/** Helper structures for the Collada loader */

/*
Open Asset Import Library (assimp)
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*/

#ifndef AI_COLLADAHELPER_H_INC
#define AI_COLLADAHELPER_H_INC

namespace Assimp	{
namespace Collada		{

/** Collada file versions which evolved during the years ... */
enum FormatVersion
{
	FV_1_5_n,
	FV_1_4_n,
	FV_1_3_n
};


/** Transformation types that can be applied to a node */
enum TransformType
{
	TF_LOOKAT,
	TF_ROTATE,
	TF_TRANSLATE,
	TF_SCALE,
	TF_SKEW,
	TF_MATRIX
};

/** Different types of input data to a vertex or face */
enum InputType
{
	IT_Invalid,
	IT_Vertex,  // special type for per-index data referring to the <vertices> element carrying the per-vertex data.
	IT_Position,
	IT_Normal,
	IT_Texcoord,
	IT_Color,
	IT_Tangent,
	IT_Bitangent
};

/** Contains all data for one of the different transformation types */
struct Transform
{
	std::string mID;  ///< SID of the transform step, by which anim channels address their target node
	TransformType mType;
	float f[16]; ///< Interpretation of data depends on the type of the transformation 
};

/** A collada camera. */
struct Camera
{
	Camera()
		:	mOrtho  (false)
		,	mHorFov (10e10f)
		,	mVerFov (10e10f)
		,	mAspect (10e10f)
		,	mZNear  (0.1f)
		,	mZFar   (1000.f)
	{}

	// Name of camera
	std::string mName;

	// True if it is an orthografic camera
	bool mOrtho;

	//! Horizontal field of view in degrees
	float mHorFov;

	//! Vertical field of view in degrees
	float mVerFov;

	//! Screen aspect
	float mAspect;

	//! Near& far z
	float mZNear, mZFar;
};

#define aiLightSource_AMBIENT 0xdeaddead

/** A collada light source. */
struct Light
{	
	Light()
		:	mAttConstant     (1.f)
		,	mAttLinear       (0.f)
		,	mAttQuadratic    (0.f)
		,	mFalloffAngle    (180.f)
		,	mFalloffExponent (0.f)
		,	mPenumbraAngle	 (10e10f)
		,	mOuterAngle		 (10e10f)
		,	mIntensity		 (1.f)
	{}

	//! Type of the light source aiLightSourceType + ambient
	unsigned int mType;

	//! Color of the light
	aiColor3D mColor;

	//! Light attenuation
	float mAttConstant,mAttLinear,mAttQuadratic;

	//! Spot light falloff
	float mFalloffAngle;
	float mFalloffExponent;

	// -----------------------------------------------------
	// FCOLLADA extension from here

	//! ... related stuff from maja and max extensions
	float mPenumbraAngle;
	float mOuterAngle;

	//! Common light intensity
	float mIntensity;
};

/** Short vertex index description */
struct InputSemanticMapEntry
{
	InputSemanticMapEntry()
		:	mSet	(0)
	{}

	//! Index of set, optional
	unsigned int mSet;

	//! Name of referenced vertex input
	InputType mType;
};

/** Table to map from effect to vertex input semantics */
struct SemanticMappingTable
{
	//! Name of material
	std::string mMatName;

	//! List of semantic map commands, grouped by effect semantic name
	std::map<std::string, InputSemanticMapEntry> mMap;

	//! For std::find
	bool operator == (const std::string& s) const {
		return s == mMatName;
	}
};

/** A reference to a mesh inside a node, including materials assigned to the various subgroups.
 * The ID refers to either a mesh or a controller which specifies the mesh
 */
struct MeshInstance
{
	///< ID of the mesh or controller to be instanced
	std::string mMeshOrController;

	///< Map of materials by the subgroup ID they're applied to
	std::map<std::string, SemanticMappingTable> mMaterials;
};

/** A reference to a camera inside a node*/
struct CameraInstance
{
	 ///< ID of the camera
	std::string mCamera;
};

/** A reference to a light inside a node*/
struct LightInstance
{
	 ///< ID of the camera
	std::string mLight;
};

/** A reference to a node inside a node*/
struct NodeInstance
{
	 ///< ID of the node
	std::string mNode;
};

/** A node in a scene hierarchy */
struct Node
{
	std::string mName;
	std::string mID;
  std::string mSID;
	Node* mParent;
	std::vector<Node*> mChildren;

	/** Operations in order to calculate the resulting transformation to parent. */
	std::vector<Transform> mTransforms;

	/** Meshes at this node */
	std::vector<MeshInstance> mMeshes;    

	/** Lights at this node */
	std::vector<LightInstance> mLights;  

	/** Cameras at this node */
	std::vector<CameraInstance> mCameras; 

	/** Node instances at this node */
	std::vector<NodeInstance> mNodeInstances;

	/** Rootnodes: Name of primary camera, if any */
	std::string mPrimaryCamera;

	//! Constructor. Begin with a zero parent
	Node() { 
		mParent = NULL;
	}

	//! Destructor: delete all children subsequently
	~Node() { 
		for( std::vector<Node*>::iterator it = mChildren.begin(); it != mChildren.end(); ++it) 
			delete *it; 
	}
};

