{-|
Module      : Gargantext.Database.Schema.NgramsPostag
Description : Ngram connection to the Database
Copyright   : (c) CNRS, 2017-Present
License     : AGPL + CECILL v3
Maintainer  : team@gargantext.org
Stability   : experimental
Portability : POSIX

Ngrams connection to the Database.

-}

{-# LANGUAGE Arrows                     #-}
{-# LANGUAGE FunctionalDependencies     #-}
{-# LANGUAGE QuasiQuotes            #-}
{-# LANGUAGE TemplateHaskell        #-}

module Gargantext.Database.Schema.Ngrams
  where

import Data.Hashable (Hashable)
import Codec.Serialise (Serialise())
import Control.Lens (over)
import Control.Monad (mzero)
import Data.Aeson
import Data.Aeson.Types (toJSONKeyText)
import Data.Map (Map, fromList, lookup)
import Data.Text (Text, splitOn, pack, strip)
import Gargantext.Core.Types (TODO(..), Typed(..))
import Gargantext.Prelude
import Prelude (Functor)
import Servant (FromHttpApiData, parseUrlPiece, Proxy(..))
import Text.Read (read)
import Gargantext.Database.Types
import Gargantext.Database.Schema.Prelude
import qualified Database.PostgreSQL.Simple as PGS


type NgramsId  = Int
type Size      = Int

data NgramsPoly id terms n = NgramsDB { _ngrams_id    :: !id
                                      , _ngrams_terms :: !terms
                                      , _ngrams_n     :: !n
                                      } deriving (Show)

type NgramsWrite = NgramsPoly (Maybe (Column PGInt4))
                                   (Column PGText)
                                   (Column PGInt4)

type NgramsRead  = NgramsPoly (Column PGInt4)
                              (Column PGText)
                              (Column PGInt4)

type NgramsReadNull = NgramsPoly (Column (Nullable PGInt4))
                                 (Column (Nullable PGText))
                                 (Column (Nullable PGInt4))

type NgramsDB = NgramsPoly Int Text Int

$(makeAdaptorAndInstance "pNgramsDb"    ''NgramsPoly)
makeLenses ''NgramsPoly


ngramsTable :: Table NgramsWrite NgramsRead
ngramsTable = Table "ngrams" (pNgramsDb NgramsDB { _ngrams_id    = optional "id"
                                                 , _ngrams_terms = required "terms"
                                                 , _ngrams_n     = required "n"
                                                 }
                              )

-- | Main Ngrams Types
-- | Typed Ngrams
-- Typed Ngrams localize the context of the ngrams
-- ngrams in source  field  of document  has Sources Type
-- ngrams in authors field  of document  has Authors Type
-- ngrams in text    fields of documents has Terms   Type (i.e. either title or abstract)
data NgramsType = Authors | Institutes | Sources | NgramsTerms
  deriving (Eq, Show, Read, Ord, Enum, Bounded, Generic)

instance Serialise NgramsType

ngramsTypes :: [NgramsType]
ngramsTypes = [minBound..]

instance ToSchema NgramsType
{-  where
  declareNamedSchema = genericDeclareNamedSchema (unPrefixSwagger "_nre_")
--}

newtype NgramsTypeId = NgramsTypeId Int
  deriving (Eq, Show, Ord, Num)

instance ToField NgramsTypeId where
  toField (NgramsTypeId n) = toField n

instance FromField NgramsTypeId where
  fromField fld mdata = do
    n <- fromField fld mdata
    if (n :: Int) > 0 then return $ NgramsTypeId n
                      else mzero

instance FromJSON NgramsType
instance FromJSONKey NgramsType where
   fromJSONKey = FromJSONKeyTextParser (parseJSON . String)

instance ToJSON NgramsType
instance ToJSONKey NgramsType where
   toJSONKey = toJSONKeyText (pack . show)

instance FromHttpApiData NgramsType where
  parseUrlPiece n = pure $ (read . cs) n

instance ToParamSchema NgramsType where
  toParamSchema _ = toParamSchema (Proxy :: Proxy TODO)


instance QueryRunnerColumnDefault (Nullable PGInt4) NgramsTypeId
  where
    queryRunnerColumnDefault = fieldQueryRunnerColumn

pgNgramsType :: NgramsType -> Column PGInt4
pgNgramsType = pgNgramsTypeId . ngramsTypeId

pgNgramsTypeId :: NgramsTypeId -> Column PGInt4
pgNgramsTypeId (NgramsTypeId n) = pgInt4 n

ngramsTypeId :: NgramsType -> NgramsTypeId
ngramsTypeId Authors     = 1
ngramsTypeId Institutes  = 2
ngramsTypeId Sources     = 3
ngramsTypeId NgramsTerms = 4

fromNgramsTypeId :: NgramsTypeId -> Maybe NgramsType
fromNgramsTypeId id = lookup id
                    $ fromList [ (ngramsTypeId nt,nt)
                               | nt <- [minBound .. maxBound] :: [NgramsType]
                               ]

------------------------------------------------------------------------
------------------------------------------------------------------------
-- | TODO put it in Gargantext.Core.Text.Ngrams
data Ngrams = UnsafeNgrams { _ngramsTerms :: Text
                           , _ngramsSize  :: Int
                           }
  deriving (Generic, Show, Eq, Ord)

makeLenses ''Ngrams
instance PGS.ToRow Ngrams where
  toRow (UnsafeNgrams t s) = [toField t, toField s]

instance FromField Ngrams where
  fromField fld mdata = do
    x <- fromField fld mdata
    pure $ text2ngrams x

text2ngrams :: Text -> Ngrams
text2ngrams txt = UnsafeNgrams txt' $ length $ splitOn " " txt'
  where
    txt' = strip txt


------------------------------------------------------------------------
-------------------------------------------------------------------------
-- | TODO put it in Gargantext.Core.Text.Ngrams
-- Named entity are typed ngrams of Terms Ngrams
data NgramsT a =
  NgramsT { _ngramsType :: NgramsType
          , _ngramsT    :: a
          } deriving (Generic, Show, Eq, Ord)

makeLenses ''NgramsT

instance Functor NgramsT where
  fmap = over ngramsT

-----------------------------------------------------------------------
withMap :: Map Text NgramsId -> Text -> NgramsId
withMap m n = maybe (panic "withMap: should not happen") identity (lookup n m)

indexNgramsT :: Map Text NgramsId -> NgramsT Ngrams -> NgramsT (Indexed Int Ngrams)
indexNgramsT = fmap . indexNgramsWith . withMap

-- | TODO replace NgramsT whith Typed NgramsType Ngrams
indexTypedNgrams :: Map Text NgramsId
                 -> Typed NgramsType Ngrams
                 -> Typed NgramsType (Indexed Int Ngrams)
indexTypedNgrams = fmap . indexNgramsWith . withMap

indexNgrams :: Map Text NgramsId -> Ngrams -> Indexed Int Ngrams
indexNgrams = indexNgramsWith . withMap

indexNgramsWith :: (Text -> NgramsId) -> Ngrams -> Indexed Int Ngrams
indexNgramsWith f n = Indexed (f $ _ngramsTerms n) n