Reorganize

src/TaskMachine/Task.hs

@@ -21,6 +21,8 @@ module TaskMachine.Task
   , Description
   , Snippet(..)
   -- * Misc stuff
+  , emptyTask
+  , newTask
   , compareTasks
   -- * Formatting
   , formatTask
@@ -313,6 +315,13 @@ pTasks = many pTask <* eof
 
  {- Misc stuff -}
 
+emptyTask :: Task
+emptyTask = Task Incomplete Nothing Nothing Nothing []
+
+-- | Create a new task with empty description and the given date as creation date
+newTask :: Day -> Task
+newTask day = Task Incomplete Nothing Nothing (Just day) []
+
 compareTasks :: Task -> Task -> Ordering
 compareTasks a b = mconcat
   [ compare (taskCompletion a) (taskCompletion b)

src/TaskMachine/UI.hs

@@ -5,21 +5,19 @@ module TaskMachine.UI
 
 import qualified Brick                     as B
 import qualified Brick.Themes              as B
-import           Control.Monad.Trans
 import qualified Data.Vector               as V
 import qualified Graphics.Vty.Input.Events as VTY
 
 import           TaskMachine.Options
 import           TaskMachine.UI.Behaviors
 import           TaskMachine.UI.Popup
-import           TaskMachine.UI.Stuff
 import           TaskMachine.UI.TaskList
 import           TaskMachine.UI.Types
 
 {- Rendering -}
 
 drawTaskList :: UIState -> B.Widget RName
-drawTaskList s = renderTaskList (taskEdit s) True (tasks s)
+drawTaskList s = renderTaskList (editor s) True (tasks s)
 
 drawUIState :: UIState -> [B.Widget RName]
 drawUIState s@UIState{errorPopup=Just p} = [renderPopup p, drawTaskList s]
@@ -27,27 +25,13 @@ drawUIState s                            = [drawTaskList s]
 
 {- Updating the state -}
 
-closeBehavior :: (UIState -> VTY.Event -> NewState) -> UIState -> VTY.Event -> NewState
-closeBehavior _ s (VTY.EvKey VTY.KEsc        []) = B.halt s
-closeBehavior _ s (VTY.EvKey (VTY.KChar 'q') []) = B.halt s
-closeBehavior f s e                              = f s e -- wrapper around another behavior
-
-popupBehavior :: Popup RName (UIState -> NewState) -> UIState -> VTY.Event -> NewState
-popupBehavior p s (VTY.EvKey VTY.KEnter []) =
-  case popupSelection p of
-    Nothing     -> B.continue s{errorPopup=Nothing}
-    Just action -> action s{errorPopup=Nothing}
-popupBehavior p s e = do
-  newPopup <- handlePopupEvent e p
-  B.continue s{errorPopup=Just newPopup}
-
 selectBehavior :: UIState -> VTY.Event -> NewState
 -- Deal with popup if there is one
-selectBehavior s@UIState{errorPopup=Just p} e = popupBehavior p s e
+selectBehavior s@UIState{errorPopup=Just p} e = closeModifier (popupBehavior p) s e
--- Under the assumption that tasks can only be edited while the task list is focused, edit a task
+-- Continue editing task if previously editing a task
-selectBehavior s@UIState{taskEdit=Just edit} e = taskEditBehavior edit s e
+selectBehavior s@UIState{editor=Just edit} e = taskEditBehavior edit s e
--- If nothing immediately jumps out at you, see which part has focus.
+-- Default task list behavior
-selectBehavior s e = closeBehavior taskListBehavior s e
+selectBehavior s e = closeModifier taskListBehavior s e
 
 updateUIState :: UIState -> B.BrickEvent RName () -> NewState
 updateUIState s (B.VtyEvent e) = selectBehavior s e
@@ -55,15 +39,12 @@ updateUIState s _              = B.continue s
 
