/*************************************************************************/
/*  FBXMeshGeometry.cpp                                                  */
/*************************************************************************/
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/*
Open Asset Import Library (assimp)
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Copyright (c) 2006-2019, assimp team


All rights reserved.

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*/

/** @file  FBXMeshGeometry.cpp
 *  @brief Assimp::FBX::MeshGeometry implementation
 */

#include <functional>

#include "FBXDocument.h"
#include "FBXDocumentUtil.h"
#include "FBXImportSettings.h"
#include "FBXMeshGeometry.h"
#include "core/math/vector3.h"

namespace FBXDocParser {

using namespace Util;

// ------------------------------------------------------------------------------------------------
Geometry::Geometry(uint64_t id, const ElementPtr element, const std::string &name, const Document &doc) :
		Object(id, element, name), skin() {
	const std::vector<const Connection *> &conns = doc.GetConnectionsByDestinationSequenced(ID(), "Deformer");
	for (const Connection *con : conns) {
		const Skin *sk = ProcessSimpleConnection<Skin>(*con, false, "Skin -> Geometry", element);
		if (sk) {
			skin = sk;
		}
		const BlendShape *bsp = ProcessSimpleConnection<BlendShape>(*con, false, "BlendShape -> Geometry",
				element);
		if (bsp) {
			blendShapes.push_back(bsp);
		}
	}
}

// ------------------------------------------------------------------------------------------------
Geometry::~Geometry() {
	// empty
}

// ------------------------------------------------------------------------------------------------
const std::vector<const BlendShape *> &Geometry::get_blend_shapes() const {
	return blendShapes;
}

// ------------------------------------------------------------------------------------------------
const Skin *Geometry::DeformerSkin() const {
	return skin;
}

// ------------------------------------------------------------------------------------------------
MeshGeometry::MeshGeometry(uint64_t id, const ElementPtr element, const std::string &name, const Document &doc) :
		Geometry(id, element, name, doc) {
	print_verbose("mesh name: " + String(name.c_str()));

	ScopePtr sc = element->Compound();
	ERR_FAIL_COND_MSG(sc == nullptr, "failed to read geometry, prevented crash");
	ERR_FAIL_COND_MSG(!HasElement(sc, "Vertices"), "Detected mesh with no vertices, didn't populate the mesh");

	// must have Mesh elements:
	const ElementPtr Vertices = GetRequiredElement(sc, "Vertices", element);
	const ElementPtr PolygonVertexIndex = GetRequiredElement(sc, "PolygonVertexIndex", element);

	if (HasElement(sc, "Edges")) {
		const ElementPtr element_edges = GetRequiredElement(sc, "Edges", element);
		ParseVectorDataArray(m_edges, element_edges);
	}

	// read mesh data into arrays
	ParseVectorDataArray(m_vertices, Vertices);
	ParseVectorDataArray(m_face_indices, PolygonVertexIndex);

	ERR_FAIL_COND_MSG(m_vertices.empty(), "mesh with no vertices in FBX file, did you mean to delete it?");
	ERR_FAIL_COND_MSG(m_face_indices.empty(), "mesh has no faces, was this intended?");

	// Retrieve layer elements, for all of the mesh
	const ElementCollection &Layer = sc->GetCollection("Layer");

	// Store all layers
	std::vector<std::tuple<int, std::string>> valid_layers;

	// now read the sub mesh information from the geometry (normals, uvs, etc)
	for (ElementMap::const_iterator it = Layer.first; it != Layer.second; ++it) {
		const ScopePtr layer = GetRequiredScope(it->second);
		const ElementCollection &LayerElement = layer->GetCollection("LayerElement");
		for (ElementMap::const_iterator eit = LayerElement.first; eit != LayerElement.second; ++eit) {
			std::string layer_name = eit->first;
			ElementPtr element_layer = eit->second;
			const ScopePtr layer_element = GetRequiredScope(element_layer);

			// Actual usable 'type' LayerElementUV, LayerElementNormal, etc
			const ElementPtr Type = GetRequiredElement(layer_element, "Type");
			const ElementPtr TypedIndex = GetRequiredElement(layer_element, "TypedIndex");
			const std::string &type = ParseTokenAsString(GetRequiredToken(Type, 0));
			const int typedIndex = ParseTokenAsInt(GetRequiredToken(TypedIndex, 0));

			// we only need the layer name and the typed index.
			valid_layers.push_back(std::tuple<int, std::string>(typedIndex, type));
		}
	}

	// get object / mesh directly from the FBX by the element ID.
	const ScopePtr top = GetRequiredScope(element);

	// iterate over all layers for the mesh (uvs, normals, smoothing groups, colors, etc)
	for (size_t x = 0; x < valid_layers.size(); x++) {
		const int layer_id = std::get<0>(valid_layers[x]);
		const std::string &layer_type_name = std::get<1>(valid_layers[x]);

		// Get collection of elements from the XLayerMap (example: LayerElementUV)
		// this must contain our proper elements.

