# frozen_string_literal: true
module Gitlab
  module Kubernetes
    module Helm
      module V2
        class Certificate
          INFINITE_EXPIRY = 1000.years
          SHORT_EXPIRY = 30.minutes

          attr_reader :key, :cert

          def key_string
            @key.to_s
          end

          def cert_string
            @cert.to_pem
          end

          def self.from_strings(key_string, cert_string)
            key = OpenSSL::PKey::RSA.new(key_string)
            cert = OpenSSL::X509::Certificate.new(cert_string)
            new(key, cert)
          end

          def self.generate_root
            _issue(signed_by: nil, expires_in: INFINITE_EXPIRY, certificate_authority: true)
          end

          def issue(expires_in: SHORT_EXPIRY)
            self.class._issue(signed_by: self, expires_in: expires_in, certificate_authority: false)
          end

          private

          def self._issue(signed_by:, expires_in:, certificate_authority:)
            key = OpenSSL::PKey::RSA.new(4096)
            public_key = key.public_key

            subject = OpenSSL::X509::Name.parse("/C=US")

            cert = OpenSSL::X509::Certificate.new
            cert.subject = subject

            cert.issuer = signed_by&.cert&.subject || subject

            cert.not_before = Time.now.utc
            cert.not_after = expires_in.from_now.utc
            cert.public_key = public_key
            cert.serial = 0x0
            cert.version = 2

            if certificate_authority
              extension_factory = OpenSSL::X509::ExtensionFactory.new
              extension_factory.subject_certificate = cert
              extension_factory.issuer_certificate = cert
              cert.add_extension(extension_factory.create_extension('subjectKeyIdentifier', 'hash'))
              cert.add_extension(extension_factory.create_extension('basicConstraints', 'CA:TRUE', true))
              cert.add_extension(extension_factory.create_extension('keyUsage', 'cRLSign,keyCertSign', true))
            end

            cert.sign(signed_by&.key || key, OpenSSL::Digest::SHA256.new)

            new(key, cert)
          end

          def initialize(key, cert)
            @key = key
            @cert = cert
          end
        end
      end
    end
  end
end