class JWT::JWK::RSA

def []=(key, value)
  if RSA_KEY_ELEMENTS.include?(key.to_sym)
    raise ArgumentError, 'cannot overwrite cryptographic key attributes'
  end
  super(key, value)
end

def check_jwk_params!(key_params, params)
  raise ArgumentError, 'cannot overwrite cryptographic key attributes' unless (RSA_KEY_ELEMENTS & params.keys).empty?
  raise JWT::JWKError, "Incorrect 'kty' value: #{key_params[:kty]}, expected #{KTY}" unless key_params[:kty] == KTY
  raise JWT::JWKError, 'Key format is invalid for RSA' unless key_params[:n] && key_params[:e]
end

def create_rsa_key_using_accessors(rsa_parameters) # rubocop:disable Metrics/AbcSize
  validate_rsa_parameters!(rsa_parameters)
  OpenSSL::PKey::RSA.new.tap do |rsa_key|
    rsa_key.n = rsa_parameters[:n]
    rsa_key.e = rsa_parameters[:e]
    rsa_key.d = rsa_parameters[:d] if rsa_parameters[:d]
    rsa_key.p = rsa_parameters[:p] if rsa_parameters[:p]
    rsa_key.q = rsa_parameters[:q] if rsa_parameters[:q]
    rsa_key.dmp1 = rsa_parameters[:dp] if rsa_parameters[:dp]
    rsa_key.dmq1 = rsa_parameters[:dq] if rsa_parameters[:dq]
    rsa_key.iqmp = rsa_parameters[:qi] if rsa_parameters[:qi]
  end
end

def create_rsa_key_using_der(rsa_parameters)
  validate_rsa_parameters!(rsa_parameters)
  sequence = RSA_ASN1_SEQUENCE.each_with_object([]) do |key, arr|
    next if rsa_parameters[key].nil?
    arr << OpenSSL::ASN1::Integer.new(rsa_parameters[key])
  end
  if sequence.size > 2 # Append "two-prime" version for private key
    sequence.unshift(OpenSSL::ASN1::Integer.new(0))
    raise JWT::JWKError, 'Creating a RSA key with a private key requires the CRT parameters to be defined' if sequence.size < RSA_ASN1_SEQUENCE.size
  end
  OpenSSL::PKey::RSA.new(OpenSSL::ASN1::Sequence(sequence).to_der)
end

def create_rsa_key_using_sets(rsa_parameters)
  validate_rsa_parameters!(rsa_parameters)
  OpenSSL::PKey::RSA.new.tap do |rsa_key|
    rsa_key.set_key(rsa_parameters[:n], rsa_parameters[:e], rsa_parameters[:d])
    rsa_key.set_factors(rsa_parameters[:p], rsa_parameters[:q]) if rsa_parameters[:p] && rsa_parameters[:q]
    rsa_key.set_crt_params(rsa_parameters[:dp], rsa_parameters[:dq], rsa_parameters[:qi]) if rsa_parameters[:dp] && rsa_parameters[:dq] && rsa_parameters[:qi]
  end
end

def decode_open_ssl_bn(jwk_data)
  self.class.decode_open_ssl_bn(jwk_data)
end

def decode_open_ssl_bn(jwk_data)
  return nil unless jwk_data
  OpenSSL::BN.new(::JWT::Base64.url_decode(jwk_data), BINARY)
end

def encode_open_ssl_bn(key_part)
  return unless key_part
  ::JWT::Base64.url_encode(key_part.to_s(BINARY))
end

def export(options = {})
  exported = parameters.clone
  exported.reject! { |k, _| RSA_PRIVATE_KEY_ELEMENTS.include? k } unless private? && options[:include_private] == true
  exported
end

def extract_key_params(key)
  case key
  when JWT::JWK::RSA
    key.export(include_private: true)
  when OpenSSL::PKey::RSA # Accept OpenSSL key as input
    @rsa_key = key # Preserve the object to avoid recreation
    parse_rsa_key(key)
  when Hash
    key.transform_keys(&:to_sym)
  else
    raise ArgumentError, 'key must be of type OpenSSL::PKey::RSA or Hash with key parameters'
  end
end

def import(jwk_data)
  new(jwk_data)
end

def initialize(key, params = nil, options = {})
  params ||= {}
  # For backwards compatibility when kid was a String
  params = { kid: params } if params.is_a?(String)
  key_params = extract_key_params(key)
  params = params.transform_keys(&:to_sym)
  check_jwk_params!(key_params, params)
  super(options, key_params.merge(params))
end

def jwk_attributes(*attributes)
  attributes.each_with_object({}) do |attribute, hash|
    hash[attribute] = decode_open_ssl_bn(self[attribute])
  end
end

def key_digest
  sequence = OpenSSL::ASN1::Sequence([OpenSSL::ASN1::Integer.new(public_key.n),
                                      OpenSSL::ASN1::Integer.new(public_key.e)])
  OpenSSL::Digest::SHA256.hexdigest(sequence.to_der)
end

def keypair
  rsa_key
end

def members
  RSA_PUBLIC_KEY_ELEMENTS.each_with_object({}) { |i, h| h[i] = self[i] }
end

def parse_rsa_key(key)
  {
    kty: KTY,
    n: encode_open_ssl_bn(key.n),
    e: encode_open_ssl_bn(key.e),
    d: encode_open_ssl_bn(key.d),
    p: encode_open_ssl_bn(key.p),
    q: encode_open_ssl_bn(key.q),
    dp: encode_open_ssl_bn(key.dmp1),
    dq: encode_open_ssl_bn(key.dmq1),
    qi: encode_open_ssl_bn(key.iqmp)
  }.compact
end

def private?
  rsa_key.private?
end

def public_key
  rsa_key.public_key
end

def rsa_key
  @rsa_key ||= self.class.create_rsa_key(jwk_attributes(*(RSA_KEY_ELEMENTS - [:kty])))
end

def signing_key
  rsa_key if private?
end

def validate_rsa_parameters!(rsa_parameters)
  return unless rsa_parameters.key?(:d)
  parameters = RSA_OPT_PARAMS - rsa_parameters.keys
  return if parameters.empty? || parameters.size == RSA_OPT_PARAMS.size
  raise JWT::JWKError, 'When one of p, q, dp, dq or qi is given all the other optimization parameters also needs to be defined' # https://www.rfc-editor.org/rfc/rfc7518.html#section-6.3.2
end

def verify_key
  rsa_key.public_key
end