/*
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
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* Neither the name of the assimp team, nor the names of its
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*/

/** @file ColladaExporter.h
 * Declares the exporter class to write a scene to a Collada file
 */
#ifndef AI_COLLADAEXPORTER_H_INC
#define AI_COLLADAEXPORTER_H_INC

#include <assimp/ai_assert.h>
#include <assimp/material.h>
#include <assimp/mesh.h>
#include <assimp/light.h>
#include <assimp/Exporter.hpp>
#include <sstream>
#include <vector>
#include <map>

#include "StringUtils.h"

struct aiScene;
struct aiNode;

namespace Assimp
{

/// Helper class to export a given scene to a Collada file. Just for my personal
/// comfort when implementing it.
class ColladaExporter
{
public:
    /// Constructor for a specific scene to export
    ColladaExporter( const aiScene* pScene, IOSystem* pIOSystem, const std::string& path, const std::string& file);

    /// Destructor
    virtual ~ColladaExporter();

protected:
    /// Starts writing the contents
    void WriteFile();

    /// Writes the asset header
    void WriteHeader();

    /// Writes the embedded textures
    void WriteTextures();

    /// Writes the material setup
    void WriteMaterials();

    /// Writes the cameras library
    void WriteCamerasLibrary();

    // Write a camera entry
    void WriteCamera(size_t pIndex);

    /// Writes the cameras library
    void WriteLightsLibrary();

    // Write a camera entry
    void WriteLight(size_t pIndex);
    void WritePointLight(const aiLight *const light);
    void WriteDirectionalLight(const aiLight *const light);
    void WriteSpotLight(const aiLight *const light);
    void WriteAmbienttLight(const aiLight *const light);

    /// Writes the geometry library
    void WriteGeometryLibrary();

    /// Writes the given mesh
    void WriteGeometry( size_t pIndex);

    enum FloatDataType { FloatType_Vector, FloatType_TexCoord2, FloatType_TexCoord3, FloatType_Color };

    /// Writes a float array of the given type
    void WriteFloatArray( const std::string& pIdString, FloatDataType pType, const ai_real* pData, size_t pElementCount);

    /// Writes the scene library
    void WriteSceneLibrary();

    /// Recursively writes the given node
    void WriteNode( const aiScene* scene, aiNode* pNode);

    /// Enters a new xml element, which increases the indentation
    void PushTag() { startstr.append( "  "); }
    /// Leaves an element, decreasing the indentation
    void PopTag() { ai_assert( startstr.length() > 1); startstr.erase( startstr.length() - 2); }

    /// Creates a mesh ID for the given mesh
    std::string GetMeshId( size_t pIndex) const {
        return std::string( "meshId" ) + to_string(pIndex);
    }

public:
    /// Stringstream to write all output into
    std::stringstream mOutput;

protected:
    /// The IOSystem for output
    IOSystem* mIOSystem;

    /// Path of the directory where the scene will be exported
    const std::string mPath;

    /// Name of the file (without extension) where the scene will be exported
    const std::string mFile;

    /// The scene to be written
    const aiScene* mScene;
    bool mSceneOwned;

    /// current line start string, contains the current indentation for simple stream insertion
    std::string startstr;
    /// current line end string for simple stream insertion
    std::string endstr;

  // pair of color and texture - texture precedences color
  struct Surface
  {
    bool exist;
    aiColor4D color;
    std::string texture;
    size_t channel;
    Surface() { exist = false; channel = 0; }
  };

  struct Property
  {
    bool exist;
     ai_real value;
     Property()
         : exist(false)
         , value(0.0)
     {}
  };

  // summarize a material in an convinient way.
  struct Material
  {
    std::string name;
    std::string shading_model;
    Surface ambient, diffuse, specular, emissive, reflective, transparent, normal;
    Property shininess, transparency, index_refraction;

    Material() {}
  };

  std::vector<Material> materials;

  std::map<unsigned int, std::string> textures;

protected:
  /// Dammit C++ - y u no compile two-pass? No I have to add all methods below the struct definitions
  /// Reads a single surface entry from the given material keys
  void ReadMaterialSurface( Surface& poSurface, const aiMaterial* pSrcMat, aiTextureType pTexture, const char* pKey, size_t pType, size_t pIndex);
  /// Writes an image entry for the given surface
  void WriteImageEntry( const Surface& pSurface, const std::string& pNameAdd);
  /// Writes the two parameters necessary for referencing a texture in an effect entry
  void WriteTextureParamEntry( const Surface& pSurface, const std::string& pTypeName, const std::string& pMatName);
  /// Writes a color-or-texture entry into an effect definition
  void WriteTextureColorEntry( const Surface& pSurface, const std::string& pTypeName, const std::string& pImageName);
  /// Writes a scalar property
  void WriteFloatEntry( const Property& pProperty, const std::string& pTypeName);
};

}

#endif // !! AI_COLLADAEXPORTER_H_INC