add ScanSess type & refactor

2 files changed, 44 insertions, 48 deletions

diff --git a/Main.hs b/Main.hs
index b94c2f8..47104a8 100644
--- a/Main.hs
+++ b/Main.hs
@@ -40,9 +40,10 @@ drawUI st = [ui]
               , hBorderWithLabel (str "[ Actions ]")
               , vLimit 6 $ C.center $ actionsBox
               ]
-    status = str $ case st^.stPageCount of
-      Just n  -> "Scanned " ++ show n ++ " pages"
-      Nothing -> "Ready to scan first page"
+    status = str $ maybe
+        "Ready to scan first page"
+        (\(ScanSess _ p) -> "Scanned " ++ show p ++ " pages")
+        (st^.stScanSess)
     settingsBox = defnList AlignRight Nothing
         [ ("run OCRmyPDF", if st^.stOCR then "yes" else "no")
         , ("colour data",   show $ st^.stColour)
@@ -101,29 +102,23 @@ beginScanSess :: St -> IO St
 beginScanSess st = do
     temp <- getTemporaryDirectory
         >>= \tmpdir -> createTempDirectory tmpdir "sscan"
-    return $ st
-        & stScanningSession .~ (Just temp)
-        & stPageCount .~ (Just 0)
+    return $ st & stScanSess .~ (Just $ ScanSess temp 0)
 
 abortScanSess :: St -> IO St
 abortScanSess st = do
     maybe (return ())
-        removeDirectoryRecursive
-        (st^.stScanningSession)
-    return $ st
-        & stScanningSession .~ Nothing
-        & stPageCount .~ Nothing
+        (\(ScanSess d _) -> removeDirectoryRecursive d)
+        (st^.stScanSess)
+    return $ st & stScanSess .~ Nothing
 
 finishScanSess :: St -> IO St
 finishScanSess st = do
     void $ forkFinally (finishScanSess' st) $ \result ->
         case result of
           Right _ -> maybe (return ())
-              removeDirectoryRecursive
-              (st^.stScanningSession)
-    return $ st
-        & stScanningSession .~ Nothing
-        & stPageCount .~ Nothing
+              (\(ScanSess d _) -> removeDirectoryRecursive d)
+              (st^.stScanSess)
+    return $ st & stScanSess .~ Nothing
 
 -- run OCRmyPDF, pdftk etc., and if any process existed non-zero,
 -- record to a log file in the outdir
@@ -139,20 +134,17 @@ scanNextPage st = undefined
 handleHotKey :: St -> Char -> EventM () (Next St)
 handleHotKey st 'q' = handleQ st
 handleHotKey st ' ' = handleSPC st
-handleHotKey st 'o' = updateStateOutsideSession st
+handleHotKey st 'o' = continue $ updateSt st
     (\s -> s & stOCR .~ (not $ st^.stOCR))
-handleHotKey st 'c' = updateStateOutsideSession st
+handleHotKey st 'c' = continue $ updateSt st
     (\s -> s & stColour .~ (cycleColour $ st^.stColour))
-handleHotKey st 'p' = updateStateOutsideSession st
+handleHotKey st 'p' = continue $ updateSt st
     (\s -> s & stPaper .~ (cyclePaper $ st^.stPaper))
-handleHotKey st c = updateStateOutsideSession st $
+handleHotKey st c = continue $ updateSt st $
     case lookupPreset c of
       Just (Preset _ _ f) -> f
       _                   -> id
 
-updateStateOutsideSession :: St -> (St -> St) -> EventM () (Next St)
-updateStateOutsideSession st f = continue $ ifScanSess st st (f st)
-
 appEvent :: St -> BrickEvent () e -> EventM () (Next St)
 appEvent st (VtyEvent e) =
     case e of
@@ -176,14 +168,13 @@ main = do
     papersize <- init <$> readFile "/etc/papersize"
     let paper = if papersize == "letter" then Letter else A4
         initialState = St
-            { _stScanningSession = Nothing
-            , _stPageCount       = Nothing
-            , _stOCR             = True
-            , _stColour          = Greyscale
-            , _stPaper           = paper
-            , _stDefaultPaper    = paper
-            , _stDPI             = 300
-            , _stOutFormat       = PDF
-            , _stOutdir          = home </> "tmp"
+            { _stScanSess     = Nothing
+            , _stOCR          = True
+            , _stColour       = Greyscale
+            , _stPaper        = paper
+            , _stDefaultPaper = paper
+            , _stDPI          = 300
+            , _stOutFormat    = PDF
+            , _stOutdir       = home </> "tmp"
             }
     void $ defaultMain theApp initialState
diff --git a/Types/State.hs b/Types/State.hs
index e37d7a8..68ef188 100644
--- a/Types/State.hs
+++ b/Types/State.hs
@@ -33,26 +33,31 @@ type DPI = Int
 data OutputFormat = PDF | PNG
     deriving (Eq, Show)
 
+-- | An active multi-page scanning session
+data ScanSess = ScanSess
+    FilePath                    -- ^ session's tmpdir
+    Int                         -- ^ total pages scanner thus far
+
 -- | Application state
 data St =
-    St { _stScanningSession :: Maybe FilePath -- ^ if a session is in
-                                              -- progress, accmulate
-                                              -- scans in this dir
-       , _stPageCount       :: Maybe Int -- ^ if a session is in
-                                         -- progress, the number of
-                                         -- pages scanned thus far
-       , _stOCR             :: Bool -- ^ whether to use OCRmyPDF
-       , _stColour          :: Colour
-       , _stPaper           :: Paper -- ^ currently selected paper size
-       , _stDefaultPaper    :: Paper -- ^ locale's default paper size
-       , _stDPI             :: DPI
-       , _stOutFormat       :: OutputFormat
-       , _stOutdir          :: FilePath -- ^ where to save final PDFs
+    St { _stScanSess     :: Maybe ScanSess
+       , _stOCR          :: Bool -- ^ whether to use OCRmyPDF
+       , _stColour       :: Colour
+       , _stPaper        :: Paper -- ^ currently selected paper size
+       , _stDefaultPaper :: Paper -- ^ locale's default paper size
+       , _stDPI          :: DPI
+       , _stOutFormat    :: OutputFormat
+       , _stOutdir       :: FilePath -- ^ where to save final PDFs
        }
-
--- other device-specific scanimage options we could support: --swdespeck; --color-filter; --depth
+-- other device-specific scanimage options the old script supported: --swdespeck; --color-filter; --depth
 
 makeLenses ''St
 
 ifScanSess :: St -> a -> a -> a
-ifScanSess st a b = if isJust $ st^.stScanningSession then a else b
+ifScanSess st a b = if isJust $ st^.stScanSess then a else b
+
+-- | Update a state when there is no scanning session in progress (the
+-- state should not be changed when some pages have already been
+-- scanned)
+updateSt :: St -> (St -> St) -> St
+updateSt st f = ifScanSess st st (f st)