/** Defines the collada loader class */

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*/

#ifndef AI_COLLADALOADER_H_INC
#define AI_COLLADALOADER_H_INC

#include <assimp/BaseImporter.h>
#include "ColladaParser.h"

struct aiNode;
struct aiCamera;
struct aiLight;
struct aiTexture;
struct aiAnimation;

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 override;

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

    void SetupProperties(const Importer* pImp) override;

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

    /** 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);
		
    aiMesh *findMesh(const std::string& meshid);

    /** 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);

    /** 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
     */
    ai_real 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);

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;
	
    /** Accumulated morph target meshes */
    std::vector<aiMesh*> mTargetMeshes;

    /** 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;

    bool noSkeletonMesh;
    bool ignoreUpDirection;
    bool useColladaName;

    /** Used by FindNameForNode() to generate unique node names */
    unsigned int mNodeNameCounter;
};

} // end of namespace Assimp

#endif // AI_COLLADALOADER_H_INC
