/*
---------------------------------------------------------------------------
Open Asset Import Library (assimp)
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* Redistributions of source code must retain the above
  copyright notice, this list of conditions and the
  following disclaimer.

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*/

/** @file Implementation of the IrrMesh importer class */

#ifndef ASSIMP_BUILD_NO_IRRMESH_IMPORTER

#include "IRRMeshLoader.h"
#include <assimp/ParsingUtils.h>
#include <assimp/fast_atof.h>
#include <assimp/importerdesc.h>
#include <assimp/material.h>
#include <assimp/mesh.h>
#include <assimp/scene.h>
#include <assimp/DefaultLogger.hpp>
#include <assimp/IOSystem.hpp>
#include <memory>

using namespace Assimp;

static const aiImporterDesc desc = {
	"Irrlicht Mesh Reader",
	"",
	"",
	"http://irrlicht.sourceforge.net/",
	aiImporterFlags_SupportTextFlavour,
	0,
	0,
	0,
	0,
	"xml irrmesh"
};

// ------------------------------------------------------------------------------------------------
// Constructor to be privately used by Importer
IRRMeshImporter::IRRMeshImporter() :
        BaseImporter(),
        IrrlichtBase() {
    // empty
}

// ------------------------------------------------------------------------------------------------
// Destructor, private as well
IRRMeshImporter::~IRRMeshImporter() {}

// ------------------------------------------------------------------------------------------------
// Returns whether the class can handle the format of the given file.
bool IRRMeshImporter::CanRead(const std::string &pFile, IOSystem *pIOHandler, bool checkSig) const {
	/* NOTE: A simple check for the file extension is not enough
     * here. Irrmesh and irr are easy, but xml is too generic
     * and could be collada, too. So we need to open the file and
     * search for typical tokens.
     */
	const std::string extension = GetExtension(pFile);

	if (extension == "irrmesh")
		return true;
	else if (extension == "xml" || checkSig) {
		/*  If CanRead() is called to check whether the loader
         *  supports a specific file extension in general we
         *  must return true here.
         */
		if (!pIOHandler) return true;
		const char *tokens[] = { "irrmesh" };
		return SearchFileHeaderForToken(pIOHandler, pFile, tokens, 1);
	}
	return false;
}

// ------------------------------------------------------------------------------------------------
// Get a list of all file extensions which are handled by this class
const aiImporterDesc *IRRMeshImporter::GetInfo() const {
	return &desc;
}

static void releaseMaterial(aiMaterial **mat) {
	if (*mat != nullptr) {
		delete *mat;
		*mat = nullptr;
	}
}

static void releaseMesh(aiMesh **mesh) {
	if (*mesh != nullptr) {
		delete *mesh;
		*mesh = nullptr;
	}
}

// ------------------------------------------------------------------------------------------------
// Imports the given file into the given scene structure.
void IRRMeshImporter::InternReadFile(const std::string &pFile,
		aiScene *pScene, IOSystem *pIOHandler) {
	std::unique_ptr<IOStream> file(pIOHandler->Open(pFile));

	// Check whether we can read from the file
	if (file.get() == NULL)
		throw DeadlyImportError("Failed to open IRRMESH file " + pFile + "");

	// Construct the irrXML parser
	XmlParser parser;
    if (!parser.parse( file.get() )) {
        return;
    }
    XmlNode root = parser.getRootNode();

	// final data
	std::vector<aiMaterial *> materials;
	std::vector<aiMesh *> meshes;
	materials.reserve(5);
	meshes.reserve(5);

	// temporary data - current mesh buffer
	aiMaterial *curMat = nullptr;
	aiMesh *curMesh = nullptr;
	unsigned int curMatFlags = 0;

	std::vector<aiVector3D> curVertices, curNormals, curTangents, curBitangents;
	std::vector<aiColor4D> curColors;
	std::vector<aiVector3D> curUVs, curUV2s;

	// some temporary variables
	int textMeaning = 0;
	int vertexFormat = 0; // 0 = normal; 1 = 2 tcoords, 2 = tangents
	bool useColors = false;

