#
# License:: Apache License, Version 2.0
#
# 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.
#

module OpenSSLCookbook
  # Helper functions for the OpenSSL cookbook.
  module Helpers
    def self.included(_base)
      require 'openssl' unless defined?(::OpenSSL)
    end

    # determine the key filename from the cert filename
    # @param [String] cert_filename the path to the certfile
    # @return [String] the path to the keyfile
    def get_key_filename(cert_filename)
      cert_file_path, cert_filename = ::File.split(cert_filename)
      cert_filename = ::File.basename(cert_filename, ::File.extname(cert_filename))
      cert_file_path + ::File::SEPARATOR + cert_filename + '.key'
    end

    # is the key length a valid key length
    # @param [Integer] number
    # @return [Boolean] is length valid
    def key_length_valid?(number)
      number >= 1024 && (number & (number - 1) == 0)
    end

    # validate a dhparam file from path
    # @param [String] dhparam_pem_path the path to the pem file
    # @return [Boolean] is the key valid
    def dhparam_pem_valid?(dhparam_pem_path)
      # Check if the dhparam.pem file exists
      # Verify the dhparam.pem file contains a key
      return false unless ::File.exist?(dhparam_pem_path)
      dhparam = ::OpenSSL::PKey::DH.new File.read(dhparam_pem_path)
      dhparam.params_ok?
    end

    # given either a key file path or key file content see if it's actually
    # a private key
    # @param [String] key_file the path to the keyfile or the key contents
    # @param [String] key_password optional password to the keyfile
    # @return [Boolean] is the key valid?
    def priv_key_file_valid?(key_file, key_password = nil)
      # if the file exists try to read the content
      # if not assume we were passed the key and set the string to the content
      key_content = ::File.exist?(key_file) ? File.read(key_file) : key_file

      begin
        key = ::OpenSSL::PKey.read key_content, key_password
      rescue ::OpenSSL::PKey::PKeyError, ArgumentError
        return false
      end

      if key.is_a?(::OpenSSL::PKey::EC)
        key.private_key?
      else
        key.private?
      end
    end

    # given a crl file path see if it's actually a crl
    # @param [String] crl_file the path to the crlfile
    # @return [Boolean] is the key valid?
    def crl_file_valid?(crl_file)
      begin
        ::OpenSSL::X509::CRL.new ::File.read(crl_file)
      rescue ::OpenSSL::X509::CRLError, Errno::ENOENT
        return false
      end
      true
    end

    # check is a serial given is revoked in a crl given
    # @param [OpenSSL::X509::CRL] crl X509 CRL to check
    # @param [String, Integer] serial X509 Certificate Serial Number
    # @return [true, false]
    def serial_revoked?(crl, serial)
      raise TypeError, 'crl must be a Ruby OpenSSL::X509::CRL object' unless crl.is_a?(::OpenSSL::X509::CRL)
      raise TypeError, 'serial must be a Ruby String or Integer object' unless serial.is_a?(String) || serial.is_a?(Integer)

      serial_to_verify = if serial.is_a?(String)
                           serial.to_i(16)
                         else
                           serial
                         end
      status = false
      crl.revoked.each do |revoked|
        status = true if revoked.serial == serial_to_verify
      end
      status
    end

    # generate a dhparam file
    # @param [String] key_length the length of the key
    # @param [Integer] generator the dhparam generator to use
    # @return [OpenSSL::PKey::DH]
    def gen_dhparam(key_length, generator)
      raise ArgumentError, 'Key length must be a power of 2 greater than or equal to 1024' unless key_length_valid?(key_length)
      raise TypeError, 'Generator must be an integer' unless generator.is_a?(Integer)

      ::OpenSSL::PKey::DH.new(key_length, generator)
    end

    # generate an RSA private key given key length
    # @param [Integer] key_length the key length of the private key
    # @return [OpenSSL::PKey::DH]
    def gen_rsa_priv_key(key_length)
      raise ArgumentError, 'Key length must be a power of 2 greater than or equal to 1024' unless key_length_valid?(key_length)

