module Chez.Grater.Parser where

import Chez.Grater.Internal.Prelude

import Chez.Grater.Parser.Types
  ( ParsedIngredient(..), ParsedIngredientName(..), ParsedQuantity(..), ParsedUnit(..)
  )
import Chez.Grater.Scraper.Types (ScrapedIngredient(..), ScrapedStep(..))
import Chez.Grater.Types
  ( Ingredient(..), IngredientName(..), Quantity(..), Step(..), Unit(..), box, cup, gram, liter
  , milligram, milliliter, ounce, pinch, pound, splash, sprinkle, tablespoon, teaspoon, whole
  )
import Data.Char (isAlpha, isDigit, isSpace)
import Data.Function (fix)
import Text.Read (readMaybe)
import qualified Data.Attoparsec.Text as Atto
import qualified Data.CaseInsensitive as CI
import qualified Data.Map.Strict as Map
import qualified Data.Text as Text

unitAliasTable :: Map (CI Text) Unit
unitAliasTable = Map.fromList
  [ ("ounce", ounce)
  , ("ounces", ounce)
  , ("oz", ounce)
  , ("c", cup)
  , ("cup", cup)
  , ("cups", cup)
  , ("tablespoon", tablespoon)
  , ("tablespoons", tablespoon)
  , ("tbsp", tablespoon)
  , ("teaspoon", teaspoon)
  , ("teaspoons", teaspoon)
  , ("tsp", teaspoon)
  , ("pinch", pinch)
  , ("pinches", pinch)
  , ("box", box)
  , ("boxes", box)
  , ("pound", pound)
  , ("pounds", pound)
  , ("splash", splash)
  , ("splashes", splash)
  , ("sprinkle", sprinkle)
  , ("sprinkles", sprinkle)
  , ("whole", whole)

  , ("milliliter", milliliter)
  , ("millilitre", milliliter)
  , ("ml", milliliter)
  , ("liter", liter)
  , ("litre", liter)
  , ("l", liter)
  , ("milligram", milligram)
  , ("mg", milligram)
  , ("gram", gram)
  , ("g", gram)
  ]

quantityAliasTable :: Map (CI Text) Quantity
quantityAliasTable = Map.fromList $
  [ ("half dozen", 6)
  , ("dozen", 12)
  , ("quarter", 0.25)
  , ("third", 1 / 3)
  , ("half", 0.5)
  , ("one", 1)
  , ("two", 2)
  , ("three", 3)
  , ("four", 4)
  , ("five", 5)
  , ("six", 6)
  , ("seven", 7)
  , ("eight", 8)
  , ("nine", 9)
  , ("ten", 10)
  , ("eleven", 11)
  , ("twelve", 12)
  ]

scrubIngredientName :: ParsedIngredientName -> IngredientName
scrubIngredientName = IngredientName . unParsedIngredientName

scrubUnit :: ParsedUnit -> Unit
scrubUnit = \case
  ParsedUnit x -> Map.findWithDefault (Unit x) x unitAliasTable
  ParsedUnitMissing -> UnitMissing

scrubQuantity :: ParsedQuantity -> Quantity
scrubQuantity = \case
  ParsedQuantity q -> Quantity q
  ParsedQuantityWord w -> Map.findWithDefault QuantityMissing w quantityAliasTable
  ParsedQuantityMissing -> QuantityMissing

scrubIngredient :: ParsedIngredient -> Ingredient
scrubIngredient ParsedIngredient {..} = Ingredient
  { ingredientName = scrubIngredientName parsedIngredientName
  , ingredientQuantity = scrubQuantity parsedIngredientQuantity
  , ingredientUnit = scrubUnit parsedIngredientUnit
  }

quantityP :: Atto.Parser ParsedQuantity
quantityP = quantityExpression <|> quantityWord <|> quantityMissing
  where
    isIgnoredC c = elem c ['Â']
    isQuantityC c = isDigit c || isSpace c || elem c ['/', '.', '-', '⁄', '¼', '½', '¾', '⅓', '⅔'] || isIgnoredC c
    quantityParser p = p . Text.filter (not . isIgnoredC) =<< Atto.takeWhile isQuantityC
    strictQuantityParser p = p . Text.strip . Text.filter (not . isIgnoredC) =<< Atto.takeWhile1 isQuantityC

    quantitySingle str = maybe (fail $ Text.unpack str <> " is not a single quantity") pure . readMaybe . Text.unpack . Text.filter (not . isSpace) $ str
    quantityUnicode = \case
      "¼" -> pure 0.25
      "½" -> pure 0.5
      "¾" -> pure 0.75
      "⅓" -> pure $ 1 / 3
      "⅔" -> pure $ 2 / 3
      str -> fail $ Text.unpack str <> " is not a unicode quantity"
    quantityDecimal str = case Text.split ((==) '.') str of
      [x, y] -> maybe (fail $ Text.unpack str <> " is not a decimal quantity") pure $ do
        x' <- fromInteger <$> readMaybe (Text.unpack x)
        y' <- fromInteger <$> readMaybe (Text.unpack y)
        pure $ x' + (y' / (fromIntegral $ 10 * Text.length y))
      _ -> fail $ Text.unpack str <> " is not a decimal quantity"
    quantityFraction str = case Text.split ((==) '/') $ Text.replace "⁄" "/" str of
      [x, y] -> maybe (fail $ Text.unpack str <> " is not a fractional quantity") pure $
        (/) <$> readMaybe (Text.unpack x) <*> readMaybe (Text.unpack y)
      _ -> fail $ Text.unpack str <> " is not a fractional quantity"

