{-# LANGUAGE CPP                #-}
{-# LANGUAGE NoImplicitPrelude  #-}
{-# LANGUAGE OverloadedStrings  #-}
{-# LANGUAGE RecordWildCards    #-}
{-# LANGUAGE TemplateHaskell    #-}
{-# LANGUAGE MultiWayIf         #-}
{-# LANGUAGE StandaloneDeriving #-}
{-# LANGUAGE DerivingStrategies #-}
{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE KindSignatures #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# OPTIONS_GHC -fno-warn-orphans #-}
-- | 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
  ( module Settings
  , module Settings.Cluster
  ) where

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

import Data.Time (NominalDiffTime)

import Data.Scientific (toBoundedInteger)
import Data.Word (Word16)

import qualified Data.Text as Text
import qualified Data.Text.Encoding as Text

import qualified Ldap.Client as Ldap

import Utils hiding (MessageClass(..))
import Control.Lens

import Data.Maybe (fromJust)
import qualified Data.Char as Char

import qualified Network.HaskellNet.Auth as HaskellNet (UserName, Password, AuthType(..))
import qualified Network.Socket as HaskellNet (PortNumber(..), HostName)

import Network.Mail.Mime (Address)

import Mail (VerpMode)

import Model
import Settings.Cluster

-- | 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.
    , appLdapConf               :: Maybe LdapConf
    -- ^ Configuration settings for accessing the LDAP-directory
    , appSmtpConf               :: Maybe SmtpConf
    -- ^ Configuration settings for accessing a SMTP Mailserver
    , appRoot                   :: Maybe Text
    -- ^ Base for all generated URLs. If @Nothing@, determined
    -- from the request headers.
    , 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.
    , appMailFrom               :: Address
    , appMailObjectDomain       :: Text
    , appMailVerp               :: VerpMode
    , appMailSupport            :: Address
    , appJobWorkers             :: Int
    , appJobFlushInterval       :: Maybe NominalDiffTime
    , appJobCronInterval        :: NominalDiffTime
    , appJobStaleThreshold      :: NominalDiffTime
    , appNotificationRateLimit  :: NominalDiffTime
    , appNotificationCollateDelay :: NominalDiffTime
    , appNotificationExpiration :: NominalDiffTime
    , appSessionTimeout         :: NominalDiffTime

    , appInitialLogSettings     :: LogSettings

    , appReloadTemplates        :: Bool
    -- ^ Use the reload version of templates
    , appMutableStatic          :: Bool
    -- ^ Assume that files in the static dir may change after compilation
    , appSkipCombining          :: Bool
    -- ^ Perform no stylesheet/script combining
    , appAuthDummyLogin         :: Bool
    -- ^ Indicate if auth dummy login should be enabled.
    , appAllowDeprecated        :: Bool
    -- ^ Indicate if deprecated routes are accessible for everyone
    , appEncryptErrors          :: Bool

    , appUserDefaults           :: UserDefaultConf
    , appAuthPWHash             :: PWHashConf

    , appInitialInstanceID      :: Maybe (Either FilePath UUID)
    } deriving (Show)

data LogSettings = LogSettings
  { logAll, logDetailed :: Bool
  , logMinimumLevel :: LogLevel
  } deriving (Show, Read, Generic, Eq, Ord)

deriving instance Generic LogLevel
instance Hashable LogLevel
instance Hashable LogSettings

data UserDefaultConf = UserDefaultConf
  { userDefaultTheme :: Theme
  , userDefaultMaxFavourites :: Int
  , userDefaultDateTimeFormat, userDefaultDateFormat, userDefaultTimeFormat :: DateTimeFormat
  , userDefaultDownloadFiles :: Bool
  } deriving (Show)
 
data PWHashConf = PWHashConf
  { pwHashAlgorithm :: PWHashAlgorithm
  , pwHashStrength :: Int
  }

instance Show PWHashConf where
  show PWHashConf{..} = "PWHashConf { pwHashStrength = " <> show pwHashStrength <> ", .. }"

