{-# LANGUAGE DeriveAnyClass #-}
{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE NoGeneralisedNewtypeDeriving #-}
{-# OPTIONS_GHC -fno-warn-orphans #-}

module Hasura.Backends.BigQuery.Source
  ( BigQueryConnSourceConfig (..),
    RetryOptions (..),
    BigQueryConnection (..),
    BigQuerySourceConfig (..),
    ConfigurationInput (..),
    ConfigurationInputs (..),
    ConfigurationJSON (..),
    GoogleAccessToken (GoogleAccessToken),
    PKey (unPKey),
    ServiceAccount (..),
    TokenResp (..),
  )
where

import Control.Concurrent.MVar
import Crypto.PubKey.RSA.Types qualified as Cry
import Data.Aeson qualified as J
import Data.Aeson.Casing qualified as J
import Data.Aeson.KeyMap qualified as KM
import Data.Aeson.TH qualified as J
import Data.ByteString.Lazy qualified as BL
import Data.Int qualified as Int
import Data.Text.Encoding qualified as TE
import Data.X509 qualified as X509
import Data.X509.Memory qualified as X509
import Hasura.Incremental (Cacheable (..))
import Hasura.Prelude

data PKey = PKey
  { unPKey :: Cry.PrivateKey,
    originalBS :: Text
  }
  deriving (Show, Eq, Data, Generic, NFData, Hashable)

deriving instance Generic Cry.PrivateKey -- orphan

deriving instance Generic Cry.PublicKey -- orphan

deriving instance J.ToJSON Cry.PrivateKey -- orphan

deriving instance J.ToJSON Cry.PublicKey -- orphan

deriving instance Hashable Cry.PrivateKey -- orphan

deriving instance Hashable Cry.PublicKey -- orphan

instance J.FromJSON PKey where
  parseJSON = J.withText "private_key" $ \k ->
    case X509.readKeyFileFromMemory $ TE.encodeUtf8 k of
      [X509.PrivKeyRSA k'] -> return $ PKey k' k
      _ -> fail "unable to parse private key"

instance J.ToJSON PKey where
  toJSON PKey {..} = J.toJSON originalBS

newtype GoogleAccessToken
  = GoogleAccessToken Text
  deriving (Show, Eq, J.FromJSON, J.ToJSON, Hashable, Generic, Data, NFData)

data TokenResp = TokenResp
  { _trAccessToken :: GoogleAccessToken,
    _trExpiresAt :: Integer -- Number of seconds until expiry from `now`, but we add `now` seconds to this for easy tracking
  }
  deriving (Eq, Show, Data, NFData, Generic, Hashable)

instance J.FromJSON TokenResp where
  parseJSON = J.withObject "TokenResp" $ \o ->
    TokenResp
      <$> o J..: "access_token"
      <*> o J..: "expires_in"

data ServiceAccount = ServiceAccount
  { _saClientEmail :: Text,
    _saPrivateKey :: PKey,
    _saProjectId :: Text
  }
  deriving (Eq, Show, Data, NFData, Generic, Hashable)

$(J.deriveJSON (J.aesonDrop 3 J.snakeCase) {J.omitNothingFields = False} ''ServiceAccount)

data ConfigurationJSON a
  = FromEnvJSON Text
  | FromYamlJSON a
  deriving stock (Show, Eq, Generic)
  deriving (NFData, Hashable)

instance J.FromJSON a => J.FromJSON (ConfigurationJSON a) where
  parseJSON = \case
    J.Object o | Just (J.String text) <- KM.lookup "from_env" o -> pure (FromEnvJSON text)
    J.String s -> case J.eitherDecode . BL.fromStrict . TE.encodeUtf8 $ s of
      Left {} -> fail "error parsing configuration json"
      Right sa -> pure sa
    j -> fmap FromYamlJSON (J.parseJSON j)

instance J.ToJSON a => J.ToJSON (ConfigurationJSON a) where
  toJSON = \case
    FromEnvJSON i -> J.object ["from_env" J..= i]
    FromYamlJSON j -> J.toJSON j

