#if HAVE_OPENSSL && NODE_OPENSSL_HAS_QUIC

#include "tokens.h"

#include <crypto/crypto_util.h>

#include <ngtcp2/ngtcp2_crypto.h>

#include <node_sockaddr-inl.h>

#include <string_bytes.h>

#include <util-inl.h>

#include <algorithm>

namespace node {

namespace quic {

// ============================================================================

// TokenSecret

TokenSecret::TokenSecret() : buf_() {

  // As a performance optimization later, we could consider creating an entropy

  // cache here similar to what we use for random CIDs so that we do not have

  // to engage CSPRNG on every call. That, however, is suboptimal for secrets.

  // If someone manages to get visibility into that cache then they would know

  // the secrets for a larger number of tokens, which could be bad. For now,

  // generating on each call is safer, even if less performant.

  CHECK(crypto::CSPRNG(buf_, QUIC_TOKENSECRET_LEN).is_ok());

}

TokenSecret::TokenSecret(const uint8_t* secret) : buf_() {

  CHECK_NOT_NULL(secret);

  memcpy(buf_, secret, QUIC_TOKENSECRET_LEN);

}

TokenSecret::~TokenSecret() {

  memset(buf_, 0, QUIC_TOKENSECRET_LEN);

}

TokenSecret::operator const uint8_t*() const {

  return buf_;

}

uint8_t TokenSecret::operator[](int pos) const {

  CHECK_GE(pos, 0);

  CHECK_LT(pos, QUIC_TOKENSECRET_LEN);

  return buf_[pos];

}

TokenSecret::operator const char*() const {

  return reinterpret_cast<const char*>(buf_);

}

std::string TokenSecret::ToString() const {

  char dest[QUIC_TOKENSECRET_LEN * 2];

  size_t written = StringBytes::hex_encode(

      *this, QUIC_TOKENSECRET_LEN, dest, arraysize(dest));

  DCHECK_EQ(written, arraysize(dest));

  return std::string(dest, written);

}

// ============================================================================

// StatelessResetToken

StatelessResetToken::StatelessResetToken() : ptr_(nullptr), buf_() {}

StatelessResetToken::StatelessResetToken(const uint8_t* token) : ptr_(token) {}

StatelessResetToken::StatelessResetToken(const TokenSecret& secret,

                                         const CID& cid)

    : ptr_(buf_) {

  CHECK_EQ(ngtcp2_crypto_generate_stateless_reset_token(

               buf_, secret, kStatelessTokenLen, cid),

           0);

}

StatelessResetToken::StatelessResetToken(uint8_t* token,

                                         const TokenSecret& secret,

                                         const CID& cid)

    : ptr_(token) {

  CHECK_EQ(ngtcp2_crypto_generate_stateless_reset_token(

               token, secret, kStatelessTokenLen, cid),

           0);

}

StatelessResetToken::StatelessResetToken(const StatelessResetToken& other)

    : ptr_(buf_) {

  if (other) {

    memcpy(buf_, other.ptr_, kStatelessTokenLen);

  } else {

    ptr_ = nullptr;

  }

}

StatelessResetToken::operator const uint8_t*() const {

  return ptr_ != nullptr ? ptr_ : buf_;

}

StatelessResetToken::operator const char*() const {

  return reinterpret_cast<const char*>(ptr_ != nullptr ? ptr_ : buf_);

}

StatelessResetToken::operator bool() const {

  return ptr_ != nullptr;

}

bool StatelessResetToken::operator==(const StatelessResetToken& other) const {

  if (ptr_ == other.ptr_) return true;

  if ((ptr_ == nullptr && other.ptr_ != nullptr) ||

      (ptr_ != nullptr && other.ptr_ == nullptr)) {

    return false;

  }

  return memcmp(ptr_, other.ptr_, kStatelessTokenLen) == 0;

}

bool StatelessResetToken::operator!=(const StatelessResetToken& other) const {

  return !(*this == other);

}

std::string StatelessResetToken::ToString() const {

  if (ptr_ == nullptr) return std::string();

  char dest[kStatelessTokenLen * 2];

  size_t written =

      StringBytes::hex_encode(*this, kStatelessTokenLen, dest, arraysize(dest));

  DCHECK_EQ(written, arraysize(dest));

  return std::string(dest, written);

}

size_t StatelessResetToken::Hash::operator()(

    const StatelessResetToken& token) const {

  size_t hash = 0;

  if (token.ptr_ == nullptr) return hash;

  for (size_t n = 0; n < kStatelessTokenLen; n++)

    hash ^= std::hash<uint8_t>{}(token.ptr_[n]) + 0x9e3779b9 + (hash << 6) +

            (hash >> 2);

  return hash;

}

StatelessResetToken StatelessResetToken::kInvalid;

// ============================================================================

// RetryToken and RegularToken

namespace {

ngtcp2_vec GenerateRetryToken(uint8_t* buffer,

                              uint32_t version,

                              const SocketAddress& address,

                              const CID& retry_cid,

                              const CID& odcid,

                              const TokenSecret& token_secret) {

  ssize_t ret =

      ngtcp2_crypto_generate_retry_token(buffer,

                                         token_secret,

                                         TokenSecret::QUIC_TOKENSECRET_LEN,

                                         version,

                                         address.data(),

                                         address.length(),

                                         retry_cid,

                                         odcid,

                                         uv_hrtime());

  DCHECK_GE(ret, 0);