/** Data source array: either floats or strings */
struct Data
{
	bool mIsStringArray;
	std::vector<float> mValues;
	std::vector<std::string> mStrings;
};

/** Accessor to a data array */
struct Accessor
{
	size_t mCount;   // in number of objects
	size_t mSize;    // size of an object, in elements (floats or strings, mostly 1)
	size_t mOffset;  // in number of values
	size_t mStride;  // Stride in number of values
	std::vector<std::string> mParams; // names of the data streams in the accessors. Empty string tells to ignore. 
	size_t mSubOffset[4]; // Suboffset inside the object for the common 4 elements. For a vector, thats XYZ, for a color RGBA and so on.
						  // For example, SubOffset[0] denotes which of the values inside the object is the vector X component.
	std::string mSource;   // URL of the source array
	mutable const Data* mData; // Pointer to the source array, if resolved. NULL else

	Accessor() 
	{ 
		mCount = 0; mSize = 0; mOffset = 0; mStride = 0; mData = NULL; 
		mSubOffset[0] = mSubOffset[1] = mSubOffset[2] = mSubOffset[3] = 0;
	}
};

/** A single face in a mesh */
struct Face
{
	std::vector<size_t> mIndices;
};

/** An input channel for mesh data, referring to a single accessor */
struct InputChannel
{
	InputType mType;      // Type of the data
	size_t mIndex;		  // Optional index, if multiple sets of the same data type are given
	size_t mOffset;       // Index offset in the indices array of per-face indices. Don't ask, can't explain that any better.
	std::string mAccessor; // ID of the accessor where to read the actual values from.
	mutable const Accessor* mResolved; // Pointer to the accessor, if resolved. NULL else

	InputChannel() { mType = IT_Invalid; mIndex = 0; mOffset = 0; mResolved = NULL; }
};

/** Subset of a mesh with a certain material */
struct SubMesh
{
	std::string mMaterial; ///< subgroup identifier
	size_t mNumFaces; ///< number of faces in this submesh
};

/** Contains data for a single mesh */
struct Mesh
{
	Mesh()
	{
		for (unsigned int i = 0; i < AI_MAX_NUMBER_OF_TEXTURECOORDS;++i)
			mNumUVComponents[i] = 2;
	}

	// just to check if there's some sophisticated addressing involved...
	// which we don't support, and therefore should warn about.
	std::string mVertexID; 

	// Vertex data addressed by vertex indices
	std::vector<InputChannel> mPerVertexData; 

	// actual mesh data, assembled on encounter of a <p> element. Verbose format, not indexed
	std::vector<aiVector3D> mPositions;
	std::vector<aiVector3D> mNormals;
	std::vector<aiVector3D> mTangents;
	std::vector<aiVector3D> mBitangents;
	std::vector<aiVector3D> mTexCoords[AI_MAX_NUMBER_OF_TEXTURECOORDS];
	std::vector<aiColor4D>  mColors[AI_MAX_NUMBER_OF_COLOR_SETS];

	unsigned int mNumUVComponents[AI_MAX_NUMBER_OF_TEXTURECOORDS];

	// Faces. Stored are only the number of vertices for each face.
	// 1 == point, 2 == line, 3 == triangle, 4+ == poly
	std::vector<size_t> mFaceSize;
	
	// Position indices for all faces in the sequence given in mFaceSize - 
	// necessary for bone weight assignment
	std::vector<size_t> mFacePosIndices;

	// Submeshes in this mesh, each with a given material
	std::vector<SubMesh> mSubMeshes;
};

/** Which type of primitives the ReadPrimitives() function is going to read */
enum PrimitiveType
{
	Prim_Invalid,
	Prim_Lines,
	Prim_LineStrip,
	Prim_Triangles,
	Prim_TriStrips,
	Prim_TriFans,
	Prim_Polylist,
	Prim_Polygon
};

/** A skeleton controller to deform a mesh with the use of joints */
struct Controller
{
	// the URL of the mesh deformed by the controller.
	std::string mMeshId; 

	// accessor URL of the joint names
	std::string mJointNameSource;

  ///< The bind shape matrix, as array of floats. I'm not sure what this matrix actually describes, but it can't be ignored in all cases
  float mBindShapeMatrix[16];

	// accessor URL of the joint inverse bind matrices
	std::string mJointOffsetMatrixSource;

	// input channel: joint names. 
	InputChannel mWeightInputJoints;
	// input channel: joint weights
	InputChannel mWeightInputWeights;

	// Number of weights per vertex.
	std::vector<size_t> mWeightCounts;

	// JointIndex-WeightIndex pairs for all vertices
	std::vector< std::pair<size_t, size_t> > mWeights;
};

/** A collada material. Pretty much the only member is a reference to an effect. */
struct Material
{
	std::string mEffect;
};

/** Type of the effect param */
enum ParamType
{
	Param_Sampler,
	Param_Surface
};

/** A param for an effect. Might be of several types, but they all just refer to each other, so I summarize them */
struct EffectParam
{
	ParamType mType;
	std::string mReference; // to which other thing the param is referring to. 
};