-- | Configuration inputs when they are a YAML array or an Env var whos value is
-- a comma-separated string
data ConfigurationInputs
  = FromYamls [Text]
  | FromEnvs Text
  deriving stock (Show, Eq, Generic)
  deriving (NFData, Hashable)

instance J.ToJSON ConfigurationInputs where
  toJSON = \case
    FromYamls i -> J.toJSON i
    FromEnvs i -> J.object ["from_env" J..= i]

instance J.FromJSON ConfigurationInputs where
  parseJSON = \case
    J.Object o -> FromEnvs <$> o J..: "from_env"
    s@(J.Array _) -> FromYamls <$> J.parseJSON s
    _ -> fail "one of array or object must be provided"

-- | Configuration input when the YAML value as well as the Env var have
-- singlular values
data ConfigurationInput
  = FromYaml Text
  | FromEnv Text
  deriving stock (Show, Eq, Generic)
  deriving (NFData, Hashable)

instance J.ToJSON ConfigurationInput where
  toJSON = \case
    FromYaml i -> J.toJSON i
    FromEnv i -> J.object ["from_env" J..= i]

instance J.FromJSON ConfigurationInput where
  parseJSON = \case
    J.Object o -> FromEnv <$> o J..: "from_env"
    s@(J.String _) -> FromYaml <$> J.parseJSON s
    (J.Number n) -> FromYaml <$> J.parseJSON (J.String (tshow n))
    _ -> fail "one of string or number or object must be provided"

data BigQueryConnSourceConfig = BigQueryConnSourceConfig
  { _cscServiceAccount :: ConfigurationJSON ServiceAccount,
    _cscDatasets :: ConfigurationInputs,
    _cscProjectId :: ConfigurationInput, -- this is part of service-account.json, but we put it here on purpose
    _cscGlobalSelectLimit :: Maybe ConfigurationInput,
    _cscRetryBaseDelay :: Maybe ConfigurationInput,
    _cscRetryLimit :: Maybe ConfigurationInput
  }
  deriving (Eq, Generic, NFData)

$(J.deriveJSON (J.aesonDrop 4 J.snakeCase) {J.omitNothingFields = True} ''BigQueryConnSourceConfig)

deriving instance Show BigQueryConnSourceConfig

deriving instance Hashable BigQueryConnSourceConfig

instance Cacheable BigQueryConnSourceConfig where
  unchanged _ = (==)

data RetryOptions = RetryOptions
  { _retryBaseDelay :: Microseconds,
    _retryNumRetries :: Int
  }
  deriving (Eq)

data BigQueryConnection = BigQueryConnection
  { _bqServiceAccount :: ServiceAccount,
    _bqProjectId :: Text, -- this is part of service-account.json, but we put it here on purpose
    _bqRetryOptions :: Maybe RetryOptions,
    _bqAccessTokenMVar :: MVar (Maybe TokenResp)
  }
  deriving (Eq)

data BigQuerySourceConfig = BigQuerySourceConfig
  { _scConnection :: BigQueryConnection,
    _scDatasets :: [Text],
    _scGlobalSelectLimit :: Int.Int64
  }
  deriving (Eq)

instance Cacheable BigQuerySourceConfig where
  unchanged _ = (==)

instance J.ToJSON BigQuerySourceConfig where
  toJSON BigQuerySourceConfig {..} =
    J.object $
      [ "service_account" J..= _bqServiceAccount _scConnection,
        "datasets" J..= _scDatasets,
        "project_id" J..= _bqProjectId _scConnection,
        "global_select_limit" J..= _scGlobalSelectLimit
      ]
        <> case _bqRetryOptions _scConnection of
          Just RetryOptions {..} ->
            [ "base_delay" J..= diffTimeToMicroSeconds (microseconds _retryBaseDelay),
              "retry_limit" J..= _retryNumRetries
            ]
          Nothing -> []