{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE RecordWildCards   #-}
{-# LANGUAGE TemplateHaskell   #-}

{-|
Module: AWSLambda.Events.S3Event
Description: Types for S3 Lambda events

Based on https://github.com/aws/aws-lambda-dotnet/tree/master/Libraries/src/Amazon.Lambda.S3Events
-}
module AWSLambda.Events.S3Event where

import           Control.Lens.TH
import           Control.Monad            (guard)
import           Data.Aeson               (FromJSON (..), withObject, (.:))
import           Data.Aeson.Casing        (aesonDrop, camelCase)
import           Data.Aeson.TH            (deriveFromJSON)
import           Data.Text                (Text)
import           Data.Time.Clock          (UTCTime)
import qualified Network.AWS.S3           as S3
import qualified Network.AWS.Types        as AWS

import           AWSLambda.Events.Records
import           AWSLambda.Orphans        ()

newtype UserIdentityEntity = UserIdentityEntity
  { _uiePrincipalId :: Text
  } deriving (Eq, Show)

$(deriveFromJSON (aesonDrop 4 camelCase) ''UserIdentityEntity)
$(makeLenses ''UserIdentityEntity)

data S3BucketEntity = S3BucketEntity
  { _sbeArn           :: !Text
  , _sbeName          :: !S3.BucketName
  , _sbeOwnerIdentity :: !UserIdentityEntity
  } deriving (Eq, Show)

$(deriveFromJSON (aesonDrop 4 camelCase) ''S3BucketEntity)
$(makeLenses ''S3BucketEntity)

data S3ObjectEntity = S3ObjectEntity
  { _soeETag      :: !(Maybe S3.ETag)
  , _soeKey       :: !S3.ObjectKey
  , _soeSize      :: !(Maybe Integer)
  , _soeSequencer :: !Text
  , _soeVersionId :: !(Maybe S3.ObjectVersionId)
  } deriving (Eq, Show)

$(deriveFromJSON (aesonDrop 4 camelCase) ''S3ObjectEntity)
$(makeLenses ''S3ObjectEntity)

newtype RequestParametersEntity = RequestParametersEntity
  { _rpeSourceIPAddress :: Text
  } deriving (Eq, Show)

$(deriveFromJSON (aesonDrop 4 camelCase) ''RequestParametersEntity)
$(makeLenses ''RequestParametersEntity)

data ResponseElementsEntity = ResponseElementsEntity
  { _reeXAmzId2       :: !Text
  , _reeXAmzRequestId :: !Text
  } deriving (Eq, Show)

instance FromJSON ResponseElementsEntity where
  parseJSON =
    withObject "ResponseElementsEntity" $
    \o ->
       ResponseElementsEntity <$> o .: "x-amz-id-2" <*> o .: "x-amz-request-id"
$(makeLenses ''ResponseElementsEntity)

data S3Entity = S3Entity
  { _seBucket          :: !S3BucketEntity
  , _seConfigurationId :: !Text
  , _seObject          :: !S3ObjectEntity
  , _seS3SchemaVersion :: !Text
  } deriving (Eq, Show)

$(deriveFromJSON (aesonDrop 3 camelCase) ''S3Entity)
$(makeLenses ''S3Entity)

data S3EventNotification = S3EventNotification
  { _senAwsRegion         :: !AWS.Region
  , _senEventName         :: !S3.Event
  , _senEventSource       :: !Text
  , _senEventTime         :: !UTCTime
  , _senEventVersion      :: !Text
  , _senRequestParameters :: !RequestParametersEntity
  , _senResponseElements  :: !ResponseElementsEntity
  , _senS3                :: !S3Entity
  , _senUserIdentity      :: !UserIdentityEntity
  } deriving (Eq, Show)

instance FromJSON S3EventNotification where
  parseJSON = withObject "S3EventNotification" $ \o -> do
    _senEventSource <- o .: "eventSource"
    guard $ _senEventSource == "aws:s3"
    _senAwsRegion <- o .: "awsRegion"
    _senEventName <- o .: "eventName"
    _senEventTime <- o .: "eventTime"
    _senEventVersion <- o .: "eventVersion"
    _senRequestParameters <- o .: "requestParameters"
    _senResponseElements <- o .: "responseElements"
    _senS3 <- o .: "s3"
    _senUserIdentity <- o .: "userIdentity"
    return S3EventNotification {..}
$(makeLenses ''S3EventNotification)

type S3Event = RecordsEvent S3EventNotification