Sort playlists by last video date

src/Twitch.elm

@@ -50,7 +50,32 @@ decodePlaylist =
 
 decodePlaylists : Decode.Decoder (List Playlist)
 decodePlaylists =
-    Decode.map (List.sortBy .url >> List.reverse) (Decode.list decodePlaylist)
+    Decode.map (sortPlaylists >> List.reverse) (Decode.list decodePlaylist)
+
+
+mostRecentVideo : List Video -> Maybe Time.Posix
+mostRecentVideo videos =
+    case ( videos, List.map .date videos ) of
+        ( _, (Just t) :: _ ) ->
+            Just t
+
+        ( _ :: t, Nothing :: _ ) ->
+            mostRecentVideo t
+
+        _ ->
+            Nothing
+
+
+playlistDate : Playlist -> Int
+playlistDate playlist =
+    mostRecentVideo playlist.videos
+        |> Maybe.map Time.posixToMillis
+        |> Maybe.withDefault 0
+
+
+sortPlaylists : List Playlist -> List Playlist
+sortPlaylists list =
+    List.sortBy playlistDate list
 
 
 fetchPlaylists : (Result Http.Error (List Playlist) -> msg) -> Cmd msg