taffybar: add AIUsage stack widget that switches on scratchpad state

Reads $XDG_STATE_HOME/hypr/ai-scratchpad (written by the Super+Alt+C
toggle) to show either the OpenAI or Anthropic usage section. Uses a
Gtk.Stack for instant switching and fsnotify to watch the state file
for live updates without polling.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

dotfiles/config/taffybar/TaffybarConfig/AIUsage.hs

@@ -0,0 +1,116 @@
+{-# LANGUAGE OverloadedStrings #-}
+
+-- | A usage widget that follows the Hyprland AI scratchpad selection.
+--
+-- The Hyprland config (scratchpads.lua) lets SUPER+ALT+C toggle whichever AI
+-- app is currently selected via rofi_ai_scratchpad.sh, which records the
+-- choice in $XDG_STATE_HOME/hypr/ai-scratchpad. This widget reads the same
+-- state file and shows the matching provider's usage section (OpenAI for
+-- "codex", Anthropic for "claude"), switching live when the file changes.
+module TaffybarConfig.AIUsage
+  ( aiUsageWidget,
+  )
+where
+
+import Control.Exception (IOException, try)
+import Control.Monad (void)
+import Control.Monad.IO.Class (liftIO)
+import Data.Text (Text)
+import qualified Data.Text as T
+import qualified GI.Gtk as Gtk
+import qualified System.FSNotify as FSNotify
+import System.Directory (createDirectoryIfMissing, getHomeDirectory)
+import System.Environment (lookupEnv)
+import System.FilePath (takeFileName, (</>))
+import System.Taffybar.Context (TaffyIO)
+import System.Taffybar.Util (postGUIASync)
+import System.Taffybar.Widget.AnthropicUsage
+  ( AnthropicUsageDisplayMode (AnthropicUsageDisplayRemaining),
+    AnthropicUsageStackConfig (..),
+    anthropicUsageSectionNewWith,
+    defaultAnthropicUsageStackConfig,
+  )
+import System.Taffybar.Widget.OpenAIUsage
+  ( OpenAIUsageDisplayMode (OpenAIUsageDisplayRemaining),
+    OpenAIUsageStackConfig (..),
+    defaultOpenAIUsageStackConfig,
+    openAIUsageSectionNewWith,
+  )
+import TaffybarConfig.WidgetUtil (decorateWithClassAndBox, usageLogoWidget)
+
+codexChild, claudeChild :: Text
+codexChild = "codex"
+claudeChild = "claude"
+
+aiScratchpadStateDir :: IO FilePath
+aiScratchpadStateDir = do
+  stateHome <- lookupEnv "XDG_STATE_HOME"
+  base <- case stateHome of
+    Just dir | not (null dir) -> pure dir
+    _ -> (</> ".local/state") <$> getHomeDirectory
+  pure (base </> "hypr")
+
+aiScratchpadStateFile :: FilePath
+aiScratchpadStateFile = "ai-scratchpad"
+
+-- | Read the currently selected AI scratchpad, defaulting to codex like the
+-- Hyprland side does.
+readActiveAIScratchpad :: IO Text
+readActiveAIScratchpad = do
+  dir <- aiScratchpadStateDir
+  result <- try (readFile (dir </> aiScratchpadStateFile)) :: IO (Either IOException String)
+  pure $ case result of
+    Right contents
+      | T.strip (T.pack contents) == claudeChild -> claudeChild
+    _ -> codexChild
+
+openAIUsageSection :: TaffyIO Gtk.Widget
+openAIUsageSection = do
+  iconWidget <- liftIO $ usageLogoWidget "openai-symbol.svg" "OpenAI usage"
+  openAIUsageSectionNewWith
+    iconWidget
+    defaultOpenAIUsageStackConfig
+      { openAIUsageStackDefaultDisplayMode = OpenAIUsageDisplayRemaining
+      }
+
+anthropicUsageSection :: TaffyIO Gtk.Widget
+anthropicUsageSection = do
+  iconWidget <- liftIO $ usageLogoWidget "claude-symbol.svg" "Claude usage"
+  anthropicUsageSectionNewWith
+    iconWidget
+    defaultAnthropicUsageStackConfig
+      { anthropicUsageStackDefaultDisplayMode = AnthropicUsageDisplayRemaining
+      }
+
+-- | Show usage for whichever AI app the Hyprland AI scratchpad currently
+-- targets, switching live when the selection changes.
+aiUsageWidget :: TaffyIO Gtk.Widget
+aiUsageWidget = do
+  openAIWidget <- openAIUsageSection
+  anthropicWidget <- anthropicUsageSection
+  stackWidget <- liftIO $ do
+    stack <- Gtk.stackNew
+    Gtk.stackAddNamed stack openAIWidget codexChild
+    Gtk.stackAddNamed stack anthropicWidget claudeChild
+    readActiveAIScratchpad >>= Gtk.stackSetVisibleChildName stack
+
+    let syncVisibleChild =
+          readActiveAIScratchpad
+            >>= \name -> postGUIASync (Gtk.stackSetVisibleChildName stack name)
+
+    void $ Gtk.onWidgetRealize stack $ do
+      stateDir <- aiScratchpadStateDir
+      createDirectoryIfMissing True stateDir
+      manager <- FSNotify.startManager
+      void $
+        FSNotify.watchDir
+          manager
+          stateDir
+          ((== aiScratchpadStateFile) . takeFileName . FSNotify.eventPath)
+          (const syncVisibleChild)
+      syncVisibleChild
+      void $ Gtk.onWidgetUnrealize stack $ FSNotify.stopManager manager
+
+    Gtk.widgetShowAll stack
+    Gtk.toWidget stack
+  decorateWithClassAndBox "ai-usage" stackWidget