	// Parse the XML file
	for (pugi::xml_node child : root.children()) {
		if (child.type() == pugi::node_element) {
			if (!ASSIMP_stricmp(child.name(), "buffer") && (curMat || curMesh)) {
				// end of previous buffer. A material and a mesh should be there
				if (!curMat || !curMesh) {
					ASSIMP_LOG_ERROR("IRRMESH: A buffer must contain a mesh and a material");
					releaseMaterial(&curMat);
					releaseMesh(&curMesh);
				} else {
					materials.push_back(curMat);
					meshes.push_back(curMesh);
				}
				curMat = nullptr;
				curMesh = nullptr;

				curVertices.clear();
				curColors.clear();
				curNormals.clear();
				curUV2s.clear();
				curUVs.clear();
				curTangents.clear();
				curBitangents.clear();
			}

			if (!ASSIMP_stricmp(child.name(), "material")) {
				if (curMat) {
					ASSIMP_LOG_WARN("IRRMESH: Only one material description per buffer, please");
					releaseMaterial(&curMat);
				}
				curMat = ParseMaterial(curMatFlags);
			}
			/* no else here! */ if (!ASSIMP_stricmp(child.name(), "vertices")) {
				pugi::xml_attribute attr = child.attribute("vertexCount");
				int num = attr.as_int();
                //int num = reader->getAttributeValueAsInt("vertexCount");

				if (!num) {
					// This is possible ... remove the mesh from the list and skip further reading
					ASSIMP_LOG_WARN("IRRMESH: Found mesh with zero vertices");

					releaseMaterial(&curMat);
					releaseMesh(&curMesh);
					textMeaning = 0;
					continue;
				}

				curVertices.reserve(num);
				curNormals.reserve(num);
				curColors.reserve(num);
				curUVs.reserve(num);

				// Determine the file format
				//const char *t = reader->getAttributeValueSafe("type");
                pugi::xml_attribute t = child.attribute("type");
				if (!ASSIMP_stricmp("2tcoords", t.name())) {
					curUV2s.reserve(num);
					vertexFormat = 1;

					if (curMatFlags & AI_IRRMESH_EXTRA_2ND_TEXTURE) {
						// *********************************************************
						// We have a second texture! So use this UV channel
						// for it. The 2nd texture can be either a normal
						// texture (solid_2layer or lightmap_xxx) or a normal
						// map (normal_..., parallax_...)
						// *********************************************************
						int idx = 1;
						aiMaterial *mat = (aiMaterial *)curMat;

						if (curMatFlags & AI_IRRMESH_MAT_lightmap) {
							mat->AddProperty(&idx, 1, AI_MATKEY_UVWSRC_LIGHTMAP(0));
						} else if (curMatFlags & AI_IRRMESH_MAT_normalmap_solid) {
							mat->AddProperty(&idx, 1, AI_MATKEY_UVWSRC_NORMALS(0));
						} else if (curMatFlags & AI_IRRMESH_MAT_solid_2layer) {
							mat->AddProperty(&idx, 1, AI_MATKEY_UVWSRC_DIFFUSE(1));
						}
					}
				} else if (!ASSIMP_stricmp("tangents", t.name())) {
					curTangents.reserve(num);
					curBitangents.reserve(num);
					vertexFormat = 2;
				} else if (ASSIMP_stricmp("standard", t.name())) {
					releaseMaterial(&curMat);
					ASSIMP_LOG_WARN("IRRMESH: Unknown vertex format");
				} else
					vertexFormat = 0;
				textMeaning = 1;
			} else if (!ASSIMP_stricmp(child.name(), "indices")) {
				if (curVertices.empty() && curMat) {
					releaseMaterial(&curMat);
					throw DeadlyImportError("IRRMESH: indices must come after vertices");
				}

				textMeaning = 2;

				// start a new mesh
				curMesh = new aiMesh();

				// allocate storage for all faces
				pugi::xml_attribute attr = child.attribute("indexCount");
				curMesh->mNumVertices = attr.as_int();
				if (!curMesh->mNumVertices) {
					// This is possible ... remove the mesh from the list and skip further reading
					ASSIMP_LOG_WARN("IRRMESH: Found mesh with zero indices");

					// mesh - away
					releaseMesh(&curMesh);

					// material - away
					releaseMaterial(&curMat);

					textMeaning = 0;
					continue;
				}

				if (curMesh->mNumVertices % 3) {
					ASSIMP_LOG_WARN("IRRMESH: Number if indices isn't divisible by 3");
				}

				curMesh->mNumFaces = curMesh->mNumVertices / 3;
				curMesh->mFaces = new aiFace[curMesh->mNumFaces];

