{-# LANGUAGE CPP #-}
{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE OverloadedStrings #-}
-- | 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 ~project~.hs file.
module Settings
    ( hamletFile
    , cassiusFile
    , juliusFile
    , luciusFile
    , widgetFile
    , staticRoot
    , staticDir
    , loadConfig
    , AppEnvironment(..)
    , AppConfig(..)
    ) where

import qualified Text.Hamlet as H
import qualified Text.Cassius as H
import qualified Text.Julius as H
import qualified Text.Lucius as H
import Language.Haskell.TH.Syntax
import Yesod.Widget (addWidget, addCassius, addJulius, addLucius)
import Data.Monoid (mempty, mappend)
import System.Directory (doesFileExist)
import Data.Text (Text)
import Data.Object
import qualified Data.Object.Yaml as YAML
import Control.Monad (join)

data AppEnvironment = Test
                    | Development
                    | Staging
                    | Production
                    deriving (Eq, Show, Read, Enum, Bounded)

-- | Dynamic per-environment configuration loaded from the YAML file Settings.yaml.
-- Use dynamic settings to avoid the need to re-compile the application (between staging and production environments).
--
-- By convention these settings should be overwritten by any command line arguments.
-- See config/~sitearg~.hs for command line arguments
-- Command line arguments provide some convenience but are also required for hosting situations where a setting is read from the environment (appPort on Heroku).
--
data AppConfig = AppConfig {
    appEnv :: AppEnvironment

  , appPort :: Int

    -- | The base URL for your application. This will usually be different for
    -- development and production. Yesod automatically constructs URLs for you,
    -- so this value must be accurate to create valid links.
    -- Please note that there is no trailing slash.
    --
    -- You probably want to change this! If your domain name was "yesod.com",
    -- you would probably want it to be:
    -- > "http://yesod.com"
  , appRoot :: Text
} deriving (Show)

loadConfig :: AppEnvironment -> IO AppConfig
loadConfig env = do
    allSettings <- (join $ YAML.decodeFile ("config/settings.yml" :: String)) >>= fromMapping
    settings <- lookupMapping (show env) allSettings
    appPortS <- lookupScalar "appPort" settings
    appRootS <- lookupScalar "appRoot" settings
    return $ AppConfig {
      appEnv = env
    , appPort = read $ appPortS
    , appRoot = read $ (show appRootS)
    }

-- | The location of static files on your system. This is a file system
-- path. The default value works properly with your scaffolded site.
staticDir :: FilePath
staticDir = "static"

-- | The base URL for your static files. As you can see by the default
-- value, this can simply be "static" appended to your application root.
-- A powerful optimization can be serving static files from a separate
-- domain name. This allows you to use a web server optimized for static
-- files, more easily set expires and cache values, and avoid possibly
-- costly transference of cookies on static files. For more information,
-- please see:
--   http://code.google.com/speed/page-speed/docs/request.html#ServeFromCookielessDomain
--
-- If you change the resource pattern for StaticR in ~project~.hs, you will
-- have to make a corresponding change here.
--
-- To see how this value is used, see urlRenderOverride in ~project~.hs
staticRoot :: AppConfig ->  Text
staticRoot conf = (appRoot conf) `mappend` "/static"

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

-- The following three functions are used for calling HTML, CSS and
-- Javascript templates from your Haskell code. During development,
-- the "Debug" versions of these functions are used so that changes to
-- the templates are immediately reflected in an already running
-- application. When making a production compile, the non-debug version
-- is used for increased performance.
--
-- You can see an example of how to call these functions in Handler/Root.hs
--
-- Note: due to polymorphic Hamlet templates, hamletFileDebug is no longer
-- used; to get the same auto-loading effect, it is recommended that you
-- use the devel server.

toHamletFile, toCassiusFile, toJuliusFile, toLuciusFile :: String -> FilePath
toHamletFile x = "hamlet/" ++ x ++ ".hamlet"
toCassiusFile x = "cassius/" ++ x ++ ".cassius"
toJuliusFile x = "julius/" ++ x ++ ".julius"
toLuciusFile x = "lucius/" ++ x ++ ".lucius"

hamletFile :: FilePath -> Q Exp
hamletFile = H.hamletFile . toHamletFile

cassiusFile :: FilePath -> Q Exp
#ifdef PRODUCTION
cassiusFile = H.cassiusFile . toCassiusFile
#else
cassiusFile = H.cassiusFileDebug . toCassiusFile
#endif

luciusFile :: FilePath -> Q Exp
#ifdef PRODUCTION
luciusFile = H.luciusFile . toLuciusFile
#else
luciusFile = H.luciusFileDebug . toLuciusFile
#endif

juliusFile :: FilePath -> Q Exp
#ifdef PRODUCTION
juliusFile = H.juliusFile . toJuliusFile
#else
juliusFile = H.juliusFileDebug . toJuliusFile
#endif

widgetFile :: FilePath -> Q Exp
widgetFile x = do
    let h = unlessExists toHamletFile hamletFile
    let c = unlessExists toCassiusFile cassiusFile
    let j = unlessExists toJuliusFile juliusFile
    let l = unlessExists toLuciusFile luciusFile
    [|addWidget $h >> addCassius $c >> addJulius $j >> addLucius $l|]
  where
    unlessExists tofn f = do
        e <- qRunIO $ doesFileExist $ tofn x
        if e then f x else [|mempty|]