/** @file Implementation of the MD3 importer class */
#include "MD3Loader.h"
#include "MaterialSystem.h"

#include "../include/IOStream.h"
#include "../include/IOSystem.h"
#include "../include/aiMesh.h"
#include "../include/aiScene.h"
#include "../include/aiAssert.h"

#include <boost/scoped_ptr.hpp>

using namespace Assimp;


// ------------------------------------------------------------------------------------------------
// Constructor to be privately used by Importer
MD3Importer::MD3Importer()
{
}

// ------------------------------------------------------------------------------------------------
// Destructor, private as well 
MD3Importer::~MD3Importer()
{
}

// ------------------------------------------------------------------------------------------------
// Returns whether the class can handle the format of the given file. 
bool MD3Importer::CanRead( const std::string& pFile, IOSystem* pIOHandler) const
{
	// simple check of file extension is enough for the moment
	std::string::size_type pos = pFile.find_last_of('.');
	// no file extension - can't read
	if( pos == std::string::npos)
		return false;
	std::string extension = pFile.substr( pos);

	// not brilliant but working ;-)
	if( extension == ".md3" || extension == ".MD3" || 
		extension == ".mD3" || extension == ".Md3")
		return true;

	return false;
}
// ------------------------------------------------------------------------------------------------
// Imports the given file into the given scene structure. 
void MD3Importer::InternReadFile( 
	const std::string& pFile, aiScene* pScene, IOSystem* pIOHandler)
{
	boost::scoped_ptr<IOStream> file( pIOHandler->Open( pFile));

	// Check whether we can read from the file
	if( file.get() == NULL)
	{
		throw new ImportErrorException( "Failed to open md3 file " + pFile + ".");
	}

	// check whether the md3 file is large enough to contain
	// at least the file header
	size_t fileSize = file->FileSize();
	if( fileSize < sizeof(MD3::Header))
	{
		throw new ImportErrorException( ".md3 File is too small.");
	}

	// allocate storage and copy the contents of the file to a memory buffer
	this->mBuffer = new unsigned char[fileSize];
	file->Read( (void*)mBuffer, 1, fileSize);

	this->m_pcHeader = (const MD3::Header*)this->mBuffer;

	// check magic number
	if (this->m_pcHeader->IDENT != AI_MD3_MAGIC_NUMBER_BE &&
		this->m_pcHeader->IDENT != AI_MD3_MAGIC_NUMBER_LE)
	{
		throw new ImportErrorException( "Invalid md3 file: Magic bytes not found");
	}

	// check file format version
	if (this->m_pcHeader->VERSION > 15)
	{
		throw new ImportErrorException( "Unsupported md3 file version");
	}

	// check some values whether they are valid
	if (0 == this->m_pcHeader->NUM_FRAMES)
	{
		throw new ImportErrorException( "Invalid md3 file: NUM_FRAMES is 0");
	}
	if (0 == this->m_pcHeader->NUM_SURFACES)
	{
		throw new ImportErrorException( "Invalid md3 file: NUM_SURFACES is 0");
	}
	if (this->m_pcHeader->OFS_EOF > (int32_t)fileSize)
	{
		throw new ImportErrorException( "Invalid md3 file: File is too small");
	}

	// now navigate to the list of surfaces
	const MD3::Surface* pcSurfaces = (const MD3::Surface*)
		(this->mBuffer + this->m_pcHeader->OFS_SURFACES);

	// allocate output storage
	pScene->mNumMeshes = this->m_pcHeader->NUM_SURFACES;
	pScene->mMeshes = new aiMesh*[pScene->mNumMeshes];

	pScene->mNumMaterials = this->m_pcHeader->NUM_SURFACES;
	pScene->mMaterials = new aiMaterial*[pScene->mNumMeshes];

	unsigned int iNum = this->m_pcHeader->NUM_SURFACES;
	unsigned int iNumMaterials = 0;
	unsigned int iDefaultMatIndex = 0xFFFFFFFF;
	while (iNum-- > 0)
	{
		// navigate to the vertex list of the surface
		const MD3::Vertex* pcVertices = (const MD3::Vertex*)
			(((unsigned char*)pcSurfaces) + pcSurfaces->OFS_XYZNORMAL);

		// navigate to the triangle list of the surface
		const MD3::Triangle* pcTriangles = (const MD3::Triangle*)
			(((unsigned char*)pcSurfaces) + pcSurfaces->OFS_TRIANGLES);

