towards lazy reading (broken)

1 files changed, 61 insertions, 0 deletions

diff --git a/Handlers.hs b/Handlers.hs
new file mode 100644
index 0000000..566fca9
--- /dev/null
+++ b/Handlers.hs
@@ -0,0 +1,61 @@
+{- Event handlers for Lazymail
+ -
+ - Copyright 2013 Raúl Benencia <rul@kalgan.cc>
+ -
+ - Licensed under the GNU GPL version 3 or higher
+ -}
+
+module Handlers where
+
+import Control.Monad.State
+
+import Maildir
+import State
+import Types (LazymailCurses)
+
+previousMode :: Mode -> LazymailCurses ()
+previousMode IndexMode   = (=<<) put $ get >>= \st -> return st { mode = MaildirMode }
+previousMode EmailMode   = (=<<) put $ get >>= \st -> return st { mode = IndexMode }
+previousMode MaildirMode = (=<<) put $ get >>= \st -> return st { exitRequested = True }
+
+changeMode IndexMode   = (=<<) put $ get >>= \st -> return st { mode = EmailMode }
+changeMode EmailMode   = return ()
+changeMode MaildirMode =  do
+  st <- get
+  selectedEmails' <- liftIO $ do
+    let md = (selectedMD . maildirState) $ st
+    getMaildirEmails md
+  let indexState' = (indexState st) {
+          selectedEmails = selectedEmails'
+        , currentInLen   = length selectedEmails'
+        , scrollBufferIn = scrollCrop (scrollRowIn . indexState $ st) (screenRows st)  selectedEmails'
+        }
+  put $ st { mode = IndexMode, indexState = indexState' }
+
+incSelectedRow IndexMode = do
+  st <- get
+  let inSt = indexState st
+  if (selectedRowIn inSt) > (div (screenRows st) 2)
+     then do
+       let scrollRowIn'    = scrollRowIn inSt + 1
+       let scrollBufferIn' = scrollCrop scrollRowIn' (screenRows st) $ selectedEmails inSt
+       let inSt'           = inSt { scrollRowIn = scrollRowIn', scrollBufferIn = scrollBufferIn' }
+       put st { indexState = inSt' }
+     else put $ incrementSelectedRow st
+incSelectedRow _ = (=<<) put $ get >>= \st -> return $ incrementSelectedRow st
+
+decSelectedRow IndexMode = do
+  st <- get
+  let inSt = indexState st
+  if (scrollRowIn inSt) > 0
+     then do
+       let scrollRowIn'    = scrollRowIn inSt - 1
+       let scrollBufferIn' = scrollCrop scrollRowIn' (screenRows st) $ selectedEmails inSt
+       let inSt'           = inSt { scrollRowIn = scrollRowIn', scrollBufferIn = scrollBufferIn' }
+       put st { indexState = inSt' }
+     else put $ decrementSelectedRow st
+decSelectedRow _ = (=<<) put $ get >>= \st -> return $ decrementSelectedRow st
+
+{- Given a list, it returns the elements that will be in the next screen refresh
+ - TODO: find a better name -}
+scrollCrop top rows xs = take rows $ drop top xs