fix: account email validation during signup (#11307)

- Refactor email validation logic to be a service
- Use the service for both email/pass signup and Google SSO
- fix account email validation during signup
- Use `blocked_domain` setting for both email/pass signup and Google
Sign In [`BLOCKED_DOMAIN` via GlobalConfig]
- add specs for `account_builder`
- add specs for the new service

---------

Co-authored-by: Sojan Jose <sojan@pepalo.com>

app/builders/account_builder.rb

@@ -32,14 +32,7 @@ class AccountBuilder
   end
 
   def validate_email
-    raise InvalidEmail.new({ domain_blocked: domain_blocked }) if domain_blocked?
-
-    address = ValidEmail2::Address.new(@email)
-    if address.valid? && !address.disposable?
-      true
-    else
-      raise InvalidEmail.new({ valid: address.valid?, disposable: address.disposable? })
-    end
+    Account::SignUpEmailValidationService.new(@email).perform
   end
 
   def validate_user
@@ -81,21 +74,4 @@ class AccountBuilder
     @user.confirm if @confirmed
     @user.save!
   end
-
-  def domain_blocked?
-    domain = @email.split('@').last
-
-    blocked_domains.each do |blocked_domain|
-      return true if domain.match?(blocked_domain)
-    end
-
-    false
-  end
-
-  def blocked_domains
-    domains = GlobalConfigService.load('BLOCKED_EMAIL_DOMAINS', '')
-    return [] if domains.blank?
-
-    domains.split("\n").map(&:strip)
-  end
 end

app/controllers/devise_overrides/omniauth_callbacks_controller.rb

@@ -21,7 +21,7 @@ class DeviseOverrides::OmniauthCallbacksController < DeviseTokenAuth::OmniauthCa
 
   def sign_up_user
     return redirect_to login_page_url(error: 'no-account-found') unless account_signup_allowed?
-    return redirect_to login_page_url(error: 'business-account-only') unless validate_business_account?
+    return redirect_to login_page_url(error: 'business-account-only') unless validate_signup_email_is_business_domain?
 
     create_account_for_user
     token = @resource.send(:set_reset_password_token)
@@ -53,9 +53,11 @@ class DeviseOverrides::OmniauthCallbacksController < DeviseTokenAuth::OmniauthCa
     ).first
   end
 
-  def validate_business_account?
-    # return true if the user is a business account, false if it is a gmail account
-    auth_hash['info']['email'].downcase.exclude?('@gmail.com')
+  def validate_signup_email_is_business_domain?
+    # return true if the user is a business account, false if it is a blocked domain account
+    Account::SignUpEmailValidationService.new(auth_hash['info']['email']).perform
+  rescue CustomExceptions::Account::InvalidEmail
+    false
   end
 
   def create_account_for_user

app/services/account/sign_up_email_validation_service.rb

@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+class Account::SignUpEmailValidationService
+  include CustomExceptions::Account
+  attr_reader :email
+
+  def initialize(email)
+    @email = email
+  end
+
+  def perform
+    address = ValidEmail2::Address.new(email)
+
+    raise InvalidEmail.new({ valid: false, disposable: nil }) unless address.valid?
+
+    raise InvalidEmail.new({ domain_blocked: true }) if domain_blocked?
+
+    raise InvalidEmail.new({ valid: true, disposable: true }) if address.disposable?
+
+    true
+  end
+
+  private
+
+  def domain_blocked?
+    domain = email.split('@').last&.downcase
+    blocked_domains.any? { |blocked_domain| domain.match?(blocked_domain.downcase) }
+  end
+
+  def blocked_domains
+    domains = GlobalConfigService.load('BLOCKED_EMAIL_DOMAINS', '')
+    return [] if domains.blank?
+
+    domains.split("\n").map(&:strip)
+  end
+end