      ::OpenSSL::PKey::RSA.new(key_length)
    end

    # generate pem format of the public key given a private key
    # @param [String] priv_key either the contents of the private key or the path to the file
    # @param [String] priv_key_password optional password for the private key
    # @return [String] pem format of the public key
    def gen_rsa_pub_key(priv_key, priv_key_password = nil)
      # if the file exists try to read the content
      # if not assume we were passed the key and set the string to the content
      key_content = ::File.exist?(priv_key) ? File.read(priv_key) : priv_key
      key = ::OpenSSL::PKey::RSA.new key_content, priv_key_password
      key.public_key.to_pem
    end

    # generate a pem file given a cipher, key, an optional key_password
    # @param [OpenSSL::PKey::RSA] rsa_key the private key object
    # @param [String] key_password the password for the private key
    # @param [String] key_cipher the cipher to use
    # @return [String] pem contents
    def encrypt_rsa_key(rsa_key, key_password, key_cipher)
      raise TypeError, 'rsa_key must be a Ruby OpenSSL::PKey::RSA object' unless rsa_key.is_a?(::OpenSSL::PKey::RSA)
      raise TypeError, 'key_password must be a string' unless key_password.is_a?(String)
      raise TypeError, 'key_cipher must be a string' unless key_cipher.is_a?(String)
      raise ArgumentError, 'Specified key_cipher is not available on this system' unless ::OpenSSL::Cipher.ciphers.include?(key_cipher)

      cipher = ::OpenSSL::Cipher.new(key_cipher)
      rsa_key.to_pem(cipher, key_password)
    end

    # generate an ec private key given curve type
    # @param [String] curve the kind of curve to use
    # @return [OpenSSL::PKey::DH]
    def gen_ec_priv_key(curve)
      raise TypeError, 'curve must be a string' unless curve.is_a?(String)
      raise ArgumentError, 'Specified curve is not available on this system' unless curve == 'prime256v1' || curve == 'secp384r1' || curve == 'secp521r1'
      ::OpenSSL::PKey::EC.new(curve).generate_key
    end

    # generate pem format of the public key given a private key
    # @param [String] priv_key either the contents of the private key or the path to the file
    # @param [String] priv_key_password optional password for the private key
    # @return [String] pem format of the public key
    def gen_ec_pub_key(priv_key, priv_key_password = nil)
      # if the file exists try to read the content
      # if not assume we were passed the key and set the string to the content
      key_content = ::File.exist?(priv_key) ? File.read(priv_key) : priv_key
      key = ::OpenSSL::PKey::EC.new key_content, priv_key_password

      # Get curve type (prime256v1...)
      group = ::OpenSSL::PKey::EC::Group.new(key.group.curve_name)
      # Get Generator point & public point (priv * generator)
      generator = group.generator
      pub_point = generator.mul(key.private_key)
      key.public_key = pub_point

      # Public Key in pem
      public_key = ::OpenSSL::PKey::EC.new
      public_key.group = group
      public_key.public_key = pub_point
      public_key.to_pem
    end

    # generate a pem file given a cipher, key, an optional key_password
    # @param [OpenSSL::PKey::EC] ec_key the private key object
    # @param [String] key_password the password for the private key
    # @param [String] key_cipher the cipher to use
    # @return [String] pem contents
    def encrypt_ec_key(ec_key, key_password, key_cipher)
      raise TypeError, 'ec_key must be a Ruby OpenSSL::PKey::EC object' unless ec_key.is_a?(::OpenSSL::PKey::EC)
      raise TypeError, 'key_password must be a string' unless key_password.is_a?(String)
      raise TypeError, 'key_cipher must be a string' unless key_cipher.is_a?(String)
      raise ArgumentError, 'Specified key_cipher is not available on this system' unless ::OpenSSL::Cipher.ciphers.include?(key_cipher)

      cipher = ::OpenSSL::Cipher.new(key_cipher)
      ec_key.to_pem(cipher, key_password)
    end

