{-
Copyright (C) 2022 Yuchen Pei.

This file is part of fsd.

fsd is free software: you can redistribute it and/or modify it under
the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

fsd is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Affero General
Public License for more details.

You should have received a copy of the GNU Affero General Public
License along with fsd.  If not, see <https://www.gnu.org/licenses/>.

-}

{-# LANGUAGE ImportQualifiedPost #-}
module FSD.ChangeLog where

import Data.Generics
import Data.Time
import Data.Text qualified as T
import Debian.Changes
import Debian.Version
import Text.Regex.TDFA
import FSD.Types

readChangeLog :: String -> Maybe ChangeLogEntry
readChangeLog raw = case parseEntry raw of
  Left _ -> Nothing
  Right (entry, _) -> Just entry

-- Debian version is an abstract type with no constructor, hence the ugly hack.
getVersion :: DebianVersion -> Maybe String
getVersion v =
  let match = show v =~ ("\".*\"" :: String)
   in if null match then Nothing else Just $ init $ tail match

convertChangeLogEntry :: ChangeLogEntry -> Maybe FSDChangeLogEntry
convertChangeLogEntry entry = do
  version <- getVersion $ logVersion entry
  time <- parseTime' $ logDate entry
  return $
    FSDChangeLogEntry
      (T.pack $ logPackage entry)
      (T.pack version)
      (T.pack $ logWho entry)
      time
  where
    parseTime' raw =
      orElse
        (parseTimeM False defaultTimeLocale "%a, %d %b %Y %T %Z" raw)
        (parseTimeM False defaultTimeLocale "%a, %e %b %Y %T %Z" raw)

getChangeLogEntry :: String -> Maybe FSDChangeLogEntry
getChangeLogEntry raw = readChangeLog raw >>= convertChangeLogEntry