 {- Starting the app -}
 
-startEvent :: UIState -> B.EventM RName UIState
-startEvent = liftIO . loadTasks
-
 myApp :: B.App UIState () RName
 myApp = B.App
   { B.appDraw         = drawUIState
   , B.appChooseCursor = B.showFirstCursor
   , B.appHandleEvent  = updateUIState
-  , B.appStartEvent   = startEvent
+  , B.appStartEvent   = actionLoad
   , B.appAttrMap      = const (B.themeToAttrMap defaultTheme)
   }
 
@@ -72,5 +53,5 @@ startUIState o = UIState
   { options    = o
   , errorPopup = Nothing
   , tasks      = taskList RTaskList V.empty
-  , taskEdit   = Nothing
+  , editor   = Nothing
   }

src/TaskMachine/UI/Behaviors.hs

@@ -1,58 +1,212 @@
 module TaskMachine.UI.Behaviors
-  ( taskListBehavior
+  ( Behavior
+  --, emptyBehavior
+  -- * Miscellaneous
+  , getCurrentDay
+  , closeModifier
+  -- * Behaviors
+  , popupBehavior
+  , taskListBehavior
   , taskEditBehavior
+  -- * Actions
+  , actionLoad
+  , actionSave
+  , actionDelete
+  , actionEditNew
+  , actionEditSelected
+  , actionSortTasks
+  , actionFinishEdit
   ) where
 
-import qualified Brick                   as B
+import           Control.Monad
-import qualified Brick.Widgets.Edit      as B
-import           Control.Monad.Trans
-import qualified Data.Text.Zipper        as T
-import qualified Graphics.Vty            as VTY
-import           Text.Megaparsec
 
+import qualified Brick                   as B
+--import qualified Brick.Widgets.Edit      as B
+import           Control.Monad.Trans
+--import qualified Data.Text.Zipper        as T
+import qualified Graphics.Vty            as VTY
+--import           Text.Megaparsec
+import           Data.Time
+
+import           TaskMachine.LTask
+import           TaskMachine.Options
 import           TaskMachine.Task
-import           TaskMachine.UI.Stuff
+import           TaskMachine.UI.Popup
+import           TaskMachine.UI.TaskEdit
 import           TaskMachine.UI.TaskList
 import           TaskMachine.UI.Types
 
-startEdit :: UIState -> UIState
+type Behavior = UIState -> VTY.Event -> B.EventM RName (B.Next UIState)
-startEdit s =
+
-  case taskListSelectedElement (tasks s) of
+type Action = UIState -> B.EventM RName UIState
-    Nothing -> undefined -- TODO: Add popup notification
+
+{- Miscellaneous -}
+
+getCurrentDay :: IO Day
+getCurrentDay = utctDay <$> liftIO getCurrentTime
+
+closeModifier :: Behavior -> Behavior
+closeModifier _ s (VTY.EvKey VTY.KEsc        []) = B.halt s
+closeModifier _ s (VTY.EvKey (VTY.KChar 'q') []) = B.halt s
+closeModifier f s e                              = f s e -- wrapper around another behavior
+
+{- Popups -}
+
+popupBehavior :: Popup RName (UIState -> NewState) -> Behavior
+popupBehavior p s (VTY.EvKey VTY.KEnter []) =
+  case popupSelection p of
+    Nothing     -> B.continue s{errorPopup=Nothing} -- Just close, no action was specified
+    Just action -> action s{errorPopup=Nothing} -- Do the thing! (and close the popup)
+popupBehavior p s e = do
+  newPopup <- handlePopupEvent e p
+  B.continue s{errorPopup=Just newPopup}
+
+{- On the task list -}
+
+-- (re-)loading
+
+actionLoad :: Action
+actionLoad s = do
+  let file = oTodofile $ options s
+  result <- liftIO $ loadLTasks file
+  case result of
+    Right ltasks      -> pure s{tasks=taskList RTaskList ltasks}
+    Left errorMessage ->
+      let p = popup "Error loading tasks" errorMessage
+                [ ("Retry", actionLoad >=> B.continue)
+                , ("Quit", B.halt)
+                ]
+      in  pure s{errorPopup=Just p}
+
+-- saving
+
+actionSave :: Action
+actionSave s = do
+  let filepath = oTodofile (options s)
+      ltasks = taskListElements (tasks s)
+  result <- liftIO $ saveLTasks filepath ltasks
+  case result of
+    Right _ -> pure s
+    Left errorMessage ->
+      let p = popup "Error saving tasks" errorMessage
+                [ ("Retry", actionSave >=> B.continue)
+                , ("Continue without saving", B.continue)
+                , ("Quit", B.halt)
+                ]
+      in  pure s{errorPopup=Just p}
+
+-- deleting a task
+
+actionDelete :: Action
+actionDelete s = pure s{tasks=deleteTask (tasks s)}
+
+-- beginning an edit
+
+actionEditNew :: Action
+actionEditNew s = do
+  today <- liftIO getCurrentDay
+  let task = newTask today
+      edit = taskEdit RTaskEdit task NewTask
+  pure s{editor=Just edit}
+
+actionEditSelected :: Action
+actionEditSelected s =
+  case selectedTask (tasks s) of
+    Nothing -> error "no task selected" -- TODO: Add popup notification
     Just t  ->
-      let edit = B.editor RTaskEdit (Just 1) (formatTask t)
+      let edit = taskEdit RTaskEdit t ExistingTask
-      in s{taskEdit=Just edit}
+      in pure s{editor=Just edit}
 
