// Copyright 2026 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//

#include "jumbf/internal/consume_box.h"

#include <cstddef>
#include <cstdint>
#include <cstring>
#include <string>

#include "absl/status/status.h"
#include "absl/status/status_matchers.h"
#include "absl/strings/str_cat.h"
#include "absl/strings/string_view.h"
#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include "jumbf/internal/intermediate.h"
#include "jumbf/test_utils.h"
#include "riegeli/endian/endian_writing.h"

namespace jumbf_internal {
namespace {

using ::absl_testing::IsOkAndHolds;
using ::absl_testing::StatusIs;
using ::jumbf::WrapBox;
using ::testing::Eq;
using ::testing::HasSubstr;
using ::testing::IsEmpty;

TEST(ConsumeBoxTest, ConsumeSuccessfulExtraData) {
  constexpr absl::string_view kExtraData = R"(this is not JUMBF data)";
  constexpr absl::string_view kPayload = R"(this is the box's payload)";

  const std::string buffer = absl::StrCat(WrapBox(kPayload, 1234), kExtraData);
  absl::string_view input = buffer;

  EXPECT_THAT(ConsumeBox(&input, /*allow_implicit_length=*/true),
              IsOkAndHolds(IntermediateBox{
                  .payload = kPayload,
                  .serialized = buffer.substr(0, kPayload.size() + 8),
                  .type = 1234,
              }));
  EXPECT_THAT(input, Eq(kExtraData));
}

TEST(ConsumeBoxTest, ConsumeSuccessfulTwoBoxes) {
  constexpr absl::string_view kFirstPayload =
      R"(this is the first box's payload)";
  constexpr absl::string_view kSecondPayload =
      R"(this is the second box's payload)";

  const std::string buffer =
      absl::StrCat(WrapBox(kFirstPayload, 1234), WrapBox(kSecondPayload, 5678));
  absl::string_view input = buffer;

  size_t first_box_size = kFirstPayload.size() + 8;
  size_t second_box_size = kSecondPayload.size() + 8;

  EXPECT_THAT(ConsumeBox(&input, /*allow_implicit_length=*/true),
              IsOkAndHolds(IntermediateBox{
                  .payload = kFirstPayload,
                  .serialized = buffer.substr(0, first_box_size),
                  .type = 1234,
              }));
  EXPECT_THAT(ConsumeBox(&input, /*allow_implicit_length=*/true),
              IsOkAndHolds(IntermediateBox{
                  .payload = kSecondPayload,
                  .serialized = buffer.substr(first_box_size, second_box_size),
                  .type = 5678,
              }));
  EXPECT_THAT(input, IsEmpty());
}

TEST(ConsumeBoxTest, ConsumeSuccessful) {
  constexpr absl::string_view kPayload = R"(this is the box's payload)";

  const std::string buffer = WrapBox(kPayload, 1234);
  absl::string_view input = buffer;

  EXPECT_THAT(ConsumeBox(&input, /*allow_implicit_length=*/true),
              IsOkAndHolds(IntermediateBox{
                  .payload = kPayload, .serialized = buffer, .type = 1234}));
  EXPECT_THAT(input, IsEmpty());
}

TEST(ConsumeBoxTest, EmptyInputFails) {
  absl::string_view input = "";

  EXPECT_THAT(ConsumeBox(&input, /*allow_implicit_length=*/true),
              StatusIs(absl::StatusCode::kOutOfRange,
                       "cannot read LBox value: not enough input bytes "
                       "remaining; have 0 need 4"));
  EXPECT_THAT(input, IsEmpty());
}

TEST(ConsumeBoxTest, SizeTooLargeFails) {
  constexpr absl::string_view kPayload = R"(this is the box's payload)";

  std::string buffer = WrapBox(kPayload, 1234);
  char* buffer_data = buffer.data();
  // Overwrite size with too large of  value
  riegeli::WriteBigEndian<uint32_t>(5280, buffer_data);
  buffer_data += sizeof(uint32_t);
  absl::string_view input = buffer;

  EXPECT_THAT(ConsumeBox(&input, /*allow_implicit_length=*/true),
              StatusIs(absl::StatusCode::kInvalidArgument,
                       "not enough input bytes for declared box size; have 33 "
                       "input bytes, box declares its size as 5280 bytes"));
  EXPECT_THAT(input, Eq(buffer));
}