instance FromJSON PWHashConf where
  parseJSON = withObject "PWHashConf" $ \o -> do
    pwHashAlgorithm' <- (o .: "algorithm" :: Aeson.Parser Text)
    pwHashAlgorithm <- if
      | pwHashAlgorithm' == "pbkdf1" -> return PWStore.pbkdf1
      | pwHashAlgorithm' == "pbkdf2" -> return PWStore.pbkdf2
      | otherwise -> fail "Unsupported hash algorithm"
    pwHashStrength <- o .: "strength"

    return PWHashConf{..}

data LdapConf = LdapConf
  { ldapHost :: Ldap.Host, ldapPort :: Ldap.PortNumber
  , ldapDn :: Ldap.Dn, ldapPassword :: Ldap.Password
  , ldapBase :: Ldap.Dn
  , ldapScope :: Ldap.Scope
  , ldapTimeout :: Int32
  } deriving (Show)
 
data SmtpConf = SmtpConf
  { smtpHost :: HaskellNet.HostName
  , smtpPort :: HaskellNet.PortNumber
  , smtpAuth :: Maybe SmtpAuthConf
  , smtpSsl  :: SmtpSslMode
  , smtpPool :: ResourcePoolConf
  } deriving (Show)

data ResourcePoolConf = ResourcePoolConf
  { poolStripes :: Int
  , poolTimeout :: NominalDiffTime
  , poolLimit :: Int
  } deriving (Show)

data SmtpSslMode = SmtpSslNone | SmtpSslSmtps | SmtpSslStarttls
  deriving (Show)

data SmtpAuthConf = SmtpAuthConf
  { smtpAuthType :: HaskellNet.AuthType
  , smtpAuthUsername :: HaskellNet.UserName
  , smtpAuthPassword :: HaskellNet.Password
  } deriving (Show)

deriveJSON defaultOptions
  { fieldLabelModifier = intercalate "-" . map toLower . splitCamel
  } ''LogSettings
  
deriveFromJSON defaultOptions ''Ldap.Scope
deriveFromJSON defaultOptions
  { fieldLabelModifier = intercalate "-" . map toLower . drop 2 . splitCamel
  } ''UserDefaultConf

instance FromJSON LdapConf where
    parseJSON = withObject "LdapConf" $ \o -> do
        ldapTls <- o .:? "tls"
        tlsSettings <- case ldapTls :: Maybe String of
          Just spec
            | spec == "insecure" -> return $ Just Ldap.insecureTlsSettings
            | spec == "default"  -> return $ Just Ldap.defaultTlsSettings
            | null spec          -> return Nothing
          Nothing                -> return Nothing
          _otherwise             -> fail "Could not parse LDAP TLSSettings"
        ldapHost <- maybe Ldap.Plain (flip Ldap.Tls) tlsSettings <$> o .: "host"
        ldapPort <- (fromIntegral :: Int -> Ldap.PortNumber) <$> o .: "port"
        ldapDn <- Ldap.Dn <$> o .: "user"
        ldapPassword <- Ldap.Password . Text.encodeUtf8 <$> o .: "pass"
        ldapBase <- Ldap.Dn <$> o .: "baseDN"
        ldapScope <- o .: "scope"
        ldapTimeout <- o .: "timeout"
        return LdapConf{..}

deriveFromJSON
  defaultOptions
    { fieldLabelModifier = intercalate "-" . map toLower . drop 1 . splitCamel
    }
  ''ResourcePoolConf

deriveJSON
  defaultOptions
    { constructorTagModifier = over (ix 1) Char.toLower . fromJust . stripPrefix "Level"
    , sumEncoding = UntaggedValue
    }
  ''LogLevel

instance FromJSON HaskellNet.PortNumber where
  parseJSON = withScientific "PortNumber" $ \sciNum -> case toBoundedInteger sciNum of
    Just int -> return $ fromIntegral (int :: Word16)
    Nothing -> fail "Expected whole number of plausible size to denote port"

deriveFromJSON
  defaultOptions
    { constructorTagModifier = unpack . intercalate "-" . Text.splitOn "_" . toLower . pack
    , allNullaryToStringTag = True
    }
  ''HaskellNet.AuthType

