{-# LANGUAGE DeriveAnyClass    #-}
{-# LANGUAGE DeriveGeneric     #-}
{-# LANGUAGE LambdaCase        #-}
{-# LANGUAGE NamedFieldPuns    #-}
{-# LANGUAGE OverloadedStrings #-}

-- | Module that contains the high-level checking functions
{-# OPTIONS_GHC -Wno-deferred-out-of-scope-variables #-}
module CheckMap (loadAndLintMap) where

import           Data.Aeson   (ToJSON)
import           Data.Map     (Map, fromList, toList)
import           Data.Maybe   (mapMaybe)
import           Data.Text    (Text)
import qualified Data.Text    as T
import qualified Data.Vector  as V
import           GHC.Generics (Generic)

import           LintWriter   (LayerContext (..), LintResult (..), LintWriter,
                               lintToDep, resultToDeps, resultToLints,
                               runLintWriter)
import           Properties   (checkLayerProperty, checkMap)
import           Tiled2       (Layer (layerName, layerProperties),
                               Tiledmap (tiledmapLayers), loadTiledmap)
import           Types        (Dep, Level (..), Lint (..), hint, lintLevel)
import           Util         (PrettyPrint (prettyprint), prettyprint)



-- | What this linter produces: lints for a single map
data MapResult a = MapResult
  { mapresultLayer   :: Maybe (Map Text (LintResult LayerContext))
  , mapresultGeneral :: [Lint]
  , mapresultDepends :: [Dep]
  } deriving (Generic, ToJSON)



-- | this module's raison d'être
loadAndLintMap :: FilePath -> IO (MapResult ())
loadAndLintMap path = loadTiledmap path >>= pure . \case
    Left err -> MapResult
      { mapresultLayer = Nothing
      , mapresultDepends = []
      , mapresultGeneral =
        [ hint Fatal . T.pack $
          path <> ": parse error (probably invalid json/not a tiled map): " <> err
        ]
      }
    Right waMap ->
      runLinter waMap

-- | lint a loaded map
runLinter :: Tiledmap -> MapResult ()
runLinter tiledmap = MapResult
  { mapresultLayer = Just layerMap
  , mapresultGeneral = generalLints  -- no general lints for now
  , mapresultDepends = concatMap (resultToDeps . snd) layer
    <> mapMaybe lintToDep generalLints
  }
  where
    layerMap :: Map Text (LintResult LayerContext)
    layerMap = fromList layer
    layer = V.toList . V.map runCheck $ tiledmapLayers tiledmap
      where runCheck l = (layerName l, runLintWriter (LayerContext ()) (checkLayer l))

    -- lints collected from properties
    generalLints =
      resultToLints $ runLintWriter () (checkMap tiledmap)


-- | collect lints on a single map layer
checkLayer :: Layer -> LintWriter LayerContext
checkLayer layer =
  mapM_ (checkLayerProperty layer) (layerProperties layer)

-- human-readable lint output, e.g. for consoles
instance PrettyPrint a => PrettyPrint (MapResult a) where
  prettyprint mapResult = T.concat $ prettyGeneral <> prettyLayer
    where
      -- TODO: this can be simplified further
      prettyLayer :: [Text]
      prettyLayer = mapMaybe
        (uncurry showResult)
        (maybe [] toList . mapresultLayer $ mapResult)
      prettyGeneral :: [Text]
      prettyGeneral = flip (<>) "\n" . prettyprint <$> mapresultGeneral mapResult


-- TODO: possibly expand this to something more detailed?
showContext :: Text -> Text
showContext ctxt = " (in layer " <> ctxt <> ")\n"

-- | pretty-printer for a LintResult. Isn't an instance of PrettyPrint since
-- it needs to know about the result's context (yes, there could be
-- a wrapper type for that – but I wasn't really in the mood)
showResult :: Text -> LintResult c -> Maybe Text
showResult ctxt (LintResult (_, lints)) =
  Just $ T.concat (mapMaybe showHint lints)
  where
    -- TODO: make the "log level" configurable
    showHint hint = case lintLevel hint of
      Info -> Nothing
      _    -> Just $ prettyprint hint <> ctxtHint
    ctxtHint = showContext ctxt