/*
Open Asset Import Library (assimp)
----------------------------------------------------------------------

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  copyright notice, this list of conditions and the
  following disclaimer.

* Redistributions in binary form must reproduce the above
  copyright notice, this list of conditions and the
  following disclaimer in the documentation and/or other
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* Neither the name of the assimp team, nor the names of its
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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*/

/** @file  SMDLoader.h
 *  @brief Definition of the Valve SMD file format
 */

#pragma once
#ifndef AI_SMDLOADER_H_INCLUDED
#define AI_SMDLOADER_H_INCLUDED

#include <assimp/BaseImporter.h>
#include <assimp/ParsingUtils.h>
#include <assimp/types.h>
#include <assimp/texture.h>
#include <assimp/anim.h>
#include <assimp/material.h>

#include <vector>

struct aiNode;

namespace Assimp {
namespace SMD {

// ---------------------------------------------------------------------------
/** Data structure for a vertex in a SMD file
*/
struct Vertex {
    Vertex() AI_NO_EXCEPT : iParentNode(UINT_MAX) {
        // empty
    }

    //! Vertex position, normal and texture coordinate
    aiVector3D pos,nor,uv;

    //! Vertex parent node
    unsigned int iParentNode;

    //! Links to bones: pair.first is the bone index,
    //! pair.second is the vertex weight.
    //! WARN: The remaining weight (to reach 1.0f) is assigned
    //! to the parent node/bone
    std::vector<std::pair<unsigned int, float> > aiBoneLinks;
};

// ---------------------------------------------------------------------------
/** Data structure for a face in a SMD file
*/
struct Face {
    Face() AI_NO_EXCEPT :
            iTexture(0x0) {
        // empty
    }

    //! Texture index for the face
    unsigned int iTexture;

    //! The three vertices of the face
    Vertex avVertices[3];
};

// ---------------------------------------------------------------------------
/** Data structure for a bone in a SMD file
*/
struct Bone {
    //! Default constructor
    Bone() AI_NO_EXCEPT : iParent(UINT_MAX), bIsUsed(false) {
        // empty
    }

    //! Name of the bone
    std::string mName;

    //! Parent of the bone
    uint32_t iParent;

    //! Animation of the bone
    struct Animation {
        //! Public default constructor
        Animation() AI_NO_EXCEPT : iFirstTimeKey() {
            asKeys.reserve(20);
        }

        //! Data structure for a matrix key
        struct MatrixKey {
            //! Matrix at this time
            aiMatrix4x4 matrix;

            //! Absolute transformation matrix
            aiMatrix4x4 matrixAbsolute;

            //! Position
            aiVector3D vPos;

            //! Rotation (euler angles)
            aiVector3D vRot;

            //! Current time. may be negative, this
            //! will be fixed later
            double dTime;
        };

        //! Index of the key with the smallest time value
        uint32_t iFirstTimeKey;

        //! Array of matrix keys
        std::vector<MatrixKey> asKeys;

    } sAnim;

    //! Offset matrix of the bone
    aiMatrix4x4 mOffsetMatrix;

    //! true if the bone is referenced by at least one mesh
    bool bIsUsed;
};

} //! namespace SMD

// ---------------------------------------------------------------------------
/** Used to load Half-life 1 and 2 SMD models
*/
class ASSIMP_API SMDImporter : public BaseImporter {
public:
    SMDImporter();
    ~SMDImporter() override = default;

    // -------------------------------------------------------------------
    /** 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;

    // -------------------------------------------------------------------
    /** Called prior to ReadFile().
     * The function is a request to the importer to update its configuration
     * basing on the Importer's configuration property list.
     */
    void SetupProperties(const Importer* pImp) override;

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

    // -------------------------------------------------------------------
    /** Parse the SMD file and create the output scene
    */
    void ParseFile();
    void ReadSmd(const std::string &pFile, IOSystem* pIOHandler);

    // -------------------------------------------------------------------
    /** Parse the triangles section of the SMD file
     * \param szCurrent Current position in the file. Points to the first
     * data line of the section.
     * \param szCurrentOut Receives a pointer to the heading line of
     * the next section (or to EOF)
    */
    void ParseTrianglesSection(const char* szCurrent,
            const char **szCurrentOut, const char *end);

    // -------------------------------------------------------------------
    /** Parse the vertex animation section in VTA files
     * \param szCurrent Current position in the file. Points to the first
     * data line of the section.
     * \param szCurrentOut Receives a pointer to the heading line of
     * the next section (or to EOF)
    */
    void ParseVASection(const char* szCurrent,
            const char **szCurrentOu, const char *end);

    // -------------------------------------------------------------------
    /** Parse the nodes section of the SMD file
     * \param szCurrent Current position in the file. Points to the first
     * data line of the section.
     * \param szCurrentOut Receives a pointer to the heading line of
     * the next section (or to EOF)
    */
    void ParseNodesSection(const char* szCurrent,
            const char **szCurrentOut, const char *end);

