customize log entry bodies on a per field basis

Lorenzo Tello · Lorenzo Tello · commit 2b41634d6a6a · 2017-07-25T10:04:53.000+01:00
diff --git a/lib/logga/active_record.rb b/lib/logga/active_record.rb
@@ -2,30 +2,42 @@ module Logga
   module ActiveRecord
     extend ActiveSupport::Concern
 
+    EXCLUDED_KEYS          = [:created_at, :updated_at, :log, :sent_photos_chaser_email, :sent_after_sales_emails]
+    EXCLUDED_KEYS_SUFFIXES = [:_id, :_filenames]
+
+    included do
+      class_attribute :log_fields, instance_writer: false
+      self.log_fields = {}
+    end
+
     class_methods do
-      def add_log_entries_for(*actions, to: :self)
+      def add_log_entries_for(*actions, to: :self, fields: {})
         after_create :log_model_creation if actions.include?(:create)
         after_update :log_model_changes  if actions.include?(:update)
         define_method(:log_receiver) { to == :self ? self : send(to) }
+        self.log_fields = fields
       end
     end
 
     def log_model_creation
-      body = "#{self.class} created"
+      body_generator = ->(record) { default_creation_log_body(record) }
+      body = log_fields.fetch(:created_at, body_generator).call(self)
       log_receiver.log_entries.create(author_data.merge(body: body))
     end
 
     def log_model_changes
-      field_changes = changes.except(:created_at, :updated_at, :log)
+      field_changes = changes.reject do |k, _|
+        EXCLUDED_KEYS.include?(k.to_sym) ||
+        EXCLUDED_KEYS_SUFFIXES.any? { |suffix| k.to_s.end_with?(suffix.to_s) }
+      end
       log_field_changes(field_changes)
     end
 
     def log_field_changes(changes)
-      changes.each { |field, values| log_field_change(field, *values) }
-    end
-
-    def log_field_change(field, old_value, new_value)
-      body = "changed #{field} from #{old_value} to #{new_value}"
+      body_generator = ->(record, field, old_value, new_value) { default_change_log_body(record, field, old_value, new_value) }
+      body = changes.inject([]) do |body, (field, (old_value, new_value))|
+        body << log_fields.fetch(field.to_sym, body_generator).call(self, field, old_value, new_value)
+      end.join('\n')
       log_receiver.log_entries.create(author_data.merge(body: body))
     end
 
@@ -37,5 +49,16 @@ def author_data
           author_name: data[:name]
       }
     end
+
+    def default_creation_log_body(record)
+      [
+        "#{record.class.name.demodulize} created",
+        ("(#{record.state})" if record.try(:state))
+      ].compact.join(' ')
+    end
+
+    def default_change_log_body(record, field, old_value, new_value)
+      "#{record.class.name.demodulize} #{field} set to #{new_value}"
+    end
   end
-end
+end
