/* Copyright 2017 - 2026 R. Thomas
 * Copyright 2017 - 2026 Quarkslab
 *
 * 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
 *
 *     http://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.
 */
#ifndef LIEF_PE_X509_H
#define LIEF_PE_X509_H
#include <array>
#include <memory>
#include <vector>

#include "LIEF/Object.hpp"
#include "LIEF/visibility.h"

#include "LIEF/PE/enums.hpp"

#include "LIEF/PE/signature/types.hpp"

#include "LIEF/enums.hpp"

struct mbedtls_x509_crt;


namespace LIEF::PE {

class Parser;
class SignatureParser;
class Signature;

class RsaInfo;

/// Interface over a x509 certificate
class LIEF_API x509 : public Object {

  friend class Parser;
  friend class SignatureParser;
  friend class Signature;

  public:
  /// Tuple (Year, Month, Day, Hour, Minute, Second)
  using date_t = std::array<int32_t, 6>;

  using certificates_t = std::vector<x509>;

  /// Parse x509 certificate(s) from file path
  static certificates_t parse(const std::string& path);

  /// Parse x509 certificate(s) from raw blob
  static certificates_t parse(const std::vector<uint8_t>& content);

  /// Return True if ``before`` is *before* than ``after``. False otherwise
  static bool check_time(const date_t& before, const date_t& after);

  /// True if the given time is in the **past** according to the clock's system
  static bool time_is_past(const date_t& to);

  /// True if the given time is in the future according to the clock's system
  static bool time_is_future(const date_t& from);

  /// Public key scheme
  enum class KEY_TYPES : uint32_t {
    NONE = 0,   ///< Unknown scheme
    RSA,        ///< RSA Scheme
    ECKEY,      ///< Elliptic-curve scheme
    ECKEY_DH,   ///< Elliptic-curve Diffie-Hellman
    ECDSA,      ///< Elliptic-curve Digital Signature Algorithm
    RSA_ALT,    ///< RSA scheme with an alternative implementation for signing and
                ///< decrypting
    RSASSA_PSS, ///< RSA Probabilistic signature scheme
  };

  /// Mirror of mbedtls's X509 Verify codes: MBEDTLS_X509_XX
  ///
  /// It must be sync with include/mbedtls/x509.h
  enum class VERIFICATION_FLAGS : uint32_t {
    /// The verification succeed
    OK = 0,

    /// The certificate validity has expired.
    BADCERT_EXPIRED = 1 << 0,

    /// The certificate has been revoked (is on a CRL).
    BADCERT_REVOKED = 1 << 1,

    /// The certificate Common Name (CN) does not match with the expected CN.
    BADCERT_CN_MISMATCH = 1 << 2,

    /// The certificate is not correctly signed by the trusted CA.
    BADCERT_NOT_TRUSTED = 1 << 3,

    /// The CRL is not correctly signed by the trusted CA.
    BADCRL_NOT_TRUSTED = 1 << 4,

    /// The CRL is expired.
    BADCRL_EXPIRED = 1 << 5,

    /// Certificate was missing.
    BADCERT_MISSING = 1 << 6,

    /// Certificate verification was skipped.
    BADCERT_SKIP_VERIFY = 1 << 7,

    ///
    /// Other reason (can be used by verify callback)
    BADCERT_OTHER = 1 << 8,

    /// The certificate validity starts in the future.
    BADCERT_FUTURE = 1 << 9,

    /// The CRL is from the future
    BADCRL_FUTURE = 1 << 10,

    /// Usage does not match the keyUsage extension.
    BADCERT_KEY_USAGE = 1 << 11,

    /// Usage does not match the extendedKeyUsage extension.
    BADCERT_EXT_KEY_USAGE = 1 << 12,

    /// Usage does not match the nsCertType extension.
    BADCERT_NS_CERT_TYPE = 1 << 13,

    /// The certificate is signed with an unacceptable hash.
    BADCERT_BAD_MD = 1 << 14,

    /// The certificate is signed with an unacceptable PK alg (e.g. RSA vs ECDSA).
    BADCERT_BAD_PK = 1 << 15,

