Revert "Migrates alerts to an object-oriented implementation"

This reverts commit fbc283f12f.

scripts/lua/modules/alert_definitions/alert_ghost_network.lua

@@ -2,48 +2,30 @@
 -- (C) 2019-20 - ntop.org
 --
 
--- ##############################################
-
 local alert_keys = require "alert_keys"
 
--- Import the classes library.
-local classes = require "classes"
--- Make sure to import the Superclass!
-local alert = require "alert"
-
--- ##############################################
-
-local alert_ghost_network = classes.class(alert)
-
--- ##############################################
-
-alert_ghost_network.meta = {
-  alert_key = alert_keys.ntopng.alert_ghost_network,
-  i18n_title = "alerts_dashboard.ghost_network_detected",
-  icon = "fas fa-ghost",
-}
-
--- ##############################################
+-- #######################################################
 
 -- @brief Prepare an alert table used to generate the alert
--- @param one_param The first alert param
--- @param another_param The second alert param
+-- @param alert_severity A severity as defined in `alert_severities`
+-- @param alert_granularity A granularity as defined in `alert_consts.alerts_granularities`
+-- @param network The string CIDR of the ghost network
 -- @return A table with the alert built
-function alert_ghost_network:init()
-   -- Call the paren constructor
-   self.super:init()
+local function createGhostNetwork(alert_severity, alert_granularity, network)
+   local built = {
+      alert_severity = alert_severity,
+      alert_granularity = alert_granularity,
+      alert_subtype = network,
+      alert_type_params = {
+      },
+   }
 
-   self.alert_type_params = {}
+   return built
 end
 
 -- #######################################################
 
--- @brief Format an alert into a human-readable string
--- @param ifid The integer interface id of the generated alert
--- @param alert The alert description table, including alert data such as the generating entity, timestamp, granularity, type
--- @param alert_type_params Table `alert_type_params` as built in the `:init` method
--- @return A human-readable string
-function alert_ghost_network.format(ifid, alert, alert_type_params)
+local function ghostNetworkFormatter(ifid, alert, info)
   return(i18n("alerts_dashboard.ghost_network_detected_description", {
     network = alert.alert_subtype,
     entity = getInterfaceName(ifid),
@@ -53,4 +35,10 @@ end
 
 -- #######################################################
 
-return alert_ghost_network
+return {
+  alert_key = alert_keys.ntopng.alert_ghost_network,
+  i18n_title = "alerts_dashboard.ghost_network_detected",
+  i18n_description = ghostNetworkFormatter,
+  icon = "fas fa-ghost",
+  creator = createGhostNetwork,
+}