Main.hs

{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE NoImplicitPrelude #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE ExtendedDefaultRules #-}
{-# LANGUAGE CPP #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE PatternGuards #-}
{-# OPTIONS_GHC -fno-warn-deprecations #-}
module Main where

import Control.Exception.Base
import Control.Lens hiding ((.=))
import Control.Monad
import Data.Aeson (encode)
import Data.Bool
import Data.ByteString
import Data.Char(toUpper)
import Data.Maybe
import Data.Monoid ((<>))
import qualified Data.Text as T
import GHC.Types (IO (..))
import Network.HTTP.Base
import Network.HTTP.Client
import Network.HTTP.Types
import Network.HTTP.Types.Status (statusCode)
import Network.Linklater
import Network.TLS
import Network.Wai.Handler.Warp (run)
import Network.Wreq
import Prelude
import Reddit
import Reddit.Types.Post
import Reddit.Types.SearchOptions (Order (..))
import Servant.Client (ClientEnv(ClientEnv), runClientM)
import Servant.Common.Req
import System.Environment (getEnv, setEnv)

readSlackFile :: FilePath -> IO T.Text
readSlackFile filename =
  T.filter (/= '\n') . T.pack <$> Prelude.readFile filename

configIO :: IO Config
configIO =
  Config <$> (readSlackFile "hook")

parseText :: T.Text -> Maybe T.Text
parseText text = case T.strip text of
  "" -> Nothing
  x -> Just x

liftMaybe :: Maybe a -> IO a
liftMaybe = maybe mzero return

printPost :: Post -> T.Text
printPost post = do
  title post <> "\n" <> (T.pack . show . created $ post) <> "\n" <> "http://reddit.com"<> permalink post <> "\n" <> "Score: " <> (T.pack . show . score $ post)

--searches for Hot programming posts given input (ie haskell)
findQPosts:: T.Text -> RedditT IO PostListing
findQPosts c = search (Just $ R "programming") (Reddit.Options Nothing (Just 0)) Hot c

--gets Reddit posts, and creates the message that will be 
--posted to Slack. 
messageOfCommandReddit :: Command -> IO Network.Linklater.Message
messageOfCommandReddit (Command "redditbot" user channel (Just text)) = do
  query <- liftMaybe (parseText text)
  posts <- runRedditAnon (findQPosts query)
  case posts of
    Right posts' ->
       return (messageOf [FormatAt user, FormatString (T.intercalate "\n\n". Prelude.map printPost $ contents posts')]) where
        messageOf =
          FormattedMessage(EmojiIcon "gift") "redditbot" channel
          
--calls *messageOfCommandReddit*, which actually posts the 
--message to Slack after running *stack build*, then *stack 
--exec redditbot*, and then opening up a Ngrok tunnel at the same port.
redditify :: Maybe Command -> IO T.Text
redditify Nothing =
  return "Unrecognized Slack request!"

redditify(Just command) = do
  Prelude.putStrLn ("+ Incoming command: " <> show command)
  message <- (messageOfCommandReddit) command
  config <- configIO
  --putStrLn ("+ Outgoing message: " <> show (message))
  case (debug, message) of
    (False,  m) -> do
      _ <- say m config
      return ""
    _ ->
      return ""
  where
    debug = False

main :: IO ()
main =  do
	Prelude.putStrLn ("+ Listening on port " <> show port)
	run port (slashSimple redditify)
	where 
		port = 3000