{-# LANGUAGE ConstraintKinds   #-}
{-# LANGUAGE FlexibleContexts  #-}
{-# LANGUAGE NoImplicitPrelude #-}
{-# LANGUAGE OverloadedStrings #-}
module Hbro.Gui.NotificationBar
    ( NotificationBar
    , buildFrom
    , asNotificationBar
    , initialize
    ) where

-- {{{ Imports
import           Hbro.Gui.Builder
import           Hbro.Logger
import           Hbro.Prelude

import           Control.Monad.Trans.Maybe

import           Graphics.Rendering.Pango.Extended
import           Graphics.UI.Gtk.Abstract.Misc
import           Graphics.UI.Gtk.Abstract.Widget
import qualified Graphics.UI.Gtk.Builder                  as Gtk
import           Graphics.UI.Gtk.Display.Label
import           Graphics.UI.Gtk.General.General.Extended

import           System.Glib.Types
-- }}}

-- TODO: make it possible to expand the notification bar to display the last N log lines
-- TODO: make it possible to change the log level

-- {{{ Types
-- | A 'NotificationBar' can be manipulated as a 'Label'.
data NotificationBar = NotificationBar Label

-- | Useful to help the type checker
asNotificationBar :: NotificationBar -> NotificationBar
asNotificationBar = id

-- | A 'NotificationBar' can be built from an XML file.
buildFrom :: (MonadIO m) => Gtk.Builder -> m NotificationBar
buildFrom builder = NotificationBar <$> getWidget builder "notificationLabel"

instance GObjectClass NotificationBar where
    toGObject (NotificationBar l) = toGObject l
    unsafeCastGObject = NotificationBar . unsafeCastGObject

instance WidgetClass NotificationBar
instance MiscClass NotificationBar
instance LabelClass NotificationBar
-- }}}

initialize :: (ControlIO m, MonadThreadedLogger m) => NotificationBar -> m NotificationBar
initialize notifBar = do
  addLogHandler $ \(_loc, _source, level, message) -> void . runMaybeT $ do
    guard $ level >= LevelInfo
    write' message (logColor level) notifBar
  return notifBar

logColor :: LogLevel -> Color
logColor LevelError = red
logColor LevelWarn  = yellow
logColor _          = gray

write :: (MonadIO m) => Text -> NotificationBar -> m NotificationBar
write message = write' message gray

write' :: (MonadIO m) => Text -> Color -> NotificationBar -> m NotificationBar
write' message color bar = do
    gAsync $ do
        labelSetAttributes bar [AttrForeground {paStart = 0, paEnd = -1, paColor = color}]
        labelSetText bar message
    return bar