FEATURE: Group logs.

app/services/group_action_logger.rb

@@ -0,0 +1,78 @@
+class GroupActionLogger
+  def initialize(acting_user, group)
+    @acting_user = acting_user
+    @group = group
+  end
+
+  def log_make_user_group_owner(target_user)
+    can_edit?
+
+    GroupHistory.create!(default_params.merge(
+      action: GroupHistory.actions[:make_user_group_owner],
+      target_user: target_user
+    ))
+  end
+
+  def log_remove_user_as_group_owner(target_user)
+    can_edit?
+
+    GroupHistory.create!(default_params.merge(
+      action: GroupHistory.actions[:remove_user_as_group_owner],
+      target_user: target_user
+    ))
+  end
+
+  def log_add_user_to_group(target_user)
+    @group.public || can_edit?
+
+    GroupHistory.create!(default_params.merge(
+      action: GroupHistory.actions[:add_user_to_group],
+      target_user: target_user
+    ))
+  end
+
+  def log_remove_user_from_group(target_user)
+    @group.public || can_edit?
+
+    GroupHistory.create!(default_params.merge(
+      action: GroupHistory.actions[:remove_user_from_group],
+      target_user: target_user
+    ))
+  end
+
+  def log_change_group_settings
+    can_edit?
+
+    @group.previous_changes.except(*excluded_attributes).each do |attribute_name, value|
+      next if value[0].blank? && value[1].blank?
+
+      GroupHistory.create!(default_params.merge(
+        action: GroupHistory.actions[:change_group_setting],
+        subject: attribute_name,
+        prev_value: value[0],
+        new_value: value[1]
+      ))
+    end
+  end
+
+  private
+
+  def excluded_attributes
+    [
+      :bio_cooked,
+      :updated_at,
+      :created_at,
+      :user_count
+    ]
+  end
+
+  def default_params
+    { group: @group, acting_user: @acting_user }
+  end
+
+  def can_edit?
+    unless Guardian.new(@acting_user).can_log_group_changes?(@group)
+      raise Discourse::InvalidParameter
+    end
+  end
+end