// Copyright 2022 Google LLC

// SPDX-License-Identifier: BSD-2-Clause

#ifndef LIBAVIF_TESTS_OSS_FUZZ_AVIF_FUZZTEST_HELPERS_H_

#define LIBAVIF_TESTS_OSS_FUZZ_AVIF_FUZZTEST_HELPERS_H_

#include <cstdint>

#include <cstdlib>

#include <limits>

#include <type_traits>

#include <utility>

#include <vector>

#include "avif/avif.h"

#include "aviftest_helpers.h"

#include "avifutil.h"

#include "fuzztest/fuzztest.h"

#include "gtest/gtest.h"

namespace avif {

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

// Custom FuzzTest printer for libavif types. Needed to avoid compile-time

// errors due to structs with C-style array fields.

//

// These should reside in the same namespace as the types they print to enable

// Argument-Dependent Lookup (ADL).

// See https://github.com/google/fuzztest/blob/main/doc/domains-reference.md.

template <typename Sink, typename Ptr,

          typename = std::enable_if_t<std::is_same_v<Ptr, ImagePtr> ||

                                      std::is_same_v<Ptr, EncoderPtr> ||

                                      std::is_same_v<Ptr, DecoderPtr>>>

void FuzzTestPrintSourceCode(Sink& sink, const Ptr& ptr) {

  // Stub to avoid compile error for structs with C-style array fields.

  // Consider adding a useful source code representation here:

  //   `absl::Format(&sink, ...);`

}

namespace testutil {

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

// C++ wrapper for scoped memory management of C API objects.

// Exposed for convenient fuzztest reproducer output.

ImagePtr CreateAvifImage8b(size_t width, size_t height,

                           avifPixelFormat pixel_format, bool has_alpha,

                           const std::vector<uint8_t>& samples);

ImagePtr CreateAvifImage16b(size_t width, size_t height, int depth,

                            avifPixelFormat pixel_format, bool has_alpha,

                            const std::vector<uint16_t>& samples);

std::vector<ImagePtr> CreateAvifAnim8b(size_t num_frames, size_t width,

                                       size_t height,

                                       avifPixelFormat pixel_format,

                                       bool has_alpha,

                                       const std::vector<uint8_t>& samples);

std::vector<ImagePtr> CreateAvifAnim16b(size_t num_frames, size_t width,

                                        size_t height, int depth,

                                        avifPixelFormat pixel_format,

                                        bool has_alpha,

                                        const std::vector<uint16_t>& samples);

EncoderPtr CreateAvifEncoder(avifCodecChoice codec_choice, int max_threads,

                             int min_quantizer, int max_quantizer,

                             int min_quantizer_alpha, int max_quantizer_alpha,

                             int tile_rows_log2, int tile_cols_log2, int speed);

DecoderPtr CreateAvifDecoder(avifCodecChoice codec_choice, int max_threads,

                             avifDecoderSource requested_source,

                             bool allow_progressive, bool allow_incremental,

                             bool ignore_exif, bool ignore_xmp,

                             uint32_t image_size_limit,

                             uint32_t image_dimension_limit,

                             uint32_t image_count_limit,

                             avifStrictFlags strict_flags);

DecoderPtr AddGainMapOptionsToDecoder(

    DecoderPtr decoder, avifImageContentTypeFlags image_content_to_decode);

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

// Custom fuzztest generators.

// See https://github.com/google/fuzztest/blob/main/doc/domains-reference.md.

// Do not generate images wider or taller than this.

inline constexpr size_t kMaxDimension = 512;  // In pixels.

// Used to reduce kMaxDimension to keep the same complexity as a still image.

inline constexpr size_t kMaxNumFramesSquareRoot = 2;

// Do not generate animations with more than this number of frames.

inline constexpr size_t kMaxNumFrames =

    kMaxNumFramesSquareRoot * kMaxNumFramesSquareRoot;

size_t GetNumSamples(size_t num_frames, size_t width, size_t height,

                     avifPixelFormat pixel_format, bool has_alpha);

// To avoid using fuzztest::internal, the return type of the functions below is

// auto.

inline auto ArbitraryPixelFormat() {

  return fuzztest::ElementOf<avifPixelFormat>(

      {AVIF_PIXEL_FORMAT_YUV444, AVIF_PIXEL_FORMAT_YUV422,

       AVIF_PIXEL_FORMAT_YUV420, AVIF_PIXEL_FORMAT_YUV400});

