// Copyright (C) 2009-2015, Panagiotis Christopoulos Charitos.
// All rights reserved.
// Code licensed under the BSD License.
// http://www.anki3d.org/LICENSE

#include "anki/resource/MeshLoader.h"
#include "anki/util/File.h"

namespace anki {

//==============================================================================
MeshLoader::~MeshLoader()
{
	// WARNING: Watch the order of deallocation. Reverse of the deallocation to
	// have successful cleanups
	m_verts.destroy(m_alloc);
	m_indices.destroy(m_alloc);
	m_subMeshes.destroy(m_alloc);
}

//==============================================================================
Error MeshLoader::load(
	GenericMemoryPoolAllocator<U8> alloc,
	const CString& filename)
{
	m_alloc = alloc;
	
	Error err = loadInternal(filename);
	if(err)
	{
		ANKI_LOGE("Failed to load mesh %s", &filename[0]);
	}

	return err;
}

//==============================================================================
Error MeshLoader::loadInternal(const CString& filename)
{
	Error err = ErrorCode::NONE;

	File file;
	err = file.open(filename, 
		File::OpenFlag::READ | File::OpenFlag::BINARY 
		| File::OpenFlag::LITTLE_ENDIAN);
	if(err) return err;

	// Load header
	err = file.read(&m_header, sizeof(m_header));
	if(err) return err;

	//
	// Check header
	//
	if(memcmp(&m_header.m_magic[0], "ANKIMES2", 8) != 0)
	{
		ANKI_LOGE("Wrong magic word");
		return ErrorCode::USER_DATA;
	}

	if(checkFormat(m_header.m_positionsFormat, "positions", true)
		|| checkFormat(m_header.m_normalsFormat, "normals", true)
		|| checkFormat(m_header.m_tangentsFormat, "tangents", true)
		|| checkFormat(m_header.m_colorsFormat, "colors", false)
		|| checkFormat(m_header.m_uvsFormat, "UVs", true)
		|| checkFormat(m_header.m_boneWeightsFormat, "bone weights", false)
		|| checkFormat(m_header.m_boneIndicesFormat, "bone ids", false)
		|| checkFormat(m_header.m_indicesFormat, "indices format", true))
	{
		return ErrorCode::USER_DATA;
	}

	// Check positions
	if(m_header.m_positionsFormat.m_components != ComponentFormat::R32G32B32
		|| m_header.m_positionsFormat.m_transform != FormatTransform::FLOAT)
	{
		ANKI_LOGE("Incorrect/unsupported positions format");
		return ErrorCode::USER_DATA;
	}

	// Check normals
	if(m_header.m_normalsFormat.m_components != ComponentFormat::R10G10B10A2
		|| m_header.m_normalsFormat.m_transform != FormatTransform::SNORM)
	{
		ANKI_LOGE("Incorrect/unsupported normals format");
		return ErrorCode::USER_DATA;
	}

	// Check tangents
	if(m_header.m_tangentsFormat.m_components != ComponentFormat::R10G10B10A2
		|| m_header.m_tangentsFormat.m_transform != FormatTransform::SNORM)
	{
		ANKI_LOGE("Incorrect/unsupported tangents format");
		return ErrorCode::USER_DATA;
	}

	// Check colors
	if(m_header.m_colorsFormat.m_components != ComponentFormat::NONE
		|| m_header.m_colorsFormat.m_transform != FormatTransform::NONE)
	{
		ANKI_LOGE("Incorrect/unsupported color format");
		return ErrorCode::USER_DATA;
	}

	// Check UVs
	if(m_header.m_uvsFormat.m_components != ComponentFormat::R16G16
		|| m_header.m_uvsFormat.m_transform != FormatTransform::FLOAT)
	{
		ANKI_LOGE("Incorrect/unsupported UVs format");
		return ErrorCode::USER_DATA;
	}

	Bool hasBoneInfo = false;
	if(m_header.m_boneWeightsFormat.m_components != ComponentFormat::NONE)
	{
		// Has bone info

		hasBoneInfo = true;

		// Bone weights
		if(m_header.m_boneWeightsFormat.m_components 
			!= ComponentFormat::R8G8B8A8
			|| m_header.m_boneWeightsFormat.m_transform 
			!= FormatTransform::UNORM)
		{
			ANKI_LOGE("Incorrect/unsupported UVs format");
			return ErrorCode::USER_DATA;
		}

		// Bone indices
		if(m_header.m_boneIndicesFormat.m_components 
			!= ComponentFormat::R16G16B16A16
			|| m_header.m_boneIndicesFormat.m_transform 
			!= FormatTransform::UINT)
		{
			ANKI_LOGE("Incorrect/unsupported UVs format");
			return ErrorCode::USER_DATA;
		}
	}
	else
	{
		// No bone info

