/*
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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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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----------------------------------------------------------------------
*/
#pragma once

/** @file  MD5Parser.h
 *  @brief Definition of the .MD5 parser class.
 *  http://www.modwiki.net/wiki/MD5_(file_format)
 */
#ifndef AI_MD5PARSER_H_INCLUDED
#define AI_MD5PARSER_H_INCLUDED

#include <assimp/types.h>
#include <assimp/ParsingUtils.h>
#include <vector>
#include <cstdint>

struct aiFace;

namespace Assimp {
namespace MD5 {

// ---------------------------------------------------------------------------
/** Represents a single element in a MD5 file
 *
 *  Elements are always contained in sections.
*/
struct Element {
    //! Points to the starting point of the element
    //! Whitespace at the beginning and at the end have been removed,
    //! Elements are terminated with \0
    char* szStart;

    const char *end;

    //! Original line number (can be used in error messages
    //! if a parsing error occurs)
    unsigned int iLineNumber;
};

using ElementArray = std::vector<Element>;

// ---------------------------------------------------------------------------
/** Represents a section of a MD5 file (such as the mesh or the joints section)
 *
 *  A section is always enclosed in { and } brackets.
*/
struct Section {
    //! Original line number (can be used in error messages
    //! if a parsing error occurs)
    unsigned int iLineNumber;

    //! List of all elements which have been parsed in this section.
    ElementArray mElements;

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

    //! For global elements: the value of the element as string
    //! if !length() the section is not a global element
    std::string mGlobalValue;
};

using SectionArray = std::vector<Section>;

// ---------------------------------------------------------------------------
/** Basic information about a joint
*/
struct BaseJointDescription {
    //! Name of the bone
    aiString mName;

    //! Parent index of the bone
    int mParentIndex;
};

// ---------------------------------------------------------------------------
/** Represents a bone (joint) descriptor in a MD5Mesh file
*/
struct BoneDesc : BaseJointDescription {
    //! Absolute position of the bone
    aiVector3D mPositionXYZ;

    //! Absolute rotation of the bone
    aiVector3D mRotationQuat;
    aiQuaternion mRotationQuatConverted;

    //! Absolute transformation of the bone
    //! (temporary)
    aiMatrix4x4 mTransform;

    //! Inverse transformation of the bone
    //! (temporary)
    aiMatrix4x4 mInvTransform;

    //! Internal
    unsigned int mMap;
};

using BoneArray = std::vector<BoneDesc>;

// ---------------------------------------------------------------------------
/** Represents a bone (joint) descriptor in a MD5Anim file
*/
struct AnimBoneDesc : BaseJointDescription {
    //! Flags (AI_MD5_ANIMATION_FLAG_xxx)
    unsigned int iFlags;

    //! Index of the first key that corresponds to this anim bone
    unsigned int iFirstKeyIndex;
};

using AnimBoneArray = std::vector< AnimBoneDesc >;

// ---------------------------------------------------------------------------
/** Represents a base frame descriptor in a MD5Anim file
*/
struct BaseFrameDesc {
    aiVector3D vPositionXYZ;
    aiVector3D vRotationQuat;
};

using BaseFrameArray = std::vector<BaseFrameDesc>;

// ---------------------------------------------------------------------------
/** Represents a camera animation frame in a MDCamera file
*/
struct CameraAnimFrameDesc : BaseFrameDesc {
    float fFOV;
};

using CameraFrameArray = std::vector<CameraAnimFrameDesc>;

// ---------------------------------------------------------------------------
/** Represents a frame descriptor in a MD5Anim file
*/
struct FrameDesc {
    //! Index of the frame
    unsigned int iIndex;

    //! Animation keyframes - a large blob of data at first
    std::vector< float > mValues;
};

using FrameArray = std::vector<FrameDesc>;

// ---------------------------------------------------------------------------
/** Represents a vertex  descriptor in a MD5 file
*/
struct VertexDesc {
    VertexDesc() AI_NO_EXCEPT
            : mFirstWeight(0), mNumWeights(0) {
        // empty
    }

    //! UV coordinate of the vertex
    aiVector2D mUV;

    //! Index of the first weight of the vertex in
    //! the vertex weight list
    unsigned int mFirstWeight;

    //! Number of weights assigned to this vertex
    unsigned int mNumWeights;
};

using VertexArray = std::vector<VertexDesc>;

// ---------------------------------------------------------------------------
/** Represents a vertex weight descriptor in a MD5 file
*/
struct WeightDesc {
    //! Index of the bone to which this weight refers
    unsigned int mBone;

    //! The weight value
    float mWeight;

    //! The offset position of this weight
    // ! (in the coordinate system defined by the parent bone)
    aiVector3D vOffsetPosition;
};

using WeightArray = std::vector<WeightDesc>;
using FaceArray   = std::vector<aiFace>;

// ---------------------------------------------------------------------------
/** Represents a mesh in a MD5 file
*/
struct MeshDesc {
    //! Weights of the mesh
    WeightArray mWeights;

    //! Vertices of the mesh
    VertexArray mVertices;

    //! Faces of the mesh
    FaceArray mFaces;

    //! Name of the shader (=texture) to be assigned to the mesh
    aiString mShader;
};

using MeshArray = std::vector<MeshDesc>;

// ---------------------------------------------------------------------------
// Convert a quaternion to its usual representation
inline void ConvertQuaternion (const aiVector3D& in, aiQuaternion& out) {

    out.x = in.x;
    out.y = in.y;
    out.z = in.z;

    const float t = 1.0f - (in.x*in.x) - (in.y*in.y) - (in.z*in.z);

    if (t < 0.0f) {
        out.w = 0.0f;
    } else {
        out.w = std::sqrt (t);
    }

