/*************************************************************************/
/*  xr_interface.cpp                                                     */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                      https://godotengine.org                          */
/*************************************************************************/
/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2022 Godot Engine contributors (cf. AUTHORS.md).   */
/*                                                                       */
/* 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 "xr_interface.h"
#include "servers/rendering/renderer_compositor.h"

void XRInterface::_bind_methods() {
	ADD_SIGNAL(MethodInfo("play_area_changed", PropertyInfo(Variant::INT, "mode")));

	ClassDB::bind_method(D_METHOD("get_name"), &XRInterface::get_name);
	ClassDB::bind_method(D_METHOD("get_capabilities"), &XRInterface::get_capabilities);

	ClassDB::bind_method(D_METHOD("is_primary"), &XRInterface::is_primary);
	ClassDB::bind_method(D_METHOD("set_primary", "primary"), &XRInterface::set_primary);

	ClassDB::bind_method(D_METHOD("is_initialized"), &XRInterface::is_initialized);
	ClassDB::bind_method(D_METHOD("initialize"), &XRInterface::initialize);
	ClassDB::bind_method(D_METHOD("uninitialize"), &XRInterface::uninitialize);

	ClassDB::bind_method(D_METHOD("get_tracking_status"), &XRInterface::get_tracking_status);

	ClassDB::bind_method(D_METHOD("get_render_target_size"), &XRInterface::get_render_target_size);
	ClassDB::bind_method(D_METHOD("get_view_count"), &XRInterface::get_view_count);

	ClassDB::bind_method(D_METHOD("trigger_haptic_pulse", "action_name", "tracker_name", "frequency", "amplitude", "duration_sec", "delay_sec"), &XRInterface::trigger_haptic_pulse);

	ADD_GROUP("Interface", "interface_");
	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "interface_is_primary"), "set_primary", "is_primary");

	// methods and properties specific to VR...
	ClassDB::bind_method(D_METHOD("supports_play_area_mode", "mode"), &XRInterface::supports_play_area_mode);
	ClassDB::bind_method(D_METHOD("get_play_area_mode"), &XRInterface::get_play_area_mode);
	ClassDB::bind_method(D_METHOD("set_play_area_mode", "mode"), &XRInterface::set_play_area_mode);
	ClassDB::bind_method(D_METHOD("get_play_area"), &XRInterface::get_play_area);

	ADD_GROUP("XR", "xr_");
	ADD_PROPERTY(PropertyInfo(Variant::INT, "xr_play_area_mode", PROPERTY_HINT_ENUM, "Unknown,3DOF,Sitting,Roomscale,Stage"), "set_play_area_mode", "get_play_area_mode");

	// methods and properties specific to AR....
	ClassDB::bind_method(D_METHOD("get_anchor_detection_is_enabled"), &XRInterface::get_anchor_detection_is_enabled);
	ClassDB::bind_method(D_METHOD("set_anchor_detection_is_enabled", "enable"), &XRInterface::set_anchor_detection_is_enabled);
	ClassDB::bind_method(D_METHOD("get_camera_feed_id"), &XRInterface::get_camera_feed_id);

	ClassDB::bind_method(D_METHOD("is_passthrough_supported"), &XRInterface::is_passthrough_supported);
	ClassDB::bind_method(D_METHOD("is_passthrough_enabled"), &XRInterface::is_passthrough_enabled);
	ClassDB::bind_method(D_METHOD("start_passthrough"), &XRInterface::start_passthrough);
	ClassDB::bind_method(D_METHOD("stop_passthrough"), &XRInterface::stop_passthrough);
	ClassDB::bind_method(D_METHOD("get_transform_for_view", "view", "cam_transform"), &XRInterface::get_transform_for_view);
	ClassDB::bind_method(D_METHOD("get_projection_for_view", "view", "aspect", "near", "far"), &XRInterface::get_projection_for_view);

	ADD_GROUP("AR", "ar_");
	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "ar_is_anchor_detection_enabled"), "set_anchor_detection_is_enabled", "get_anchor_detection_is_enabled");

	BIND_ENUM_CONSTANT(XR_NONE);
	BIND_ENUM_CONSTANT(XR_MONO);
	BIND_ENUM_CONSTANT(XR_STEREO);
	BIND_ENUM_CONSTANT(XR_QUAD);
	BIND_ENUM_CONSTANT(XR_VR);
	BIND_ENUM_CONSTANT(XR_AR);
	BIND_ENUM_CONSTANT(XR_EXTERNAL);

	BIND_ENUM_CONSTANT(XR_NORMAL_TRACKING);
	BIND_ENUM_CONSTANT(XR_EXCESSIVE_MOTION);
	BIND_ENUM_CONSTANT(XR_INSUFFICIENT_FEATURES);
	BIND_ENUM_CONSTANT(XR_UNKNOWN_TRACKING);
	BIND_ENUM_CONSTANT(XR_NOT_TRACKING);

	BIND_ENUM_CONSTANT(XR_PLAY_AREA_UNKNOWN);
	BIND_ENUM_CONSTANT(XR_PLAY_AREA_3DOF);
	BIND_ENUM_CONSTANT(XR_PLAY_AREA_SITTING);
	BIND_ENUM_CONSTANT(XR_PLAY_AREA_ROOMSCALE);
	BIND_ENUM_CONSTANT(XR_PLAY_AREA_STAGE);
};

bool XRInterface::is_primary() {
	XRServer *xr_server = XRServer::get_singleton();
	ERR_FAIL_NULL_V(xr_server, false);

	return xr_server->get_primary_interface() == this;
}

void XRInterface::set_primary(bool p_primary) {
	XRServer *xr_server = XRServer::get_singleton();
	ERR_FAIL_NULL(xr_server);

	if (p_primary) {
		ERR_FAIL_COND(!is_initialized());

		xr_server->set_primary_interface(this);
	} else if (xr_server->get_primary_interface() == this) {
		xr_server->set_primary_interface(nullptr);
	}
}