-finishEdit :: B.Editor String RName -> UIState -> UIState
+-- toggling completion
+
+actionToggleCompletion :: Action
+actionToggleCompletion s =
+  case selectedTask (tasks s) of
+    Nothing -> pure s
+    Just task -> do
+      newCompletion <- case taskCompletion task of
+        Complete _ -> pure Incomplete
+        Incomplete -> Complete . Just <$> liftIO getCurrentDay
+      let task' = task{taskCompletion=newCompletion}
+          newTaskList = replaceTask task' (tasks s)
+      pure s{tasks=newTaskList}
+
+-- sorting
+
+actionSortTasks :: Action
+actionSortTasks s = pure s{tasks=sortTaskList (tasks s)}
+
+-- combining all of the above...
+
+taskListBehavior :: Behavior
+-- Clean up: Add todays date where creation/completion date is missing
+--taskListBehavior s (VTY.EvKey (VTY.KChar 'c') []) = undefined s
+-- Delete currently selected task (implicit save)
+taskListBehavior s (VTY.EvKey (VTY.KChar 'd') []) =
+  actionDelete >=> actionSave >=> B.continue $ s
+-- Begin editing currently selected task
+taskListBehavior s (VTY.EvKey (VTY.KChar 'e') []) =
+  actionEditSelected >=> B.continue $ s
+-- Begin creating new task
+taskListBehavior s (VTY.EvKey (VTY.KChar 'n') []) =
+  actionEditNew >=> B.continue $ s
+-- Reload tasks (and sort them)
+taskListBehavior s (VTY.EvKey (VTY.KChar 'r') []) =
+  actionLoad >=> B.continue $ s
+-- Sort tasks
+taskListBehavior s (VTY.EvKey (VTY.KChar 's') []) =
+  actionSortTasks >=> B.continue $ s
+-- Toggle completion (implicit save)
+taskListBehavior s (VTY.EvKey (VTY.KChar 'x') []) =
+  actionToggleCompletion >=> actionSave >=> B.continue $ s
+-- Update the task list (scroll etc.)
+taskListBehavior s e = do
+  newTasks <- updateTaskList e (tasks s)
+  B.continue s{tasks=newTasks}
+
+{- In the task editor -}
+
+actionFinishEdit :: TaskEdit RName -> Action
+actionFinishEdit t = pure . finishEdit t
+
+-- get result of task editing
+-- if editing an existing task, modify that task
+-- if editing a new task, append that task
+finishEdit :: TaskEdit RName -> UIState -> UIState
 finishEdit edit s =
-  let editedText = unlines $ B.getEditContents edit
+  case editedTask edit of
-  in  case parse pTask "edited task" editedText of
+    Left e     -> error e -- TODO: Error popup
-    Left parseError -> undefined parseError -- TODO: Add popup notification
+    Right task -> s{tasks=modify task, editor=Nothing}
-    Right newTask   ->
+  where
-      let newTaskList = taskListModify (const newTask) (tasks s)
+    modify :: Task -> TaskList RName
-      in  s{tasks=newTaskList, taskEdit=Nothing}
+    modify task = case editState edit of
+      ExistingTask -> replaceTask task $ tasks s
+      NewTask      -> appendTask task $ tasks s
 
