Add navigation and proper webkit integration with basic chapter display

app/Gui.hs

@@ -1,30 +1,65 @@
 {-# LANGUAGE OverloadedStrings, OverloadedLabels #-}
 
-module Gui (runWindow) where
+module Gui (runReader) where
 
 import qualified GI.Gtk as Gtk
 import qualified GI.Gio as Gio
+import qualified GI.Gdk as Gdk
 import qualified GI.WebKit as WebKit
-import qualified Data.Text as T
 
-runWindow :: String -> IO ()
-runWindow htmlContent = do
+import Data.IORef (newIORef, readIORef, writeIORef)
+import Control.Monad.Reader (runReaderT)
+import Text.HTML.TagSoup (renderTags)
 
+import EpubParser (EpubEnv, resolveSpine, getChapter)
+
+runReader :: EpubEnv -> IO ()
+runReader env = do
   app <- Gtk.applicationNew (Just "com.svitak.reader") []
 
   _ <- Gtk.on app #activate $ do
-
     window <- Gtk.applicationWindowNew app
     Gtk.windowSetTitle window (Just "Svitak")
-
     Gtk.windowSetDefaultSize window 800 600
 
+    -- Web View
     webView <- WebKit.webViewNew
-
-    WebKit.webViewLoadHtml webView (T.pack htmlContent) (Just "file:///")
-
     Gtk.windowSetChild window (Just webView)
 
+    -- Book Data
+    spine <- runReaderT resolveSpine env
+    currentChapterIndex <- newIORef 0
+
+    let loadChapter index = do
+          let maxIdx = length spine - 1
+          -- index to valid range 
+          let safeIdx = max 0 (min index maxIdx)
+          
+          -- Update state
+          writeIORef currentChapterIndex safeIdx
+
+          let filename = spine !! safeIdx
+          tags <- runReaderT (getChapter filename) env
+
+          WebKit.webViewLoadHtml webView (renderTags tags) (Just "file:///")
+
+    loadChapter 0
+
+    -- Keyboard Input
+    keyController <- Gtk.eventControllerKeyNew
+    Gtk.widgetAddController window keyController
+
+    _ <- Gtk.on keyController #keyPressed $ \keyval _ _ -> do
+        currentIndex <- readIORef currentChapterIndex
+        case keyval of
+            Gdk.KEY_Right -> do
+                loadChapter (currentIndex + 1)
+                return True
+            Gdk.KEY_Left -> do
+                loadChapter (currentIndex - 1)
+                return True
+            _ -> return False
+
     #present window
 
   _ <- Gio.applicationRun app Nothing

app/Main.hs

@@ -1,37 +1,16 @@
-module Main (main) where
+module Main where
 
 import System.Environment (getArgs)
-import Control.Monad.Reader (runReaderT)
-import EpubParser (EpubAction, openEpub, resolveSpine, getChapter)
-import Gui (runWindow)
-import qualified Data.Text as T
-import Text.HTML.TagSoup (renderTags)
+import EpubParser (openEpub)
+import UI (runApp)
 
 main :: IO ()
 main = do
-  args <- getArgs
-  case args of
-    [] -> do
-        putStrLn "Starting GUI..."
-        runWindow "<h1>Welcome to Svitak</h1><p>Please input an epub file.</p>"
-
-    (path:_) -> runSvitak path
-
-runSvitak :: FilePath -> IO ()
-runSvitak path = do
-  result <- openEpub path
-  case result of
-    Left err -> putStrLn $ "Error: " ++ err
-    Right env -> do
-      htmlContent <- runReaderT loadBook env
-      runWindow htmlContent
-
-loadBook :: EpubAction String
-loadBook = do
-  spine <- resolveSpine
-  case spine of
-    [] -> pure "<h1>No chapters found</h1>"
-    (firstChapter:_) -> do
-      tags <- getChapter firstChapter
-      pure $ T.unpack $ renderTags tags
-
+    args <- getArgs
+    case args of
+        [path] -> do
+            result <- openEpub path
+            case result of
+                Left err  -> putStrLn $ "Error: " ++ err
+                Right env -> runApp env
+        _ -> putStrLn "Usage: svitak <file.epub>"