    /// The certificate is signed with an unacceptable key (e.g. bad curve, RSA too
    /// short).
    BADCERT_BAD_KEY = 1 << 16,

    /// The CRL is signed with an unacceptable hash.
    BADCRL_BAD_MD = 1 << 17,

    /// The CRL is signed with an unacceptable PK alg (e.g. RSA vs ECDSA).
    BADCRL_BAD_PK = 1 << 18,

    /// The CRL is signed with an unacceptable key (e.g. bad curve, RSA too short).
    BADCRL_BAD_KEY = 1 << 19,
  };

  /// Key usage as defined in [RFC #5280 -
  /// section-4.2.1.3](https://tools.ietf.org/html/rfc5280#section-4.2.1.3)
  enum class KEY_USAGE : uint32_t {
    /// The key is used for digital signature
    DIGITAL_SIGNATURE = 0,
    /// The key is used for digital signature AND to protect against falsely
    /// denying some action
    NON_REPUDIATION,

    /// The key is used for enciphering private or secret keys
    KEY_ENCIPHERMENT,

    /// The key is used for directly enciphering raw user data without the use of
    /// an intermediate symmetric cipher
    DATA_ENCIPHERMENT,

    /// The Key is used for key agreement. (e.g. with Diffie-Hellman)
    KEY_AGREEMENT,

    /// The key is used for verifying signatures on public key certificates
    KEY_CERT_SIGN,

    /// The key is used for verifying signatures on certificate revocation lists
    CRL_SIGN,

    /// In **association with** KEY_AGREEMENT (otherwise the meaning is undefined),
    /// the key is only used for enciphering data while performing key agreement
    ENCIPHER_ONLY,

    /// In **association with** KEY_AGREEMENT (otherwise the meaning is undefined),
    /// the key is only used for deciphering data while performing key agreement
    DECIPHER_ONLY,
  };

  x509(mbedtls_x509_crt* ca);
  x509(const x509& other);
  x509& operator=(x509 other);
  void swap(x509& other);

  /// X.509 version. (1=v1, 2=v2, 3=v3)
  uint32_t version() const;

  /// Unique id for certificate issued by a specific CA.
  std::vector<uint8_t> serial_number() const;

  /// Signature algorithm (OID)
  oid_t signature_algorithm() const;

  /// Start time of certificate validity
  date_t valid_from() const;

  /// End time of certificate validity
  date_t valid_to() const;

  /// Issuer information
  std::string issuer() const;

  /// Subject information
  std::string subject() const;

  /// Try to decrypt the given signature and check if it matches the given hash
  /// according to the hash algorithm provided
  bool check_signature(const std::vector<uint8_t>& hash,
                       const std::vector<uint8_t>& signature,
                       ALGORITHMS digest) const;

  /// The raw x509 bytes (DER encoded)
  std::vector<uint8_t> raw() const;

  /// Return the underlying public-key scheme
  KEY_TYPES key_type() const;

  /// **If** the underlying public-key scheme is RSA, return the RSA information.
  /// Otherwise, return a nullptr
  std::unique_ptr<RsaInfo> rsa_info() const;

  /// Verify that this certificate has been used **to trust** the given certificate
  VERIFICATION_FLAGS verify(const x509& ca) const;

  /// Verify that this certificate **is trusted** by the given CA list
  VERIFICATION_FLAGS is_trusted_by(const std::vector<x509>& ca) const;

  /// Policy information terms as OID (see RFC #5280)
  std::vector<oid_t> certificate_policies() const;

  /// Purpose of the key contained in the certificate
  std::vector<KEY_USAGE> key_usage() const;

  /// Indicates one or more purposes for which the certified public key may be used
  /// (OID types)
  std::vector<oid_t> ext_key_usage() const;

  bool is_ca() const;

  /// The signature of the certificate
  std::vector<uint8_t> signature() const;

  void accept(Visitor& visitor) const override;

  ~x509() override;

  LIEF_API friend std::ostream& operator<<(std::ostream& os,
                                           const x509& x509_cert);

  private:
  x509();
  mbedtls_x509_crt* x509_cert_ = nullptr;
};

}


ENABLE_BITMASK_OPERATORS(LIEF::PE::x509::VERIFICATION_FLAGS);

#endif
