#include "drone_controller.hh"
#include "opengl_widget.hh"
#include "load_obj.hh"

#include <QJsonArray>
#include <QDebug>
#include <QFile>


Waypoint::Waypoint(unsigned frame, QVector3D pos)
	:frame(frame),
	 pos(pos) {}


Waypoint::Waypoint(const QJsonObject &json)
	:Waypoint(json["frame"].toInt(),
			  QVector3D(json["position"]["lng_X"].toInt() / 100.0,
						json["position"]["alt_Y"].toInt() / 100.0,
						json["position"]["lat_Z"].toInt() / 100.0)) {}


bool Drone::mesh_initialized = false;
OpenGLMesh *Drone::mesh = nullptr;

Drone::Drone(int id)
	:id(id) {
	if (!mesh_initialized) {
		QVector<GLfloat> verts = load_obj(":/mdl/dji600.obj", LOAD_OBJ_NORMALS | LOAD_OBJ_UVS);
		QOpenGLTexture *texture = new QOpenGLTexture(QImage(":/img/dji600.jpg").mirrored());
		mesh = new OpenGLMesh(verts, texture);
		mesh_initialized = true;
	}
	OpenGLWidget::instance->meshes.append(*mesh);
	mesh_id = OpenGLWidget::instance->meshes.size() - 1;
}


Drone::Drone(const QJsonObject &json)
	:Drone(json["id"].toInt()) {
	QJsonArray ja = json["waypoints"].toArray();
	waypoints.reserve(ja.size());
	for (const QJsonValue &o : ja) {
		waypoints.append(Waypoint(o.toObject()));
	}
}


const QVector<Waypoint> Drone::getWaypoints() const {
	return waypoints;
}


void Drone::setTo(int frame) {
	int prev = -1, next = -1;
	const Waypoint *prev_wp, *next_wp;
	for (const Waypoint &wp : waypoints) { // TODO: this can be optimized
		if (wp.frame < frame) {
			prev = wp.frame;
			prev_wp = &wp;
		} else {
			next = wp.frame;
			next_wp = &wp;
			break;
		}
	}
	OpenGLMesh &mesh = OpenGLWidget::instance->meshes[mesh_id];
	mesh.mat = QMatrix4x4();
	if (next > -1 && prev == -1) {
		pos = next_wp->pos;
	} else if (prev > -1 && next == -1) {
		pos = prev_wp->pos;
	} else {
		pos = lerp(prev_wp->pos, next_wp->pos, (double) (frame-prev) / (next-prev));
	}
	mesh.mat.translate(pos);
}


QVector3D Drone::getPos() const {
	return pos;
}


int Drone::getId() const {
	return id;
}


DroneController::DroneController(const QJsonObject &json)
	:framerate(json["framerate"].toInt()) {

	QJsonArray ja = json["drones"].toArray();
	drones.reserve(ja.size());
	for (const QJsonValue &o : ja) {
		drones.append(Drone(o.toObject()));
	}
	for (const Drone &d : drones) {
		for (const Waypoint &wp : d.getWaypoints()) {
			if (wp.frame > duration) duration = wp.frame;
		}
	}

	OpenGLWidget::instance->makeCurrent();
	QOpenGLTexture *ground_tex = new QOpenGLTexture(QImage(":/img/ground.jpg").mirrored());
	ground_tex->setMagnificationFilter(QOpenGLTexture::LinearMipMapLinear);
	ground_tex->setMinificationFilter(QOpenGLTexture::LinearMipMapLinear);
	ground_tex->setWrapMode(QOpenGLTexture::MirroredRepeat);
	OpenGLMesh *ground = new OpenGLMesh({
			-1000, 0, -1000, 0, 1000, 0, 0, 0,
			1000, 0, -1000, 0, 1000, 0, 1000, 0,
			-1000, 0, 1000, 0, 1000, 0, 0, 1000,
			1000, 0, -1000, 0, 1000, 0, 1000, 0,
			-1000, 0, 1000, 0, 1000, 0, 0, 1000,
			1000, 0, 1000, 0, 1000, 0, 1000, 1000,
		}, ground_tex);
	OpenGLWidget::instance->meshes.append(*ground);
	OpenGLWidget::instance->doneCurrent();

	connect(&timer, &QTimer::timeout, this, &DroneController::step);
}


int DroneController::getDuration() const {
	return duration;
}


void DroneController::step() {
	for (Drone d : drones) {
		d.setTo(frame);
	}
	OpenGLWidget::instance->update();
	emit frameChanged(frame);
	if (frame == duration) {
		pause();
	} else {
		frame++;
	}
}


void DroneController::play() {
	if (!paused) return;
	paused = false;
	timer.start(1000. / framerate);
	emit playing();
}


void DroneController::pause() {
	if (paused) return;
	paused = true;
	timer.stop();
	emit pausing();
}


void DroneController::suspend() {
	if (!paused) {
		pause();
		paused = false;
	}
}


void DroneController::resume() {
	if (!paused) {
		paused = true;
		play();
	}
}


void DroneController::seek(int frame) {
	if (this->frame == frame) return;
	this->frame = frame;
	step();
}


void DroneController::computeCollisions(double sphere_radius) {
	double sqDist = sphere_radius * sphere_radius * 2;
	for (int i = 0; i < duration; i++) {
		for (const Drone &a : drones) {
			for (const Drone &b : drones) {
				if (&a == &b) continue;
				if (collides(a, b, sqDist)) {
					emit collision(a.getId(), b.getId(), frame);
				}
			}
		}
	}
}


bool DroneController::collides(const Drone &a, const Drone &b, double sqDist) {
	return (b.getPos() - a.getPos()).lengthSquared() < sqDist;
}