// 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.
//

// Support for RFC 3161 TimestampToken verification.
#ifndef THIRD_PARTY_CREDENTIO_TSP_TIMESTAMP_VERIFIER_H_
#define THIRD_PARTY_CREDENTIO_TSP_TIMESTAMP_VERIFIER_H_

#include "absl/base/attributes.h"
#include "absl/base/nullability.h"
#include "absl/status/statusor.h"
#include "openssl/pki/verify.h"
#include "tsp/parsed_timestamp_token.h"
#include "tsp/verified_timestamp.h"

namespace credentio {

// Verifier for RFC 3161 TimestampTokens, implemented using SimpleCMS.
class TimestampVerifier {
 public:
  // If `tsa_roots` is `nullptr`, the verifier will skip trust checks (only for
  // use in tests).
  explicit TimestampVerifier(const bssl::VerifyTrustStore* absl_nullable
                                 tsa_roots ABSL_ATTRIBUTE_LIFETIME_BOUND)
      : tsa_roots_(tsa_roots) {}

  // Verifies the signature of an RFC 3161 TimestampToken, and
  // checks that the TSA is trusted. Error codes reported include
  //   kInvalidArgument: Malformed timestamp token
  //   kUnauthenticated: Signature verification errors, missing/untrusted certs
  //   kOutOfRange: A certificate was not within its validity period
  absl::StatusOr<VerifiedTimestamp> VerifyTimestampToken(
      const ParsedTimestampToken& parsed_token) const;

 private:
  const bssl::VerifyTrustStore* tsa_roots_;
};

}  // namespace credentio

#endif  // THIRD_PARTY_CREDENTIO_TSP_TIMESTAMP_VERIFIER_H_