    # generate a csr pem file given a subject and a private key
    # @param [OpenSSL::X509::Name] subject the x509 subject object
    # @param [OpenSSL::PKey::EC, OpenSSL::PKey::RSA] key the private key object
    # @return [OpenSSL::X509::Request]
    def gen_x509_request(subject, key)
      raise TypeError, 'subject must be a Ruby OpenSSL::X509::Name object' unless subject.is_a?(::OpenSSL::X509::Name)
      raise TypeError, 'key must be a Ruby OpenSSL::PKey::EC or a Ruby OpenSSL::PKey::RSA object' unless key.is_a?(::OpenSSL::PKey::EC) || key.is_a?(::OpenSSL::PKey::RSA)

      request = ::OpenSSL::X509::Request.new
      request.version = 0
      request.subject = subject
      request.public_key = key

      # Chef 12 backward compatibility
      ::OpenSSL::PKey::EC.send(:alias_method, :private?, :private_key?)

      request.sign(key, ::OpenSSL::Digest::SHA256.new)
      request
    end

    # generate an array of X509 Extensions given a hash of extensions
    # @param [Hash] extensions hash of extensions
    # @return [Array]
    def gen_x509_extensions(extensions)
      raise TypeError, 'extensions must be a Ruby Hash object' unless extensions.is_a?(Hash)

      exts = []
      extensions.each do |ext_name, ext_prop|
        raise TypeError, "#{ext_name} must contain a Ruby Hash" unless ext_prop.is_a?(Hash)
        raise ArgumentError, "keys in #{ext_name} must be 'values' and 'critical'" unless ext_prop.key?('values') && ext_prop.key?('critical')
        raise TypeError, "the key 'values' must contain a Ruby Arrays" unless ext_prop['values'].is_a?(Array)
        raise TypeError, "the key 'critical' must be a Ruby Boolean true/false" unless ext_prop['critical'].is_a?(TrueClass) || ext_prop['critical'].is_a?(FalseClass)

        exts << ::OpenSSL::X509::ExtensionFactory.new.create_extension(ext_name, ext_prop['values'].join(','), ext_prop['critical'])
      end
      exts
    end

    # generate a random Serial
    # @return [Integer]
    def gen_serial
      ::OpenSSL::BN.generate_prime(160)
    end

    # generate a Certificate given a X509 request
    # @param [OpenSSL::X509::Request] request X509 Certificate Request
    # @param [Array] extension Array of X509 Certificate Extension
    # @param [Hash] info issuer & validity
    # @param [OpenSSL::PKey::EC, OpenSSL::PKey::RSA] key private key to sign with
    # @return [OpenSSL::X509::Certificate]
    def gen_x509_cert(request, extension, info, key)
      raise TypeError, 'request must be a Ruby OpenSSL::X509::Request' unless request.is_a?(::OpenSSL::X509::Request)
      raise TypeError, 'extension must be a Ruby Array' unless extension.is_a?(Array)
      raise TypeError, 'info must be a Ruby Hash' unless info.is_a?(Hash)
      raise TypeError, 'key must be a Ruby OpenSSL::PKey::EC object or a Ruby OpenSSL::PKey::RSA object' unless key.is_a?(::OpenSSL::PKey::EC) || key.is_a?(::OpenSSL::PKey::RSA)

      raise ArgumentError, 'info must contain a validity' unless info.key?('validity')
      raise TypeError, 'info[\'validity\'] must be a Ruby Integer object' unless info['validity'].is_a?(Integer)

      cert = ::OpenSSL::X509::Certificate.new
      ef = ::OpenSSL::X509::ExtensionFactory.new

      cert.serial = gen_serial()
      cert.version = 2
      cert.subject = request.subject
      cert.public_key = request.public_key
      cert.not_before = Time.now
      cert.not_after = cert.not_before + info['validity'] * 24 * 60 * 60

