diff --git a/app/Types.hs b/app/Types.hs
index fbcb8b2..6395e73 100644
--- a/app/Types.hs
+++ b/app/Types.hs
@@ -3,6 +3,7 @@ module Types
     ChapterView(..),
     Chapter(..),
     AppState(..),
+    UserAction(..),
     EpubAction
   )
 where
@@ -47,3 +48,10 @@ data AppState = AppState
   }
 
 type EpubAction a = ReaderT EpubEnv IO a
+
+data UserAction
+  = NextChapter
+  | PrevChapter
+  | ZoomIn
+  | ZoomOut
+  | LoadSpecific Int
diff --git a/app/UI.hs b/app/UI.hs
index 050bcb4..0cbfb07 100644
--- a/app/UI.hs
+++ b/app/UI.hs
@@ -5,7 +5,8 @@ module UI (runApp) where
 
 import Codec.Epub.Data.Metadata (metaTitles, titleText, titleType)
 import Control.Concurrent.Async (async)
-import Control.Concurrent.STM (atomically, modifyTVar, newTVarIO, readTVar)
+import Control.Concurrent.STM (TVar, atomically, modifyTVar, newTVarIO, readTVar)
+import Control.Monad (zipWithM)
 import Control.Monad.Reader (runReaderT)
 import Data.GI.Base (AttrOp (..))
 import Data.List (find)
@@ -20,82 +21,87 @@ import qualified GI.Gtk.Enums as GtkEnums
 import qualified GI.WebKit as WebKit
 import Persistence (loadLastRead, saveLastRead)
 import State (initialState, prepareView)
-import Types (AppState(..), ChapterView(..))
-import Control.Monad (zipWithM)
+import Types (AppState (..), ChapterView (..), UserAction (..))
+
+updateUI :: Gtk.ApplicationWindow -> WebKit.WebView -> ChapterView -> IO ()
+updateUI window webView view = do
+  Gtk.set window [#title := viewTitle view]
+  WebKit.webViewLoadHtml webView (viewHtml view) Nothing
+
+handleAction :: TVar AppState -> Gtk.ApplicationWindow -> WebKit.WebView -> UserAction -> IO ()
+handleAction stateTVar window webView action = do
+  st <- atomically $ readTVar stateTVar
+  case action of
+    ZoomIn -> updateZoom stateTVar webView (zoomlvl st + 0.1)
+    ZoomOut -> updateZoom stateTVar webView (max 0.1 (zoomlvl st - 0.1))
+    _ -> do
+      let nextIdx = case action of
+            NextChapter -> cIdx st + 1
+            PrevChapter -> cIdx st - 1
+            LoadSpecific i -> i
+            _ -> cIdx st
+
+      case prepareView st nextIdx of
+        Nothing -> pure ()
+        Just view -> do
+          updateUI window webView view
+          atomically $ modifyTVar stateTVar $ \s -> s {cIdx = viewIdx view}
+          _ <- async $ saveLastRead (bookPath (cEnv st)) (viewIdx view)
+          pure ()
+
+updateZoom :: TVar AppState -> WebKit.WebView -> Double -> IO ()
+updateZoom stateTVar webView level = do
+  atomically $ modifyTVar stateTVar $ \s -> s {zoomlvl = level}
+  WebKit.webViewSetZoomLevel webView level
+
+initAppServices :: EpubEnv -> TVar AppState -> (UserAction -> IO ()) -> IO ()
+initAppServices env stateTVar actionHandler = do
+  _ <- async $ do
+    ispine <- runReaderT resolveSpine env
+    allChapters <- runReaderT (zipWithM getChapter ispine [0 ..]) env
+
+    let titles = metaTitles (eMetadata env)
+    let bookTitle = case find (\t -> titleType t == Just "main") titles of
+          Just t -> titleText t
+          Nothing -> if null titles then "Unknown" else titleText (head titles)
+
+    atomically $ modifyTVar stateTVar $ \s ->
+      s {cSpine = ispine, cAllChapters = allChapters, bTitle = T.pack bookTitle}
+
+    _ <- GLib.idleAdd GLibConst.PRIORITY_DEFAULT $ do
+      maybeSaved <- loadLastRead
+      case maybeSaved of
+        Just (path, idx) | path == bookPath env -> actionHandler (LoadSpecific idx)
+        _ -> actionHandler (LoadSpecific 0)
+      pure False
+    pure ()
+  pure ()
 
 runApp :: EpubEnv -> IO ()
-runApp env' = do
-  app <- Gtk.applicationNew (Just "com.svitak.reader.v2") []
+runApp env = do
+  app <- Gtk.applicationNew (Just "com.svitak.reader.v3") []
 
