module Handler.Utils.Profile
  ( checkDisplayName
  , validDisplayName
  , fixDisplayName
  , validPostAddress  
  ) where

import Import.NoFoundation

import Data.Char
import qualified Data.Text as Text
import qualified Data.Text.Lazy as LT

import qualified Data.MultiSet as MultiSet
import qualified Data.Set as Set

-- | remove last comma and swap order of the two parts, ie. transforming "surname, givennames" into "givennames surname".
--   Input "givennames surname" is left unchanged, except for removing excess whitespace
fixDisplayName :: UserDisplayName -> UserDisplayName 
fixDisplayName udn = 
  let (Text.strip . Text.dropEnd 1 -> surname, Text.strip -> firstnames) = Text.breakOnEnd "," udn 
  in Text.strip $ firstnames <> Text.cons ' ' surname

-- | Like `validDisplayName` but may return an automatically corrected name
checkDisplayName :: Maybe UserTitle -> UserFirstName -> UserSurname -> UserDisplayName -> Maybe UserDisplayName
checkDisplayName mTitle fName sName (fixDisplayName -> dName)
  | validDisplayName mTitle fName sName dName = Just dName
  | otherwise = Nothing

validDisplayName :: Maybe UserTitle
                 -> UserFirstName
                 -> UserSurname
                 -> UserDisplayName
                 -> Bool
validDisplayName (fmap Text.strip -> mTitle) (Text.strip -> fName) (Text.strip -> sName) (Text.strip -> dName)
  = and [ dNameFrags `MultiSet.isSubsetOf` MultiSet.unions [titleFrags, fNameFrags, sNameFrags]
        , sName `Text.isInfixOf` dName
        , all ((<= 1) . Text.length) . filter (Text.any isAdd) $ Text.group dName
        , dNameLetters `Set.isSubsetOf` Set.unions [titleLetters, fNameLetters, sNameLetters, addLetters]
        ]
  where
    titleFrags   = foldMap makeMultiSet mTitle
    dNameFrags   =         makeMultiSet dName
    fNameFrags   =         makeMultiSet fName
    sNameFrags   =         makeMultiSet sName

    titleLetters = foldMap (Set.fromList . unpack) mTitle
    fNameLetters =          Set.fromList $ unpack  fName
    sNameLetters =          Set.fromList $ unpack  sName
    dNameLetters =          Set.fromList $ unpack  dName
    addLetters   =          Set.fromList [' ', '.', '-']

    isAdd = (`Set.member` addLetters)
    splitAdd = Text.split isAdd
    makeMultiSet = MultiSet.fromList . filter (not . Text.null) . splitAdd

-- | Primitive postal address requires at least one alphabetic character, one digit and a line break
validPostAddress :: Maybe StoredMarkup -> Bool
validPostAddress (Just StoredMarkup {markupInput = addr})
  | Just _ <- LT.find isLetter addr
  , Just _ <- LT.find isNumber addr 
  -- , Just _ <- LT.find ((LineSeparator ==) . generalCategory) addr -- THIS DID NOT WORK
  , 1 < length (LT.lines addr) 
    = True
validPostAddress _ = False