}

// avifImage generator type: Width, height, pixel format and 8-bit samples.

inline auto ArbitraryAvifImage8b() {

  return fuzztest::FlatMap(

      [](size_t width, size_t height, avifPixelFormat pixel_format,

         bool has_alpha) {

        return fuzztest::Map(

            CreateAvifImage8b, fuzztest::Just(width), fuzztest::Just(height),

            fuzztest::Just(pixel_format), fuzztest::Just(has_alpha),

            fuzztest::Arbitrary<std::vector<uint8_t>>().WithSize(GetNumSamples(

                /*num_frames=*/1, width, height, pixel_format, has_alpha)));

      },

      fuzztest::InRange<uint16_t>(1, kMaxDimension),

      fuzztest::InRange<uint16_t>(1, kMaxDimension), ArbitraryPixelFormat(),

      fuzztest::Arbitrary<bool>());

}

// avifImage generator type: Width, height, depth, pixel format and 16-bit

// samples.

inline auto ArbitraryAvifImage16b() {

  return fuzztest::FlatMap(

      [](size_t width, size_t height, int depth, avifPixelFormat pixel_format,

         bool has_alpha) {

        return fuzztest::Map(

            CreateAvifImage16b, fuzztest::Just(width), fuzztest::Just(height),

            fuzztest::Just(depth), fuzztest::Just(pixel_format),

            fuzztest::Just(has_alpha),

            fuzztest::ContainerOf<std::vector<uint16_t>>(

                fuzztest::InRange<uint16_t>(0, (1 << depth) - 1))

                .WithSize(GetNumSamples(/*num_frames=*/1, width, height,

                                        pixel_format, has_alpha)));

      },

      fuzztest::InRange<uint16_t>(1, kMaxDimension),

      fuzztest::InRange<uint16_t>(1, kMaxDimension),

      fuzztest::ElementOf({10, 12}), ArbitraryPixelFormat(),

      fuzztest::Arbitrary<bool>());

}

// avifImage generator type: Number of frames, width, height, pixel format and

// 8-bit samples.

inline auto ArbitraryAvifAnim8b() {

  return fuzztest::FlatMap(

      [](size_t num_frames, size_t width, size_t height,

         avifPixelFormat pixel_format, bool has_alpha) {

        return fuzztest::Map(

            CreateAvifAnim8b, fuzztest::Just(num_frames), fuzztest::Just(width),

            fuzztest::Just(height), fuzztest::Just(pixel_format),

            fuzztest::Just(has_alpha),

            fuzztest::Arbitrary<std::vector<uint8_t>>().WithSize(GetNumSamples(

                num_frames, width, height, pixel_format, has_alpha)));

      },

      fuzztest::InRange<uint16_t>(1, kMaxNumFrames),

      fuzztest::InRange<uint16_t>(1, kMaxDimension / kMaxNumFramesSquareRoot),

      fuzztest::InRange<uint16_t>(1, kMaxDimension / kMaxNumFramesSquareRoot),

      ArbitraryPixelFormat(), fuzztest::Arbitrary<bool>());

}

// avifImage generator type: Number of frames, width, height, depth, pixel

// format and 16-bit samples.

inline auto ArbitraryAvifAnim16b() {

  return fuzztest::FlatMap(

      [](size_t num_frames, size_t width, size_t height, int depth,

         avifPixelFormat pixel_format, bool has_alpha) {

        return fuzztest::Map(

            CreateAvifAnim16b, fuzztest::Just(num_frames),

            fuzztest::Just(width), fuzztest::Just(height),

            fuzztest::Just(depth), fuzztest::Just(pixel_format),

            fuzztest::Just(has_alpha),

            fuzztest::ContainerOf<std::vector<uint16_t>>(

                fuzztest::InRange<uint16_t>(0, (1 << depth) - 1))

                .WithSize(GetNumSamples(num_frames, width, height, pixel_format,

                                        has_alpha)));

