-- SPDX-FileCopyrightText: 2022-24 Gregor Kleen <gregor.kleen@ifi.lmu.de>,Steffen Jost <jost@tcs.ifi.lmu.de>,Steffen Jost <s.jost@fraport.de>
--
-- SPDX-License-Identifier: AGPL-3.0-or-later

-- TODO: why is this Handler.Utils.Profile instead of Utils.Profile? 
-- TODO: consider merging with Handler.Utils.Users?
module Handler.Utils.Profile
  ( module Utils.Mail
  , module Utils.Postal
  , validDisplayName, checkDisplayName, fixDisplayName
  , validFraportPersonalNumber
  ) where

import Import.NoFoundation

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

import Utils.Mail 
import Utils.Postal

-- | 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.toTitle $ 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 stripFold -> mTitle) (stripFold -> fName) (stripFold -> sName) (stripFold -> 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
    
validFraportPersonalNumber :: Maybe Text -> Bool
validFraportPersonalNumber Nothing = False
validFraportPersonalNumber (Just t)
  | (Just pn) <- readMay t
    = pn >= (10000::Int) && pn <= (99999::Int) -- used to filter for SAP export    
  | otherwise = False