		// navigate to the texture coordinate list of the surface
		const MD3::TexCoord* pcUVs = (const MD3::TexCoord*)
			(((unsigned char*)pcSurfaces) + pcSurfaces->OFS_ST);

		// navigate to the shader list of the surface
		const MD3::Shader* pcShaders = (const MD3::Shader*)
			(((unsigned char*)pcSurfaces) + pcSurfaces->OFS_SHADERS);


		// if the submesh is empty ignore it
		if (0 == pcSurfaces->NUM_VERTICES || 0 == pcSurfaces->NUM_TRIANGLES)
		{
			pcSurfaces = (const MD3::Surface*)(((unsigned char*)pcSurfaces) + pcSurfaces->OFS_END);
			pScene->mNumMeshes--;
			continue;
		}

		// allocate the output mesh
		pScene->mMeshes[iNum] = new aiMesh();
		aiMesh* pcMesh = pScene->mMeshes[iNum];

		pcMesh->mNumVertices = pcSurfaces->NUM_VERTICES;
		pcMesh->mNumBones = 0;
		pcMesh->mColors[0] = pcMesh->mColors[1] = pcMesh->mColors[2] = pcMesh->mColors[3] = NULL;
		pcMesh->mNumFaces = pcSurfaces->NUM_TRIANGLES;
		pcMesh->mFaces = new aiFace[pcSurfaces->NUM_TRIANGLES];
		pcMesh->mNormals = new aiVector3D[pcMesh->mNumVertices];
		pcMesh->mVertices = new aiVector3D[pcMesh->mNumVertices];
		pcMesh->mTextureCoords[0] = new aiVector3D[pcMesh->mNumVertices];
		pcMesh->mTextureCoords[1] = pcMesh->mTextureCoords[2] = pcMesh->mTextureCoords[3] = NULL;
		pcMesh->mNumUVComponents[0] = 2;

		// fill in all vertices and normals
		// fill in all texture coordinates
		for (unsigned int i = 0; i < (unsigned int)pcSurfaces->NUM_VERTICES;++i)
		{
			pcMesh->mVertices[i].x = pcVertices->X;
			pcMesh->mVertices[i].y = pcVertices->Y;
			pcMesh->mVertices[i].z = -1.0f*pcVertices->Z;

			// convert the normal vector to uncompressed float3 format
			LatLngNormalToVec3(pcVertices->NORMAL,(float*)&pcMesh->mNormals[i]);

			// read texture coordinates
			pcMesh->mTextureCoords[0][i].x = pcUVs->U;
			pcMesh->mTextureCoords[0][i].y = 1.0f - pcUVs->V;

			pcVertices++;
			pcUVs++;
		}

		// fill in all triangles
		for (unsigned int i = 0; i < (unsigned int)pcSurfaces->NUM_TRIANGLES;++i)
		{
			pcMesh->mFaces[i].mIndices = new unsigned int[3];
			pcMesh->mFaces[i].mNumIndices = 3;

			pcMesh->mFaces[i].mIndices[0] = pcTriangles->INDEXES[0];
			pcMesh->mFaces[i].mIndices[1] = pcTriangles->INDEXES[1];
			pcMesh->mFaces[i].mIndices[2] = pcTriangles->INDEXES[2];

			pcTriangles++;
		}

		// get the first shader (= texture?) assigned to the surface
		if (0 != pcSurfaces->NUM_SHADER)
		{
			// make a relative path.
			// if the MD3's internal path itself and the given path are using
			// the same directory remove it
			const char* szEndDir1 = strrchr((const char*)this->m_pcHeader->NAME,'\\');
			if (!szEndDir1)szEndDir1 = strrchr((const char*)this->m_pcHeader->NAME,'/');

			const char* szEndDir2 = strrchr((const char*)pcShaders->NAME,'\\');
			if (!szEndDir2)szEndDir2 = strrchr((const char*)pcShaders->NAME,'/');

			if (szEndDir1 && szEndDir2)
			{
				// both of them are valid
				const unsigned int iLen1 = (unsigned int)(szEndDir1 - (const char*)this->m_pcHeader->NAME);
				const unsigned int iLen2 = std::min (iLen1, (unsigned int)(szEndDir2 - (const char*)pcShaders->NAME) );

				bool bSuccess = true;
				for (unsigned int a = 0; a  < iLen2;++a)
				{
					char sz = tolower ( pcShaders->NAME[a] );
					char sz2 = tolower ( this->m_pcHeader->NAME[a] );
					if (sz != sz2)
					{
						bSuccess = false;
						break;
					}
				}
				if (bSuccess)
				{
					// use the file name only
					szEndDir2++;
				}
				else
				{
					// use the full path
					szEndDir2 = (const char*)pcShaders->NAME;
				}
			}

