qDebug("OpenGL debug output unavailable");
	}
	connect(logger, &QOpenGLDebugLogger::messageLogged,
			[](const QOpenGLDebugMessage &message) {
				qDebug() << "OpenGL: " << message.message();
			});
    logger->startLogging();
#endif

	QOpenGLShader vertex_shader(QOpenGLShader::Vertex);
	if (!vertex_shader.compileSourceFile(":/shader.vert")) {
		qCritical() << vertex_shader.log();
	}

	QOpenGLShader fragment_shader(QOpenGLShader::Fragment);
	if (fragment_shader.compileSourceFile(":/shader.frag")) {
		qCritical() << fragment_shader.log();
	}
	if (!program.addShader(&vertex_shader)) {
		qCritical() << program.log();
	}
	if (!program.addShader(&fragment_shader)) {
		qCritical() << program.log();
	}
	if (!program.link()) {
		qCritical() << program.log();
	}
	program.bind();

	program.setUniformValue("alpha", (GLfloat) 1);
	program.setUniformValue("wf_col", WIREFRAME_COLOR);

	glf->glClearColor(1, 1, 1, 0);

	glf->glEnable(GL_DEPTH_TEST);
	glf->glEnable(GL_MULTISAMPLE);

	qDebug("Mesh viewer: initialization complete");
	emit initialized();
}


void MeshViewer::resizeGL(int w, int h) {
	QMatrix4x4 projection;
	projection.perspective(FOV, (float) w/h, .01, 100);
	program.setUniformValue("proj", projection);
}


void MeshViewer::paintGL() {
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	QMatrix4x4 trans;
	trans.translate(0, 0, -cam_dist);
	QMatrix4x4 view = trans * rot;
	program.setUniformValue("view", view);
	for (MeshView &m : meshes) {
		m.paint(program);
	}
}


void MeshViewer::addMesh(const MyMesh &mesh) {
	Q_ASSERT(isValid());
	makeCurrent();
	meshes.emplace_back(mesh, program);
	doneCurrent();
	update();
}


void MeshViewer::removeMesh(const MyMesh &mesh) {
	makeCurrent();
	meshes.remove_if([&](const MeshView &mv) {
		return &mv.mesh == &mesh;
	});
	doneCurrent();
	update();
}


void MeshViewer::mousePressEvent(QMouseEvent *e) {
	if (e->button() == Qt::LeftButton) {
		mouse_pos = e->pos();
	}
}


void MeshViewer::mouseReleaseEvent(QMouseEvent *e) {
	(void) e;
	rot_start = rot;
}


void MeshViewer::mouseMoveEvent(QMouseEvent *e) {
	if (e->buttons() & Qt::LeftButton) {
		QPoint delta = e->pos() - mouse_pos;
		rot = rot_start;
		rot.rotate(delta.x() / 5., 0, 1, 0);
		rot.rotate(delta.y() / 5., QVector3D(1, 0, 0) * rot);
		update();
	}
}


void MeshViewer::wheelEvent(QWheelEvent *e) {
	cam_dist -= e->angleDelta().y() / 1000. * cam_dist;
	update();
}