////////////////////////////////////////////////////////////////////////////////
// Copyright 2019 Google LLC.
//
// This software is licensed under the terms defined in the Widevine Master
// License Agreement. For a copy of this agreement, please contact
// widevine-licensing@google.com.
////////////////////////////////////////////////////////////////////////////////

#include "common/signer_public_key.h"

#include "absl/memory/memory.h"
#include "common/ec_key.h"
#include "common/rsa_key.h"

namespace widevine {

// SignerPublicKeyImpl is a generic implementation of SignerPublicKey. The
// initialization details are in the SignerPublicKey factory method.
template <typename T>
class SignerPublicKeyImpl : public SignerPublicKey {
 public:
  explicit SignerPublicKeyImpl(std::unique_ptr<T> signer_public_key)
      : signer_public_key_(std::move(signer_public_key)) {}
  ~SignerPublicKeyImpl() override {}
  SignerPublicKeyImpl(const SignerPublicKeyImpl&) = delete;
  SignerPublicKeyImpl& operator=(const SignerPublicKeyImpl&) = delete;

  bool VerifySignature(const std::string& message, HashAlgorithm hash_algorithm,
                       const std::string& signature) const override {
    if (!signer_public_key_->VerifySignature(message, hash_algorithm,
                                             signature)) {
      return false;
    }
    return true;
  }

 private:
  std::unique_ptr<T> signer_public_key_;
};

std::unique_ptr<SignerPublicKey> SignerPublicKey::Create(
    const std::string& signer_public_key, DrmCertificate::Algorithm algorithm) {
  switch (algorithm) {
    case DrmCertificate::RSA: {
      std::unique_ptr<RsaPublicKey> public_key(
          RsaPublicKey::Create(signer_public_key));
      if (public_key == nullptr) {
        return nullptr;
      }
      return absl::make_unique<SignerPublicKeyImpl<RsaPublicKey>>(
          std::move(public_key));
    }
    // All supported ECC curves are specified here.
    case DrmCertificate::ECC_SECP256R1:
    case DrmCertificate::ECC_SECP384R1:
    case DrmCertificate::ECC_SECP521R1: {
      std::unique_ptr<ECPublicKey> public_key =
          ECPublicKey::Create(signer_public_key);
      if (public_key == nullptr) {
        return nullptr;
      }
      return absl::make_unique<SignerPublicKeyImpl<ECPublicKey>>(
          std::move(public_key));
    }
    default:
      return nullptr;
  }
}

}  // namespace widevine