/*************************************************************************/
/*  xr_server.cpp                                                        */
/*************************************************************************/
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/*                           GODOT ENGINE                                */
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/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md).   */
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#include "xr_server.h"
#include "core/config/project_settings.h"
#include "xr/xr_interface.h"
#include "xr/xr_positional_tracker.h"

XRServer *XRServer::singleton = nullptr;

XRServer *XRServer::get_singleton() {
	return singleton;
};

void XRServer::_bind_methods() {
	ClassDB::bind_method(D_METHOD("get_world_scale"), &XRServer::get_world_scale);
	ClassDB::bind_method(D_METHOD("set_world_scale", "scale"), &XRServer::set_world_scale);
	ClassDB::bind_method(D_METHOD("get_reference_frame"), &XRServer::get_reference_frame);
	ClassDB::bind_method(D_METHOD("center_on_hmd", "rotation_mode", "keep_height"), &XRServer::center_on_hmd);
	ClassDB::bind_method(D_METHOD("get_hmd_transform"), &XRServer::get_hmd_transform);

	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "world_scale"), "set_world_scale", "get_world_scale");

	ClassDB::bind_method(D_METHOD("add_interface", "interface"), &XRServer::add_interface);
	ClassDB::bind_method(D_METHOD("get_interface_count"), &XRServer::get_interface_count);
	ClassDB::bind_method(D_METHOD("remove_interface", "interface"), &XRServer::remove_interface);
	ClassDB::bind_method(D_METHOD("get_interface", "idx"), &XRServer::get_interface);
	ClassDB::bind_method(D_METHOD("get_interfaces"), &XRServer::get_interfaces);
	ClassDB::bind_method(D_METHOD("find_interface", "name"), &XRServer::find_interface);

	ClassDB::bind_method(D_METHOD("add_tracker", "tracker"), &XRServer::add_tracker);
	ClassDB::bind_method(D_METHOD("remove_tracker", "tracker"), &XRServer::remove_tracker);
	ClassDB::bind_method(D_METHOD("get_trackers", "tracker_types"), &XRServer::get_trackers);
	ClassDB::bind_method(D_METHOD("get_tracker", "tracker_name"), &XRServer::get_tracker);

	ClassDB::bind_method(D_METHOD("get_primary_interface"), &XRServer::get_primary_interface);
	ClassDB::bind_method(D_METHOD("set_primary_interface", "interface"), &XRServer::set_primary_interface);

	ADD_PROPERTY(PropertyInfo(Variant::OBJECT, "primary_interface"), "set_primary_interface", "get_primary_interface");

	ClassDB::bind_method(D_METHOD("get_last_process_usec"), &XRServer::get_last_process_usec);
	ClassDB::bind_method(D_METHOD("get_last_commit_usec"), &XRServer::get_last_commit_usec);
	ClassDB::bind_method(D_METHOD("get_last_frame_usec"), &XRServer::get_last_frame_usec);

	BIND_ENUM_CONSTANT(TRACKER_HEAD);
	BIND_ENUM_CONSTANT(TRACKER_CONTROLLER);
	BIND_ENUM_CONSTANT(TRACKER_BASESTATION);
	BIND_ENUM_CONSTANT(TRACKER_ANCHOR);
	BIND_ENUM_CONSTANT(TRACKER_ANY_KNOWN);
	BIND_ENUM_CONSTANT(TRACKER_UNKNOWN);
	BIND_ENUM_CONSTANT(TRACKER_ANY);

	BIND_ENUM_CONSTANT(RESET_FULL_ROTATION);
	BIND_ENUM_CONSTANT(RESET_BUT_KEEP_TILT);
	BIND_ENUM_CONSTANT(DONT_RESET_ROTATION);

	ADD_SIGNAL(MethodInfo("interface_added", PropertyInfo(Variant::STRING_NAME, "interface_name")));
	ADD_SIGNAL(MethodInfo("interface_removed", PropertyInfo(Variant::STRING_NAME, "interface_name")));

	ADD_SIGNAL(MethodInfo("tracker_added", PropertyInfo(Variant::STRING_NAME, "tracker_name"), PropertyInfo(Variant::INT, "type")));
	ADD_SIGNAL(MethodInfo("tracker_updated", PropertyInfo(Variant::STRING_NAME, "tracker_name"), PropertyInfo(Variant::INT, "type")));
	ADD_SIGNAL(MethodInfo("tracker_removed", PropertyInfo(Variant::STRING_NAME, "tracker_name"), PropertyInfo(Variant::INT, "type")));
};

double XRServer::get_world_scale() const {
	return world_scale;
};

void XRServer::set_world_scale(double p_world_scale) {
	if (p_world_scale < 0.01) {
		p_world_scale = 0.01;
	} else if (p_world_scale > 1000.0) {
		p_world_scale = 1000.0;
	}

	world_scale = p_world_scale;
};

