{-# LANGUAGE ConstraintKinds #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE GADTs #-}
{-# LANGUAGE TypeApplications #-}
{-# LANGUAGE TypeOperators #-}

module Test.Sandwich.Contexts.Kubernetes.Waits where

import Control.Monad.IO.Unlift
import Control.Monad.Logger
import qualified Data.List as L
import qualified Data.Map as M
import Data.String.Interpolate
import qualified Data.Text as T
import Kubernetes.OpenAPI.API.CoreV1 as Kubernetes
import Kubernetes.OpenAPI.Core as Kubernetes
import Kubernetes.OpenAPI.MimeTypes
import Kubernetes.OpenAPI.Model as Kubernetes
import Relude
import System.Exit
import Test.Sandwich
import Test.Sandwich.Contexts.Files
import Test.Sandwich.Contexts.Kubernetes.Run
import Test.Sandwich.Contexts.Kubernetes.Types
import Test.Sandwich.Waits
import UnliftIO.Process


-- | Wait for a service to have its set of endpoints ready, i.e.:
--
-- * They each have at least one IP address
-- * They each have an empty set of "not ready addresses"
waitForServiceEndpointsToExist :: (
  MonadUnliftIO m, MonadLogger m
  , MonadReader context m, HasKubernetesClusterContext context
  )
  -- | Namespace
  => Text
  -- | Service name
  -> Text
  -- | Time in seconds to wait
  -> Double
  -> m ()
waitForServiceEndpointsToExist namespace serviceName timeInSeconds = do
  waitUntil timeInSeconds $ do
    endpoints <- listEndpoints namespace mempty
    case Relude.filter v1EndpointsSatisfies endpoints of
      [] -> expectationFailure [i|No endpoints were satisfactory|]
      (x:_) -> do
        debug [i|(#{namespace}) Got satisfactory endpoint for #{serviceName}: #{x}|]
        return ()

  where
    v1EndpointsSatisfies (V1Endpoints {v1EndpointsMetadata=(Just (V1ObjectMeta {v1ObjectMetaName=(Just name)})), v1EndpointsSubsets})
      | name == serviceName = L.all isSatisfactoryV1EndpointSubset (fromMaybe [] v1EndpointsSubsets)
    v1EndpointsSatisfies _ = False

    isSatisfactoryV1EndpointSubset (V1EndpointSubset {
                                       v1EndpointSubsetAddresses=(Just addrs)
                                       , v1EndpointSubsetNotReadyAddresses=(fromMaybe [] -> notReadyAddrs)
                                       }) =
      not (L.null addrs)
      && L.null notReadyAddrs
    isSatisfactoryV1EndpointSubset _ = False


listEndpoints :: (
  MonadUnliftIO m, MonadLogger m
  , MonadReader context m, HasKubernetesClusterContext context
  ) => Text -> Map Text Text -> m [V1Endpoints]
listEndpoints namespace labels =
  (v1EndpointsListItems <$>) $ k8sRunException (
      (listNamespacedEndpoints (Accept MimeJSON) (Namespace namespace))
      -&- (LabelSelector (T.intercalate "," [k <> "=" <> v | (k, v) <- M.toList labels]))
    )

-- | Wait for a set of pods to exist, specified by a set of labels.
waitForPodsToExist :: (
  MonadUnliftIO m, MonadLogger m
  , MonadReader context m, HasKubernetesClusterContext context
  )
  -- | Namespace
  => Text
  -- | Pod labels
  -> Map Text Text
  -- | Time in seconds to wait
  -> Double
  -- | Optional desired pod count to wait for
  -> Maybe Int
  -> m ()
waitForPodsToExist namespace labels timeInSeconds maybeDesiredCount = do
  waitUntil timeInSeconds $ do
    pods <- listPods namespace labels
    case maybeDesiredCount of
      Nothing -> when (L.null pods) $ expectationFailure [i|Found no pods.|]
      Just n -> when (L.length pods /= n) $ expectationFailure [i|Expected #{n} pods, but found #{L.length pods}|]

-- | List the pods matching a set of labels.
listPods :: (
  MonadUnliftIO m, MonadLogger m
  , MonadReader context m, HasKubernetesClusterContext context
  ) => Text -> Map Text Text -> m [V1Pod]
listPods namespace labels =
  (v1PodListItems <$>) $ k8sRunException (
      (listNamespacedPod (Accept MimeJSON) (Namespace namespace))
      -&- (LabelSelector (T.intercalate "," [k <> "=" <> v | (k, v) <- M.toList labels]))
    )

-- | Wait for a set of pods to be in the Ready condition, specified by a set of labels.
waitForPodsToBeReady :: (
  MonadUnliftIO m, MonadLogger m
  , MonadReader context m, HasKubernetesClusterContext context, HasFile context "kubectl"
  )
  -- | Namespace
  => Text
  -- | Pod labels
  -> Map Text Text
  -- | Time in seconds to wait
  -> Double
  -> m ()
waitForPodsToBeReady namespace labels timeInSeconds = do
  kubectlBinary <- askFile @"kubectl"
  kubeConfigFile <- kubernetesClusterKubeConfigPath <$> getContext kubernetesCluster

  let labelArgs = [[i|-l #{k}=#{v}|] | (k, v) <- M.toList labels]
  p <- createProcessWithLogging (proc kubectlBinary (
                                  ["wait", "pods"
                                  , "--kubeconfig", kubeConfigFile
                                  , "-n", toString namespace
                                  ]
                                  <> labelArgs
                                  <> [
                                    "--for", "condition=Ready"
                                    , "--timeout=" <> show timeInSeconds <> "s"
                                    ]
                                ))
  waitForProcess p >>= \case
    ExitSuccess -> return ()
    ExitFailure n -> expectationFailure [i|Failed to wait for pods to exist (code #{n})|]