[Bugfix] Fix off-by-1 error for retention date logic (#432)

* Added a sanity check test to the media context

* Improves logic for handing media item culling dates

lib/pinchflat/downloading/media_retention_worker.ex

@@ -49,6 +49,8 @@ defmodule Pinchflat.Downloading.MediaRetentionWorker do
     end)
   end
 
+  # NOTE: Since this is a date and not a datetime, we can't add logic to have to-the-minute
+  # comparison like we can with retention periods. We can only compare to the day.
   defp delete_media_items_from_before_cutoff do
     deletable_media =
       MediaQuery.new()

lib/pinchflat/media/media_query.ex

@@ -88,7 +88,7 @@ defmodule Pinchflat.Media.MediaQuery do
       [mi, source],
       fragment("""
         IFNULL(retention_period_days, 0) > 0 AND
-        DATETIME('now', '-' || retention_period_days || ' day') > media_downloaded_at
+        DATETIME(media_downloaded_at, '+' || retention_period_days || ' day') < DATETIME('now')
       """)
     )
   end
@@ -100,8 +100,8 @@ defmodule Pinchflat.Media.MediaQuery do
       # downloaded_at minus the redownload_delay_days is before the upload date
       fragment("""
         IFNULL(redownload_delay_days, 0) > 0 AND
-        DATETIME('now', '-' || redownload_delay_days || ' day') > uploaded_at AND
-        DATETIME(media_downloaded_at, '-' || redownload_delay_days || ' day') < uploaded_at
+        DATE('now', '-' || redownload_delay_days || ' day') > DATE(uploaded_at) AND
+        DATE(media_downloaded_at, '-' || redownload_delay_days || ' day') < DATE(uploaded_at)
       """)
     )
   end