      if info['issuer'].nil?
        cert.issuer = request.subject
        ef.issuer_certificate = cert
        extension << ef.create_extension('basicConstraints', 'CA:TRUE', true)
      else
        raise TypeError, 'info[\'issuer\'] must be a Ruby OpenSSL::X509::Certificate object' unless info['issuer'].is_a?(::OpenSSL::X509::Certificate)
        cert.issuer = info['issuer'].subject
        ef.issuer_certificate = info['issuer']
      end
      ef.subject_certificate = cert
      ef.config = ::OpenSSL::Config.load(::OpenSSL::Config::DEFAULT_CONFIG_FILE)

      cert.extensions = extension
      cert.add_extension ef.create_extension('subjectKeyIdentifier', 'hash')
      cert.add_extension ef.create_extension('authorityKeyIdentifier',
                                             'keyid:always,issuer:always')

      cert.sign(key, ::OpenSSL::Digest::SHA256.new)
      cert
    end

    # generate a X509 CRL given a CA
    # @param [OpenSSL::PKey::EC, OpenSSL::PKey::RSA] ca_private_key private key from the CA
    # @param [Hash] info issuer & validity
    # @return [OpenSSL::X509::CRL]
    def gen_x509_crl(ca_private_key, info)
      raise TypeError, 'ca_private_key must be a Ruby OpenSSL::PKey::EC object or a Ruby OpenSSL::PKey::RSA object' unless ca_private_key.is_a?(::OpenSSL::PKey::EC) || ca_private_key.is_a?(::OpenSSL::PKey::RSA)
      raise TypeError, 'info must be a Ruby Hash' unless info.is_a?(Hash)

      raise ArgumentError, 'info must contain a issuer and a validity' unless info.key?('issuer') && info.key?('validity')
      raise TypeError, 'info[\'issuer\'] must be a Ruby OpenSSL::X509::Certificate object' unless info['issuer'].is_a?(::OpenSSL::X509::Certificate)
      raise TypeError, 'info[\'validity\'] must be a Ruby Integer object' unless info['validity'].is_a?(Integer)

      crl = ::OpenSSL::X509::CRL.new
      ef = ::OpenSSL::X509::ExtensionFactory.new

      crl.version = 1
      crl.issuer = info['issuer'].subject
      crl.last_update = Time.now
      crl.next_update = Time.now + 3600 * 24 * info['validity']

      ef.config = ::OpenSSL::Config.load(::OpenSSL::Config::DEFAULT_CONFIG_FILE)
      ef.issuer_certificate = info['issuer']

      crl.add_extension ::OpenSSL::X509::Extension.new('crlNumber', ::OpenSSL::ASN1::Integer(1))
      crl.add_extension ef.create_extension('authorityKeyIdentifier',
                                            'keyid:always,issuer:always')
      crl.sign(ca_private_key, ::OpenSSL::Digest::SHA256.new)
      crl
    end

    # generate the next CRL number available for a X509 CRL given
    # @param [OpenSSL::X509::CRL] crl x509 CRL
    # @return [Integer]
    def get_next_crl_number(crl)
      raise TypeError, 'crl must be a Ruby OpenSSL::X509::CRL object' unless crl.is_a?(::OpenSSL::X509::CRL)
      crlnum = 1
      crl.extensions.each do |e|
        crlnum = e.value if e.oid == 'crlNumber'
      end
      crlnum.to_i + 1
    end

    # add a serial given in the crl given
    # @param [Hash] revoke_info serial to revoke & revokation reason
    # @param [OpenSSL::X509::CRL] crl X509 CRL
    # @param [OpenSSL::PKey::EC, OpenSSL::PKey::RSA] ca_private_key private key from the CA
    # @param [Hash] info issuer & validity
    # @return [OpenSSL::X509::CRL]
    def revoke_x509_crl(revoke_info, crl, ca_private_key, info)
      raise TypeError, 'revoke_info must be a Ruby Hash oject' unless revoke_info.is_a?(Hash)
      raise TypeError, 'crl must be a Ruby OpenSSL::X509::CRL object' unless crl.is_a?(::OpenSSL::X509::CRL)
      raise TypeError, 'ca_private_key must be a Ruby OpenSSL::PKey::EC object or a Ruby OpenSSL::PKey::RSA object' unless ca_private_key.is_a?(::OpenSSL::PKey::EC) || ca_private_key.is_a?(::OpenSSL::PKey::RSA)
      raise TypeError, 'info must be a Ruby Hash' unless info.is_a?(Hash)