-taskEditBehavior :: B.Editor String RName -> UIState -> VTY.Event -> NewState
+taskEditBehavior :: TaskEdit RName  -> Behavior
-taskEditBehavior _    s (VTY.EvKey VTY.KEsc   []) = B.continue s{taskEdit=Nothing}
+taskEditBehavior _    s (VTY.EvKey VTY.KEsc []) = B.continue s{editor=Nothing}
-taskEditBehavior edit s (VTY.EvKey VTY.KHome  []) = B.continue s{taskEdit=Just (B.applyEdit T.gotoBOL edit)}
+taskEditBehavior edit s (VTY.EvKey VTY.KEnter []) =
-taskEditBehavior edit s (VTY.EvKey VTY.KEnd   []) = B.continue s{taskEdit=Just (B.applyEdit T.gotoEOL edit)}
+  actionFinishEdit edit >=> actionSave >=> B.continue $ s
-taskEditBehavior edit s (VTY.EvKey VTY.KEnter []) = do
+--taskEditBehavior edit s (VTY.EvKey VTY.KEnter []) = do
-  newState <- liftIO $ saveTasks $ finishEdit edit s
+--  newState <- liftIO $ saveTasks $ finishEdit edit s
-  B.continue newState
+--  B.continue newState
 taskEditBehavior edit s e = do
-  newEdit <- B.handleEditorEvent e edit
+  newEdit <- updateTaskEdit e edit
-  B.continue s{taskEdit=Just newEdit}
+  B.continue s{editor=Just newEdit}
 
-taskListBehavior :: UIState -> VTY.Event -> NewState
+{-
 -- Reload while running
 taskListBehavior s (VTY.EvKey (VTY.KChar 'r') []) = actionLoad s
 -- Mark/unmark a task as completed
 taskListBehavior s (VTY.EvKey (VTY.KChar 'x') []) = undefined s
 -- Delete tasks
 taskListBehavior s (VTY.EvKey (VTY.KChar 'd') []) = undefined s
+-- Delete tasks
+taskListBehavior s (VTY.EvKey (VTY.KChar 'd') []) = undefined s
 -- Start editing a new task
 taskListBehavior s (VTY.EvKey (VTY.KChar 'e') []) = B.continue (startEdit s)
 -- Update the task list (scroll etc.)
 taskListBehavior s e = do
   newTasks <- updateTaskList e (tasks s)
   B.continue s{tasks=newTasks}
+-}

src/TaskMachine/UI/Popup.hs

@@ -1,23 +1,17 @@
 module TaskMachine.UI.Popup
-  ( minPopupWidth
+  ( Popup
-  -- * Ok popup
-  , Popup
   , popup
   , popup'
   , renderPopup
   , handlePopupEvent
   , popupSelection
+  , minPopupWidth
   ) where
 
 import qualified Brick                as B
 import qualified Brick.Widgets.Dialog as B
 import qualified Graphics.Vty         as VTY
 