/** Shading type supported by the standard effect spec of Collada */
enum ShadeType
{
	Shade_Invalid,
	Shade_Constant,
	Shade_Lambert,
	Shade_Phong,
	Shade_Blinn
};

/** Represents a texture sampler in collada */
struct Sampler
{
	Sampler()
		:	mWrapU		(true)
		,	mWrapV		(true)
		,	mMirrorU	()
		,	mMirrorV	()
		,	mOp			(aiTextureOp_Multiply)
		,	mUVId		(UINT_MAX)
		,	mWeighting  (1.f)
		,	mMixWithPrevious (1.f)
	{}

	/** Name of image reference
	 */
	std::string mName;

	/** Wrap U?
	 */
	bool mWrapU;

	/** Wrap V?
	 */
	bool mWrapV;

	/** Mirror U?
	 */
	bool mMirrorU;

	/** Mirror V?
	 */
	bool mMirrorV;

	/** Blend mode
	 */
	aiTextureOp mOp;

	/** UV transformation
	 */
	aiUVTransform mTransform;

	/** Name of source UV channel
	 */
	std::string mUVChannel;

	/** Resolved UV channel index or UINT_MAX if not known
	 */
	unsigned int mUVId;

	// OKINO/MAX3D extensions from here
	// -------------------------------------------------------

	/** Weighting factor
	 */
	float mWeighting;

	/** Mixing factor from OKINO
	 */
	float mMixWithPrevious;
};

/** A collada effect. Can contain about anything according to the Collada spec,
    but we limit our version to a reasonable subset. */
struct Effect
{
	// Shading mode
	ShadeType mShadeType;

	// Colors
	aiColor4D mEmissive, mAmbient, mDiffuse, mSpecular,
		mTransparent, mReflective;

	// Textures
	Sampler mTexEmissive, mTexAmbient, mTexDiffuse, mTexSpecular,
		mTexTransparent, mTexBump, mTexReflective;

	// Scalar factory
	float mShininess, mRefractIndex, mReflectivity;
	float mTransparency;

	// local params referring to each other by their SID
	typedef std::map<std::string, Collada::EffectParam> ParamLibrary;
	ParamLibrary mParams;

	// MAX3D extensions
	// ---------------------------------------------------------
	// Double-sided?
	bool mDoubleSided, mWireframe, mFaceted;
	
	Effect()
		: mShadeType    (Shade_Phong)
		, mEmissive		( 0, 0, 0, 1)
		, mAmbient		( 0.1f, 0.1f, 0.1f, 1)
		, mDiffuse		( 0.6f, 0.6f, 0.6f, 1)
		, mSpecular		( 0.4f, 0.4f, 0.4f, 1)
		, mTransparent	( 0, 0, 0, 1)
		, mShininess    (10.0f)
		, mRefractIndex (1.f)
		, mReflectivity (1.f)
		, mTransparency (0.f)
		, mDoubleSided	(false)
		, mWireframe    (false)
		, mFaceted      (false)
	{ 
	}
};

/** An image, meaning texture */
struct Image
{
	std::string mFileName;

	/** If image file name is zero, embedded image data
	 */
	std::vector<uint8_t> mImageData;

	/** If image file name is zero, file format of
	 *  embedded image data.
	 */
	std::string mEmbeddedFormat;

};

/** An animation channel. */
struct AnimationChannel
{
	/** URL of the data to animate. Could be about anything, but we support only the 
	 * "NodeID/TransformID.SubElement" notation 
	 */
	std::string mTarget;

	/** Source URL of the time values. Collada calls them "input". Meh. */
	std::string mSourceTimes;
	/** Source URL of the value values. Collada calls them "output". */
	std::string mSourceValues;
};

/** An animation. Container for 0-x animation channels or 0-x animations */
struct Animation
{
	/** Anim name */
	std::string mName;

	/** the animation channels, if any */
	std::vector<AnimationChannel> mChannels;

	/** the sub-animations, if any */
	std::vector<Animation*> mSubAnims;

	/** Destructor */
	~Animation()
	{
		for( std::vector<Animation*>::iterator it = mSubAnims.begin(); it != mSubAnims.end(); ++it)
			delete *it;
	}
};

/** Description of a collada animation channel which has been determined to affect the current node */
struct ChannelEntry
{
	const Collada::AnimationChannel* mChannel; ///> the source channel
	std::string mTransformId;   // the ID of the transformation step of the node which is influenced
	size_t mTransformIndex; // Index into the node's transform chain to apply the channel to
	size_t mSubElement; // starting index inside the transform data

	// resolved data references
	const Collada::Accessor* mTimeAccessor; ///> Collada accessor to the time values
	const Collada::Data* mTimeData; ///> Source data array for the time values
	const Collada::Accessor* mValueAccessor; ///> Collada accessor to the key value values
	const Collada::Data* mValueData; ///> Source datat array for the key value values

	ChannelEntry() { mChannel = NULL; mSubElement = 0; }
};

} // end of namespace Collada
} // end of namespace Assimp

#endif // AI_COLLADAHELPER_H_INC