Reindex resource when link status changes

app/models/link_monitor.rb

@@ -1,6 +1,7 @@
 class LinkMonitor < ApplicationRecord
   belongs_to :link_checkable, polymorphic: true, foreign_key: :lcheck_id, foreign_type: :lcheck_type
   before_create :set_initial_date
+  after_commit :reindex_resource, on: :update
 
   FAILURE_THRESHOLD = 4
 
@@ -37,4 +38,18 @@ def success!
   def failing?
     fail_count >= FAILURE_THRESHOLD
   end
+
+  def status_changed?
+    prev_count = fail_count_previously_was || 0
+    (prev_count >= FAILURE_THRESHOLD && fail_count == 0) ||
+      (prev_count < FAILURE_THRESHOLD && failing?)
+  end
+
+  private
+
+  def reindex_resource
+    return unless TeSS::Config.solr_enabled
+    return unless status_changed?
+    link_checkable.solr_index
+  end
 end

test/models/link_monitor_test.rb

@@ -96,4 +96,28 @@ class LinkMonitorTest < ActiveSupport::TestCase
     refute @link_monitor.failing?
     assert_equal 0, @link_monitor.fail_count
   end
+
+  test 'link monitor status changed' do
+    refute @link_monitor.status_changed?
+
+    @link_monitor.update_column(:fail_count, 3)
+    refute @link_monitor.failing?
+    refute @link_monitor.status_changed?
+
+    @link_monitor.fail!(404)
+    assert @link_monitor.failing?
+    assert @link_monitor.status_changed?
+
+    @link_monitor.fail!(404)
+    assert @link_monitor.failing?
+    refute @link_monitor.status_changed?
+
+    @link_monitor.success!
+    refute @link_monitor.failing?
+    assert @link_monitor.status_changed?
+
+    @link_monitor.success!
+    refute @link_monitor.failing?
+    refute @link_monitor.status_changed?
+  end
 end