    quantityImproper = quantityParser $ \str -> case filter (not . Text.null) . mconcat . fmap (Text.split isSpace) . Text.split ((==) '-') $ str of
      [x, y] -> do
        x' <- quantitySimple x
        y' <- quantitySimple y
        pure $ if x' < y' then (x' + y') / 2 else x' + y'
      _ -> fail $ Text.unpack str <> " is not an improper quantity"

    quantitySimple str =
      quantitySingle str
        <|> quantityUnicode str
        <|> quantityDecimal str
        <|> quantityFraction str

    quantityExpression = ParsedQuantity <$> (strictQuantityParser quantitySimple <|> quantityImproper)
    quantityWord = ParsedQuantityWord . CI.mk <$> ((\str -> if CI.mk str `elem` Map.keys quantityAliasTable then pure str else fail $ Text.unpack str <> " is not a quantity") =<< spaced (Atto.takeWhile1 isAlpha))
    quantityMissing = pure ParsedQuantityMissing

spaced :: Atto.Parser a -> Atto.Parser a
spaced p = optional (void Atto.space) *> (p <* optional (void Atto.space))

unitP :: Atto.Parser ParsedUnit
unitP = unitWord <|> pure ParsedUnitMissing
  where
    isIgnoredC c = elem c ['.']
    isUnitC c = isAlpha c || isIgnoredC c
    unitWord = do
      unit <- CI.mk . Text.filter (not . isIgnoredC) <$> spaced (Atto.takeWhile1 isUnitC)
      case unit `elem` Map.keys unitAliasTable of
        True -> pure $ ParsedUnit unit
        False -> fail "No unit found"

nameP :: Atto.Parser ParsedIngredientName
nameP = ParsedIngredientName . CI.mk . Text.strip . Text.unwords . filter (not . Text.null) . fmap Text.strip . Text.words <$> Atto.takeText

ingredientP :: Atto.Parser ParsedIngredient
ingredientP = mk <$> ((,,) <$> quantityP <*> unitP <*> nameP)
  where
    mk (q, u, n) = ParsedIngredient n q u

sanitize :: Text -> Text
sanitize = replacements . Text.filter (not . isIgnoredC)
  where
    replacements str = foldr (uncurry Text.replace) str
      [ ("\194", " ")
      , ("\226\150\162", "")
      ]
    isIgnoredC c = elem c ['▢', '☐']

runParser :: Atto.Parser a -> Text -> Either String a
runParser parser x = Atto.parseOnly parser (Text.strip (sanitize x))

requireNonEmpty :: Text -> [a] -> Either Text [a]
requireNonEmpty typ = \case
  [] -> Left $ "No " <> typ <> " found"
  xs -> Right xs

-- |Parse scraped ingredients.
parseScrapedIngredients :: [ScrapedIngredient] -> Either Text [Ingredient]
parseScrapedIngredients xs = do
  let parseOne = \case
        ScrapedIngredient raw | Text.null raw -> pure Nothing
        ScrapedIngredient raw -> Just <$> runParser ingredientP raw
  ingredients <- left (\err -> "Failed to parse " <> tshow xs <> "\n" <> Text.pack err)
    . fmap (nubOrd . fmap scrubIngredient . catMaybes)
    $ for xs parseOne
  requireNonEmpty "ingredients" ingredients

-- |Parse raw ingredients, i.e. ones we know should be separated by newlines.
parseRawIngredients :: Text -> Either Text [Ingredient]
parseRawIngredients content = do
  ingredients <- either (const $ Left "Failed to parse ingredients") (pure . fmap scrubIngredient)
    . traverse (runParser ingredientP)
    . filter (not . Text.null)
    . Text.lines
    $ content
  requireNonEmpty "ingredients" ingredients

-- |Passive ingredient parser which separates on newlines.
mkIngredients :: Text -> [Ingredient]
mkIngredients =
  fmap (\str -> Ingredient (IngredientName (CI.mk str)) QuantityMissing UnitMissing) . Text.lines

-- |Parse scraped steps.
parseScrapedSteps :: [ScrapedStep] -> Either Text [Step]
parseScrapedSteps xs = do
  steps <- case xs of
    [ScrapedStep single] | "1." `Text.isPrefixOf` single -> flip fix (filter (not . Text.null) . Text.words . Text.drop 2 $ single, (1 :: Int), []) $ \f -> \case
      ([], _, parsed) -> Right $ reverse parsed
      (toParse, ordinal, parsed) ->
        let nextOrdinal = tshow (ordinal + 1) <> "."
            (next, rest) = span (not . Text.isSuffixOf nextOrdinal) toParse
        in case rest of
          y:ys -> case Text.stripSuffix nextOrdinal y of
            Just z -> f (ys, ordinal + 1, (Step (Text.unwords (next <> [z]))):parsed)
            Nothing -> f (ys, ordinal + 1, (Step (Text.unwords next)):parsed)
          [] -> f ([], ordinal + 1, (Step (Text.unwords next)):parsed)
    [ScrapedStep single] -> Right $ fmap (Step . Text.unwords . filter (not . Text.null) . Text.words) . filter (not . Text.null) . fmap Text.strip . Text.lines $ single
    _ -> Right $ fmap (\(ScrapedStep step) -> Step . Text.unwords . filter (not . Text.null) . Text.words $ step) xs
  requireNonEmpty "steps" steps