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

#include "core/io/resource_loader.h"
#include "core/object/class_db.h"
#include "core/error/error_macros.h"
#include "core/containers/list.h"
#include "core/containers/rb_map.h"
#include "core/math/aabb.h"
#include "core/math/math_defs.h"
#include "core/math/math_funcs.h"
#include "core/math/plane.h"
#include "core/math/transform.h"
#include "core/math/vector2.h"
#include "core/math/vector3.h"
#include "core/os/memory.h"
#include "core/typedefs.h"
#include "core/string/ustring.h"
#include "core/variant/variant.h"
#include "editor/editor_file_dialog.h"
#include "editor/editor_node.h"
#include "editor/scene_tree_editor.h"
#include "scene/main/spatial.h"
#include "scene/3d/visual_instance.h"
#include "scene/gui/box_container.h"
#include "scene/gui/button.h"
#include "scene/gui/dialogs.h"
#include "scene/gui/option_button.h"
#include "scene/gui/spin_box.h"
#include "scene/main/node.h"

bool ParticlesEditorBase::_generate(PoolVector<Vector3> &points, PoolVector<Vector3> &normals) {
	bool use_normals = emission_fill->get_selected() == 1;

	if (emission_fill->get_selected() < 2) {
		float area_accum = 0;
		RBMap<float, int> triangle_area_map;

		for (int i = 0; i < geometry.size(); i++) {
			float area = geometry[i].get_area();
			if (area < CMP_EPSILON) {
				continue;
			}
			triangle_area_map[area_accum] = i;
			area_accum += area;
		}

		if (!triangle_area_map.size() || area_accum == 0) {
			EditorNode::get_singleton()->show_warning(TTR("The geometry's faces don't contain any area."));
			return false;
		}

		int emissor_count = emission_amount->get_value();

		for (int i = 0; i < emissor_count; i++) {
			float areapos = Math::random(0.0f, area_accum);

			RBMap<float, int>::Element *E = triangle_area_map.find_closest(areapos);
			ERR_FAIL_COND_V(!E, false);
			int index = E->get();
			ERR_FAIL_INDEX_V(index, geometry.size(), false);

			// ok FINALLY get face
			Face3 face = geometry[index];
			//now compute some position inside the face...

			Vector3 pos = face.get_random_point_inside();

			points.push_back(pos);

			if (use_normals) {
				Vector3 normal = face.get_plane().normal;
				normals.push_back(normal);
			}
		}
	} else {
		int gcount = geometry.size();

		if (gcount == 0) {
			EditorNode::get_singleton()->show_warning(TTR("The geometry doesn't contain any faces."));
			return false;
		}

		PoolVector<Face3>::Read r = geometry.read();

		AABB aabb;

		for (int i = 0; i < gcount; i++) {
			for (int j = 0; j < 3; j++) {
				if (i == 0 && j == 0) {
					aabb.position = r[i].vertex[j];
				} else {
					aabb.expand_to(r[i].vertex[j]);
				}
			}
		}

		int emissor_count = emission_amount->get_value();

		for (int i = 0; i < emissor_count; i++) {
			int attempts = 5;

			for (int j = 0; j < attempts; j++) {
				Vector3 dir;
				dir[Math::rand() % 3] = 1.0;
				Vector3 ofs = (Vector3(1, 1, 1) - dir) * Vector3(Math::randf(), Math::randf(), Math::randf()) * aabb.size + aabb.position;

				Vector3 ofsv = ofs + aabb.size * dir;

				//space it a little
				ofs -= dir;
				ofsv += dir;

				float max = -1e7, min = 1e7;

				for (int k = 0; k < gcount; k++) {
					const Face3 &f3 = r[k];

					Vector3 res;
					if (f3.intersects_segment(ofs, ofsv, &res)) {
						res -= ofs;
						float d = dir.dot(res);

						if (d < min) {
							min = d;
						}
						if (d > max) {
							max = d;
						}
					}
				}

				if (max < min) {
					continue; //lost attempt
				}

				float val = min + (max - min) * Math::randf();

				Vector3 point = ofs + dir * val;

				points.push_back(point);
				break;
			}
		}
	}

	return true;
}

void ParticlesEditorBase::_node_selected(const NodePath &p_path) {
	Node *sel = get_node(p_path);
	if (!sel) {
		return;
	}

	if (!sel->is_class("Spatial")) {
		EditorNode::get_singleton()->show_warning(vformat(TTR("\"%s\" doesn't inherit from Spatial."), sel->get_name()));
		return;
	}

	VisualInstance *vi = Object::cast_to<VisualInstance>(sel);
	if (!vi) {
		EditorNode::get_singleton()->show_warning(vformat(TTR("\"%s\" doesn't contain geometry."), sel->get_name()));
		return;
	}

	geometry = vi->get_faces(VisualInstance::FACES_SOLID);

	if (geometry.size() == 0) {
		EditorNode::get_singleton()->show_warning(vformat(TTR("\"%s\" doesn't contain face geometry."), sel->get_name()));
		return;
	}

	Transform geom_xform = base_node->get_global_transform().affine_inverse() * vi->get_global_transform();

	int gc = geometry.size();
	PoolVector<Face3>::Write w = geometry.write();

	for (int i = 0; i < gc; i++) {
		for (int j = 0; j < 3; j++) {
			w[i].vertex[j] = geom_xform.xform(w[i].vertex[j]);
		}
	}

	w.release();

	emission_dialog->popup_centered(Size2(300, 130));
}

void ParticlesEditorBase::_bind_methods() {
	ClassDB::bind_method("_node_selected", &ParticlesEditorBase::_node_selected);
	ClassDB::bind_method("_generate_emission_points", &ParticlesEditorBase::_generate_emission_points);
}

ParticlesEditorBase::ParticlesEditorBase() {
	emission_dialog = memnew(ConfirmationDialog);
	emission_dialog->set_title(TTR("Create Emitter"));
	add_child(emission_dialog);
	VBoxContainer *emd_vb = memnew(VBoxContainer);
	emission_dialog->add_child(emd_vb);

	emission_amount = memnew(SpinBox);
	emission_amount->set_min(1);
	emission_amount->set_max(100000);
	emission_amount->set_value(512);
	emd_vb->add_margin_child(TTR("Emission Points:"), emission_amount);

	emission_fill = memnew(OptionButton);
	emission_fill->add_item(TTR("Surface Points"));
	emission_fill->add_item(TTR("Surface Points+Normal (Directed)"));
	emission_fill->add_item(TTR("Volume"));
	emd_vb->add_margin_child(TTR("Emission Source: "), emission_fill);

	emission_dialog->get_ok()->set_text(TTR("Create"));
	emission_dialog->connect("confirmed", this, "_generate_emission_points");

	emission_file_dialog = memnew(EditorFileDialog);
	add_child(emission_file_dialog);
	emission_file_dialog->connect("file_selected", this, "_resource_seleted");
	emission_tree_dialog = memnew(SceneTreeDialog);
	add_child(emission_tree_dialog);
	emission_tree_dialog->connect("selected", this, "_node_selected");

	List<String> extensions;
	ResourceLoader::get_recognized_extensions_for_type("Mesh", &extensions);

	emission_file_dialog->clear_filters();
	for (int i = 0; i < extensions.size(); i++) {
		emission_file_dialog->add_filter("*." + extensions[i] + " ; " + extensions[i].to_upper());
	}

	emission_file_dialog->set_mode(EditorFileDialog::MODE_OPEN_FILE);
}