TEST(ConsumeBoxTest, XlBoxSizeSmallPayloadSucceeds) {
  // Small payload, could have fit without using XLBox but the standard never
  // states a minimum size to use XLBox.
  constexpr absl::string_view kFakePayload = "some random data blah blah";
  constexpr uint32_t kLBox = 1;
  constexpr uint32_t kTBox = 12345;
  constexpr uint64_t kXlBox =
      /*LBox*/ 4 + /*TBox*/ 4 + /*XLBox*/ 8 + kFakePayload.length();

  std::string buffer(kXlBox, 'X');
  char* cursor = buffer.data();

  riegeli::WriteBigEndian<uint32_t>(kLBox, cursor);
  cursor += sizeof(uint32_t);
  riegeli::WriteBigEndian<uint32_t>(kTBox, cursor);
  cursor += sizeof(uint32_t);
  riegeli::WriteBigEndian<uint64_t>(kXlBox, cursor);
  cursor += sizeof(uint64_t);
  // Safe because size of string was computed to be large enough for
  // kFakePayload above.
  memcpy(cursor, kFakePayload.data(), kFakePayload.size());

  absl::string_view input = buffer;

  EXPECT_THAT(ConsumeBox(&input, /*allow_implicit_length=*/true),
              IsOkAndHolds(IntermediateBox{
                  .payload = kFakePayload,
                  .serialized = buffer,
                  .type = kTBox,
                  .implicit_length = false,
              }));
  EXPECT_THAT(input, IsEmpty());
}

TEST(ConsumeBoxTest, XlBoxSizeLargePayloadSucceeds) {
  // Large payload, could not have fit without using XLBox.
  const std::string payload(5'000'000'000, 'X');
  constexpr uint32_t kLBox = 1;
  constexpr uint32_t kTBox = 12345;
  const uint64_t XlBox =
      /*LBox=*/4 + /*TBox=*/4 + /*XLBox=*/8 + payload.length();

  std::string buffer(XlBox, 'X');
  char* cursor = buffer.data();

  riegeli::WriteBigEndian<uint32_t>(kLBox, cursor);
  cursor += sizeof(uint32_t);
  riegeli::WriteBigEndian<uint32_t>(kTBox, cursor);
  cursor += sizeof(uint32_t);
  riegeli::WriteBigEndian<uint64_t>(XlBox, cursor);
  cursor += sizeof(uint64_t);
  // Safe because size of string was computed to be large enough for
  // kFakePayload above.
  memcpy(cursor, payload.data(), payload.size());

  absl::string_view input = buffer;

  EXPECT_THAT(ConsumeBox(&input, /*allow_implicit_length=*/true),
              IsOkAndHolds(IntermediateBox{
                  .payload = payload,
                  .serialized = buffer,
                  .type = kTBox,
                  .implicit_length = false,
              }));
  EXPECT_THAT(input, IsEmpty());
}

TEST(ConsumeBoxTest, XlBoxSizeTooLargeFails) {
  constexpr absl::string_view kFakePayload = "some random data blah blah";
  constexpr uint32_t kLBox = 1;
  constexpr uint32_t kTBox = 12345;
  constexpr uint64_t kXlBox = 8008888888;

  std::string buffer(
      /*LBox=*/4 + /*XLBox=*/8 + /*TBox=*/4 + kFakePayload.length(), 'X');
  char* cursor = buffer.data();

  riegeli::WriteBigEndian<uint32_t>(kLBox, cursor);
  cursor += sizeof(uint32_t);
  riegeli::WriteBigEndian<uint32_t>(kTBox, cursor);
  cursor += sizeof(uint32_t);
  riegeli::WriteBigEndian<uint64_t>(kXlBox, cursor);
  cursor += sizeof(uint64_t);
  // Safe because size of string was computed to be large enough for
  // kFakePayload above.
  memcpy(cursor, kFakePayload.data(), kFakePayload.size());

  absl::string_view input = buffer;

  EXPECT_THAT(
      ConsumeBox(&input, /*allow_implicit_length=*/true),
      StatusIs(absl::StatusCode::kInvalidArgument,
               "not enough input bytes for declared box size; have 42 "
               "input bytes, box declares its size as 8008888888 bytes"));
  EXPECT_THAT(input, Eq(buffer));
}