    // -------------------------------------------------------------------
    /** Parse the skeleton section of the SMD file
     * \param szCurrent Current position in the file. Points to the first
     * data line of the section.
     * \param szCurrentOut Receives a pointer to the heading line of
     * the next section (or to EOF)
    */
    void ParseSkeletonSection(const char* szCurrent,
            const char **szCurrentOut, const char *end);

    // -------------------------------------------------------------------
    /** Parse a single triangle in the SMD file
     * \param szCurrent Current position in the file. Points to the first
     * data line of the section.
     * \param szCurrentOut Receives the output cursor position
    */
    void ParseTriangle(const char* szCurrent,
            const char **szCurrentOut, const char *end);

    // -------------------------------------------------------------------
    /** Parse a single vertex in the SMD file
     * \param szCurrent Current position in the file. Points to the first
     * data line of the section.
     * \param szCurrentOut Receives the output cursor position
     * \param vertex Vertex to be filled
    */
    void ParseVertex(const char* szCurrent,
            const char **szCurrentOut, const char *end, SMD::Vertex &vertex,
        bool bVASection = false);

    // -------------------------------------------------------------------
    /** Get  the index of a texture. If the texture was not yet known
     *  it will be added to the internal texture list.
     * \param filename Name of the texture
     * \return Value texture index
     */
    unsigned int GetTextureIndex(const std::string& filename);

    // -------------------------------------------------------------------
    /** Parse a line in the skeleton section
     */
    void ParseSkeletonElement(const char* szCurrent,
            const char **szCurrentOut, const char *end, int iTime);

    // -------------------------------------------------------------------
    /** Parse a line in the nodes section
     */
    void ParseNodeInfo(const char* szCurrent,
            const char **szCurrentOut, const char *end);

    // -------------------------------------------------------------------
    /** Parse a floating-point value
     */
    bool ParseFloat(const char* szCurrent,
            const char **szCurrentOut, const char *end, float &out);

    // -------------------------------------------------------------------
    /** Parse an unsigned integer. There may be no sign!
     */
    bool ParseUnsignedInt(const char* szCurrent,
            const char **szCurrentOut, const char *end, unsigned int &out);

    // -------------------------------------------------------------------
    /** Parse a signed integer. Signs (+,-) are handled.
     */
    bool ParseSignedInt(const char* szCurrent,
            const char **szCurrentOut, const char *end, int &out);

    // -------------------------------------------------------------------
    /** Fix invalid time values in the file
     */
    void FixTimeValues();

    // -------------------------------------------------------------------
    /** Add all children of a bone as sub-nodes to a node
     * \param pcNode Parent node
     * \param iParent Parent bone index
     */
    void AddBoneChildren(aiNode* pcNode, uint32_t iParent);

    // -------------------------------------------------------------------
    /** Build output meshes/materials/nodes/animations
     */
    void CreateOutputMeshes();
    void CreateOutputNodes();
    void CreateOutputAnimations(const std::string &pFile, IOSystem* pIOHandler);
    void CreateOutputAnimation(int index, const std::string &name);
    void GetAnimationFileList(const std::string &pFile, IOSystem* pIOHandler, std::vector<std::tuple<std::string, std::string>>& outList);
    void CreateOutputMaterials();


    // -------------------------------------------------------------------
    /** Print a log message together with the current line number
     */
    void LogErrorNoThrow(const char* msg);
    void LogWarning(const char* msg);


    // -------------------------------------------------------------------
    inline bool SkipLine( const char* in, const char** out, const char *end) {
        Assimp::SkipLine(in, out, end);
        ++iLineNumber;
        return true;
    }
    // -------------------------------------------------------------------
    inline bool SkipSpacesAndLineEnd(const char *in, const char **out, const char *end) {
        ++iLineNumber;
        return Assimp::SkipSpacesAndLineEnd(in, out, end);
    }

private:

    /** Configuration option: frame to be loaded */
    unsigned int configFrameID;

    /** Buffer to hold the loaded file */
    std::vector<char> mBuffer;
    char *mEnd;

    /** Output scene to be filled
    */
    aiScene* pScene;

    /** Size of the input file in bytes
     */
    unsigned int iFileSize;

    /** Array of textures found in the file
     */
    std::vector<std::string> aszTextures;

    /** Array of triangles found in the file
     */
    std::vector<SMD::Face> asTriangles;

    /** Array of bones found in the file
     */
    std::vector<SMD::Bone> asBones;

    /** Smallest frame index found in the skeleton
     */
    int iSmallestFrame;

    /** Length of the whole animation, in frames
     */
    double dLengthOfAnim;

    /** Do we have texture coordinates?
     */
    bool bHasUVs;

    /** Current line number
     */
    unsigned int iLineNumber;

    bool bLoadAnimationList = true;
    bool noSkeletonMesh = false;
};

} // end of namespace Assimp

#endif // AI_SMDIMPORTER_H_INC
