{- This Source Code Form is subject to the terms of the Mozilla Public License,
   v. 2.0. If a copy of the MPL was not distributed with this file, You can
   obtain one at https://mozilla.org/MPL/2.0/. -}

module SlackBuilder.Package
    ( DownloadPlaceholder(..)
    , Download(..)
    , DownloadTemplate(..)
    , PackageDescription(..)
    , PackageUpdateData(..)
    , Maintainer(..)
    , Updater(..)
    , renderDownloadWithVersion
    ) where

import Data.List.NonEmpty (NonEmpty(..))
import Data.Text (Text)
import qualified Data.Text as Text
import Text.URI (URI(..))
import qualified Text.URI as URI
import Crypto.Hash (Digest, MD5)
import SlackBuilder.Trans
import Control.Monad.Catch (MonadThrow)
import Data.Map (Map)

-- | Contains information how a package can be updated.
data PackageDescription = PackageDescription
    { latest :: Updater
    , downloaders :: Map Text Updater
    , name :: Text
    }

data PackageUpdateData = PackageUpdateData
    { description :: PackageDescription
    , category :: Text
    , version :: Text
    }

-- | Download URI with the MD5 checksum of the target.
data Download = Download
    { download :: URI
    , md5sum :: Digest MD5
    } deriving (Eq, Show)

-- | Package maintainer information.
data Maintainer = Maintainer
    { name :: Text
    , email :: Text
    } deriving (Eq, Show)

-- | Appears in the download URI template and specifies which part of the URI
-- should be replaced with the package version.
data DownloadPlaceholder
    = StaticPlaceholder Text
    | VersionPlaceholder
    deriving Eq

instance Show DownloadPlaceholder
  where
    show (StaticPlaceholder staticPlaceholder) = Text.unpack staticPlaceholder
    show VersionPlaceholder = "{version}"

-- | List of URI components, including version placeholders.
newtype DownloadTemplate = DownloadTemplate (NonEmpty DownloadPlaceholder)
    deriving Eq

instance Show DownloadTemplate
  where
    show (DownloadTemplate components) = concatMap show components

-- | Replaces placeholders in the URL template with the given version.
renderDownloadWithVersion :: MonadThrow m => DownloadTemplate -> Text -> m URI
renderDownloadWithVersion (DownloadTemplate components) version =
    URI.mkURI $ foldr f "" components
  where
    f (StaticPlaceholder staticPlaceholder) = (staticPlaceholder <>)
    f VersionPlaceholder = (version <>)

-- | Function used to get the latest version of a source.
data Updater = Updater
    { detectLatest :: SlackBuilderT (Maybe Text)
    , is64 :: Bool
    , getVersion :: Text -> Text -> SlackBuilderT Download
    }