instance FromJSON SmtpConf where
  parseJSON = withObject "SmtpConf" $ \o -> do
    smtpHost <- o .: "host"
    smtpPort <- o .: "port"
    smtpAuth <- assertM (not . null . smtpAuthUsername) <$> o .:? "auth"
    smtpSsl <- o .: "ssl"
    smtpPool <- o .: "pool"
    return SmtpConf{..}

deriveFromJSON
  defaultOptions
    { constructorTagModifier = intercalate "-" . map toLower . drop 2 . splitCamel
    , allNullaryToStringTag = True
    }
  ''SmtpSslMode

deriveFromJSON
  defaultOptions
    { fieldLabelModifier = let
                             nameMap "username" = "user"
                             nameMap "password" = "pass"
                             nameMap x = x
                           in nameMap . intercalate "-" . map toLower . drop 2 . splitCamel
    }
  ''SmtpAuthConf

deriveFromJSON
  defaultOptions
    { fieldLabelModifier = intercalate "-" . map toLower . drop 1 . splitCamel
    }
  ''Address


instance FromJSON AppSettings where
    parseJSON = withObject "AppSettings" $ \o -> do
        let defaultDev =
#ifdef DEVELOPMENT
                True
#else
                False
#endif
        appStaticDir              <- o .: "static-dir"
        appDatabaseConf           <- o .: "database"
        let nonEmptyHost LdapConf{..} = case ldapHost of
              Ldap.Tls host _ -> not $ null host
              Ldap.Plain host -> not $ null host
        appLdapConf               <- assertM nonEmptyHost <$> o .:? "ldap"
        appSmtpConf               <- assertM (not . null . smtpHost) <$> o .:? "smtp"
        appRoot                   <- o .:? "approot"
        appHost                   <- fromString <$> o .: "host"
        appPort                   <- o .: "port"
        appIpFromHeader           <- o .: "ip-from-header"

        appMailFrom               <- o .: "mail-from"
        appMailObjectDomain       <- o .: "mail-object-domain"
        appMailVerp               <- o .: "mail-verp"
        appMailSupport            <- o .: "mail-support"

        appJobWorkers             <- o .:  "job-workers"
        appJobFlushInterval       <- o .:? "job-flush-interval"
        appJobCronInterval        <- o .:  "job-cron-interval"
        appJobStaleThreshold      <- o .:  "job-stale-threshold"
        appNotificationRateLimit  <- o .:  "notification-rate-limit"
        appNotificationCollateDelay <- o .: "notification-collate-delay"
        appNotificationExpiration <- o .: "notification-expiration"

        appSessionTimeout         <- o .: "session-timeout"

        appReloadTemplates        <- o .:? "reload-templates" .!= defaultDev
        appMutableStatic          <- o .:? "mutable-static"   .!= defaultDev
        appSkipCombining          <- o .:? "skip-combining"   .!= defaultDev
        appAuthDummyLogin         <- o .:? "auth-dummy-login" .!= defaultDev
        appAllowDeprecated        <- o .:? "allow-deprecated" .!= defaultDev
        appEncryptErrors          <- o .:? "encrypt-errors"   .!= not defaultDev

        appInitialLogSettings     <- o .:  "log-settings"

        appUserDefaults           <- o .:  "user-defaults"
        appAuthPWHash             <- o .:  "auth-pw-hash"

        appInitialInstanceID      <- (o .:? "instance-id") >>= maybe (return Nothing) (\v -> Just <$> ((Right <$> parseJSON v) <|> (Left <$> parseJSON v)))

        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

-- The following two functions can be used to combine multiple CSS or JS files
-- at compile time to decrease the number of http requests.
-- Sample usage (inside a Widget):
--
-- > $(combineStylesheets 'StaticR [style1_css, style2_css])

combineStylesheets :: Name -> [Route Static] -> Q Exp
combineStylesheets = combineStylesheets'
    (appSkipCombining compileTimeAppSettings)
    combineSettings

combineScripts :: Name -> [Route Static] -> Q Exp
combineScripts = combineScripts'
    (appSkipCombining compileTimeAppSettings)
    combineSettings