{-# LANGUAGE ConstraintKinds   #-}
{-# LANGUAGE LambdaCase        #-}
{-# LANGUAGE OverloadedStrings #-}

-- |
-- Module      : Network.AWS.Request
-- Copyright   : (c) 2013-2015 Brendan Hay
-- License     : Mozilla Public License, v. 2.0.
-- Maintainer  : Brendan Hay <brendan.g.hay@gmail.com>
-- Stability   : provisional
-- Portability : non-portable (GHC extensions)
--
module Network.AWS.Request
    (
    -- * Requests
      head'
    , delete
    , get

    -- ** Empty body
    , post
    , put

    -- ** Specialised body
    , patchJSON

    , postXML
    , postJSON
    , postQuery
    , postBody

    , putXML
    , putJSON
    , putBody

    -- ** Constructors
    , defaultRequest

    -- ** Hashing
    , contentMD5

    -- ** Lenses
    , requestHeaders
    , queryString
    , requestURL
    ) where

import           Control.Lens
import           Data.Maybe
import           Data.Monoid
import           Network.AWS.Data.Body
import           Network.AWS.Data.ByteString
import           Network.AWS.Data.Headers
import           Network.AWS.Data.JSON
import           Network.AWS.Data.Path
import           Network.AWS.Data.Query
import           Network.AWS.Data.XML
import           Network.AWS.Types
import qualified Network.HTTP.Conduit        as Client
import           Network.HTTP.Types          (StdMethod (..))
import qualified Network.HTTP.Types          as HTTP

type ToRequest a = (ToPath a, ToQuery a, ToHeaders a)

head' :: ToRequest a => Service -> a -> Request a
head' s x = get s x & rqMethod .~ HEAD

delete :: ToRequest a => Service -> a -> Request a
delete s x = get s x & rqMethod .~ DELETE

get :: ToRequest a => Service -> a -> Request a
get s = defaultRequest s

post :: ToRequest a => Service -> a -> Request a
post s x = get s x & rqMethod .~ POST

put :: ToRequest a => Service -> a -> Request a
put s x = get s x & rqMethod .~ PUT

patchJSON :: (ToRequest a, ToJSON a) => Service -> a -> Request a
patchJSON s x = putJSON s x & rqMethod .~ PATCH

postXML :: (ToRequest a, ToElement a) => Service -> a -> Request a
postXML s x = putXML s x & rqMethod .~ POST

postJSON :: (ToRequest a, ToJSON a) => Service -> a -> Request a
postJSON s x = putJSON s x & rqMethod .~ POST

postQuery :: ToRequest a => Service -> a -> Request a
postQuery s x = Request
    { _rqService = s
    , _rqMethod  = POST
    , _rqPath    = rawPath x
    , _rqQuery   = mempty
    , _rqBody    = toBody (toQuery x)
    , _rqHeaders = hdr hContentType hFormEncoded (toHeaders x)
    }

postBody :: (ToRequest a, ToBody a) => Service -> a -> Request a
postBody s x = putBody s x & rqMethod .~ POST

putXML :: (ToRequest a, ToElement a) => Service -> a -> Request a
putXML s x = defaultRequest s x
    & rqMethod .~ PUT
    & rqBody   .~ toBody (toElement x)

putJSON :: (ToRequest a, ToJSON a) => Service -> a -> Request a
putJSON s x = defaultRequest s x
    & rqMethod .~ PUT
    & rqBody   .~ toBody (toJSON x)

putBody :: (ToRequest a, ToBody a) => Service -> a -> Request a
putBody s x = defaultRequest s x
    & rqMethod  .~ PUT
    & rqBody    .~ toBody x
    & rqHeaders %~ hdr hExpect "100-continue"

defaultRequest :: ToRequest a => Service -> a -> Request a
defaultRequest s x = Request
    { _rqService = s
    , _rqMethod  = GET
    , _rqPath    = rawPath x
    , _rqQuery   = toQuery x
    , _rqHeaders = toHeaders x
    , _rqBody    = ""
    }

contentMD5 :: Request a -> Request a
contentMD5 rq
    | missing, Just x <- md5 = rq & rqHeaders %~ hdr HTTP.hContentMD5 x
    | otherwise              = rq
  where
    missing = isNothing $ lookup HTTP.hContentMD5 (_rqHeaders rq)
    md5     = md5Base64 (_rqBody rq)

queryString :: Lens' Client.Request ByteString
queryString f x =
    f (Client.queryString x) <&> \y -> x { Client.queryString = y }

requestHeaders :: Lens' Client.Request HTTP.RequestHeaders
requestHeaders f x =
    f (Client.requestHeaders x) <&> \y -> x { Client.requestHeaders = y }

requestURL :: ClientRequest -> ByteString
requestURL x = scheme
    <> toBS (Client.host        x)
    <> port (Client.port        x)
    <> toBS (Client.path        x)
    <> toBS (Client.queryString x)
  where
    scheme
        | secure    = "https://"
        | otherwise = "http://"

    port = \case
        80           -> ""
        443 | secure -> ""
        n            -> ":" <> toBS n

    secure = Client.secure x