      },

      fuzztest::InRange<uint16_t>(1, kMaxNumFrames),

      fuzztest::InRange<uint16_t>(1, kMaxDimension / kMaxNumFramesSquareRoot),

      fuzztest::InRange<uint16_t>(1, kMaxDimension / kMaxNumFramesSquareRoot),

      fuzztest::ElementOf({10, 12}), ArbitraryPixelFormat(),

      fuzztest::Arbitrary<bool>());

}

// Generator for an arbitrary ImagePtr.

inline auto ArbitraryAvifImage() {

  return fuzztest::OneOf(ArbitraryAvifImage8b(), ArbitraryAvifImage16b());

}

// Generator for an arbitrary std::vector<ImagePtr>.

inline auto ArbitraryAvifAnim() {

  return fuzztest::OneOf(ArbitraryAvifAnim8b(), ArbitraryAvifAnim16b());

}

// Generates two signed fractions where the first one is smaller than or equal

// to the second one.

inline auto ArbitraryMinMaxSignedFraction() {

  return fuzztest::FlatMap(

      [](int32_t max_n, uint32_t max_d) {

        return fuzztest::Map(

            [max_n, max_d](int32_t min_n) {

              // For simplicity, use the same denominator for both fractions.

              // This does not cover all possible fractions but makes it easy

              // to guarantee that the first fraction is smaller.

              return std::pair<avifSignedFraction, avifSignedFraction>(

                  {min_n, max_d}, {max_n, max_d});

            },

            fuzztest::InRange<int32_t>(std::numeric_limits<int32_t>::min(),

                                       max_n));

      },

      fuzztest::Arbitrary<int32_t>(), fuzztest::NonZero<uint32_t>());

}

ImagePtr AddGainMapToImage(

    ImagePtr image, ImagePtr gain_map,

    const std::pair<avifSignedFraction, avifSignedFraction>& gain_map_min_max0,

    const std::pair<avifSignedFraction, avifSignedFraction>& gain_map_min_max1,

    const std::pair<avifSignedFraction, avifSignedFraction>& gain_map_min_max2,

    uint32_t gain_map_gamma_n0, uint32_t gain_map_gamma_n1,

    uint32_t gain_map_gamma_n2, uint32_t gain_map_gamma_d0,

    uint32_t gain_map_gamma_d1, uint32_t gain_map_gamma_d2,

    int32_t base_offset_n0, int32_t base_offset_n1, int32_t base_offset_n2,

    uint32_t base_offset_d0, uint32_t base_offset_d1, uint32_t base_offset_d2,

    int32_t alternate_offset_n0, int32_t alternate_offset_n1,

    int32_t alternate_offset_n2, uint32_t alternate_offset_d0,

    uint32_t alternate_offset_d1, uint32_t alternate_offset_d2,

    uint32_t base_hdr_headroom_n, uint32_t base_hdr_headroom_d,

    uint32_t alternate_hdr_headroom_n, uint32_t alternate_hdr_headroom_d,

    bool use_base_color_space);

