shared link 2fa

lib/email_verification_codes.rb

@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+module EmailVerificationCodes
+  DRIFT_BEHIND = 5.minutes
+
+  module_function
+
+  def generate(value)
+    totp = ROTP::TOTP.new(build_totp_secret(value))
+
+    totp.at(Time.current)
+  end
+
+  def verify(code, value)
+    totp = ROTP::TOTP.new(build_totp_secret(value))
+
+    totp.verify(code, drift_behind: DRIFT_BEHIND)
+  end
+
+  def build_totp_secret(value)
+    ROTP::Base32.encode(
+      Digest::SHA1.digest(
+        [Rails.application.secret_key_base, value].join(':')
+      )
+    )
+  end
+end