      raise ArgumentError, 'revoke_info must contain a serial and a reason' unless revoke_info.key?('serial') && revoke_info.key?('reason')
      raise TypeError, 'revoke_info[\'serial\'] must be a Ruby String or Integer object' unless revoke_info['serial'].is_a?(String) || revoke_info['serial'].is_a?(Integer)
      raise TypeError, 'revoke_info[\'reason\'] must be a Ruby Integer object' unless revoke_info['reason'].is_a?(Integer)

      raise ArgumentError, 'info must contain a issuer and a validity' unless info.key?('issuer') && info.key?('validity')
      raise TypeError, 'info[\'issuer\'] must be a Ruby OpenSSL::X509::Certificate object' unless info['issuer'].is_a?(::OpenSSL::X509::Certificate)
      raise TypeError, 'info[\'validity\'] must be a Ruby Integer object' unless info['validity'].is_a?(Integer)

      revoked = ::OpenSSL::X509::Revoked.new
      revoked.serial = if revoke_info['serial'].is_a?(String)
                         revoke_info['serial'].to_i(16)
                       else
                         revoke_info['serial']
                       end
      revoked.time = Time.now

      ext = ::OpenSSL::X509::Extension.new('CRLReason',
             ::OpenSSL::ASN1::Enumerated(revoke_info['reason']))
      revoked.add_extension(ext)
      crl.add_revoked(revoked)

      crl = renew_x509_crl(crl, ca_private_key, info)
      crl
    end

    # renew a X509 crl given
    # @param [OpenSSL::X509::CRL] crl CRL to renew
    # @param [OpenSSL::PKey::EC, OpenSSL::PKey::RSA] ca_private_key private key from the CA
    # @param [Hash] info issuer & validity
    # @return [OpenSSL::X509::CRL]
    def renew_x509_crl(crl, ca_private_key, info)
      raise TypeError, 'crl must be a Ruby OpenSSL::X509::CRL object' unless crl.is_a?(::OpenSSL::X509::CRL)
      raise TypeError, 'ca_private_key must be a Ruby OpenSSL::PKey::EC object or a Ruby OpenSSL::PKey::RSA object' unless ca_private_key.is_a?(::OpenSSL::PKey::EC) || ca_private_key.is_a?(::OpenSSL::PKey::RSA)
      raise TypeError, 'info must be a Ruby Hash' unless info.is_a?(Hash)

      raise ArgumentError, 'info must contain a issuer and a validity' unless info.key?('issuer') && info.key?('validity')
      raise TypeError, 'info[\'issuer\'] must be a Ruby OpenSSL::X509::Certificate object' unless info['issuer'].is_a?(::OpenSSL::X509::Certificate)
      raise TypeError, 'info[\'validity\'] must be a Ruby Integer object' unless info['validity'].is_a?(Integer)

      crl.last_update = Time.now
      crl.next_update = crl.last_update + 3600 * 24 * info['validity']

      ef = ::OpenSSL::X509::ExtensionFactory.new
      ef.config = ::OpenSSL::Config.load(::OpenSSL::Config::DEFAULT_CONFIG_FILE)
      ef.issuer_certificate = info['issuer']

      crl.extensions = [ ::OpenSSL::X509::Extension.new('crlNumber',
                 ::OpenSSL::ASN1::Integer(get_next_crl_number(crl)))]
      crl.add_extension ef.create_extension('authorityKeyIdentifier',
                                            'keyid:always,issuer:always')
      crl.sign(ca_private_key, ::OpenSSL::Digest::SHA256.new)
      crl
    end
  end
end
