// Author: Kirill Gavrilov
// Copyright (c) 2015-2019 OPEN CASCADE SAS
//
// This file is part of Open CASCADE Technology software library.
//
// This library is free software; you can redistribute it and/or modify it under
// the terms of the GNU Lesser General Public License version 2.1 as published
// by the Free Software Foundation, with special exception defined in the file
// OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
// distribution for complete text of the license and disclaimer of any warranty.
//
// Alternatively, this file may be used under the terms of Open CASCADE
// commercial license or contractual agreement.

#ifndef _Image_Texture_HeaderFile
#define _Image_Texture_HeaderFile

#include <NCollection_Buffer.hxx>
#include <TCollection_AsciiString.hxx>

class Image_CompressedPixMap;
class Image_SupportedFormats;
class Image_PixMap;

//! Texture image definition.
//! The image can be stored as path to image file, as file path with the given offset and as a data buffer of encoded image.
class Image_Texture : public Standard_Transient
{
  DEFINE_STANDARD_RTTIEXT(Image_Texture, Standard_Transient)
public:

  //! Constructor pointing to file location.
  Standard_EXPORT explicit Image_Texture (const TCollection_AsciiString& theFileName);

  //! Constructor pointing to file part.
  Standard_EXPORT explicit Image_Texture (const TCollection_AsciiString& theFileName,
                                          int64_t theOffset,
                                          int64_t theLength);

  //! Constructor pointing to buffer.
  Standard_EXPORT explicit Image_Texture (const Handle(NCollection_Buffer)& theBuffer,
                                          const TCollection_AsciiString& theId);

  //! Return generated texture id.
  const TCollection_AsciiString& TextureId() const { return myTextureId; }

  //! Return image file path.
  const TCollection_AsciiString& FilePath() const { return myImagePath; }

  //! Return offset within file.
  int64_t FileOffset() const { return myOffset; }

  //! Return length of image data within the file after offset.
  int64_t FileLength() const { return myLength; }

  //! Return buffer holding encoded image content.
  const Handle(NCollection_Buffer)& DataBuffer() const { return myBuffer; }

  //! Return mime-type of image file based on ProbeImageFileFormat().
  Standard_EXPORT TCollection_AsciiString MimeType() const;

  //! Return image file format.
  Standard_EXPORT TCollection_AsciiString ProbeImageFileFormat() const;

  //! Image reader without decoding data for formats supported natively by GPUs.
  Standard_EXPORT virtual Handle(Image_CompressedPixMap) ReadCompressedImage (const Handle(Image_SupportedFormats)& theSupported) const;

  //! Image reader.
  Standard_EXPORT virtual Handle(Image_PixMap) ReadImage (const Handle(Image_SupportedFormats)& theSupported) const;

  //! Write image to specified file without decoding data.
  Standard_EXPORT virtual Standard_Boolean WriteImage (const TCollection_AsciiString& theFile);

  //! Write image to specified stream without decoding data.
  Standard_EXPORT virtual Standard_Boolean WriteImage (std::ostream& theStream,
                                                       const TCollection_AsciiString& theFile);

public: //! @name hasher interface
  
  //! Dumps the content of me into the stream
  Standard_EXPORT virtual void DumpJson (Standard_OStream& theOStream, Standard_Integer theDepth = -1) const;

protected:

  //! Read image from normal image file.
  Standard_EXPORT virtual Handle(Image_PixMap) loadImageFile (const TCollection_AsciiString& thePath) const;

  //! Read image from file with some offset.
  Standard_EXPORT virtual Handle(Image_PixMap) loadImageOffset (const TCollection_AsciiString& thePath,
                                                                int64_t theOffset,
                                                                int64_t theLength) const;

  //! Read image from buffer.
  Standard_EXPORT virtual Handle(Image_PixMap) loadImageBuffer (const Handle(NCollection_Buffer)& theBuffer,
                                                                const TCollection_AsciiString& theId) const;

protected:

  TCollection_AsciiString myTextureId; //!< generated texture id
  TCollection_AsciiString myImagePath; //!< image file path
  Handle(NCollection_Buffer) myBuffer; //!< image buffer
  int64_t                    myOffset; //!< offset within file
  int64_t                    myLength; //!< length within file

};

namespace std
{
  template<>
  struct equal_to<Handle(Image_Texture)>
  {
    bool operator()(const Handle(Image_Texture)& theTex1,
                    const Handle(Image_Texture)& theTex2) const
    {
      if (theTex1.IsNull() != theTex2.IsNull())
      {
        return Standard_False;
      }
      else if (theTex1.IsNull())
      {
        return Standard_True;
      }
      return theTex1->TextureId().IsEqual(theTex2->TextureId());
    }
  };

  template<>
  struct hash<Handle(Image_Texture)>
  {
    size_t operator()(const Handle(Image_Texture)& theTexture) const noexcept
    {
      return !theTexture.IsNull()
        ? std::hash<TCollection_AsciiString>{}(theTexture->TextureId())
        : 0;
    }
  };
}

#endif // _Image_Texture_HeaderFile