-minPopupWidth :: Int
-minPopupWidth = 78
-
-{- Ok popup -}
-
 data Popup n r = Popup (B.Dialog r) (B.Widget n)
 
 popup :: String -> String -> [(String, r)] -> Popup n r
@@ -37,3 +31,6 @@ handlePopupEvent e (Popup dialog widget) = Popup <$> B.handleDialogEvent e dialo
 
 popupSelection :: Popup n r -> Maybe r
 popupSelection (Popup dialog _) = B.dialogSelection dialog
+
+minPopupWidth :: Int
+minPopupWidth = 78

src/TaskMachine/UI/Stuff.hs

@@ -1,54 +0,0 @@
-module TaskMachine.UI.Stuff where
-
-import qualified Brick                   as B
-import           Control.Monad.Trans
-
-import           TaskMachine.LTask
-import           TaskMachine.Options
-import           TaskMachine.UI.Popup
-import           TaskMachine.UI.TaskList
-import           TaskMachine.UI.Types
-
-actionQuit :: UIState -> NewState
-actionQuit = B.halt
-
-actionDoNothing :: UIState -> NewState
-actionDoNothing = B.continue
-
-actionLoad :: UIState -> NewState
-actionLoad s = do
-  state <- liftIO $ loadTasks s
-  B.continue state
-
-loadTasks :: UIState -> IO UIState
-loadTasks s = do
-  let file = oTodofile $ options s
-  result <- loadLTasks file
-  case result of
-    Right ltasks      -> pure s{tasks=taskList RTaskList ltasks}
-    Left errorMessage ->
-      let p = popup "Error loading tasks" errorMessage
-                [ ("Retry", actionLoad)
-                , ("Quit", actionQuit)
-                ]
-      in  pure s{errorPopup=Just p}
-
-actionSave :: UIState -> NewState
-actionSave s = do
-  state <- liftIO $ saveTasks s
-  B.continue state
-
-saveTasks :: UIState -> IO UIState
-saveTasks s = do
-  let filepath = oTodofile (options s)
-      ltasks = taskListElements (tasks s)
-  result <- saveLTasks filepath ltasks
-  case result of
-    Right _ -> pure s
-    Left errorMessage ->
-      let p = popup "Error saving tasks" errorMessage
-                [ ("Retry", actionSave)
-                , ("Continue without saving", actionDoNothing)
-                , ("Quit", actionQuit)
-                ]
-      in  pure s{errorPopup=Just p}

src/TaskMachine/UI/TaskEdit.hs

@@ -0,0 +1,56 @@
+module TaskMachine.UI.TaskEdit
+  ( TaskEdit
+  , EditState(..)
+  , taskEdit
+  , editState
+  , editedTask
+  , renderTaskEdit
+  , updateTaskEdit
+  ) where
+
+import qualified Brick              as B
+import qualified Brick.Widgets.Edit as B
+import qualified Data.Text.Zipper   as T
+import qualified Graphics.Vty       as VTY
+import           Text.Megaparsec
+
+import           TaskMachine.Task
+
+data TaskEdit n = TaskEdit EditState (B.Editor String n)
+  deriving (Show)
+
+data EditState = ExistingTask | NewTask
+  deriving (Show)
+
+taskEdit :: n -> Task -> EditState -> TaskEdit n
+taskEdit name task s = TaskEdit s $ B.editor name (Just 1) (formatTask task)
+
+editState :: TaskEdit n -> EditState
+editState (TaskEdit s _) = s
+
+editedLine :: TaskEdit n -> Either String String
+editedLine (TaskEdit _ edit) =
+  case B.getEditContents edit of
+    [s] -> Right s
+    _   -> Left "Editor empty"
+
+editedTask :: TaskEdit n -> Either String Task
+editedTask te = do
+  s <- editedLine te
+  case parse pTask "task editor" s of
+    Left parseError -> Left $ parseErrorPretty parseError
+    Right task      -> Right task
+
+renderRows :: [String] -> B.Widget n
+renderRows = B.vBox . map B.str
+
+renderTaskEdit :: (Ord n, Show n) => Bool -> TaskEdit n -> B.Widget n
+renderTaskEdit focus (TaskEdit _ edit) = B.renderEditor renderRows focus edit
+
+updateTaskEdit :: Ord n => VTY.Event -> TaskEdit n -> B.EventM n (TaskEdit n)
+updateTaskEdit (VTY.EvKey VTY.KHome []) (TaskEdit s edit) =
+  pure $ TaskEdit s $ B.applyEdit T.gotoBOL edit
+updateTaskEdit (VTY.EvKey VTY.KEnd []) (TaskEdit s edit) =
+  pure $ TaskEdit s $ B.applyEdit T.gotoEOL edit
+updateTaskEdit event (TaskEdit s edit) =
+  TaskEdit s <$> B.handleEditorEvent event edit