TEST(ConsumeBoxTest, XlBoxSizeTooSmallFails) {
  constexpr absl::string_view kFakePayload = "some random data blah blah";
  constexpr uint32_t kLBox = 1;
  constexpr uint32_t kTBox = 12345;
  constexpr uint64_t kXlBox = 2;

  std::string buffer(
      /*LBox=*/4 + /*XLBox=*/8 + /*TBox=*/4 + kFakePayload.length(), 'X');
  char* cursor = buffer.data();

  riegeli::WriteBigEndian<uint32_t>(kLBox, cursor);
  cursor += sizeof(uint32_t);
  riegeli::WriteBigEndian<uint32_t>(kTBox, cursor);
  cursor += sizeof(uint32_t);
  riegeli::WriteBigEndian<uint64_t>(kXlBox, cursor);
  cursor += sizeof(uint64_t);
  // Safe because size of string was computed to be large enough for
  // kFakePayload above.
  memcpy(cursor, kFakePayload.data(), kFakePayload.size());

  absl::string_view input = buffer;

  EXPECT_THAT(ConsumeBox(&input, /*allow_implicit_length=*/true),
              StatusIs(absl::StatusCode::kInvalidArgument,
                       "XLBox is 2, which is less than the number of bytes "
                       "already consumed by this box's header"));
  EXPECT_THAT(input, Eq(buffer));
}

TEST(ConsumeBoxTest, ReservedBoxLengthFails) {
  constexpr uint32_t kLBox = 5;
  constexpr uint32_t kTBox = 12345;

  std::string buffer(8, 'A');
  char* cursor = buffer.data();

  riegeli::WriteBigEndian<uint32_t>(kLBox, cursor);
  cursor += sizeof(uint32_t);
  riegeli::WriteBigEndian<uint32_t>(kTBox, cursor);
  cursor += sizeof(uint32_t);

  absl::string_view input = buffer;

  EXPECT_THAT(
      ConsumeBox(&input, /*allow_implicit_length=*/true),
      StatusIs(absl::StatusCode::kInvalidArgument,
               "LBox is 5; LBox values 2-7 are reserved by the standard"));
  EXPECT_THAT(input, Eq(buffer));
}

TEST(ConsumeBoxTest, ZeroBoxLengthSucceedsWhenPermitted) {
  constexpr uint32_t kLBox = 0;
  constexpr uint32_t kTBox = 12345;
  constexpr absl::string_view kContent =
      R"(blah blah blah blah when will I stop writing? I don't know so you won't know until you reach the end because the box length is 0 okay now I'm done bye)";

  std::string buffer(8 + kContent.length(), '\0');
  char* cursor = buffer.data();

  riegeli::WriteBigEndian<uint32_t>(kLBox, cursor);
  cursor += sizeof(uint32_t);
  riegeli::WriteBigEndian<uint32_t>(kTBox, cursor);
  cursor += sizeof(uint32_t);
  memcpy(cursor, kContent.data(), kContent.size());

  absl::string_view input = buffer;

  EXPECT_THAT(ConsumeBox(&input, /*allow_implicit_length=*/true),
              IsOkAndHolds(IntermediateBox{
                  .payload = kContent,
                  .serialized = buffer,
                  .type = kTBox,
                  .implicit_length = true,
              }));
  EXPECT_THAT(input, IsEmpty());
}

TEST(ConsumeBoxTest, ZeroBoxLengthFailsWhenNotPermitted) {
  constexpr uint32_t kLBox = 0;
  constexpr uint32_t kTBox = 12345;

  std::string buffer(8, '\0');
  char* cursor = buffer.data();

  riegeli::WriteBigEndian<uint32_t>(kLBox, cursor);
  cursor += sizeof(uint32_t);
  riegeli::WriteBigEndian<uint32_t>(kTBox, cursor);
  cursor += sizeof(uint32_t);

  absl::string_view input = buffer;

  EXPECT_THAT(
      ConsumeBox(&input, /*allow_implicit_length=*/false),
      StatusIs(
          absl::StatusCode::kInvalidArgument,
          HasSubstr("LBox is 0, indicating box extends to end of input, but "
                    "context does not allow for implicit box lengths")));
  EXPECT_THAT(input, Eq(buffer));
}

}  // namespace
}  // namespace jumbf_internal