inline auto ArbitraryAvifImageWithGainMap() {

  return fuzztest::Map(

      AddGainMapToImage, ArbitraryAvifImage(),

      /*gain_map=*/ArbitraryAvifImage(),

      /*gain_map_min_max0=*/ArbitraryMinMaxSignedFraction(),

      /*gain_map_min_max1=*/ArbitraryMinMaxSignedFraction(),

      /*gain_map_min_max2=*/ArbitraryMinMaxSignedFraction(),

      /*gain_map_gamma_n0=*/fuzztest::NonZero<uint32_t>(),

      /*gain_map_gamma_n1=*/fuzztest::NonZero<uint32_t>(),

      /*gain_map_gamma_n2=*/fuzztest::NonZero<uint32_t>(),

      /*gain_map_gamma_d0=*/fuzztest::NonZero<uint32_t>(),

      /*gain_map_gamma_d1=*/fuzztest::NonZero<uint32_t>(),

      /*gain_map_gamma_d2=*/fuzztest::NonZero<uint32_t>(),

      /*base_offset_n0=*/fuzztest::Arbitrary<int32_t>(),

      /*base_offset_n1=*/fuzztest::Arbitrary<int32_t>(),

      /*base_offset_n2=*/fuzztest::Arbitrary<int32_t>(),

      /*base_offset_d0=*/fuzztest::NonZero<uint32_t>(),

      /*base_offset_d1=*/fuzztest::NonZero<uint32_t>(),

      /*base_offset_d2=*/fuzztest::NonZero<uint32_t>(),

      /*alternate_offset_n0=*/fuzztest::Arbitrary<int32_t>(),

      /*alternate_offset_n1=*/fuzztest::Arbitrary<int32_t>(),

      /*alternate_offset_n2=*/fuzztest::Arbitrary<int32_t>(),

      /*alternate_offset_d0=*/fuzztest::NonZero<uint32_t>(),

      /*alternate_offset_d1=*/fuzztest::NonZero<uint32_t>(),

      /*alternate_offset_d2=*/fuzztest::NonZero<uint32_t>(),

      /*base_hdr_headroom_n=*/fuzztest::Arbitrary<uint32_t>(),

      /*base_hdr_headroom_d=*/fuzztest::NonZero<uint32_t>(),

      /*alternate_hdr_headroom_n=*/fuzztest::Arbitrary<uint32_t>(),

      /*alternate_hdr_headroom_d=*/fuzztest::NonZero<uint32_t>(),

      /*use_base_color_space=*/fuzztest::Arbitrary<bool>());

}

// Generator for an arbitrary EncoderPtr.

inline auto ArbitraryAvifEncoder() {

  const auto codec_choice = fuzztest::ElementOf<avifCodecChoice>(

      {AVIF_CODEC_CHOICE_AUTO, AVIF_CODEC_CHOICE_AOM});

  // MAX_NUM_THREADS from libaom/aom_util/aom_thread.h

  const auto max_threads = fuzztest::InRange(0, 64);

  const auto min_quantizer = fuzztest::InRange(AVIF_QUANTIZER_BEST_QUALITY,

                                               AVIF_QUANTIZER_WORST_QUALITY);

  const auto max_quantizer = fuzztest::InRange(AVIF_QUANTIZER_BEST_QUALITY,

                                               AVIF_QUANTIZER_WORST_QUALITY);

  const auto min_quantizer_alpha = fuzztest::InRange(

      AVIF_QUANTIZER_BEST_QUALITY, AVIF_QUANTIZER_WORST_QUALITY);

  const auto max_quantizer_alpha = fuzztest::InRange(

      AVIF_QUANTIZER_BEST_QUALITY, AVIF_QUANTIZER_WORST_QUALITY);

  const auto tile_rows_log2 = fuzztest::InRange(0, 6);

  const auto tile_cols_log2 = fuzztest::InRange(0, 6);

  // Fuzz only a small range of 'speed' values to avoid slowing down the fuzzer

  // too much. The main goal is to fuzz libavif, not the underlying AV1 encoder.

  const auto speed = fuzztest::InRange(6, AVIF_SPEED_FASTEST);

  return fuzztest::Map(CreateAvifEncoder, codec_choice, max_threads,

                       min_quantizer, max_quantizer, min_quantizer_alpha,

                       max_quantizer_alpha, tile_rows_log2, tile_cols_log2,

                       speed);

}

// Generator for an arbitrary DecoderPtr with base options fuzzed (i.e.

// without "experimental" options hidden behind compile flags).

inline auto ArbitraryBaseAvifDecoder() {

  // MAX_NUM_THREADS from libaom/aom_util/aom_thread.h

  const auto max_threads = fuzztest::InRange(0, 64);

  return fuzztest::Map(

      CreateAvifDecoder,

      fuzztest::ElementOf<avifCodecChoice>({AVIF_CODEC_CHOICE_AUTO,

                                            AVIF_CODEC_CHOICE_AOM,

                                            AVIF_CODEC_CHOICE_DAV1D}),

      max_threads,

      /*requested_source=*/

      fuzztest::ElementOf(

          {AVIF_DECODER_SOURCE_AUTO, AVIF_DECODER_SOURCE_PRIMARY_ITEM}),

      /*allow_progressive=*/fuzztest::Arbitrary<bool>(),

      /*allow_incremental=*/fuzztest::Arbitrary<bool>(),

      /*ignore_exif=*/fuzztest::Arbitrary<bool>(),

      /*ignore_xmp=*/fuzztest::Arbitrary<bool>(),

      /*image_size_limit=*/fuzztest::Just(kMaxDimension * kMaxDimension),

      /*image_dimension_limit=*/fuzztest::Just(kMaxDimension),

      /*image_count_limit=*/fuzztest::Just(10),

      /*strict_flags=*/

      fuzztest::BitFlagCombinationOf<avifStrictFlags>(

          {AVIF_STRICT_PIXI_REQUIRED, AVIF_STRICT_CLAP_VALID,

           AVIF_STRICT_ALPHA_ISPE_REQUIRED}));