src/TaskMachine/UI/TaskList.hs

@@ -1,16 +1,20 @@
 module TaskMachine.UI.TaskList
   ( TaskList
   , taskList
+  , taskListElements
   , renderTaskList
   , updateTaskList
-  , taskListElements
+  , sortTaskList
-  , taskListFilter
+  , selectedTask
-  , taskListSelectedElement
+  , appendTask
-  , taskListModify
+  , replaceTask
+  , deleteTask
   ) where
 
+import           Data.Function
+import           Data.List
+
 import qualified Brick                   as B
-import qualified Brick.Widgets.Edit  as B
 import qualified Brick.Widgets.List      as B
 import qualified Data.Vector             as V
 import qualified Graphics.Vty            as VTY
@@ -18,46 +22,75 @@ import qualified Graphics.Vty        as VTY
 import           TaskMachine.LTask
 import           TaskMachine.Task
 import           TaskMachine.UI.Task
+import           TaskMachine.UI.TaskEdit
 
-data TaskList n = TaskList
+newtype TaskList n = TaskList (B.List n LTask)
-  { visibleTasks   :: B.List n LTask
-  , invisibleTasks :: V.Vector LTask
-  } deriving (Show)
-
-newList :: n -> V.Vector LTask -> B.List n LTask
-newList name ltasks = B.list name ltasks 1
 
 taskList :: n -> V.Vector LTask -> TaskList n
-taskList name ltasks = TaskList{visibleTasks=newList name ltasks, invisibleTasks=V.empty}
+taskList name tasks = TaskList $ B.list name tasks 1
-
-renderLTask :: (Ord n, Show n) => Maybe (B.Editor String n) -> Bool -> LTask -> B.Widget n
-renderLTask (Just e) True _ = B.renderEditor (B.str . unlines) True e
-renderLTask _ _ lt          = renderTask (toTask lt)
-
-renderTaskList :: (Ord n, Show n) => Maybe (B.Editor String n) -> Bool -> TaskList n -> B.Widget n
-renderTaskList edit focus tl  = B.renderList (renderLTask edit) focus (visibleTasks tl)
-
-updateTaskList :: (Ord n) => VTY.Event -> TaskList n -> B.EventM n (TaskList n)
-updateTaskList e tl = do
-  updatedList <- B.handleListEventVi B.handleListEvent e (visibleTasks tl)
-  pure tl{visibleTasks=updatedList}
-
-{- Managing tasks -}
 
 taskListElements :: TaskList n -> V.Vector LTask
-taskListElements tl = B.listElements (visibleTasks tl) <> invisibleTasks tl
+taskListElements (TaskList list) = B.listElements list
 
-taskListFilter :: (Task -> Bool) -> TaskList n -> TaskList n
+renderRow :: Maybe (B.Widget n) -> Bool -> LTask -> B.Widget n
-taskListFilter f tl =
+renderRow (Just w) True _ = w
-  let (yes, no) = V.partition (f . toTask) $ taskListElements tl
+renderRow _ _ lt          = renderTask (toTask lt)
-      name = B.listName (visibleTasks tl)
-      list = newList name yes
-  in  TaskList{visibleTasks=list, invisibleTasks=no}
 
-taskListSelectedElement :: TaskList n -> Maybe Task
+renderLast :: (Ord n, Show n) => B.Widget n -> Bool -> B.List n LTask -> B.Widget n
-taskListSelectedElement tl = toTask . snd <$> B.listSelectedElement (visibleTasks tl)
+renderLast widget focus list =
+  let listWithPlaceholder = focusOnLastTask $ appendTask' emptyTask list
+  in  B.renderList (renderRow (Just widget)) focus listWithPlaceholder
 