XRInterface::XRInterface() {}

XRInterface::~XRInterface() {
	if (vrs.vrs_texture.is_valid()) {
		RS::get_singleton()->free(vrs.vrs_texture);
		vrs.vrs_texture = RID();
	}
}

// query if this interface supports this play area mode
bool XRInterface::supports_play_area_mode(XRInterface::PlayAreaMode p_mode) {
	return p_mode == XR_PLAY_AREA_UNKNOWN;
}

// get the current play area mode
XRInterface::PlayAreaMode XRInterface::get_play_area_mode() const {
	return XR_PLAY_AREA_UNKNOWN;
}

// change the play area mode, note that this should return false if the mode is not available
bool XRInterface::set_play_area_mode(XRInterface::PlayAreaMode p_mode) {
	return p_mode == XR_PLAY_AREA_UNKNOWN;
}

// if available, returns an array of vectors denoting the play area the player can move around in
PackedVector3Array XRInterface::get_play_area() const {
	// Return an empty array by default.
	// Note implementation is responsible for applying our reference frame and world scale to the raw data.
	// `play_area_changed` should be emitted if play area data is available and either the reference frame or world scale changes.
	return PackedVector3Array();
};

/** these will only be implemented on AR interfaces, so we want dummies for VR **/
bool XRInterface::get_anchor_detection_is_enabled() const {
	return false;
}

void XRInterface::set_anchor_detection_is_enabled(bool p_enable) {
}

int XRInterface::get_camera_feed_id() {
	return 0;
}

RID XRInterface::get_vrs_texture() {
	// Default logic will return a standard VRS image based on our target size and default projections.
	// Note that this only gets called if VRS is supported on the hardware.

	Size2 texel_size = Size2(16.0, 16.0); // For now we assume we always use 16x16 texels, seems to be the standard.
	int view_count = get_view_count();
	Size2 target_size = get_render_target_size();
	real_t aspect = target_size.x / target_size.y; // is this y/x ?
	Size2 vrs_size = Size2(round(0.5 + target_size.x / texel_size.x), round(0.5 + target_size.y / texel_size.y));
	real_t radius = vrs_size.length() * 0.5;
	Size2 vrs_sizei = vrs_size;

	if (vrs.size != vrs_sizei) {
		const uint8_t densities[] = {
			0, // 1x1
			1, // 1x2
			// 4, // 2x1
			5, // 2x2
			6, // 2x4
			// 9, // 4x2
			10, // 4x4
		};

		// out with the old
		if (vrs.vrs_texture.is_valid()) {
			RS::get_singleton()->free(vrs.vrs_texture);
			vrs.vrs_texture = RID();
		}

		// in with the new
		Vector<Ref<Image>> images;
		vrs.size = vrs_sizei;

		for (int i = 0; i < view_count && i < 2; i++) {
			PackedByteArray data;
			data.resize(vrs_sizei.x * vrs_sizei.y);
			uint8_t *data_ptr = data.ptrw();

			// Our near and far don't matter much for what we're doing here, but there are some interfaces that will remember this as the near and far and may fail as a result...
			Projection cm = get_projection_for_view(i, aspect, 0.1, 1000.0);
			Vector3 center = cm.xform(Vector3(0.0, 0.0, 999.0));

			Vector2i view_center;
			view_center.x = int(vrs_size.x * (center.x + 1.0) * 0.5);
			view_center.y = int(vrs_size.y * (center.y + 1.0) * 0.5);

			int d = 0;
			for (int y = 0; y < vrs_sizei.y; y++) {
				for (int x = 0; x < vrs_sizei.x; x++) {
					Vector2 offset = Vector2(x - view_center.x, y - view_center.y);
					offset.y *= aspect;
					real_t distance = offset.length();
					int idx = round(5.0 * distance / radius);
					if (idx > 4) {
						idx = 4;
					}
					uint8_t density = densities[idx];

					data_ptr[d++] = density;
				}
			}
			images.push_back(Image::create_from_data(vrs_sizei.x, vrs_sizei.y, false, Image::FORMAT_R8, data));
		}

		if (images.size() == 1) {
			vrs.vrs_texture = RS::get_singleton()->texture_2d_create(images[0]);
		} else {
			vrs.vrs_texture = RS::get_singleton()->texture_2d_layered_create(images, RS::TEXTURE_LAYERED_2D_ARRAY);
		}
	}

	return vrs.vrs_texture;
}

/** these are optional, so we want dummies **/

RID XRInterface::get_color_texture() {
	return RID();
}

RID XRInterface::get_depth_texture() {
	return RID();
}

RID XRInterface::get_velocity_texture() {
	return RID();
}

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

	return arr;
}

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

	return arr;
}

XRInterface::TrackingStatus XRInterface::get_tracking_status() const {
	return XR_UNKNOWN_TRACKING;
}

void XRInterface::trigger_haptic_pulse(const String &p_action_name, const StringName &p_tracker_name, double p_frequency, double p_amplitude, double p_duration_sec, double p_delay_sec) {
}