			// now try to find out whether we have this shader already
			bool bHave = false;
			for (unsigned int p = 0; p < iNumMaterials;++p)
			{
				if (iDefaultMatIndex == p)continue;

				aiString szOut;
				if(AI_SUCCESS == aiGetMaterialString ( (aiMaterial*)pScene->mMaterials[p],
					AI_MATKEY_TEXBLEND_DIFFUSE(0),&szOut))
				{
					if (0 == ASSIMP_stricmp(szOut.data,szEndDir2))
					{
						// equal. reuse this material (texture)
						bHave = true;
						pcMesh->mMaterialIndex = p;
						break;
					}
				}
			}

			if (!bHave)
			{
				MaterialHelper* pcHelper = new MaterialHelper();

				aiString szString;
				const size_t iLen = strlen(szEndDir2);
				memcpy(szString.data,szEndDir2,iLen+1);
				szString.length = iLen-1;

				pcHelper->AddProperty(&szString,AI_MATKEY_TEXTURE_DIFFUSE(0));

				int iMode = (int)aiShadingMode_Gouraud;
				pcHelper->AddProperty<int>(&iMode, 1, AI_MATKEY_SHADING_MODEL);

				aiColor3D clr;
				clr.b = clr.g = clr.r = 1.0f;
				pcHelper->AddProperty<aiColor3D>(&clr, 1,AI_MATKEY_COLOR_DIFFUSE);
				pcHelper->AddProperty<aiColor3D>(&clr, 1,AI_MATKEY_COLOR_SPECULAR);

				clr.b = clr.g = clr.r = 0.05f;
				pcHelper->AddProperty<aiColor3D>(&clr, 1,AI_MATKEY_COLOR_AMBIENT);

				pScene->mMaterials[iNumMaterials] = (aiMaterial*)pcHelper;
				pcMesh->mMaterialIndex = iNumMaterials++;
			}
		}
		else
		{
			if (0xFFFFFFFF != iDefaultMatIndex)
			{
				pcMesh->mMaterialIndex = iDefaultMatIndex;
			}
			else
			{
				MaterialHelper* pcHelper = new MaterialHelper();

				// fill in a default material
				int iMode = (int)aiShadingMode_Gouraud;
				pcHelper->AddProperty<int>(&iMode, 1, AI_MATKEY_SHADING_MODEL);

				aiColor3D clr;
				clr.b = clr.g = clr.r = 0.6f;
				pcHelper->AddProperty<aiColor3D>(&clr, 1,AI_MATKEY_COLOR_DIFFUSE);
				pcHelper->AddProperty<aiColor3D>(&clr, 1,AI_MATKEY_COLOR_SPECULAR);

				clr.b = clr.g = clr.r = 0.05f;
				pcHelper->AddProperty<aiColor3D>(&clr, 1,AI_MATKEY_COLOR_AMBIENT);

				pScene->mMaterials[iNumMaterials] = (aiMaterial*)pcHelper;
				pcMesh->mMaterialIndex = iNumMaterials++;
			}
		}
		pcSurfaces = (const MD3::Surface*)(((unsigned char*)pcSurfaces) + pcSurfaces->OFS_END);
	}

	if (0 == pScene->mNumMeshes)
	{
		// cleanup before returning
		delete pScene;
		throw new ImportErrorException( "Invalid md3 file: File contains no valid mesh");
	}
	pScene->mNumMaterials = iNumMaterials;

	// now we need to generate an empty node graph
	pScene->mRootNode = new aiNode();
	pScene->mRootNode->mNumChildren = pScene->mNumMeshes;
	pScene->mRootNode->mChildren = new aiNode*[pScene->mNumMeshes];

	for (unsigned int i = 0; i < pScene->mNumMeshes;++i)
	{
		pScene->mRootNode->mChildren[i] = new aiNode();
		pScene->mRootNode->mChildren[i]->mParent = pScene->mRootNode;
		pScene->mRootNode->mChildren[i]->mNumMeshes = 1;
		pScene->mRootNode->mChildren[i]->mMeshes = new unsigned int[1];
		pScene->mRootNode->mChildren[i]->mMeshes[0] = i;
	}

	delete[] this->mBuffer;
	return;
}