		// This is stupid, because it means we select them ALL not just the one we want.
		// but it's fine we can match by id.

		const ElementCollection &candidates = top->GetCollection(layer_type_name);

		ElementMap::const_iterator iter;
		for (iter = candidates.first; iter != candidates.second; ++iter) {
			const ScopePtr layer_scope = GetRequiredScope(iter->second);
			TokenPtr layer_token = GetRequiredToken(iter->second, 0);
			const int index = ParseTokenAsInt(layer_token);

			ERR_FAIL_COND_MSG(layer_scope == nullptr, "prevented crash, layer scope is invalid");

			if (index == layer_id) {
				const std::string &MappingInformationType = ParseTokenAsString(GetRequiredToken(
						GetRequiredElement(layer_scope, "MappingInformationType"), 0));

				const std::string &ReferenceInformationType = ParseTokenAsString(GetRequiredToken(
						GetRequiredElement(layer_scope, "ReferenceInformationType"), 0));

				if (layer_type_name == "LayerElementUV") {
					if (index == 0) {
						m_uv_0 = resolve_vertex_data_array<Vector2>(layer_scope, MappingInformationType, ReferenceInformationType, "UV");
					} else if (index == 1) {
						m_uv_1 = resolve_vertex_data_array<Vector2>(layer_scope, MappingInformationType, ReferenceInformationType, "UV");
					}
				} else if (layer_type_name == "LayerElementMaterial") {
					m_material_allocation_ids = resolve_vertex_data_array<int>(layer_scope, MappingInformationType, ReferenceInformationType, "Materials");
				} else if (layer_type_name == "LayerElementNormal") {
					m_normals = resolve_vertex_data_array<Vector3>(layer_scope, MappingInformationType, ReferenceInformationType, "Normals");
				} else if (layer_type_name == "LayerElementColor") {
					m_colors = resolve_vertex_data_array<Color>(layer_scope, MappingInformationType, ReferenceInformationType, "Colors", "ColorIndex");
					// NOTE: this is a useful sanity check to ensure you're getting any color data which is not default.
					//					const Color first_color_check = m_colors.data[0];
					//					bool colors_are_all_the_same = true;
					//					size_t i = 1;
					//					for(i = 1; i < m_colors.data.size(); i++)
					//					{
					//						const Color current_color = m_colors.data[i];
					//						if(current_color.is_equal_approx(first_color_check))
					//						{
					//							continue;
					//						}
					//						else
					//						{
					//							colors_are_all_the_same = false;
					//							break;
					//						}
					//					}
					//
					//					if(colors_are_all_the_same)
					//					{
					//						print_error("Color serialisation is not working for vertex colors some should be different in the test asset.");
					//					}
					//					else
					//					{
					//						print_verbose("Color array has unique colors at index: " + itos(i));
					//					}
				}
			}
		}
	}

	print_verbose("Mesh statistics \nuv_0: " + m_uv_0.debug_info() + "\nuv_1: " + m_uv_1.debug_info() + "\nvertices: " + itos(m_vertices.size()));

	// Compose the edge of the mesh.
	// You can see how the edges are stored into the FBX here: https://gist.github.com/AndreaCatania/da81840f5aa3b2feedf189e26c5a87e6
	for (size_t i = 0; i < m_edges.size(); i += 1) {
		ERR_FAIL_INDEX_MSG((size_t)m_edges[i], m_face_indices.size(), "The edge is pointing to a weird location in the face indices. The FBX is corrupted.");
		int polygon_vertex_0 = m_face_indices[m_edges[i]];
		int polygon_vertex_1;
		if (polygon_vertex_0 < 0) {
			// The polygon_vertex_0 points to the end of a polygon, so it's
			// connected with the beginning of polygon in the edge list.

