{- This file is part of Vervis.
 -
 - Written in 2016, 2019, 2020, 2022 by fr33domlover <fr33domlover@riseup.net>.
 -
 - ♡ Copying is an act of love. Please copy, reuse and share.
 -
 - The author(s) have dedicated all copyright and related and neighboring
 - rights to this software to the public domain worldwide. This software is
 - distributed without any warranty.
 -
 - You should have received a copy of the CC0 Public Domain Dedication along
 - with this software. If not, see
 - <http://creativecommons.org/publicdomain/zero/1.0/>.
 -}

module Development.PatchMediaType
    ( VersionControlSystem (..)
    , PatchMediaType (..)
    , parseVersionControlSystemName
    , parseVersionControlSystemURI
    , versionControlSystemName
    , versionControlSystemURI
    , patchMediaTypeVCS
    , parsePatchMediaType
    , renderPatchMediaType
    )
where

import Control.Monad
import Data.Text (Text)

import qualified Data.Text as T

data VersionControlSystem = VCSDarcs | VCSGit deriving Eq

data PatchMediaType = PatchMediaTypeDarcs | PatchMediaTypeGit deriving Eq

forgeFedPrefix :: Text
forgeFedPrefix = "https://forgefed.org/ns#"

parseVersionControlSystemName :: Text -> Maybe VersionControlSystem
parseVersionControlSystemName = parse . T.toLower
    where
    parse "darcs" = Just VCSDarcs
    parse "git"   = Just VCSGit
    parse _       = Nothing

parseVersionControlSystemURI :: Text -> Maybe VersionControlSystem
parseVersionControlSystemURI = parse <=< T.stripPrefix forgeFedPrefix
    where
    parse "darcs" = Just VCSDarcs
    parse "git"   = Just VCSGit
    parse _       = Nothing

versionControlSystemName :: VersionControlSystem -> Text
versionControlSystemName VCSDarcs = "Darcs"
versionControlSystemName VCSGit   = "Git"

versionControlSystemURI :: VersionControlSystem -> Text
versionControlSystemURI vcs = forgeFedPrefix <> rest vcs
    where
    rest VCSDarcs = "darcs"
    rest VCSGit   = "git"

patchMediaTypeVCS :: PatchMediaType -> VersionControlSystem
patchMediaTypeVCS PatchMediaTypeDarcs = VCSDarcs
patchMediaTypeVCS PatchMediaTypeGit   = VCSGit

-- I don't think there's any standard media type for git patches, just picked
-- something that resembles the darcs media type
parsePatchMediaType :: Text -> Maybe PatchMediaType
parsePatchMediaType "application/x-darcs-patch" = Just PatchMediaTypeDarcs
parsePatchMediaType "application/x-git-patch"   = Just PatchMediaTypeGit
parsePatchMediaType _                           = Nothing

renderPatchMediaType :: PatchMediaType -> Text
renderPatchMediaType PatchMediaTypeDarcs = "application/x-darcs-patch"
renderPatchMediaType PatchMediaTypeGit   = "application/x-git-patch"