#pragma region CPL License
/*
Nuclex Native Framework
Copyright (C) 2002-2021 Nuclex Development Labs

This library is free software; you can redistribute it and/or
modify it under the terms of the IBM Common Public License as
published by the IBM Corporation; either version 1.0 of the
License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
IBM Common Public License for more details.

You should have received a copy of the IBM Common Public
License along with this library
*/
#pragma endregion // CPL License

#ifndef NUCLEX_PIXELS_STORAGE_WEBP_LIBWEBPHELPERS_H
#define NUCLEX_PIXELS_STORAGE_WEBP_LIBWEBPHELPERS_H

#include "Nuclex/Pixels/Config.h"

#if defined(NUCLEX_PIXELS_HAVE_LIBWEBP)

#include "Nuclex/Pixels/PixelFormat.h"
#include "Nuclex/Pixels/Storage/VirtualFile.h"

#include <cstdint> // for std::uint8_t
#include <string> // for std::string

#include <webp/decode.h> // for ::VP8StatusCode

namespace Nuclex { namespace Pixels { namespace Storage { namespace WebP {

  // ------------------------------------------------------------------------------------------- //

  /// <summary>Size of the smallest valid WebP file possible</summary>
  /// <remarks>
  ///   From https://github.com/mathiasbynens/small/blob/master/webp.webp
  /// </remarks>
  constexpr const std::size_t SmallestPossibleWebPSize = 26; // bytes

  // ------------------------------------------------------------------------------------------- //

  /// <summary>Helper class for reading WebP files using libwebp</summary>
  class Helpers {

    /// <summary>
    ///   Checks whether the first 16 bytes in a file are a valid WebP file header
    /// </summary>
    /// <param name="fileHeader">File header that will be checked</param>
    /// <returns>True if the file header is a valid WebP file header</returns>
    /// <remarks>
    ///   The file header must contain at least the first 13 bytes of the file,
    ///   otherwise this will segfault.
    /// </remarks>
    public: static bool IsValidWebPHeader(const std::uint8_t *fileHeader);

    /// <summary>Returns an error message according to a VP8 status code</summary>
    /// <param name="statusCode">Status code for which an error message will be provided</param>
    /// <returns>The error message for the specified status code</returns>
    public: static std::string GetErrorMessage(::VP8StatusCode statusCode);

  };

  // ------------------------------------------------------------------------------------------- //

}}}} // namespace Nuclex::Pixels::Storage::WebP

#endif // defined(NUCLEX_PIXELS_HAVE_LIBWEBP)

#endif // NUCLEX_PIXELS_STORAGE_WEBP_LIBWEBPHELPERS_H