/** Defines the collada loader class */

/*
Open Asset Import Library (assimp)
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*/

#ifndef AI_COLLADALOADER_H_INC
#define AI_COLLADALOADER_H_INC

#include "BaseImporter.h"
#include "ColladaParser.h"

namespace Assimp
{

struct ColladaMeshIndex
{
	std::string mMeshID;
	size_t mSubMesh;
	std::string mMaterial;
	ColladaMeshIndex( const std::string& pMeshID, size_t pSubMesh, const std::string& pMaterial) 
		: mMeshID( pMeshID), mSubMesh( pSubMesh), mMaterial( pMaterial)
	{   }

	bool operator < (const ColladaMeshIndex& p) const
	{
		if( mMeshID == p.mMeshID) 
		{
			if( mSubMesh == p.mSubMesh)
				return mMaterial < p.mMaterial;
			else 
				return mSubMesh < p.mSubMesh;
		} else
		{
			return mMeshID < p.mMeshID;
		}
	}
};

/** Loader class to read Collada scenes. Collada is over-engineered to death, with every new iteration bringing
 * more useless stuff, so I limited the data to what I think is useful for games. 
*/
class ColladaLoader : public BaseImporter
{
public:
	ColladaLoader();
	~ColladaLoader();


public:
	/** Returns whether the class can handle the format of the given file. 
	 * See BaseImporter::CanRead() for details.	*/
	bool CanRead( const std::string& pFile, IOSystem* pIOHandler, bool checkSig) const;

protected:
	/** Return importer meta information.
	 * See #BaseImporter::GetInfo for the details
	 */
	const aiImporterDesc* GetInfo () const;

	/** Imports the given file into the given scene structure. 
	 * See BaseImporter::InternReadFile() for details
	 */
	void InternReadFile( const std::string& pFile, aiScene* pScene, IOSystem* pIOHandler);

	/** Recursively constructs a scene node for the given parser node and returns it. */
	aiNode* BuildHierarchy( const ColladaParser& pParser, const Collada::Node* pNode);

	/** Resolve node instances */
	void ResolveNodeInstances( const ColladaParser& pParser, const Collada::Node* pNode,
		std::vector<const Collada::Node*>& resolved);

	/** Builds meshes for the given node and references them */
	void BuildMeshesForNode( const ColladaParser& pParser, const Collada::Node* pNode, 
		aiNode* pTarget);

	/** Creates a mesh for the given ColladaMesh face subset and returns the newly created mesh */
	aiMesh* CreateMesh( const ColladaParser& pParser, const Collada::Mesh* pSrcMesh, const Collada::SubMesh& pSubMesh, 
		const Collada::Controller* pSrcController, size_t pStartVertex, size_t pStartFace);

	/** Builds cameras for the given node and references them */
	void BuildCamerasForNode( const ColladaParser& pParser, const Collada::Node* pNode, 
		aiNode* pTarget);

	/** Builds lights for the given node and references them */
	void BuildLightsForNode( const ColladaParser& pParser, const Collada::Node* pNode, 
		aiNode* pTarget);

	/** Stores all meshes in the given scene */
	void StoreSceneMeshes( aiScene* pScene);

	/** Stores all materials in the given scene */
	void StoreSceneMaterials( aiScene* pScene);

	/** Stores all lights in the given scene */
	void StoreSceneLights( aiScene* pScene);

	/** Stores all cameras in the given scene */
	void StoreSceneCameras( aiScene* pScene);

	/** Stores all textures in the given scene */
	void StoreSceneTextures( aiScene* pScene);

	/** Stores all animations 
	 * @param pScene target scene to store the anims
	 */
	void StoreAnimations( aiScene* pScene, const ColladaParser& pParser);

	/** Stores all animations for the given source anim and its nested child animations
	 * @param pScene target scene to store the anims
	 * @param pSrcAnim the source animation to process
	 * @param pPrefix Prefix to the name in case of nested animations
	 */
	void StoreAnimations( aiScene* pScene, const ColladaParser& pParser, const Collada::Animation* pSrcAnim, const std::string pPrefix);

	/** Constructs the animation for the given source anim */
	void CreateAnimation( aiScene* pScene, const ColladaParser& pParser, const Collada::Animation* pSrcAnim, const std::string& pName);
	
	/** Constructs materials from the collada material definitions */
	void BuildMaterials( ColladaParser& pParser, aiScene* pScene);

	/** Fill materials from the collada material definitions */
	void FillMaterials( const ColladaParser& pParser, aiScene* pScene);

	/** Resolve UV channel mappings*/
	void ApplyVertexToEffectSemanticMapping(Collada::Sampler& sampler,
		const Collada::SemanticMappingTable& table);

	/** Add a texture and all of its sampling properties to a material*/
	void AddTexture ( aiMaterial& mat, const ColladaParser& pParser,
		const Collada::Effect& effect,
		const Collada::Sampler& sampler,
		aiTextureType type, unsigned int idx = 0);

	/** Resolves the texture name for the given effect texture entry */
	aiString FindFilenameForEffectTexture( const ColladaParser& pParser, 
		const Collada::Effect& pEffect, const std::string& pName);

	/** Converts a path read from a collada file to the usual representation */
	void ConvertPath( aiString& ss);

	/** Reads a float value from an accessor and its data array.
	 * @param pAccessor The accessor to use for reading
	 * @param pData The data array to read from
	 * @param pIndex The index of the element to retrieve
	 * @param pOffset Offset into the element, for multipart elements such as vectors or matrices
	 * @return the specified value
	 */
	float ReadFloat( const Collada::Accessor& pAccessor, const Collada::Data& pData, size_t pIndex, size_t pOffset) const;

	/** Reads a string value from an accessor and its data array.
	 * @param pAccessor The accessor to use for reading
	 * @param pData The data array to read from
	 * @param pIndex The index of the element to retrieve
	 * @return the specified value
	 */
	const std::string& ReadString( const Collada::Accessor& pAccessor, const Collada::Data& pData, size_t pIndex) const;

	/** Recursively collects all nodes into the given array */
	void CollectNodes( const aiNode* pNode, std::vector<const aiNode*>& poNodes) const;

	/** Finds a node in the collada scene by the given name */
	const Collada::Node* FindNode( const Collada::Node* pNode, const std::string& pName) const;
	/** Finds a node in the collada scene by the given SID */
	const Collada::Node* FindNodeBySID( const Collada::Node* pNode, const std::string& pSID) const;

	/** Finds a proper name for a node derived from the collada-node's properties */
	std::string FindNameForNode( const Collada::Node* pNode) const;

protected:
	/** Filename, for a verbose error message */
	std::string mFileName;

	/** Which mesh-material compound was stored under which mesh ID */
	std::map<ColladaMeshIndex, size_t> mMeshIndexByID;

	/** Which material was stored under which index in the scene */
	std::map<std::string, size_t> mMaterialIndexByName;

	/** Accumulated meshes for the target scene */
	std::vector<aiMesh*> mMeshes;

	/** Temporary material list */
	std::vector<std::pair<Collada::Effect*, aiMaterial*> > newMats;

	/** Temporary camera list */
	std::vector<aiCamera*> mCameras;

	/** Temporary light list */
	std::vector<aiLight*> mLights;

	/** Temporary texture list */
	std::vector<aiTexture*> mTextures;

	/** Accumulated animations for the target scene */
	std::vector<aiAnimation*> mAnims;
};

} // end of namespace Assimp

#endif // AI_COLLADALOADER_H_INC