			// Fist invert the vertex.
			polygon_vertex_0 = ~polygon_vertex_0;

			// Search the start vertex of the polygon.
			// Iterate from the polygon_vertex_index backward till the start of
			// the polygon is found.
			ERR_FAIL_COND_MSG(m_edges[i] - 1 < 0, "The polygon is not yet started and we already need the final vertex. This FBX is corrupted.");
			bool found_it = false;
			for (int x = m_edges[i] - 1; x >= 0; x -= 1) {
				if (x == 0) {
					// This for sure is the start.
					polygon_vertex_1 = m_face_indices[x];
					found_it = true;
					break;
				} else if (m_face_indices[x] < 0) {
					// This is the end of the previous polygon, so the next is
					// the start of the polygon we need.
					polygon_vertex_1 = m_face_indices[x + 1];
					found_it = true;
					break;
				}
			}
			// As the algorithm above, this check is useless. Because the first
			// ever vertex is always considered the beginning of a polygon.
			ERR_FAIL_COND_MSG(found_it == false, "Was not possible to find the first vertex of this polygon. FBX file is corrupted.");

		} else {
			ERR_FAIL_INDEX_MSG((size_t)(m_edges[i] + 1), m_face_indices.size(), "FBX The other FBX edge seems to point to an invalid vertices. This FBX file is corrupted.");
			// Take the next vertex
			polygon_vertex_1 = m_face_indices[m_edges[i] + 1];
		}

		if (polygon_vertex_1 < 0) {
			// We don't care if the `polygon_vertex_1` is the end of the polygon,
			//  for `polygon_vertex_1` so we can just invert it.
			polygon_vertex_1 = ~polygon_vertex_1;
		}

		ERR_FAIL_COND_MSG(polygon_vertex_0 == polygon_vertex_1, "The vertices of this edge can't be the same, Is this a point???. This FBX file is corrupted.");

		// Just create the edge.
		edge_map.push_back({ polygon_vertex_0, polygon_vertex_1 });
	}
}

MeshGeometry::~MeshGeometry() {
	// empty
}

const std::vector<Vector3> &MeshGeometry::get_vertices() const {
	return m_vertices;
}

const std::vector<MeshGeometry::Edge> &MeshGeometry::get_edge_map() const {
	return edge_map;
}

const std::vector<int> &MeshGeometry::get_polygon_indices() const {
	return m_face_indices;
}

const std::vector<int> &MeshGeometry::get_edges() const {
	return m_edges;
}

const MeshGeometry::MappingData<Vector3> &MeshGeometry::get_normals() const {
	return m_normals;
}

const MeshGeometry::MappingData<Vector2> &MeshGeometry::get_uv_0() const {
	//print_verbose("get uv_0 " + m_uv_0.debug_info() );
	return m_uv_0;
}

const MeshGeometry::MappingData<Vector2> &MeshGeometry::get_uv_1() const {
	//print_verbose("get uv_1 " + m_uv_1.debug_info() );
	return m_uv_1;
}

const MeshGeometry::MappingData<Color> &MeshGeometry::get_colors() const {
	return m_colors;
}

const MeshGeometry::MappingData<int> &MeshGeometry::get_material_allocation_id() const {
	return m_material_allocation_ids;
}

int MeshGeometry::get_edge_id(const std::vector<Edge> &p_map, int p_vertex_a, int p_vertex_b) {
	for (size_t i = 0; i < p_map.size(); i += 1) {
		if ((p_map[i].vertex_0 == p_vertex_a && p_map[i].vertex_1 == p_vertex_b) || (p_map[i].vertex_1 == p_vertex_a && p_map[i].vertex_0 == p_vertex_b)) {
			return i;
		}
	}
	return -1;
}

MeshGeometry::Edge MeshGeometry::get_edge(const std::vector<Edge> &p_map, int p_id) {
	ERR_FAIL_INDEX_V_MSG((size_t)p_id, p_map.size(), Edge({ -1, -1 }), "ID not found.");
	return p_map[p_id];
}

template <class T>
MeshGeometry::MappingData<T> MeshGeometry::resolve_vertex_data_array(
		const ScopePtr source,
		const std::string &MappingInformationType,
		const std::string &ReferenceInformationType,
		const std::string &dataElementName,
		const std::string &indexOverride) {
	ERR_FAIL_COND_V_MSG(source == nullptr, MappingData<T>(), "Invalid scope operator preventing memory corruption");

