-- | Settings are centralized, as much as possible, into this file. This
-- includes database connection settings, static file locations, etc.
-- In addition, you can configure a number of different aspects of Yesod
-- by overriding methods in the Yesod typeclass. That instance is
-- declared in the Foundation.hs file.
module Settings where

import ClassyPrelude.Yesod
import qualified Control.Exception as Exception
import Data.Aeson                  (Result (..), fromJSON, withObject, (.!=),
                                    (.:?))
import Data.FileEmbed              (embedFile)
import Data.Yaml                   (decodeEither')
import Database.Persist.Postgresql (PostgresConf)
import Language.Haskell.TH.Syntax  (Exp, Q)
import Network.Wai.Handler.Warp    (HostPreference)
import Yesod.Default.Config2       (applyEnvValue, configSettingsYml)
import Yesod.Default.Util          (WidgetFileSettings, widgetFileNoReload,
                                    widgetFileReload)

#ifdef THERMOPRINT
import Thermoprint.Client (BaseUrl(..), parseBaseUrl)
#endif

#ifdef DEVELOPMENT
#define DEV_BOOL True
#else
#define DEV_BOOL False
#endif

-- | Runtime settings to configure this application. These settings can be
-- loaded from various sources: defaults, environment variables, config files,
-- theoretically even a database.
data AppSettings = AppSettings
    { appStaticDir              :: String
    -- ^ Directory from which to serve static files.
    , appDatabaseConf           :: PostgresConf
    -- ^ Configuration settings for accessing the database.
    , appRoot                   :: Maybe Text
    , appHost                   :: HostPreference
    -- ^ Host/interface the server should bind to.
    , appPort                   :: Int
    -- ^ Port to listen on
    , appIpFromHeader           :: Bool
    -- ^ Get the IP address from the header when logging. Useful when sitting
    -- behind a reverse proxy.

    , appDetailedRequestLogging :: Bool
    -- ^ Use detailed request logging system
    , appShouldLogAll           :: Bool
    -- ^ Should all log messages be displayed?
    , appReloadTemplates        :: Bool
    -- ^ Use the reload version of templates

#ifdef THERMORPINT
    , appThermoprintBase        :: BaseUrl
#endif
    }

instance FromJSON AppSettings where
    parseJSON = withObject "AppSettings" $ \o -> do
        let defaultDev = DEV_BOOL
        appStaticDir              <- o .: "static-dir"
        appDatabaseConf           <- o .: "database"
        appRoot'                  <- o .:? "approot"
        let
          appRoot
            | appRoot' == Just "" = Nothing
            | otherwise = appRoot'
        appHost                   <- fromString <$> o .: "host"
        appPort                   <- o .: "port"
        appIpFromHeader           <- o .: "ip-from-header"

        appDetailedRequestLogging <- o .:? "detailed-logging" .!= defaultDev
        appShouldLogAll           <- o .:? "should-log-all"   .!= defaultDev
        appReloadTemplates        <- o .:? "reload-templates" .!= defaultDev

#ifdef THERMOPRINT
        let parseUrl' = either (fail . show) return . parseBaseUrl
        appThermoprintBase        <- parseUrl' =<< o .: "thermoprint-url"
#endif

        return AppSettings {..}

-- | Settings for 'widgetFile', such as which template languages to support and
-- default Hamlet settings.
--
-- For more information on modifying behavior, see:
--
-- https://github.com/yesodweb/yesod/wiki/Overriding-widgetFile
widgetFileSettings :: WidgetFileSettings
widgetFileSettings = def

-- | How static files should be combined.
combineSettings :: CombineSettings
combineSettings = def

-- The rest of this file contains settings which rarely need changing by a
-- user.

widgetFile :: String -> Q Exp
widgetFile = (if appReloadTemplates compileTimeAppSettings
                then widgetFileReload
                else widgetFileNoReload)
              widgetFileSettings

-- | Raw bytes at compile time of @config/settings.yml@
configSettingsYmlBS :: ByteString
configSettingsYmlBS = $(embedFile configSettingsYml)

-- | @config/settings.yml@, parsed to a @Value@.
configSettingsYmlValue :: Value
configSettingsYmlValue = either Exception.throw id
                       $ decodeEither' configSettingsYmlBS

-- | A version of @AppSettings@ parsed at compile time from @config/settings.yml@.
compileTimeAppSettings :: AppSettings
compileTimeAppSettings =
    case fromJSON $ applyEnvValue False mempty configSettingsYmlValue of
        Error e -> error e
        Success settings -> settings