				// setup some members
				curMesh->mMaterialIndex = (unsigned int)materials.size();
				curMesh->mPrimitiveTypes = aiPrimitiveType_TRIANGLE;

				// allocate storage for all vertices
				curMesh->mVertices = new aiVector3D[curMesh->mNumVertices];

				if (curNormals.size() == curVertices.size()) {
					curMesh->mNormals = new aiVector3D[curMesh->mNumVertices];
				}
				if (curTangents.size() == curVertices.size()) {
					curMesh->mTangents = new aiVector3D[curMesh->mNumVertices];
				}
				if (curBitangents.size() == curVertices.size()) {
					curMesh->mBitangents = new aiVector3D[curMesh->mNumVertices];
				}
				if (curColors.size() == curVertices.size() && useColors) {
					curMesh->mColors[0] = new aiColor4D[curMesh->mNumVertices];
				}
				if (curUVs.size() == curVertices.size()) {
					curMesh->mTextureCoords[0] = new aiVector3D[curMesh->mNumVertices];
				}
				if (curUV2s.size() == curVertices.size()) {
					curMesh->mTextureCoords[1] = new aiVector3D[curMesh->mNumVertices];
				}
			}
			//break;

			//case EXN_TEXT: {
			const char *sz = child.child_value();
			if (textMeaning == 1) {
				textMeaning = 0;

				// read vertices
				do {
					SkipSpacesAndLineEnd(&sz);
					aiVector3D temp;
					aiColor4D c;

					// Read the vertex position
					sz = fast_atoreal_move<float>(sz, (float &)temp.x);
					SkipSpaces(&sz);

					sz = fast_atoreal_move<float>(sz, (float &)temp.y);
					SkipSpaces(&sz);

					sz = fast_atoreal_move<float>(sz, (float &)temp.z);
					SkipSpaces(&sz);
					curVertices.push_back(temp);

					// Read the vertex normals
					sz = fast_atoreal_move<float>(sz, (float &)temp.x);
					SkipSpaces(&sz);

					sz = fast_atoreal_move<float>(sz, (float &)temp.y);
					SkipSpaces(&sz);

					sz = fast_atoreal_move<float>(sz, (float &)temp.z);
					SkipSpaces(&sz);
					curNormals.push_back(temp);

					// read the vertex colors
					uint32_t clr = strtoul16(sz, &sz);
					ColorFromARGBPacked(clr, c);

					if (!curColors.empty() && c != *(curColors.end() - 1))
						useColors = true;

					curColors.push_back(c);
					SkipSpaces(&sz);

					// read the first UV coordinate set
					sz = fast_atoreal_move<float>(sz, (float &)temp.x);
					SkipSpaces(&sz);

					sz = fast_atoreal_move<float>(sz, (float &)temp.y);
					SkipSpaces(&sz);
					temp.z = 0.f;
					temp.y = 1.f - temp.y; // DX to OGL
					curUVs.push_back(temp);

					// read the (optional) second UV coordinate set
					if (vertexFormat == 1) {
						sz = fast_atoreal_move<float>(sz, (float &)temp.x);
						SkipSpaces(&sz);

						sz = fast_atoreal_move<float>(sz, (float &)temp.y);
						temp.y = 1.f - temp.y; // DX to OGL
						curUV2s.push_back(temp);
					}
					// read optional tangent and bitangent vectors
					else if (vertexFormat == 2) {
						// tangents
						sz = fast_atoreal_move<float>(sz, (float &)temp.x);
						SkipSpaces(&sz);

						sz = fast_atoreal_move<float>(sz, (float &)temp.z);
						SkipSpaces(&sz);

						sz = fast_atoreal_move<float>(sz, (float &)temp.y);
						SkipSpaces(&sz);
						temp.y *= -1.0f;
						curTangents.push_back(temp);

						// bitangents
						sz = fast_atoreal_move<float>(sz, (float &)temp.x);
						SkipSpaces(&sz);

						sz = fast_atoreal_move<float>(sz, (float &)temp.z);
						SkipSpaces(&sz);

						sz = fast_atoreal_move<float>(sz, (float &)temp.y);
						SkipSpaces(&sz);
						temp.y *= -1.0f;
						curBitangents.push_back(temp);
					}
				}