-taskListModify :: (Task -> Task) -> TaskList n -> TaskList n
+renderTaskList :: (Ord n, Show n) => Maybe (TaskEdit n) -> Bool -> TaskList n -> B.Widget n
-taskListModify f tl =
+renderTaskList Nothing focus (TaskList list)
-  let list = B.listModify (modifyLTask f) (visibleTasks tl)
+  | listSize list == 0 = renderLast (B.str "--- empty ---") focus list
-  in  tl{visibleTasks=list}
+  | otherwise          = B.renderList (renderRow Nothing) focus list
+renderTaskList (Just te) focus (TaskList list) =
+  case editState te of
+    ExistingTask -> B.renderList (renderRow (Just teWidget)) focus list
+    NewTask      -> renderLast teWidget focus list
+  where
+    teWidget = renderTaskEdit focus te
+
+updateTaskList :: Ord n => VTY.Event -> TaskList n -> B.EventM n (TaskList n)
+updateTaskList event (TaskList list) =
+  TaskList <$> B.handleListEventVi B.handleListEvent event list
+
+sortTaskList :: TaskList n -> TaskList n
+sortTaskList (TaskList list) =
+  let tasks = V.toList $ B.listElements list
+      sortedTasks = sortBy (compareTasks `on` toTask) tasks
+      newVector = V.fromList sortedTasks
+  in  TaskList $ B.listReplace newVector Nothing list
+
+selectedTask :: TaskList n -> Maybe Task
+selectedTask (TaskList list) = toTask . snd <$> B.listSelectedElement list
+
+appendTask' :: Task -> B.List n LTask -> B.List n LTask
+appendTask' task list =
+  let size = listSize list
+      lt = lTask task
+  in  focusOnLastTask $ B.listInsert size lt list
+
+appendTask :: Task -> TaskList n -> TaskList n
+appendTask task (TaskList list) = TaskList $ appendTask' task list
+
+replaceTask :: Task -> TaskList n -> TaskList n
+replaceTask task (TaskList list) = TaskList $ B.listModify replace list
+  where
+    replace :: LTask -> LTask
+    replace = modifyLTask (const task)
+
+deleteTask :: TaskList n -> TaskList n
+deleteTask tl@(TaskList list) =
+  case listSize list of
+    0 -> tl
+    n -> TaskList $ B.listRemove (n-1) list
+
+{- helper functions -}
+
+listSize :: B.List n e -> Int
+listSize list = V.length $ B.listElements list
+
+focusOnLastTask :: B.List n e -> B.List n e
+focusOnLastTask list = B.listMoveTo (listSize list - 1) list

src/TaskMachine/UI/Types.hs

@@ -22,6 +22,7 @@ import qualified Graphics.Vty            as VTY
 import           TaskMachine.Options
 import           TaskMachine.UI.Popup
 import           TaskMachine.UI.Task
+import           TaskMachine.UI.TaskEdit
 import           TaskMachine.UI.TaskList
 
 -- | Resource names
@@ -36,7 +37,7 @@ data UIState = UIState
   { options    :: Options -- includes todo file and other config
   , errorPopup :: Maybe (Popup RName (UIState -> NewState))
   , tasks      :: TaskList RName
-  , taskEdit   :: Maybe (B.Editor String RName)
+  , editor     :: Maybe (TaskEdit RName)
   }
 
 type NewState = B.EventM RName (B.Next UIState)

todo.txt

@@ -2,7 +2,7 @@
 - c2018-09-18 Purge - move completed tasks to a separate file
 - c2018-09-28 Move cursor to beginning of task description when editing tasks
 - c2018-09-28 Syntax highlighting while editing tasks
-- c2018-09-30 Sort tasks when (re-)loading
+x2018-10-23 c2018-09-30 Display "-empty-" when TaskList is empty
 x2018-09-27 c2018-09-18 Quit using Esc or q
 x2018-09-29 c2018-09-28 Use B.EventM's MonadIO instance instead of B.suspendAndResume (facepalm)
 x2018-09-30 c2018-09-18 Offer "retry" or "quit" +dialogue - couldn't load from todo file