}

// Generator for an arbitrary DecoderPtr with base options and gain map

// options fuzzed.

inline auto ArbitraryAvifDecoderWithGainMapOptions() {

  // Always decode at least color+alpha, since most tests

  // assume that if the file/buffer is successfully decoded.

  return fuzztest::Map(

      AddGainMapOptionsToDecoder, ArbitraryBaseAvifDecoder(),

      fuzztest::ElementOf<avifImageContentTypeFlags>(

          {AVIF_IMAGE_CONTENT_COLOR_AND_ALPHA,

           AVIF_IMAGE_CONTENT_COLOR_AND_ALPHA | AVIF_IMAGE_CONTENT_GAIN_MAP,

           AVIF_IMAGE_CONTENT_COLOR_AND_ALPHA |

               AVIF_IMAGE_CONTENT_SAMPLE_TRANSFORMS,

           AVIF_IMAGE_CONTENT_COLOR_AND_ALPHA | AVIF_IMAGE_CONTENT_GAIN_MAP |

               AVIF_IMAGE_CONTENT_SAMPLE_TRANSFORMS}));

}

// Generator for an arbitrary DecoderPtr.

inline auto ArbitraryAvifDecoder() {

  return ArbitraryAvifDecoderWithGainMapOptions();

}

// Same as ArbitraryAvifDecoder() but imageContentToDecode can be set to

// AVIF_IMAGE_CONTENT_NONE.

inline auto ArbitraryAvifDecoderPossiblyNoContent() {

  return fuzztest::Map(

      AddGainMapOptionsToDecoder, ArbitraryBaseAvifDecoder(),

      fuzztest::BitFlagCombinationOf<avifImageContentTypeFlags>(

          {AVIF_IMAGE_CONTENT_COLOR_AND_ALPHA, AVIF_IMAGE_CONTENT_GAIN_MAP}));

}

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

// Returns the paths contained in the 'TEST_DATA_DIRS' environment variable.

// Several paths can be set in the variable, separated by ';'.

// Returns nullptr if not set.

// Tests that use ArbitraryImageWithSeeds() should

// ASSERT_FALSE(GetSeedDataDirs().empty()) if they want to make sure that seeds

// are actually used.

std::vector<std::string> GetSeedDataDirs();

// Returns a list of test images contents (not paths) from the directory set in

// the 'TEST_DATA_DIRS' environment variable, that are smaller than

// 'max_file_size' and have one of the formats in 'image_formats' (or any format

// if 'image_formats' is empty).

// If TEST_DATA_DIRS is not set, returns an empty set.

// Tests that use this should ASSERT_FALSE(GetSeedDataDirs().empty())

// if they want to make sure that seeds are actually used.

// Terminates the program with abort() if TEST_DATA_DIRS is set but doesn't

// contain any matching images.

std::vector<std::string> GetTestImagesContents(

    size_t max_file_size, const std::vector<avifAppFileFormat>& image_formats);

// Generator for an arbitrary ImagePtr that uses test image files as seeds.

// Uses the 'TEST_DATA_DIRS' environment variable to load the seeds.

// If TEST_DATA_DIRS is not set, no seeds are used.

// Tests that use this should ASSERT_FALSE(GetSeedDataDirs().empty())

// if they want to make sure that seeds are actually used.

// Terminates the program with abort() if TEST_DATA_DIRS is set but doesn't

// contain any matching images.

inline auto ArbitraryImageWithSeeds(

    const std::vector<avifAppFileFormat>& image_formats) {

  constexpr uint32_t kMaxSeedFileSize = 1024 * 1024;  // 1MB.

  return fuzztest::Arbitrary<std::string>()

      .WithMaxSize(kMaxSeedFileSize)

      .WithSeeds(GetTestImagesContents(kMaxSeedFileSize, image_formats));

}

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

}  // namespace testutil

}  // namespace avif

#endif  // LIBAVIF_TESTS_OSS_FUZZ_AVIF_FUZZTEST_HELPERS_H_