Config.hs

-- | Configuration types for the Kafka adapter.
module Shibuya.Adapter.Kafka.Config
  ( -- * Main Configuration
    KafkaAdapterConfig (..),

    -- * Defaults
    defaultConfig,
  )
where

import GHC.Generics (Generic)
import Kafka.Types (BatchSize (..), Timeout (..), TopicName)

-- | Configuration for the Kafka adapter.
--
-- Consumer properties (brokers, group ID, etc.) are provided when running
-- @runKafkaConsumer@ — the adapter operates /within/ the @KafkaConsumer@
-- effect scope, not outside it.
data KafkaAdapterConfig = KafkaAdapterConfig
  { -- | Topics expected by the adapter, used for observability metadata and
    --     checked against the live consumer subscription at construction. The
    --     actual subscription, including offset-reset policy, is supplied to
    --     @runKafkaConsumer@ by the caller.
    topics :: ![TopicName],
    -- | Timeout for each poll call (default: 1000ms)
    pollTimeout :: !Timeout,
    -- | Maximum messages per poll batch (default: 100)
    batchSize :: !BatchSize
  }
  deriving stock (Show, Eq, Generic)

-- | Default adapter configuration for the given topics.
--
-- Defaults:
--
-- * @pollTimeout@: 1000ms
-- * @batchSize@: 100
defaultConfig :: [TopicName] -> KafkaAdapterConfig
defaultConfig ts =
  KafkaAdapterConfig
    { topics = ts,
      pollTimeout = Timeout 1000,
      batchSize = BatchSize 100
    }