    // Assimp convention.
    out.w *= -1.f;
}

// ---------------------------------------------------------------------------
/** Parses the data sections of a MD5 mesh file
*/
class MD5MeshParser {
public:
    // -------------------------------------------------------------------
    /** Constructs a new MD5MeshParser instance from an existing
     *  preparsed list of file sections.
     *
     *  @param mSections List of file sections (output of MD5Parser)
     */
    explicit MD5MeshParser(SectionArray& mSections);

    //! List of all meshes
    MeshArray mMeshes;

    //! List of all joints
    BoneArray mJoints;
};

// remove this flag if you need to the bounding box data
#define AI_MD5_PARSE_NO_BOUNDS

// ---------------------------------------------------------------------------
/** Parses the data sections of a MD5 animation file
*/
class MD5AnimParser {
public:
    // -------------------------------------------------------------------
    /** Constructs a new MD5AnimParser instance from an existing
     *  preparsed list of file sections.
     *
     *  @param mSections List of file sections (output of MD5Parser)
     */
    explicit MD5AnimParser(SectionArray& mSections);


    //! Output frame rate
    float fFrameRate;

    //! List of animation bones
    AnimBoneArray mAnimatedBones;

    //! List of base frames
    BaseFrameArray mBaseFrames;

    //! List of animation frames
    FrameArray mFrames;

    //! Number of animated components
    unsigned int mNumAnimatedComponents;
};

// ---------------------------------------------------------------------------
/** Parses the data sections of a MD5 camera animation file
*/
class MD5CameraParser {
public:
    // -------------------------------------------------------------------
    /** Constructs a new MD5CameraParser instance from an existing
     *  preparsed list of file sections.
     *
     *  @param mSections List of file sections (output of MD5Parser)
     */
    explicit MD5CameraParser(SectionArray& mSections);

    //! Output frame rate
    float fFrameRate;

    //! List of cuts
    std::vector<unsigned int> cuts;

    //! Frames
    CameraFrameArray frames;
};

// ---------------------------------------------------------------------------
/** Parses the block structure of MD5MESH and MD5ANIM files (but does no
 *  further processing)
*/
class MD5Parser {
public:
    // -------------------------------------------------------------------
    /** Constructs a new MD5Parser instance from an existing buffer.
     *
     *  @param buffer File buffer
     *  @param fileSize Length of the file in bytes (excluding a terminal 0)
     */
    MD5Parser(char* buffer, unsigned int fileSize);

    // -------------------------------------------------------------------
    /** Report a specific error message and throw an exception
     *  @param error Error message to be reported
     *  @param line Index of the line where the error occurred
     */
    AI_WONT_RETURN static void ReportError(const char* error, unsigned int line) AI_WONT_RETURN_SUFFIX;

    // -------------------------------------------------------------------
    /** Report a specific warning
     *  @param warn Warn message to be reported
     *  @param line Index of the line where the error occurred
     */
    static void ReportWarning(const char* warn, unsigned int line);

    // -------------------------------------------------------------------
    /** Report a specific error
     *  @param error Error message to be reported
     */
    AI_WONT_RETURN void ReportError (const char* error) AI_WONT_RETURN_SUFFIX;

    // -------------------------------------------------------------------
    /** Report a specific warning
     *  @param error Warn message to be reported
     */
    void ReportWarning (const char* warn);

    //! List of all sections which have been read
    SectionArray mSections;

private:
    bool ParseSection(Section& out);
    void ParseHeader();
    bool SkipLine(const char* in, const char** out);
    bool SkipLine( );
    bool SkipSpacesAndLineEnd( const char* in, const char** out);
    bool SkipSpacesAndLineEnd();
    bool SkipSpaces();

private:
    char* buffer;
    const char* bufferEnd;
    unsigned int fileSize;
    unsigned int lineNumber;
};

// -------------------------------------------------------------------
inline void MD5Parser::ReportWarning (const char* warn) {
    return ReportWarning(warn, lineNumber);
}

// -------------------------------------------------------------------
inline void MD5Parser::ReportError(const char* error) {
    ReportError(error, lineNumber);
}

// -------------------------------------------------------------------
inline bool MD5Parser::SkipLine(const char* in, const char** out) {
    ++lineNumber;
    return Assimp::SkipLine(in, out, bufferEnd);
}

// -------------------------------------------------------------------
inline bool MD5Parser::SkipLine( ) {
    return SkipLine(buffer,(const char**)&buffer);
}

// -------------------------------------------------------------------
inline bool MD5Parser::SkipSpacesAndLineEnd( const char* in, const char** out) {
    if (in == bufferEnd) {
        *out = in;
        return false;
    }
    
    bool bHad = false, running = true;
    while (running) {
        if( *in == '\r' || *in == '\n') {
            // we open files in binary mode, so there could be \r\n sequences ...
            if (!bHad)  {
                bHad = true;
                ++lineNumber;
            }
        } else if (*in == '\t' || *in == ' ') {
            bHad = false;
        } else {
            break;
        }
        ++in;
        if (in == bufferEnd) {
            break;
        }
    }
    *out = in;
    return *in != '\0';
}

// -------------------------------------------------------------------
inline bool MD5Parser::SkipSpacesAndLineEnd() {
    return SkipSpacesAndLineEnd(buffer,(const char**)&buffer);
}

// -------------------------------------------------------------------
inline bool MD5Parser::SkipSpaces() {
    return Assimp::SkipSpaces((const char**)&buffer, bufferEnd);
}

} // namespace Assimp
} // namespace MD5

#endif // AI_MD5PARSER_H_INCLUDED