Transform3D XRServer::get_world_origin() const {
	return world_origin;
};

void XRServer::set_world_origin(const Transform3D &p_world_origin) {
	world_origin = p_world_origin;
};

Transform3D XRServer::get_reference_frame() const {
	return reference_frame;
};

void XRServer::center_on_hmd(RotationMode p_rotation_mode, bool p_keep_height) {
	if (primary_interface == nullptr) {
		return;
	}

	if (primary_interface->get_play_area_mode() == XRInterface::XR_PLAY_AREA_STAGE) {
		// center_on_hmd is not available in this mode
		reference_frame = Transform3D();
		return;
	}

	// clear our current reference frame or we'll end up double adjusting it
	reference_frame = Transform3D();

	// requesting our EYE_MONO transform should return our current HMD position
	Transform3D new_reference_frame = primary_interface->get_camera_transform();

	// remove our tilt
	if (p_rotation_mode == 1) {
		// take the Y out of our Z
		new_reference_frame.basis.set_axis(2, Vector3(new_reference_frame.basis.elements[0][2], 0.0, new_reference_frame.basis.elements[2][2]).normalized());

		// Y is straight up
		new_reference_frame.basis.set_axis(1, Vector3(0.0, 1.0, 0.0));

		// and X is our cross reference
		new_reference_frame.basis.set_axis(0, new_reference_frame.basis.get_axis(1).cross(new_reference_frame.basis.get_axis(2)).normalized());
	} else if (p_rotation_mode == 2) {
		// remove our rotation, we're only interesting in centering on position
		new_reference_frame.basis = Basis();
	};

	// don't negate our height
	if (p_keep_height) {
		new_reference_frame.origin.y = 0.0;
	};

	reference_frame = new_reference_frame.inverse();
};

Transform3D XRServer::get_hmd_transform() {
	Transform3D hmd_transform;
	if (primary_interface != nullptr) {
		hmd_transform = primary_interface->get_camera_transform();
	};
	return hmd_transform;
};

void XRServer::add_interface(const Ref<XRInterface> &p_interface) {
	ERR_FAIL_COND(p_interface.is_null());

	for (int i = 0; i < interfaces.size(); i++) {
		if (interfaces[i] == p_interface) {
			ERR_PRINT("Interface was already added");
			return;
		};
	};

	interfaces.push_back(p_interface);
	emit_signal(SNAME("interface_added"), p_interface->get_name());
};

void XRServer::remove_interface(const Ref<XRInterface> &p_interface) {
	ERR_FAIL_COND(p_interface.is_null());

	int idx = -1;
	for (int i = 0; i < interfaces.size(); i++) {
		if (interfaces[i] == p_interface) {
			idx = i;
			break;
		};
	};

	ERR_FAIL_COND(idx == -1);

	print_verbose("XR: Removed interface" + p_interface->get_name());

	emit_signal(SNAME("interface_removed"), p_interface->get_name());
	interfaces.remove(idx);
};

int XRServer::get_interface_count() const {
	return interfaces.size();
};

Ref<XRInterface> XRServer::get_interface(int p_index) const {
	ERR_FAIL_INDEX_V(p_index, interfaces.size(), nullptr);

	return interfaces[p_index];
};

Ref<XRInterface> XRServer::find_interface(const String &p_name) const {
	int idx = -1;
	for (int i = 0; i < interfaces.size(); i++) {
		if (interfaces[i]->get_name() == p_name) {
			idx = i;
			break;
		};
	};

	ERR_FAIL_COND_V(idx == -1, nullptr);

	return interfaces[idx];
};

Array XRServer::get_interfaces() const {
	Array ret;

	for (int i = 0; i < interfaces.size(); i++) {
		Dictionary iface_info;

		iface_info["id"] = i;
		iface_info["name"] = interfaces[i]->get_name();

		ret.push_back(iface_info);
	};

	return ret;
};

Ref<XRInterface> XRServer::get_primary_interface() const {
	return primary_interface;
};

void XRServer::set_primary_interface(const Ref<XRInterface> &p_primary_interface) {
	if (p_primary_interface.is_null()) {
		print_verbose("XR: Clearing primary interface");
		primary_interface.unref();
	} else {
		primary_interface = p_primary_interface;

		print_verbose("XR: Primary interface set to: " + primary_interface->get_name());
	}
};

void XRServer::add_tracker(Ref<XRPositionalTracker> p_tracker) {
	ERR_FAIL_COND(p_tracker.is_null());

