{-# LANGUAGE GeneralizedNewtypeDeriving #-}

-- Copyright (c) 2009, Diego Souza
-- All rights reserved.
-- 
-- Redistribution and use in source and binary forms, with or without
-- modification, are permitted provided that the following conditions are met:
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--   * Redistributions of source code must retain the above copyright notice,
--     this list of conditions and the following disclaimer.
--   * Redistributions in binary form must reproduce the above copyright notice,
--     this list of conditions and the following disclaimer in the documentation
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--   * Neither the name of the <ORGANIZATION> nor the names of its contributors
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--     without specific prior written permission.
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-- | A type class that is able to perform HTTP requests.
module Network.OAuth.Http.HttpClient (HttpClient(..)
                                     ,CurlM(..)
                                     ) where

import Network.Curl
import Control.Monad.Fix
import Control.Monad.Trans
import Network.OAuth.Http.Request
import Network.OAuth.Http.Response
import Data.Char (chr)
import qualified Data.ByteString.Lazy as B

-- | The HttpClient type class.
class (Monad m) => HttpClient m where
  -- | Performs the request and returns the response wrapped into a given monad.
  request :: Request -> m Response

-- | The libcurl backend
newtype CurlM a = CurlM { unCurlM :: IO a }
  deriving (Monad,MonadIO,MonadFix,Functor)
instance HttpClient CurlM where
  request req = CurlM $ withCurlDo $ do c <- initialize
                                        setopts c opts
                                        rsp <- perform_with_response_ c
                                        return $ RspHttp (respStatus rsp)
                                                         (respStatusLine rsp)
                                                         (fromList.respHeaders $ rsp)
                                                         (respBody rsp)
    where httpVersion = case (version req)
                        of Http10 -> HttpVersion10
                           Http11 -> HttpVersion11
          
          curlMethod = case (method req)
                       of GET   -> [CurlHttpGet True]
                          POST  -> [CurlPost True]
                          PUT   -> [CurlPut True]
                          HEAD  -> [CurlNoBody True,CurlCustomRequest "HEAD"]
                          other -> if (B.null.reqPayload $ req)
                                   then [CurlHttpGet True,CurlCustomRequest (show other)]
                                   else [CurlPost True,CurlCustomRequest (show other)]
          curlPostData = if (B.null.reqPayload $ req)
                         then []
                         else [CurlPostFields [map (chr.fromIntegral).B.unpack.reqPayload $ req]]
          curlHeaders = let headers = (map (\(k,v) -> k++": "++v).toList.reqHeaders $ req)
                        in [CurlHttpHeaders $"Expect: " 
                                            :("Content-Length: " ++ (show.B.length.reqPayload $ req))
                                            :headers
                           ]

          opts = [CurlURL (showURL req)
                 ,CurlHttpVersion httpVersion
                 ,CurlHeader False
                 ] ++ curlHeaders
                   ++ curlMethod 
                   ++ curlPostData
          
-- vim:sts=2:sw=2:ts=2:et