/*
 * Copyright (c) 2020-2023, the SerenityOS developers.
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#pragma once

#include <AK/ByteBuffer.h>
#include <AK/Forward.h>
#include <AK/Optional.h>
#include <AK/Singleton.h>
#include <AK/Types.h>
#include <LibCore/ConfigFile.h>
#include <LibCore/DateTime.h>
#include <LibCrypto/BigInt/UnsignedBigInteger.h>
#include <LibCrypto/PK/RSA.h>

namespace TLS {

#define _ENUM(key, value) key,

#define __ENUM_OBJECT_CLASS                   \
    _ENUM(ApplicationProcess, "2.5.6.11"sv)   \
    _ENUM(Country, "2.5.6.2"sv)               \
    _ENUM(DcObject, "1.3.6.1.4.1.1466.344"sv) \
    _ENUM(Device, "2.5.6.14"sv)               \
    _ENUM(GroupOfNames, "2.5.6.9"sv)          \
    _ENUM(GroupOfUniqueNames, "2.5.6.17"sv)   \
    _ENUM(Locality, "2.5.6.3"sv)              \
    _ENUM(Organization, "2.5.6.4"sv)          \
    _ENUM(OrganizationalPerson, "2.5.6.7"sv)  \
    _ENUM(OrganizationalRole, "2.5.6.8"sv)    \
    _ENUM(OrganizationalUnit, "2.5.6.5"sv)    \
    _ENUM(Person, "2.5.6.6"sv)                \
    _ENUM(ResidentialPerson, "2.5.6.10"sv)    \
    _ENUM(UidObject, "1.3.6.1.1.3.1"sv)

// NOTE: Type = O
// NOTE: This list is not exhaustive. If more members are needed, find them at the link below.
// https://www.iana.org/assignments/ldap-parameters/ldap-parameters.xhtml#ldap-parameters-3
enum class ObjectClass {
    __ENUM_OBJECT_CLASS
};

#define __ENUM_ATTRIBUTE_TYPE                       \
    _ENUM(BusinessCategory, "2.5.4.15"sv)           \
    _ENUM(C, "2.5.4.6"sv)                           \
    _ENUM(Cn, "2.5.4.3"sv)                          \
    _ENUM(Dc, "0.9.2342.19200300.100.1.25"sv)       \
    _ENUM(Description, "2.5.4.13"sv)                \
    _ENUM(DestinationIndicator, "2.5.4.27"sv)       \
    _ENUM(DistinguishedName, "2.5.4.49"sv)          \
    _ENUM(DnQualifier, "2.5.4.46"sv)                \
    _ENUM(EnhancedSearchGuide, "2.5.4.47"sv)        \
    _ENUM(Email, "1.2.840.113549.1.9.1"sv)          \
    _ENUM(FacsimileTelephoneNumber, "2.5.4.23"sv)   \
    _ENUM(GenerationQualifier, "2.5.4.44"sv)        \
    _ENUM(GivenName, "2.5.4.42"sv)                  \
    _ENUM(HouseIdentifier, "2.5.4.51"sv)            \
    _ENUM(Initials, "2.5.4.43"sv)                   \
    _ENUM(InternationalISDNNumber, "2.5.4.25"sv)    \
    _ENUM(L, "2.5.4.7"sv)                           \
    _ENUM(Member, "2.5.4.31"sv)                     \
    _ENUM(Name, "2.5.4.41"sv)                       \
    _ENUM(O, "2.5.4.10"sv)                          \
    _ENUM(Ou, "2.5.4.11"sv)                         \
    _ENUM(Owner, "2.5.4.32"sv)                      \
    _ENUM(PhysicalDeliveryOfficeName, "2.5.4.19"sv) \
    _ENUM(PostalAddress, "2.5.4.16"sv)              \
    _ENUM(PostalCode, "2.5.4.17"sv)                 \
    _ENUM(PostOfficeBox, "2.5.4.18"sv)              \
    _ENUM(PreferredDeliveryMethod, "2.5.4.28"sv)    \
    _ENUM(RegisteredAddress, "2.5.4.26"sv)          \
    _ENUM(RoleOccupant, "2.5.4.33"sv)               \
    _ENUM(SearchGuide, "2.5.4.14"sv)                \
    _ENUM(SeeAlso, "2.5.4.34"sv)                    \
    _ENUM(SerialNumber, "2.5.4.5"sv)                \
    _ENUM(Sn, "2.5.4.4"sv)                          \
    _ENUM(St, "2.5.4.8"sv)                          \
    _ENUM(Street, "2.5.4.9"sv)                      \
    _ENUM(Surname, "2.5.4.4"sv)                     \
    _ENUM(TelephoneNumber, "2.5.4.20"sv)            \
    _ENUM(TeletexTerminalIdentifier, "2.5.4.22"sv)  \
    _ENUM(TelexNumber, "2.5.4.21"sv)                \
    _ENUM(Title, "2.5.4.12"sv)                      \
    _ENUM(Uid, "0.9.2342.19200300.100.1.1"sv)       \
    _ENUM(UniqueMember, "2.5.4.50"sv)               \
    _ENUM(UserPassword, "2.5.4.35"sv)               \
    _ENUM(X121Address, "2.5.4.24"sv)                \
    _ENUM(X500UniqueIdentifier, "2.5.4.45"sv)

