/** Helper structures for the Collada loader */

/*
Open Asset Import Library (assimp)
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Copyright (C) 2012 Robert Beckebans (id Tech 4 integration)
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*/

#ifndef __MODEL_COLLADAHELPER_H__
#define __MODEL_COLLADAHELPER_H__

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
{
	idStr 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
	idStr 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
	idVec3 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
	idStr mMatName;
	
	//! List of semantic map commands, grouped by effect semantic name
	idHashTable<InputSemanticMapEntry> mMap;
	
	//! For std::find
	bool operator == ( const idStr& 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
	idStr mMeshOrController;
	
	///< Map of materials by the subgroup ID they're applied to
	//idHashTable<SemanticMappingTable> mMaterials;
	idStrList mMaterials;
};

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

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

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

/** A node in a scene hierarchy */
struct Node
{
	idStr mName;
	idStr mID;
	idStr mSID;
	Node* mParent;
	idList<Node*> mChildren;
	
	/** Operations in order to calculate the resulting transformation to parent. */
	idList<Transform> mTransforms;
	
	/** Meshes at this node */
	idList<MeshInstance> mMeshes;
	
	/** Lights at this node */
	idList<LightInstance> mLights;
	
	/** Cameras at this node */
	idList<CameraInstance> mCameras;
	
	/** Node instances at this node */
	idList<NodeInstance> mNodeInstances;
	
	/** Rootnodes: Name of primary camera, if any */
	idStr mPrimaryCamera;
	
	//! Constructor. Begin with a zero parent
	Node()
	{
		mParent = NULL;
	}
	
	//! Destructor: delete all children subsequently
	~Node()
	{
		//mChildren.DeleteContents( false );
	}
};

/** Data source array: either floats or strings */
struct Data
{
	bool mIsStringArray;
	idList<float> mValues;
	idList<idStr> 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
	idList<idStr> 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.
	idStr 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
{
	idList<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.
	idStr 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
{
	idStr 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.
	idStr mVertexID;
	
	// Vertex data addressed by vertex indices
	idList<InputChannel> mPerVertexData;
	
	// actual mesh data, assembled on encounter of a <p> element. Verbose format, not indexed
	idList<idVec3> mPositions;
	idList<idVec3> mNormals;
	idList<idVec3> mTangents;
	idList<idVec3> mBitangents;
	idList<idVec2> mTexCoords;
	idList<dword> mColors;
	
	//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
	idList<int> mFaceSize;
	
	// Position indices for all faces in the sequence given in mFaceSize -
	// necessary for bone weight assignment
	idList<int> mFacePosIndices;
	
	// Submeshes in this mesh, each with a given material
	idList<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
};

struct WeightPair
{
	size_t jointIndex;
	size_t weightIndex;
};

/** A skeleton controller to deform a mesh with the use of joints */
struct Controller
{
	// the URL of the mesh deformed by the controller.
	idStr mMeshId;
	
	// accessor URL of the joint names
	idStr 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
	idStr mJointOffsetMatrixSource;
	
	// input channel: joint names.
	InputChannel mWeightInputJoints;
	// input channel: joint weights
	InputChannel mWeightInputWeights;
	
	// Number of weights per vertex.
	idList<size_t> mWeightCounts;
	
	// JointIndex-WeightIndex pairs for all vertices
	idList< WeightPair > mWeights;
};

/** A collada material. Pretty much the only member is a reference to an effect. */
struct Material
{
	idStr 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;
	idStr 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
	 */
	idStr 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
	 */
	//idStr 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
	idVec4 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 idHashTable<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
{
	idStr mFileName;
	
	/** If image file name is zero, embedded image data
	 */
	idList<uint8_t> mImageData;
	
	/** If image file name is zero, file format of
	 *  embedded image data.
	 */
	idStr 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
	 */
	idStr mTarget;
	
	/** Source URL of the time values. Collada calls them "input". Meh. */
	idStr mSourceTimes;
	/** Source URL of the value values. Collada calls them "output". */
	idStr mSourceValues;
};

/** An animation. Container for 0-x animation channels or 0-x animations */
struct Animation
{
	/** Anim name */
	idStr mName;
	
	/** the animation channels, if any */
	idList<AnimationChannel> mChannels;
	
	/** the sub-animations, if any */
	idList<Animation*> mSubAnims;
	
	/** Destructor */
	~Animation()
	{
		mSubAnims.DeleteContents( false );
	}
};

/** Description of a collada animation channel which has been determined to affect the current node */
struct ChannelEntry
{
	const Collada::AnimationChannel* mChannel; ///> the source channel
	idStr 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

#endif // __MODEL_COLLADAHELPER_H__
