{-# LANGUAGE OverloadedStrings #-}

{- HLINT ignore "Use <$>" -}

-- |
-- SPDX-License-Identifier: BSD-3-Clause
--
-- Prepares and validates scenario launch parameters
module Swarm.TUI.Launch.Prep where

import Brick (EventM)
import Brick.Focus qualified as Focus
import Brick.Widgets.Edit
import Brick.Widgets.FileBrowser qualified as FB
import Control.Arrow (left)
import Control.Carrier.Throw.Either (runThrow)
import Control.Lens ((.=), (^.))
import Control.Monad.IO.Class (MonadIO, liftIO)
import Data.Functor.Identity (runIdentity)
import Data.Text qualified as T
import Swarm.Game.Failure (SystemFailure)
import Swarm.Game.Scenario.Status (ParameterizableLaunchParams (..), ScenarioInfoPair, getLaunchParams, scenarioStatus)
import Swarm.Game.State (Seed, ValidatedLaunchParams, getRunCodePath, parseCodeFile)
import Swarm.Language.Pretty (prettyText)
import Swarm.TUI.Launch.Model
import Swarm.TUI.Model.Name
import Swarm.Util (listEnums)
import Swarm.Util.Effect (withThrow)
import System.FilePath (takeDirectory)
import Text.Read (readEither)

swarmLangFileExtension :: String
swarmLangFileExtension = "sw"

toValidatedParams :: EditingLaunchParams -> Either T.Text ValidatedLaunchParams
toValidatedParams (LaunchParams eitherSeedVal eitherInitialCode) = do
  maybeSeed <- eitherSeedVal
  maybeParsedCode <- eitherInitialCode
  return $ LaunchParams (pure maybeSeed) (pure maybeParsedCode)

parseSeedInput :: Editor T.Text Name -> Either T.Text (Maybe Seed)
parseSeedInput seedEditor =
  if T.null seedFieldText
    then Right Nothing
    else
      fmap Just
        . left T.pack
        . readEither
        . T.unpack
        $ seedFieldText
 where
  seedFieldText = mconcat $ getEditContents seedEditor

parseWidgetParams :: LaunchControls -> IO EditingLaunchParams
parseWidgetParams (LaunchControls (FileBrowserControl _fb maybeSelectedScript _) seedEditor _ _) = do
  eitherParsedCode <-
    runThrow . withThrow (prettyText @SystemFailure) $
      traverse parseCodeFile maybeSelectedScript
  return $ LaunchParams eitherMaybeSeed eitherParsedCode
 where
  eitherMaybeSeed = parseSeedInput seedEditor

makeFocusRingWith :: [ScenarioConfigPanelFocusable] -> Focus.FocusRing Name
makeFocusRingWith = Focus.focusRing . map (ScenarioConfigControl . ScenarioConfigPanelControl)

initEditorWidget :: T.Text -> Editor T.Text Name
initEditorWidget =
  editorText
    (ScenarioConfigControl $ ScenarioConfigPanelControl SeedSelector)
    (Just 1) -- only allow a single line

-- | Called before any particular scenario is selected, so we
-- supply some 'Nothing's as defaults to the 'ValidatedLaunchParams'.
initConfigPanel :: IO LaunchOptions
initConfigPanel = do
  -- NOTE: This is kind of pointless, because we must re-instantiate the 'FB.FileBrowser'
  -- when it is first displayed, anyway.
  fb <-
    FB.newFileBrowser
      FB.selectNonDirectories
      (ScenarioConfigControl $ ScenarioConfigPanelControl ScriptSelector)
      Nothing -- Initial working directory to display
  return $
    LaunchOptions
      (LaunchControls (FileBrowserControl fb Nothing False) myForm ring Nothing)
      (LaunchParams (Right Nothing) (Right Nothing))
 where
  myForm = initEditorWidget ""
  ring = makeFocusRingWith listEnums

initFileBrowserWidget ::
  (MonadIO m) =>
  Maybe FilePath ->
  m (FB.FileBrowser Name)
initFileBrowserWidget maybePlayedScript = do
  fb <-
    liftIO $
      FB.newFileBrowser
        FB.selectNonDirectories
        (ScenarioConfigControl $ ScenarioConfigPanelControl ScriptSelector)
        (takeDirectory <$> maybePlayedScript) -- Initial working directory to display
  return $ FB.setFileBrowserEntryFilter (Just $ FB.fileExtensionMatch swarmLangFileExtension) fb

-- | If the selected scenario has been launched with an initial script before,
-- set the file browser to initially open that script's directory.
-- Then set the launch dialog to be displayed.
--
-- Note that the 'FB.FileBrowser' widget normally allows multiple selections ("marked" files).
-- However, there do not exist any public "setters" set the marked files, so we have
-- some workarounds:
--
-- * When the user marks the first file, we immediately close the 'FB.FileBrowser' widget.
-- * We re-instantiate the 'FB.FileBrowser' from scratch every time it is opened, so that
--   it is not possible to mark more than one file.
-- * The "marked file" is persisted outside of the 'FB.FileBrowser' state, and the
--   "initial directory" is set upon instantiation from that external state.
prepareLaunchDialog ::
  ScenarioInfoPair ->
  EventM Name LaunchOptions ()
prepareLaunchDialog siPair@(_, si) = do
  let serializableLaunchParams = getLaunchParams $ si ^. scenarioStatus
  launchEditingParams <- liftIO $ fromSerializableParams serializableLaunchParams
  editingParams .= launchEditingParams

  let maybePlayedScript = case initialCode launchEditingParams of
        Right codeToRun -> getRunCodePath =<< codeToRun
        Left _ -> Nothing

  controls . fileBrowser . maybeSelectedFile .= maybePlayedScript
  controls . seedValueEditor .= initEditorWidget (maybe "" (T.pack . show) $ runIdentity $ seedVal serializableLaunchParams)
  controls . isDisplayedFor .= Just siPair