	StringName tracker_name = p_tracker->get_tracker_name();
	if (trackers.has(tracker_name)) {
		if (trackers[tracker_name] != p_tracker) {
			// We already have a tracker with this name, we're going to replace it
			trackers[tracker_name] = p_tracker;
			emit_signal(SNAME("tracker_updated"), tracker_name, p_tracker->get_tracker_type());
		}
	} else {
		trackers[tracker_name] = p_tracker;
		emit_signal(SNAME("tracker_added"), tracker_name, p_tracker->get_tracker_type());
	}
};

void XRServer::remove_tracker(Ref<XRPositionalTracker> p_tracker) {
	ERR_FAIL_COND(p_tracker.is_null());

	StringName tracker_name = p_tracker->get_tracker_name();
	if (trackers.has(tracker_name)) {
		// we send the signal right before removing it
		emit_signal(SNAME("tracker_removed"), p_tracker->get_tracker_name(), p_tracker->get_tracker_type());

		// and remove it
		trackers.erase(tracker_name);
	}
};

Dictionary XRServer::get_trackers(int p_tracker_types) {
	Dictionary res;

	for (int i = 0; i < trackers.size(); i++) {
		Ref<XRPositionalTracker> tracker = trackers.get_value_at_index(i);
		if (tracker.is_valid() && (tracker->get_tracker_type() & p_tracker_types) != 0) {
			res[tracker->get_tracker_name()] = tracker;
		}
	}

	return res;
}

Ref<XRPositionalTracker> XRServer::get_tracker(const StringName &p_name) const {
	if (trackers.has(p_name)) {
		return trackers[p_name];
	} else {
		// tracker hasn't been registered yet, which is fine, no need to spam the error log...
		return Ref<XRPositionalTracker>();
	}
};

PackedStringArray XRServer::get_suggested_tracker_names() const {
	PackedStringArray arr;

	for (int i = 0; i < interfaces.size(); i++) {
		Ref<XRInterface> interface = interfaces[i];
		PackedStringArray interface_arr = interface->get_suggested_tracker_names();
		for (int a = 0; a < interface_arr.size(); a++) {
			if (!arr.has(interface_arr[a])) {
				arr.push_back(interface_arr[a]);
			}
		}
	}

	if (arr.size() == 0) {
		// no suggestions from our tracker? include our defaults
		arr.push_back(String("head"));
		arr.push_back(String("left_hand"));
		arr.push_back(String("right_hand"));
	}

	return arr;
}

PackedStringArray XRServer::get_suggested_pose_names(const StringName &p_tracker_name) const {
	PackedStringArray arr;

	for (int i = 0; i < interfaces.size(); i++) {
		Ref<XRInterface> interface = interfaces[i];
		PackedStringArray interface_arr = interface->get_suggested_pose_names(p_tracker_name);
		for (int a = 0; a < interface_arr.size(); a++) {
			if (!arr.has(interface_arr[a])) {
				arr.push_back(interface_arr[a]);
			}
		}
	}

	if (arr.size() == 0) {
		// no suggestions from our tracker? include our defaults
		arr.push_back(String("default"));

		if ((p_tracker_name == "left_hand") || (p_tracker_name == "right_hand")) {
			arr.push_back(String("aim"));
			arr.push_back(String("grip"));
			arr.push_back(String("skeleton"));
		}
	}

	return arr;
}

uint64_t XRServer::get_last_process_usec() {
	return last_process_usec;
};

uint64_t XRServer::get_last_commit_usec() {
	return last_commit_usec;
};

uint64_t XRServer::get_last_frame_usec() {
	return last_frame_usec;
};

void XRServer::_process() {
	/* called from renderer_viewport.draw_viewports right before we start drawing our viewports */

	/* mark for our frame timing */
	last_process_usec = OS::get_singleton()->get_ticks_usec();

	/* process all active interfaces */
	for (int i = 0; i < interfaces.size(); i++) {
		if (!interfaces[i].is_valid()) {
			// ignore, not a valid reference
		} else if (interfaces[i]->is_initialized()) {
			interfaces.write[i]->process();
		};
	};
};

void XRServer::_mark_commit() {
	/* time this */
	last_commit_usec = OS::get_singleton()->get_ticks_usec();

	/* now store our difference as we may overwrite last_process_usec before this is accessed */
	last_frame_usec = last_commit_usec - last_process_usec;
};

XRServer::XRServer() {
	singleton = this;
	world_scale = 1.0;
};

XRServer::~XRServer() {
	primary_interface.unref();

	while (interfaces.size() > 0) {
		interfaces.remove(0);
	}

	// TODO pretty sure there is a clear function or something...
	while (trackers.size() > 0) {
		trackers.erase(trackers.get_key_at_index(0));
	}

	singleton = nullptr;
};