app/UI.hs

@@ -0,0 +1,86 @@
+{-# LANGUAGE OverloadedStrings, OverloadedLabels #-}
+
+module UI (runApp) where
+
+import qualified GI.Gtk as Gtk
+import qualified GI.Gdk as Gdk
+import qualified GI.Gio as Gio
+import qualified GI.WebKit as WebKit
+import qualified GI.Gtk.Enums as GtkEnums
+
+import Control.Monad.Reader (runReaderT)
+import Data.IORef (newIORef, readIORef, writeIORef)
+import Text.HTML.TagSoup (renderTags)
+
+import EpubParser (EpubEnv, resolveSpine, getChapter)
+
+runApp :: EpubEnv -> IO ()
+runApp env = do
+
+    app <- Gtk.applicationNew (Just "com.svitak.reader.v2") []
+
+    _ <- Gtk.on app #activate $ do
+        putStrLn "DEBUG: App Activated"
+        
+        -- Setup window
+        window <- Gtk.applicationWindowNew app
+        Gtk.windowSetTitle window (Just "Svitak")
+        Gtk.windowSetDefaultSize window 800 600
+
+        -- Setup webview
+        webView <- WebKit.webViewNew
+        Gtk.windowSetChild window (Just webView)
+
+        -- Get the spine
+        spine <- runReaderT resolveSpine env
+        let totalChapters = length spine
+        putStrLn $ "DEBUG: Spine loaded. Total chapters: " ++ show totalChapters
+
+        if totalChapters == 0 
+           then putStrLn "ERROR: This book has no chapters!" 
+           else do
+                currentIndex <- newIORef 0
+
+
+                let loadChapter index = do
+                        let maxIdx = totalChapters - 1
+                        let safeIdx = max 0 (min index maxIdx)
+                        
+                        writeIORef currentIndex safeIdx
+                        putStrLn $ "DEBUG: Loading Chapter " ++ show (safeIdx + 1)
+                        
+                        let filename = spine !! safeIdx
+                        tags <- runReaderT (getChapter filename) env
+                        
+                        let htmlContent = renderTags tags
+                        -- Load HTML
+                        WebKit.webViewLoadHtml webView htmlContent (Just "file:///")
+
+                -- Load the first chapter
+                loadChapter 0
+
+                -- Setup keyboard input
+                keyController <- Gtk.eventControllerKeyNew
+
+                Gtk.eventControllerSetPropagationPhase keyController GtkEnums.PropagationPhaseCapture
+
+                _ <- Gtk.on keyController #keyPressed $ \keyval _ _ -> do
+                    curr <- readIORef currentIndex
+                    case keyval of
+                        Gdk.KEY_Right -> do
+                            putStrLn "KEY: -> Next"
+                            loadChapter (curr + 1)
+                            return True
+                        Gdk.KEY_Left -> do
+                            putStrLn "KEY: <- Prev"
+                            loadChapter (curr - 1)
+                            return True
+                        _ -> return False
+
+                Gtk.widgetAddController window keyController
+
+        #present window
+        putStrLn "DEBUG: Window presented"
+
+    _ <- Gio.applicationRun app Nothing
+    pure ()

svitak.cabal

@@ -58,7 +58,8 @@ executable svitak
     main-is:          Main.hs
 
     other-modules:    EpubParser,
-                      Gui
+                      Gui,
+                      UI
 
     build-depends:    base ^>=4.21.0.0,
                       bytestring >= 0.12.2.0,
@@ -73,6 +74,7 @@ executable svitak
                       gi-gtk == 4.0.*,
                       gi-webkit == 6.0.*,
                       gi-gio,
+                      gi-gdk4,
                       haskell-gi-base,
                       base64-bytestring