		// Bone weights
		if(m_header.m_boneWeightsFormat.m_components 
			!= ComponentFormat::NONE
			|| m_header.m_boneWeightsFormat.m_transform 
			!= FormatTransform::NONE)
		{
			ANKI_LOGE("Incorrect/unsupported UVs format");
			return ErrorCode::USER_DATA;
		}

		// Bone indices
		if(m_header.m_boneIndicesFormat.m_components 
			!= ComponentFormat::NONE
			|| m_header.m_boneIndicesFormat.m_transform 
			!= FormatTransform::NONE)
		{
			ANKI_LOGE("Incorrect/unsupported UVs format");
			return ErrorCode::USER_DATA;
		}
	}

	// Check indices
	if(m_header.m_totalIndicesCount < 3
		|| (m_header.m_totalIndicesCount % 3) != 0
		|| m_header.m_totalIndicesCount > MAX_U16
		|| m_header.m_indicesFormat.m_components != ComponentFormat::R16
		|| m_header.m_indicesFormat.m_transform != FormatTransform::UINT)
	{
		// Only 16bit indices are supported for now
		ANKI_LOGE("Incorrect/unsuported index info");
		return ErrorCode::USER_DATA;
	}

	// Check other
	if(m_header.m_totalVerticesCount == 0)
	{
		ANKI_LOGE("Incorrect/unsuported vertex count");
		return ErrorCode::USER_DATA;
	}

	if(m_header.m_uvsChannelCount != 1)
	{
		ANKI_LOGE("Incorrect/unsuported UVs channel count");
		return ErrorCode::USER_DATA;
	}

	if(m_header.m_subMeshCount == 0)
	{
		ANKI_LOGE("Incorrect/unsuported submesh count");
		return ErrorCode::USER_DATA;
	}

	//
	// Read submesh info
	//
	err = m_subMeshes.create(m_alloc, m_header.m_subMeshCount);
	if(err) return err;
	err = file.read(&m_subMeshes[0], m_subMeshes.getSizeInBytes());
	if(err) return err;

	// Checks
	U idxSum = 0;
	for(U i = 0; i < m_subMeshes.getSize(); i++)
	{
		const SubMesh& sm = m_subMeshes[0];
		if(sm.m_firstIndex != idxSum
			|| sm.m_indicesCount < 3)
		{
			ANKI_LOGE("Incorrect sub mesh info");
			return ErrorCode::USER_DATA;
		}

		idxSum += sm.m_indicesCount;
	}

	if(idxSum != m_header.m_totalIndicesCount)
	{
		ANKI_LOGE("Incorrect sub mesh info");
		return ErrorCode::USER_DATA;
	}

	//
	// Read indices
	//
	err = m_indices.create(m_alloc, m_header.m_totalIndicesCount * sizeof(U16));
	if(err) return err;
	err = file.read(&m_indices[0], m_indices.getSizeInBytes());
	if(err) return err;

	//
	// Read vertices
	//
	m_vertSize = 
		3 * sizeof(F32) // pos
		+ 1 * sizeof(U32) // norm
		+ 1 * sizeof(U32) // tang
		+ 2 * sizeof(U16) // uvs
		+ ((hasBoneInfo) ? (4 * sizeof(U8) + 4 * sizeof(U16)) : 0);

	err = m_verts.create(m_alloc, m_header.m_totalVerticesCount * m_vertSize);
	if(err) return err;
	err = file.read(&m_verts[0], m_verts.getSizeInBytes());
	if(err) return err;

	return err;
}

//==============================================================================
Error MeshLoader::checkFormat(
	const Format& fmt, 
	const CString& attrib,
	Bool cannotBeEmpty)
{
	if(fmt.m_components >= ComponentFormat::COUNT)
	{
		ANKI_LOGE("Incorrect component format for %s", &attrib[0]);
		return ErrorCode::USER_DATA;
	}

	if(fmt.m_transform >= FormatTransform::COUNT)
	{
		ANKI_LOGE("Incorrect format transform for %s", &attrib[0]);
		return ErrorCode::USER_DATA;
	}

	if(cannotBeEmpty)
	{
		if(fmt.m_components == ComponentFormat::NONE)
		{
			ANKI_LOGE("Format cannot be zero for %s", &attrib[0]);
			return ErrorCode::USER_DATA;
		}

		if(fmt.m_transform == FormatTransform::NONE)
		{
			ANKI_LOGE("Transform cannot be zero for %s", &attrib[0]);
			return ErrorCode::USER_DATA;
		}
	}

	return ErrorCode::NONE;
}

} // end namespace anki