   _ <- Gtk.on app #activate $ do
-    stateTVar <- newTVarIO (initialState env')
-
+    stateTVar <- newTVarIO (initialState env)
     window <- Gtk.applicationWindowNew app
     webView <- WebKit.webViewNew
     Gtk.set window [#defaultWidth := 800, #defaultHeight := 600, #child := webView]
 
-    -- load all chapters on another thread
-    let loadChapter index = do
-          st <- atomically $ readTVar stateTVar
-          case prepareView st index of
-            Nothing -> pure ()
-            Just view -> do
-              Gtk.set window [#title := viewTitle view]
-              WebKit.webViewLoadHtml webView (viewHtml view) Nothing
+    let dispatch = handleAction stateTVar window webView
 
-              atomically $ modifyTVar stateTVar $ \s -> s {cIdx = viewIdx view}
-              _ <- async $ saveLastRead (bookPath env') (viewIdx view)
-              pure ()
-
-    -- keyboard handling
     keyCtrl <- Gtk.eventControllerKeyNew
     Gtk.eventControllerSetPropagationPhase keyCtrl GtkEnums.PropagationPhaseCapture
-
-    _ <- Gtk.on keyCtrl #keyPressed $ \keyval _ _ -> do
-      stNow <- atomically $ readTVar stateTVar
-      case keyval of
-        Gdk.KEY_Right -> loadChapter (cIdx stNow + 1) >> pure True
-        Gdk.KEY_Left -> loadChapter (cIdx stNow - 1) >> pure True
-        Gdk.KEY_equal -> do
-          let newZ = zoomlvl stNow + 0.1
-          atomically $ modifyTVar stateTVar $ \s -> s {zoomlvl = newZ}
-          WebKit.webViewSetZoomLevel webView newZ
-          pure True
-        Gdk.KEY_minus -> do
-          let newZ = max 0.1 (zoomlvl stNow - 0.1)
-          atomically $ modifyTVar stateTVar $ \s -> s {zoomlvl = newZ}
-          WebKit.webViewSetZoomLevel webView newZ
-          pure True
-        _ -> pure False
+    _ <- Gtk.on keyCtrl #keyPressed $ \keyval _ _ -> case keyval of
+      Gdk.KEY_Right -> dispatch NextChapter >> pure True
+      Gdk.KEY_Left -> dispatch PrevChapter >> pure True
+      Gdk.KEY_equal -> dispatch ZoomIn >> pure True
+      Gdk.KEY_minus -> dispatch ZoomOut >> pure True
+      _ -> pure False
 
     Gtk.widgetAddController window keyCtrl
     #present window
 
-    -- start eager parse
-    _ <- async $ do
-      ispine <- runReaderT resolveSpine env'
-      allChapters <- runReaderT (zipWithM getChapter ispine[0..]) env'
-
-      let titles = metaTitles (eMetadata env')
-      let rawT = case find (\t -> titleType t == Just "main") titles of
-            Just t -> titleText t
-            Nothing -> if null titles then "Unknown" else titleText (head titles)
-
-      atomically $ modifyTVar stateTVar $ \s ->
-        s
-          { cSpine = ispine,
-            cAllChapters = allChapters,
-            bTitle = T.pack rawT
-          }
-
-      _ <- GLib.idleAdd GLibConst.PRIORITY_DEFAULT $ do
-        maybeSaved <- loadLastRead
-        case maybeSaved of
-          Just (path, idx) | path == bookPath env' -> loadChapter idx
-          _ -> loadChapter 0
-        pure False
-      pure ()
-    pure ()
+    initAppServices env stateTVar dispatch
 
   _ <- Gio.applicationRun app Nothing
   pure ()