Move email env var reading to yml files (#35191)

lib/mastodon/email_configuration_helper.rb

@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+module Mastodon
+  module EmailConfigurationHelper
+    module_function
+
+    # Convert smtp settings from environment variables (or defaults in
+    # `config/email.yml`) into the format that `ActionMailer` understands
+    def smtp_settings(config)
+      enable_starttls = nil
+      enable_starttls_auto = nil
+
+      case config[:enable_starttls]
+      when 'always'
+        enable_starttls = true
+      when 'never'
+        enable_starttls = false
+      when 'auto'
+        enable_starttls_auto = true
+      else
+        enable_starttls_auto = config[:enable_starttls_auto] != 'false'
+      end
+
+      authentication = config[:authentication] == 'none' ? nil : (config[:authentication] || 'plain')
+
+      config.merge(
+        authentication:,
+        enable_starttls:,
+        enable_starttls_auto:
+      )
+    end
+  end
+end