				/* IMPORTANT: We assume that each vertex is specified in one
                line. So we can skip the rest of the line - unknown vertex
                elements are ignored.
                */

				while (SkipLine(&sz));
			} else if (textMeaning == 2) {
				textMeaning = 0;

				// read indices
				aiFace *curFace = curMesh->mFaces;
				aiFace *const faceEnd = curMesh->mFaces + curMesh->mNumFaces;

				aiVector3D *pcV = curMesh->mVertices;
				aiVector3D *pcN = curMesh->mNormals;
				aiVector3D *pcT = curMesh->mTangents;
				aiVector3D *pcB = curMesh->mBitangents;
				aiColor4D *pcC0 = curMesh->mColors[0];
				aiVector3D *pcT0 = curMesh->mTextureCoords[0];
				aiVector3D *pcT1 = curMesh->mTextureCoords[1];

				unsigned int curIdx = 0;
				unsigned int total = 0;
				while (SkipSpacesAndLineEnd(&sz)) {
					if (curFace >= faceEnd) {
						ASSIMP_LOG_ERROR("IRRMESH: Too many indices");
						break;
					}
					if (!curIdx) {
						curFace->mNumIndices = 3;
						curFace->mIndices = new unsigned int[3];
					}

					unsigned int idx = strtoul10(sz, &sz);
					if (idx >= curVertices.size()) {
						ASSIMP_LOG_ERROR("IRRMESH: Index out of range");
						idx = 0;
					}

					curFace->mIndices[curIdx] = total++;

					*pcV++ = curVertices[idx];
					if (pcN) *pcN++ = curNormals[idx];
					if (pcT) *pcT++ = curTangents[idx];
					if (pcB) *pcB++ = curBitangents[idx];
					if (pcC0) *pcC0++ = curColors[idx];
					if (pcT0) *pcT0++ = curUVs[idx];
					if (pcT1) *pcT1++ = curUV2s[idx];

					if (++curIdx == 3) {
						++curFace;
						curIdx = 0;
					}
				}

				if (curFace != faceEnd)
					ASSIMP_LOG_ERROR("IRRMESH: Not enough indices");

				// Finish processing the mesh - do some small material workarounds
				if (curMatFlags & AI_IRRMESH_MAT_trans_vertex_alpha && !useColors) {
					// Take the opacity value of the current material
					// from the common vertex color alpha
					aiMaterial *mat = (aiMaterial *)curMat;
					mat->AddProperty(&curColors[0].a, 1, AI_MATKEY_OPACITY);
				}
			}
		}
	}

	// End of the last buffer. A material and a mesh should be there
	if (curMat || curMesh) {
		if (!curMat || !curMesh) {
			ASSIMP_LOG_ERROR("IRRMESH: A buffer must contain a mesh and a material");
			releaseMaterial(&curMat);
			releaseMesh(&curMesh);
		} else {
			materials.push_back(curMat);
			meshes.push_back(curMesh);
		}
	}

	if (materials.empty()) {
		throw DeadlyImportError("IRRMESH: Unable to read a mesh from this file");
	}

	// now generate the output scene
	pScene->mNumMeshes = (unsigned int)meshes.size();
	pScene->mMeshes = new aiMesh *[pScene->mNumMeshes];
	for (unsigned int i = 0; i < pScene->mNumMeshes; ++i) {
		pScene->mMeshes[i] = meshes[i];

		// clean this value ...
		pScene->mMeshes[i]->mNumUVComponents[3] = 0;
	}

	pScene->mNumMaterials = (unsigned int)materials.size();
	pScene->mMaterials = new aiMaterial *[pScene->mNumMaterials];
	::memcpy(pScene->mMaterials, &materials[0], sizeof(void *) * pScene->mNumMaterials);

	pScene->mRootNode = new aiNode();
	pScene->mRootNode->mName.Set("<IRRMesh>");
	pScene->mRootNode->mNumMeshes = pScene->mNumMeshes;
	pScene->mRootNode->mMeshes = new unsigned int[pScene->mNumMeshes];

	for (unsigned int i = 0; i < pScene->mNumMeshes; ++i) {
		pScene->mRootNode->mMeshes[i] = i;
	}
}

#endif // !! ASSIMP_BUILD_NO_IRRMESH_IMPORTER