	// UVIndex, MaterialIndex, NormalIndex, etc..
	std::string indexDataElementName;

	if (indexOverride != "") {
		// Colors should become ColorIndex
		indexDataElementName = indexOverride;
	} else {
		// Some indexes will exist.
		indexDataElementName = dataElementName + "Index";
	}

	// goal: expand everything to be per vertex

	ReferenceType l_ref_type = ReferenceType::direct;

	// Read the reference type into the enumeration
	if (ReferenceInformationType == "IndexToDirect") {
		l_ref_type = ReferenceType::index_to_direct;
	} else if (ReferenceInformationType == "Index") {
		// set non legacy index to direct mapping
		l_ref_type = ReferenceType::index;
	} else if (ReferenceInformationType == "Direct") {
		l_ref_type = ReferenceType::direct;
	} else {
		ERR_FAIL_V_MSG(MappingData<T>(), "invalid reference type has the FBX format changed?");
	}

	MapType l_map_type = MapType::none;

	if (MappingInformationType == "None") {
		l_map_type = MapType::none;
	} else if (MappingInformationType == "ByVertice") {
		l_map_type = MapType::vertex;
	} else if (MappingInformationType == "ByPolygonVertex") {
		l_map_type = MapType::polygon_vertex;
	} else if (MappingInformationType == "ByPolygon") {
		l_map_type = MapType::polygon;
	} else if (MappingInformationType == "ByEdge") {
		l_map_type = MapType::edge;
	} else if (MappingInformationType == "AllSame") {
		l_map_type = MapType::all_the_same;
	} else {
		print_error("invalid mapping type: " + String(MappingInformationType.c_str()));
	}

	// create mapping data
	MeshGeometry::MappingData<T> tempData;
	tempData.map_type = l_map_type;
	tempData.ref_type = l_ref_type;

	// parse data into array
	ParseVectorDataArray(tempData.data, GetRequiredElement(source, dataElementName));

	// index array won't always exist
	const ElementPtr element = GetOptionalElement(source, indexDataElementName);
	if (element) {
		ParseVectorDataArray(tempData.index, element);
	}

	return tempData;
}
// ------------------------------------------------------------------------------------------------
ShapeGeometry::ShapeGeometry(uint64_t id, const ElementPtr element, const std::string &name, const Document &doc) :
		Geometry(id, element, name, doc) {
	const ScopePtr sc = element->Compound();
	if (nullptr == sc) {
		DOMError("failed to read Geometry object (class: Shape), no data scope found");
	}
	const ElementPtr Indexes = GetRequiredElement(sc, "Indexes", element);
	const ElementPtr Normals = GetRequiredElement(sc, "Normals", element);
	const ElementPtr Vertices = GetRequiredElement(sc, "Vertices", element);
	ParseVectorDataArray(m_indices, Indexes);
	ParseVectorDataArray(m_vertices, Vertices);
	ParseVectorDataArray(m_normals, Normals);
}

// ------------------------------------------------------------------------------------------------
ShapeGeometry::~ShapeGeometry() {
	// empty
}
// ------------------------------------------------------------------------------------------------
const std::vector<Vector3> &ShapeGeometry::GetVertices() const {
	return m_vertices;
}
// ------------------------------------------------------------------------------------------------
const std::vector<Vector3> &ShapeGeometry::GetNormals() const {
	return m_normals;
}
// ------------------------------------------------------------------------------------------------
const std::vector<unsigned int> &ShapeGeometry::GetIndices() const {
	return m_indices;
}
// ------------------------------------------------------------------------------------------------
LineGeometry::LineGeometry(uint64_t id, const ElementPtr element, const std::string &name, const Document &doc) :
		Geometry(id, element, name, doc) {
	const ScopePtr sc = element->Compound();
	if (!sc) {
		DOMError("failed to read Geometry object (class: Line), no data scope found");
	}
	const ElementPtr Points = GetRequiredElement(sc, "Points", element);
	const ElementPtr PointsIndex = GetRequiredElement(sc, "PointsIndex", element);
	ParseVectorDataArray(m_vertices, Points);
	ParseVectorDataArray(m_indices, PointsIndex);
}

// ------------------------------------------------------------------------------------------------
LineGeometry::~LineGeometry() {
	// empty
}
// ------------------------------------------------------------------------------------------------
const std::vector<Vector3> &LineGeometry::GetVertices() const {
	return m_vertices;
}
// ------------------------------------------------------------------------------------------------
const std::vector<int> &LineGeometry::GetIndices() const {
	return m_indices;
}

} // namespace FBXDocParser