// Copyright (c) 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "quic/core/crypto/cert_compressor.h"

#include <memory>
#include <string>

#include "absl/strings/escaping.h"
#include "absl/strings/string_view.h"
#include "quic/core/quic_utils.h"
#include "quic/platform/api/quic_test.h"
#include "quic/test_tools/crypto_test_utils.h"

namespace quic {
namespace test {

class CertCompressorTest : public QuicTest {};

TEST_F(CertCompressorTest, EmptyChain) {
  std::vector<std::string> chain;
  const std::string compressed =
      CertCompressor::CompressChain(chain, absl::string_view());
  EXPECT_EQ("00", absl::BytesToHexString(compressed));

  std::vector<std::string> chain2, cached_certs;
  ASSERT_TRUE(
      CertCompressor::DecompressChain(compressed, cached_certs, &chain2));
  EXPECT_EQ(chain.size(), chain2.size());
}

TEST_F(CertCompressorTest, Compressed) {
  std::vector<std::string> chain;
  chain.push_back("testcert");
  const std::string compressed =
      CertCompressor::CompressChain(chain, absl::string_view());
  ASSERT_GE(compressed.size(), 2u);
  EXPECT_EQ("0100", absl::BytesToHexString(compressed.substr(0, 2)));

  std::vector<std::string> chain2, cached_certs;
  ASSERT_TRUE(
      CertCompressor::DecompressChain(compressed, cached_certs, &chain2));
  EXPECT_EQ(chain.size(), chain2.size());
  EXPECT_EQ(chain[0], chain2[0]);
}

TEST_F(CertCompressorTest, Common) {
  std::vector<std::string> chain;
  chain.push_back("testcert");
  static const uint64_t set_hash = 42;
  const std::string compressed = CertCompressor::CompressChain(
      chain, absl::string_view(reinterpret_cast<const char*>(&set_hash),
                               sizeof(set_hash)));
  ASSERT_GE(compressed.size(), 2u);
  // 01 is the prefix for a zlib "compressed" cert not common or cached.
  EXPECT_EQ("0100", absl::BytesToHexString(compressed.substr(0, 2)));

  std::vector<std::string> chain2, cached_certs;
  ASSERT_TRUE(
      CertCompressor::DecompressChain(compressed, cached_certs, &chain2));
  EXPECT_EQ(chain.size(), chain2.size());
  EXPECT_EQ(chain[0], chain2[0]);
}

TEST_F(CertCompressorTest, Cached) {
  std::vector<std::string> chain;
  chain.push_back("testcert");
  uint64_t hash = QuicUtils::FNV1a_64_Hash(chain[0]);
  absl::string_view hash_bytes(reinterpret_cast<char*>(&hash), sizeof(hash));
  const std::string compressed =
      CertCompressor::CompressChain(chain, hash_bytes);

  EXPECT_EQ("02" /* cached */ + absl::BytesToHexString(hash_bytes) +
                "00" /* end of list */,
            absl::BytesToHexString(compressed));

  std::vector<std::string> cached_certs, chain2;
  cached_certs.push_back(chain[0]);
  ASSERT_TRUE(
      CertCompressor::DecompressChain(compressed, cached_certs, &chain2));
  EXPECT_EQ(chain.size(), chain2.size());
  EXPECT_EQ(chain[0], chain2[0]);
}

TEST_F(CertCompressorTest, BadInputs) {
  std::vector<std::string> cached_certs, chain;

  EXPECT_FALSE(CertCompressor::DecompressChain(
      absl::BytesToHexString("04") /* bad entry type */, cached_certs, &chain));

  EXPECT_FALSE(CertCompressor::DecompressChain(
      absl::BytesToHexString("01") /* no terminator */, cached_certs, &chain));

  EXPECT_FALSE(CertCompressor::DecompressChain(
      absl::BytesToHexString("0200") /* hash truncated */, cached_certs,
      &chain));

  EXPECT_FALSE(CertCompressor::DecompressChain(
      absl::BytesToHexString("0300") /* hash and index truncated */,
      cached_certs, &chain));

  /* without a CommonCertSets */
  EXPECT_FALSE(
      CertCompressor::DecompressChain(absl::BytesToHexString("03"
                                                             "0000000000000000"
                                                             "00000000"),
                                      cached_certs, &chain));

  /* incorrect hash and index */
  EXPECT_FALSE(
      CertCompressor::DecompressChain(absl::BytesToHexString("03"
                                                             "a200000000000000"
                                                             "00000000"),
                                      cached_certs, &chain));
}

}  // namespace test
}  // namespace quic