playlist-audit: Script to help with playlist auditing

As per Sokar's request.
It's not entirely ideal that we're copying the "should be in playlists" criteria here
and in the playlist manager, but it's simple enough (is DONE, is public, matching upload location, tags are a superset of playlist tags) that it should be fine.

playlist-audit

@@ -0,0 +1,38 @@
+#!/bin/bash
+
+if [ "$#" -lt 1 ]; then
+	echo "USAGE: $0 PLAYLIST_ID" >&2
+	echo "List all videos that should be in the playlist with the given youtube playlist id." >&2
+	exit 1
+fi
+
+PLAYLIST_ID="$1"
+# This should match $.youtube_upload_locations in docker-compose.jsonnet
+UPLOAD_LOCATIONS="('desertbus', 'desertbus_slow', 'desertbus_emergency', 'youtube-manual')"
+
+docker-compose exec postgres psql -U postgres wubloader -qtAF ' -> ' <<-EOF
+	SELECT
+		COALESCE((video_ranges[1]).start, events.event_start) as start_time,
+		events.video_title,
+		-- Calculate video duration as sum(range lengths) - sum(transition durations)
+		(
+			(SELECT SUM(r.end - r.start) FROM UNNEST(video_ranges) r)
+			- '1 second'::interval * COALESCE(
+				(SELECT SUM(t.duration) FROM UNNEST(video_transitions) t),
+				0
+			)
+		) as duration
+	FROM events
+	-- Join on "all tags in playlists.tags are in events.tags", aka. playlists.tags is subset of events.tags
+	JOIN playlists ON events.tags @> playlists.tags
+	WHERE
+		playlists.playlist_id = '"$PLAYLIST_ID"'
+		AND events.state = 'DONE'
+		AND events.public
+		AND events.upload_location IN $UPLOAD_LOCATIONS
+	ORDER BY
+		events.id = playlists.first_event_id DESC, -- true means first
+		events.id = playlists.last_event_id ASC, -- false means first
+		start_time
+	;
+EOF