// NOTE: Type = A
// NOTE: This list is not exhaustive. If more members are needed, find them at the link below.
// https://www.iana.org/assignments/ldap-parameters/ldap-parameters.xhtml#ldap-parameters-3
enum class AttributeType {
    __ENUM_ATTRIBUTE_TYPE
};

#undef _ENUM

constexpr static StringView enum_value(ObjectClass object_class)
{
#define _ENUM(key, value)  \
    case ObjectClass::key: \
        return value;

    switch (object_class) {
        __ENUM_OBJECT_CLASS
    }

    return "Unknown"sv;
#undef _ENUM
#undef __ENUM_OBJECT_CLASS
}

constexpr static StringView enum_value(AttributeType object_class)
{
#define _ENUM(key, value)    \
    case AttributeType::key: \
        return value;

    switch (object_class) {
        __ENUM_ATTRIBUTE_TYPE
    }

    return "Unknown"sv;
#undef _ENUM
#undef __ENUM_ATTRIBUTE_TYPE
}

enum class CertificateKeyAlgorithm : u8 {
    Unsupported = 0x00,
    RSA_RSA = 0x01,
    RSA_MD2 = 0x2,
    RSA_MD4 = 0x3,
    RSA_MD5 = 0x04,
    RSA_SHA1 = 0x05,
    RSA_OAEP = 0x6,
    RSAES_OAEP = 0x7,
    RSA_MGF1 = 0x8,
    RSA_SPECIFIED = 0x9,
    RSA_PSS = 0xa,
    RSA_SHA256 = 0x0b,
    RSA_SHA384 = 0x0c,
    RSA_SHA512 = 0x0d,
    RSA_SHA224 = 0xe,
    ECDSA_SHA224 = 0x10,
    ECDSA_SHA256 = 0x11,
    ECDSA_SHA384 = 0x12,
    ECDSA_SHA512 = 0x13,
    ECDSA_SECP256R1 = 0x14,
    ECDSA_SECP384R1 = 0x15,
};

struct BasicConstraints {
    bool is_certificate_authority;
    Crypto::UnsignedBigInteger path_length_constraint;
};

class RelativeDistinguishedName {
public:
    ErrorOr<String> to_string();

    ErrorOr<AK::HashSetResult> set(String key, String value)
    {
        return m_members.try_set(key, value);
    }

    Optional<String> get(StringView key)
    {
        return m_members.get(key);
    }

    Optional<String> get(AttributeType key)
    {
        return m_members.get(enum_value(key));
    }

    Optional<String> get(ObjectClass key)
    {
        return m_members.get(enum_value(key));
    }

    String common_name()
    {
        auto entry = get(AttributeType::Cn);
        if (entry.has_value()) {
            return entry.value();
        }

        return String();
    }

    String organizational_unit()
    {
        auto entry = get(AttributeType::Ou);
        if (entry.has_value()) {
            return entry.value();
        }

        return String();
    }

private:
    HashMap<String, String> m_members;
};

struct Validity {
    Core::DateTime not_before;
    Core::DateTime not_after;
};

class SubjectPublicKey {
public:
    Crypto::PK::RSAPublicKey<Crypto::UnsignedBigInteger> rsa;

    CertificateKeyAlgorithm algorithm { CertificateKeyAlgorithm::Unsupported };
    ByteBuffer raw_key;
};

class Certificate {
public:
    u16 version { 0 };
    CertificateKeyAlgorithm algorithm { CertificateKeyAlgorithm::Unsupported };
    CertificateKeyAlgorithm ec_algorithm { CertificateKeyAlgorithm::Unsupported };
    SubjectPublicKey public_key {};
    ByteBuffer exponent {};
    Crypto::PK::RSAPrivateKey<Crypto::UnsignedBigInteger> private_key {};
    RelativeDistinguishedName issuer, subject;
    Validity validity {};
    Vector<String> SAN;
    Vector<String> IAN;
    u8* ocsp { nullptr };
    Crypto::UnsignedBigInteger serial_number;
    ByteBuffer sign_key {};
    ByteBuffer fingerprint {};
    ByteBuffer der {};
    ByteBuffer data {};
    CertificateKeyAlgorithm signature_algorithm { CertificateKeyAlgorithm::Unsupported };
    ByteBuffer signature_value {};
    ByteBuffer original_asn1 {};
    bool is_allowed_to_sign_certificate { false };
    bool is_certificate_authority { false };
    Optional<size_t> path_length_constraint {};
    bool is_self_issued { false };

    static ErrorOr<Certificate> parse_certificate(ReadonlyBytes, bool client_cert = false);

    bool is_self_signed();
    bool is_valid() const;

private:
    Optional<bool> m_is_self_signed;
};

class DefaultRootCACertificates {
public:
    DefaultRootCACertificates();

    Vector<Certificate> const& certificates() const { return m_ca_certificates; }

    static ErrorOr<Vector<Certificate>> parse_pem_root_certificate_authorities(ByteBuffer&);
    static ErrorOr<Vector<Certificate>> load_certificates();

    static DefaultRootCACertificates& the() { return s_the; }

private:
    static Singleton<DefaultRootCACertificates> s_the;

    Vector<Certificate> m_ca_certificates;
};

}

using TLS::Certificate;
using TLS::DefaultRootCACertificates;