-- The error screen, showing a current error condition (such as a parse error after reloading the journal)

{-# LANGUAGE OverloadedStrings, FlexibleContexts, RecordWildCards #-}

module Hledger.UI.ErrorScreen
 (errorScreen
 ,uiReloadJournalIfChanged
 )
where

import Brick
import Control.Monad
import Control.Monad.IO.Class (liftIO)
import Data.Monoid
import Data.Time.Calendar (Day)
import Graphics.Vty hiding (char, string)-- (Event(..))
import Text.Parsec

import Hledger.Cli hiding (progname,prognameandversion,green)
import Hledger.UI.UIOptions
import Hledger.UI.UITypes
import Hledger.UI.UIState
import Hledger.UI.UIUtils
import Hledger.UI.Editor

errorScreen :: Screen
errorScreen = ErrorScreen{
   sInit    = esInit
  ,sDraw    = esDraw
  ,sHandle  = esHandle
  ,esError  = ""
  }

esInit :: Day -> Bool -> UIState -> UIState
esInit _ _ ui@UIState{aScreen=ErrorScreen{}} = ui
esInit _ _ _ = error "init function called with wrong screen type, should not happen"

esDraw :: UIState -> [Widget]
esDraw UIState{ -- aopts=_uopts@UIOpts{cliopts_=_copts@CliOpts{reportopts_=_ropts@ReportOpts{query_=querystr}}},
                             aScreen=ErrorScreen{..}
                             ,aMode=mode} =
  case mode of
    Help       -> [helpDialog, maincontent]
    -- Minibuffer e -> [minibuffer e, maincontent]
    _          -> [maincontent]
  where
    toplabel = withAttr ("border" <> "bold") (str "Oops. Please fix this problem then press g to reload")
    maincontent = Widget Greedy Greedy $ do
      render $ defaultLayout toplabel bottomlabel $ withAttr "error" $ str $ esError
      where
        bottomlabel = case mode of
                        -- Minibuffer ed -> minibuffer ed
                        _             -> quickhelp
        quickhelp = borderKeysStr [
           ("h", "help")
          ,("ESC", "cancel/top")
          ,("E", "editor")
          ,("g", "reload")
          ,("q", "quit")
          ]

esDraw _ = error "draw function called with wrong screen type, should not happen"

esHandle :: UIState -> Event -> EventM (Next UIState)
esHandle ui@UIState{
   aScreen=ErrorScreen{..}
  ,aopts=UIOpts{cliopts_=copts}
  ,ajournal=j
  ,aMode=mode
  } ev =
  case mode of
    Help ->
      case ev of
        EvKey (KChar 'q') [] -> halt ui
        _                    -> helpHandle ui ev

    _ -> do
      d <- liftIO getCurrentDay
      case ev of
        EvKey (KChar 'q') [] -> halt ui
        EvKey KEsc        [] -> continue $ resetScreens d ui
        EvKey (KChar c)   [] | c `elem` ['h','?'] -> continue $ setMode Help ui
        EvKey (KChar 'E') [] -> suspendAndResume $ void (runEditor pos f) >> uiReloadJournalIfChanged copts d j (popScreen ui)
          where
            (pos,f) = case parsewith hledgerparseerrorpositionp esError of
                        Right (f,l,c) -> (Just (l, Just c),f)
                        Left  _       -> (endPos, journalFilePath j)
        EvKey (KChar 'g') [] -> liftIO (uiReloadJournalIfChanged copts d j (popScreen ui)) >>= continue
--           (ej, _) <- liftIO $ journalReloadIfChanged copts d j
--           case ej of
--             Left err -> continue ui{aScreen=s{esError=err}} -- show latest parse error
--             Right j' -> continue $ regenerateScreens j' d $ popScreen ui  -- return to previous screen, and reload it
        _ -> continue ui

esHandle _ _ = error "event handler called with wrong screen type, should not happen"

-- | Parse the file name, line and column number from a hledger parse error message, if possible.
-- Temporary, we should keep the original parse error location. XXX
hledgerparseerrorpositionp = do
  anyChar `manyTill` char '"'
  f <- anyChar `manyTill` (oneOf ['"','\n'])
  string " (line "
  l <- read <$> many1 digit
  string ", column "
  c <- read <$> many1 digit
  return (f, l, c)

-- If journal file(s) have changed, reload the journal and regenerate all screens.
-- This is here so it can reference the error screen.
uiReloadJournalIfChanged :: CliOpts -> Day -> Journal -> UIState -> IO UIState
uiReloadJournalIfChanged copts d j ui = do
  (ej, _) <- journalReloadIfChanged copts d j
  return $ case ej of
    Right j' -> regenerateScreens j' d ui
    Left err -> screenEnter d errorScreen{esError=err} ui