Make project compile again

This commit also adds a few other files that I've been working on,
although most of it will get deleted again. This is just so I have them
logged in git.

src/TaskMachine/Task.hs

@@ -0,0 +1,93 @@
+{-# LANGUAGE RecordWildCards #-}
+
+-- | Task related stuff.
+--
+-- This module will be used by both the UI and the database modules.
+-- It contains some functionality independent of any of those modules.
+--
+-- (Although I don't really know what exactly that will be.)
+
+module TaskMachine.Task
+  ( Task(..)
+  , Subtask(..)
+  ) where
+
+import qualified Data.Text            as T
+
+import qualified TaskMachine.DateExpr as TM
+import qualified TaskMachine.Deadline as TM
+
+type SubtaskID = Integer
+
+data Subtask = Subtask
+  { subID               :: SubtaskID
+  , subLabel            :: T.Text
+  , subRepetitionsTotal :: Integer
+  , subRepetitionsDone  :: Integer
+  }
+
+type TaskID = Integer
+
+data Task = Task
+  { taskID          :: TaskID
+  , taskDeadlines   :: [TM.Deadline]
+  , taskFormula     :: Maybe TM.IntExpr
+  , taskDescription :: T.Text
+  , taskDetails     :: T.Text
+  , taskSubtasks    :: [Subtask]
+  }
+
+{-
+  ( Task(..)
+  , Deadline(..)
+  , fromTaskRow
+  , toTaskRow
+  ) where
+
+import qualified Data.Text            as T
+import           Data.Time.Calendar
+
+import qualified TaskMachine.Database as TM
+
+data Task = Task
+  { taskID               :: TM.TaskID
+  , taskDeadline         :: Deadline
+  , taskIntFormula       :: Maybe TM.IntFormula
+  , taskDescription      :: T.Text
+  , taskDetails          :: T.Text
+  , taskRepetitionsTotal :: Integer
+  , taskRepetitionsDone  :: Integer
+  }
+
+data Deadline
+  = DeadlineNone
+  | DeadlineDay Day (Maybe TM.Duration)
+  | DeadlineFormula TM.BoolFormula TM.Duration
+
+getDeadline :: TM.TaskRow -> Deadline
+getDeadline row = case TM.rowBoolFormula row of
+  Just formula -> DeadlineFormula formula $ fromMaybe 1 $ TM.rowDuration row
+  Nothing      -> case TM.rowDeadline row of
+    Just day -> DeadlineDay day $ TM.rowDuration row
+    Nothing  -> DeadlineNone
+
+fromTaskRow :: TM.TaskRow -> Task
+fromTaskRow row =
+  let taskID               = TM.rowID row
+      taskDeadline         = getDeadline row
+      taskIntFormula       = TM.rowIntFormula row
+      taskDescription      = TM.rowDescription row
+      taskDetails          = TM.rowDetails row
+      taskRepetitionsTotal = TM.rowRepetitionsTotal
+      taskRepetitionsDone  = TM.rowRepetitionsDone
+  in Task{..}
+
+toTaskRow :: Task -> TM.TaskRow
+toTaskRow task = undefined task
+
+nextDeadline :: Day -> Deadline -> Maybe Day
+updateDeadline (DeadlineFormula formula duration) =
+  let expr = boolFormulaExpr formula
+  in  Just $ TM.findNext expr day duration
+updateDeadline _ = Nothing
+-}