  DCHECK_LE(ret, RetryToken::kRetryTokenLen);

  DCHECK_EQ(buffer[0], RetryToken::kTokenMagic);

  // This shouldn't be possible but we handle it anyway just to be safe.

  if (ret == 0) return {nullptr, 0};

  return {buffer, static_cast<size_t>(ret)};

}

ngtcp2_vec GenerateRegularToken(uint8_t* buffer,

                                uint32_t version,

                                const SocketAddress& address,

                                const TokenSecret& token_secret) {

  ssize_t ret =

      ngtcp2_crypto_generate_regular_token(buffer,

                                           token_secret,

                                           TokenSecret::QUIC_TOKENSECRET_LEN,

                                           address.data(),

                                           address.length(),

                                           uv_hrtime());

  DCHECK_GE(ret, 0);

  DCHECK_LE(ret, RegularToken::kRegularTokenLen);

  DCHECK_EQ(buffer[0], RegularToken::kTokenMagic);

  // This shouldn't be possible but we handle it anyway just to be safe.

  if (ret == 0) return {nullptr, 0};

  return {buffer, static_cast<size_t>(ret)};

}

}  // namespace

RetryToken::RetryToken(uint32_t version,

                       const SocketAddress& address,

                       const CID& retry_cid,

                       const CID& odcid,

                       const TokenSecret& token_secret)

    : buf_(),

      ptr_(GenerateRetryToken(

          buf_, version, address, retry_cid, odcid, token_secret)) {}

RetryToken::RetryToken(const uint8_t* token, size_t size)

    : ptr_(ngtcp2_vec{const_cast<uint8_t*>(token), size}) {

  DCHECK_LE(size, RetryToken::kRetryTokenLen);

  DCHECK_IMPLIES(token == nullptr, size = 0);

}

std::optional<CID> RetryToken::Validate(uint32_t version,

                                        const SocketAddress& addr,

                                        const CID& dcid,

                                        const TokenSecret& token_secret,

                                        uint64_t verification_expiration) {

  if (ptr_.base == nullptr || ptr_.len == 0) return std::nullopt;

  ngtcp2_cid ocid;

  int ret = ngtcp2_crypto_verify_retry_token(

      &ocid,

      ptr_.base,

      ptr_.len,

      token_secret,

      TokenSecret::QUIC_TOKENSECRET_LEN,

      version,

      addr.data(),

      addr.length(),

      dcid,

      std::min(verification_expiration, QUIC_MIN_RETRYTOKEN_EXPIRATION),

      uv_hrtime());

  if (ret != 0) return std::nullopt;

  return std::optional<CID>(ocid);

}

RetryToken::operator const ngtcp2_vec&() const {

  return ptr_;

}

RetryToken::operator const ngtcp2_vec*() const {

  return &ptr_;

}

std::string RetryToken::ToString() const {

  if (ptr_.base == nullptr) return std::string();

  MaybeStackBuffer<char, 32> dest(ptr_.len * 2);

  size_t written =

      StringBytes::hex_encode(*this, ptr_.len, dest.out(), dest.length());

  DCHECK_EQ(written, dest.length());

  return std::string(dest.out(), written);

}

RetryToken::operator const char*() const {

  return reinterpret_cast<const char*>(ptr_.base);

}

RetryToken::operator bool() const {

  return ptr_.base != nullptr && ptr_.len > 0;

}

RegularToken::RegularToken() : buf_(), ptr_(ngtcp2_vec{nullptr, 0}) {}

RegularToken::RegularToken(uint32_t version,

                           const SocketAddress& address,

                           const TokenSecret& token_secret)

    : buf_(),

      ptr_(GenerateRegularToken(buf_, version, address, token_secret)) {}

RegularToken::RegularToken(const uint8_t* token, size_t size)

    : ptr_(ngtcp2_vec{const_cast<uint8_t*>(token), size}) {

  DCHECK_LE(size, RegularToken::kRegularTokenLen);

  DCHECK_IMPLIES(token == nullptr, size = 0);

}

RegularToken::operator bool() const {

  return ptr_.base != nullptr && ptr_.len > 0;

}

bool RegularToken::Validate(uint32_t version,

                            const SocketAddress& addr,

                            const TokenSecret& token_secret,

                            uint64_t verification_expiration) {

  if (ptr_.base == nullptr || ptr_.len == 0) return false;

  return ngtcp2_crypto_verify_regular_token(

             ptr_.base,

             ptr_.len,

             token_secret,

             TokenSecret::QUIC_TOKENSECRET_LEN,

             addr.data(),

             addr.length(),

             std::min(verification_expiration,

                      QUIC_MIN_REGULARTOKEN_EXPIRATION),

             uv_hrtime()) == 0;

}

RegularToken::operator const ngtcp2_vec&() const {

  return ptr_;

}

RegularToken::operator const ngtcp2_vec*() const {

  return &ptr_;

}

std::string RegularToken::ToString() const {

  if (ptr_.base == nullptr) return std::string();

  MaybeStackBuffer<char, 32> dest(ptr_.len * 2);

  size_t written =

      StringBytes::hex_encode(*this, ptr_.len, dest.out(), dest.length());

  DCHECK_EQ(written, dest.length());

  return std::string(dest.out(), written);

}

RegularToken::operator const char*() const {

  return reinterpret_cast<const char*>(ptr_.base);

}

}  // namespace quic

}  // namespace node

#endif  // HAVE_OPENSSL && NODE_OPENSSL_HAS_QUIC