module SlackBuilder.Package
    ( DownloadPlaceholder(..)
    , Download(..)
    , DownloadTemplate(..)
    , Package(..)
    , PackageInfo(..)
    , 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)

-- | Contains information how a package can be updated.
data Package = Package
    { latest :: Updater
    , downloaders :: [Updater]
    , category :: Text
    , name :: Text
    }

-- | Download URI with the MD5 checksum of the target.
data Download = Download
    { download :: URI
    , md5sum :: Digest MD5
    , is64 :: Bool
    } deriving (Eq, Show)

-- | Data used to generate an .info file.
data PackageInfo = PackageInfo
    { path :: FilePath
    , version :: Text
    , homepage :: Text
    , requires :: [Text]
    , maintainer :: Maintainer
    } 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)
    , getVersion :: Text -> Text -> SlackBuilderT (URI, Digest MD5)
    }