dotfiles/config/taffybar/TaffybarConfig/Widgets.hs

@@ -33,12 +33,6 @@ import qualified System.Taffybar.Widget.Audio as Audio
 import System.Taffybar.Widget.CPUMonitor (cpuMonitorNew)
 import System.Taffybar.Widget.Generic.Graph (GraphConfig (..), GraphDirection (..), GraphStyle (..), defaultGraphConfig)
 import qualified System.Taffybar.Widget.NetworkManager as NetworkManager
-import System.Taffybar.Widget.OpenAIUsage
-  ( OpenAIUsageDisplayMode (OpenAIUsageDisplayRemaining),
-    OpenAIUsageStackConfig (..),
-    defaultOpenAIUsageStackConfig,
-    openAIUsageSectionNewWith,
-  )
 import System.Taffybar.Widget.SNIMenu (withNmAppletMenu)
 import System.Taffybar.Widget.SNITray
   ( CollapsibleSNITrayParams (..),
@@ -60,6 +54,7 @@ import System.Taffybar.Widget.Util
   )
 import qualified System.Taffybar.Widget.Wlsunset as Wlsunset
 import qualified System.Taffybar.Widget.Workspaces as Workspaces
+import TaffybarConfig.AIUsage (aiUsageWidget)
 import TaffybarConfig.Host (laptopHosts)
 import TaffybarConfig.WidgetUtil
   ( decorateWithClassAndBox,
@@ -375,16 +370,6 @@ usageSectionWidget klass iconFile tooltip stackBuilder =
       section <- buildIconLabelBox iconWidget stack
       widgetSetClassGI section "usage-section"
 
-openAIUsageWidget :: TaffyIO Gtk.Widget
-openAIUsageWidget = do
-  iconWidget <- liftIO $ usageLogoWidget "openai-symbol.svg" "OpenAI usage"
-  decorateWithClassAndBoxM "openai-usage" $
-    openAIUsageSectionNewWith
-      iconWidget
-      defaultOpenAIUsageStackConfig
-        { openAIUsageStackDefaultDisplayMode = OpenAIUsageDisplayRemaining
-        }
-
 sniPriorityVisibilityThresholdDefault :: Int
 sniPriorityVisibilityThresholdDefault = 0
 
@@ -445,7 +430,7 @@ endWidgetsForHost hostName =
   let baseEndWidgets =
         [ sniTrayWidget,
           audioWidget,
-          openAIUsageWidget,
+          aiUsageWidget,
           cpuWidget,
           ramSwapWidget,
           diskUsageWidget,
@@ -458,7 +443,7 @@ endWidgetsForHost hostName =
           sniTrayWidget,
           asusDiskUsageWidget,
           audioBacklightWidget,
-          openAIUsageWidget,
+          aiUsageWidget,
           cpuWidget,
           ramSwapWidget,
           sunLockWidget,

dotfiles/config/taffybar/imalison-taffybar.cabal

@@ -13,7 +13,8 @@ cabal-version:       >=1.10
 executable taffybar
   hs-source-dirs:      .
   main-is:             taffybar.hs
-  other-modules:       TaffybarConfig.Config
+  other-modules:       TaffybarConfig.AIUsage
+                     , TaffybarConfig.Config
                      , TaffybarConfig.ChromeFavicons
                      , TaffybarConfig.Host
                      , TaffybarConfig.Widgets
@@ -27,6 +28,7 @@ executable taffybar
                      , containers
                      , directory
                      , filepath
+                     , fsnotify
                      , gi-gdk3
                      , gi-gtk3
                      , gi-gdkpixbuf