{-|
Module      : Gargantext.Database.TextSearch
Description : Postgres text search experimentation
Copyright   : (c) CNRS, 2017-Present
License     : AGPL + CECILL v3
Maintainer  : team@gargantext.org
Stability   : experimental
Portability : POSIX


-}

{-# LANGUAGE NoImplicitPrelude #-}
{-# LANGUAGE OverloadedStrings #-}

module Gargantext.Database.TextSearch where


import Data.Aeson
import Data.List (intersperse)
import Data.String (IsString(..))
import Data.Text (Text, words)

import Database.PostgreSQL.Simple
import Database.PostgreSQL.Simple.ToField

import Gargantext.Prelude

newtype TSQuery = UnsafeTSQuery [Text]

-- | TODO [""] -> panic "error"
toTSQuery :: [Text] -> TSQuery
toTSQuery txt = UnsafeTSQuery txt

instance IsString TSQuery
  where
    fromString = UnsafeTSQuery . words . cs


instance ToField TSQuery
  where
    toField (UnsafeTSQuery xs)
      = Many  $ intersperse (Plain " && ")
              $ map (\q -> Many [ Plain "plainto_tsquery("
                                , Escape (cs q)
                                , Plain ")"
                                ]
                    ) xs

type ParentId = Int
type Limit    = Int
type Offset   = Int
data Order    = Asc | Desc

instance ToField Order
  where
    toField Asc  = Plain "ASC"
    toField Desc = Plain "DESC"

-- TODO
-- FIX fav
-- ADD ngrams count
-- TESTS
textSearchQuery :: Query
textSearchQuery = "SELECT n.id, n.hyperdata->'publication_year'     \
\                   , n.hyperdata->'title'                          \
\                   , n.hyperdata->'source'                         \
\                   , n.hyperdata->'authors'                        \
\                   , COALESCE(nn.score,null)                       \
\                      FROM nodes n                                 \
\            LEFT JOIN nodes_nodes nn  ON nn.node2_id = n.id        \
\              WHERE                                                \
\                n.search @@ (?::tsquery)                           \
\                AND n.parent_id = ?   AND n.typename  = 4          \
\                ORDER BY n.hyperdata -> 'publication_date' ?       \
\            offset ? limit ?;"

-- | Text Search Function for Master Corpus
-- TODO : text search for user corpus
-- Example:
-- textSearchTest :: ParentId -> TSQuery -> Cmd [(Int, Value, Value, Value, Value, Maybe Int)]
-- textSearchTest pId q = mkCmd $ \c -> textSearch c q pId 5 0 Asc
textSearch :: Connection 
           -> TSQuery -> ParentId
           -> Limit -> Offset -> Order
           -> IO [(Int,Value,Value,Value, Value, Maybe Int)]
textSearch conn q p l o ord = query conn textSearchQuery (q,p,ord, o,l)