{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE NamedFieldPuns #-}
{-# LANGUAGE UnicodeSyntax #-}
{-# LANGUAGE ExplicitForAll #-}

module Main where

import qualified Data.ByteString.Char8 as C
import Control.Lens
import Control.Monad (forM)
import Control.Monad.Except (catchError)
import Network.Kafka
import Network.Kafka.Protocol
import System.Environment (getArgs)
-- import Text.Show.Pretty (ppShow)

main ∷ IO ()
main = do
  h:portString:_ ← getArgs
  let host  = Host (KString (C.pack h))
      port  = Port (read portString)
      topic = "open_channel"
      state = mkKafkaState "command-line-test-client" (host, port)
  result ← runKafka state $ do
    -- md ← metadata (MetadataReq [topic])
    -- putStrLnM (ppShow md)
    topicPartitionList ← brokerPartitionInfo topic
    forM topicPartitionList $ \(PartitionAndLeader { _palLeader, _palTopic, _palPartition }) → do
      let s = stateBrokers . at _palLeader
      broker ← findMetadataOrElse [topic] s (KafkaInvalidBroker _palLeader)
      flip catchError (return . Left) $ do
        result ← withBrokerHandle broker $ \handle → do
          offset ← getLastOffset' handle EarliestTime _palPartition topic
          fetchRequest offset _palPartition topic >>= fetch' handle
        return $ Right result
  print result

-- tmd :: TopicMetadata
-- tmd = TopicMetadata (NoError, "omfg", [PartitionMetadata (NoError, 0, Leader (Just 1), Replicas [], Isr []), PartitionMetadata (NoError, 1, Leader (Just 1), Replicas [], Isr [])])
-- newtype TopicMetadata = TopicMetadata { _topicMetadataFields :: (KafkaError, TopicName, [PartitionMetadata]) } deriving (Show, Eq, Deserializable)
-- newtype PartitionMetadata = PartitionMetadata { _partitionMetadataFields :: (KafkaError, Partition, Leader, Replicas, Isr) } deriving (Show, Eq, Deserializable)