module Hasura.RQL.DDL.RemoteSchema
  ( runAddRemoteSchema,
    runRemoveRemoteSchema,
    dropRemoteSchemaInMetadata,
    runReloadRemoteSchema,
    addRemoteSchemaP1,
    addRemoteSchemaP2Setup,
    runIntrospectRemoteSchema,
    dropRemoteSchemaPermissionInMetadata,
    runAddRemoteSchemaPermissions,
    runDropRemoteSchemaPermissions,
    runUpdateRemoteSchema,
  )
where

import Control.Lens ((^.))
import Control.Monad.Unique
import Data.Environment qualified as Env
import Data.HashMap.Strict qualified as Map
import Data.HashMap.Strict.InsOrd qualified as OMap
import Data.HashSet qualified as S
import Data.Text.Extended
import Hasura.Base.Error
import Hasura.EncJSON
import Hasura.GraphQL.RemoteServer
import Hasura.Prelude
import Hasura.RQL.DDL.RemoteSchema.Permission
import Hasura.RQL.Types
import Hasura.Session
import Hasura.Tracing qualified as Tracing
import Network.HTTP.Client.Manager (HasHttpManagerM (..))

runAddRemoteSchema ::
  ( QErrM m,
    CacheRWM m,
    MonadIO m,
    MonadUnique m,
    HasHttpManagerM m,
    MetadataM m,
    Tracing.MonadTrace m
  ) =>
  Env.Environment ->
  AddRemoteSchemaQuery ->
  m EncJSON
runAddRemoteSchema env q@(AddRemoteSchemaQuery name defn comment) = do
  addRemoteSchemaP1 name
  -- addRemoteSchemaP2 env q
  void $ addRemoteSchemaP2Setup env q
  buildSchemaCacheFor (MORemoteSchema name) $
    MetadataModifier $ metaRemoteSchemas %~ OMap.insert name remoteSchemaMeta
  pure successMsg
  where
    -- NOTE: permissions here are empty, manipulated via a separate API with
    -- runAddRemoteSchemaPermissions below
    remoteSchemaMeta = RemoteSchemaMetadata name defn comment mempty

doesRemoteSchemaPermissionExist :: Metadata -> RemoteSchemaName -> RoleName -> Bool
doesRemoteSchemaPermissionExist metadata remoteSchemaName roleName =
  any ((== roleName) . _rspmRole) $ metadata ^. (metaRemoteSchemas . ix remoteSchemaName . rsmPermissions)

runAddRemoteSchemaPermissions ::
  ( QErrM m,
    CacheRWM m,
    HasServerConfigCtx m,
    MetadataM m
  ) =>
  AddRemoteSchemaPermission ->
  m EncJSON
runAddRemoteSchemaPermissions q = do
  metadata <- getMetadata
  remoteSchemaPermsCtx <- _sccRemoteSchemaPermsCtx <$> askServerConfigCtx
  unless (remoteSchemaPermsCtx == RemoteSchemaPermsEnabled) $ do
    throw400 ConstraintViolation $
      "remote schema permissions can only be added when "
        <> "remote schema permissions are enabled in the graphql-engine"
  remoteSchemaMap <- scRemoteSchemas <$> askSchemaCache
  remoteSchemaCtx <-
    onNothing (Map.lookup name remoteSchemaMap) $
      throw400 NotExists $ "remote schema " <> name <<> " doesn't exist"
  when (doesRemoteSchemaPermissionExist metadata name role) $
    throw400 AlreadyExists $
      "permissions for role: " <> role <<> " for remote schema:"
        <> name <<> " already exists"
  void $ resolveRoleBasedRemoteSchema providedSchemaDoc remoteSchemaCtx
  buildSchemaCacheFor (MORemoteSchemaPermissions name role) $
    MetadataModifier $ metaRemoteSchemas . ix name . rsmPermissions %~ (:) remoteSchemaPermMeta
  pure successMsg
  where
    AddRemoteSchemaPermission name role defn comment = q

    remoteSchemaPermMeta = RemoteSchemaPermissionMetadata role defn comment

    providedSchemaDoc = _rspdSchema defn

runDropRemoteSchemaPermissions ::
  ( QErrM m,
    CacheRWM m,
    MetadataM m
  ) =>
  DropRemoteSchemaPermissions ->
  m EncJSON
runDropRemoteSchemaPermissions (DropRemoteSchemaPermissions name roleName) = do
  metadata <- getMetadata
  remoteSchemaMap <- scRemoteSchemas <$> askSchemaCache
  void $
    onNothing (Map.lookup name remoteSchemaMap) $
      throw400 NotExists $ "remote schema " <> name <<> " doesn't exist"
  unless (doesRemoteSchemaPermissionExist metadata name roleName) $
    throw400 NotExists $
      "permissions for role: " <> roleName <<> " for remote schema:"
        <> name <<> " doesn't exist"
  buildSchemaCacheFor (MORemoteSchemaPermissions name roleName) $
    dropRemoteSchemaPermissionInMetadata name roleName
  pure successMsg

addRemoteSchemaP1 ::
  (QErrM m, CacheRM m) =>
  RemoteSchemaName ->
  m ()
addRemoteSchemaP1 name = do
  remoteSchemaNames <- getAllRemoteSchemas <$> askSchemaCache
  when (name `elem` remoteSchemaNames) $
    throw400 AlreadyExists $
      "remote schema with name "
        <> name <<> " already exists"

addRemoteSchemaP2Setup ::
  (QErrM m, MonadIO m, MonadUnique m, HasHttpManagerM m, Tracing.MonadTrace m) =>
  Env.Environment ->
  AddRemoteSchemaQuery ->
  m RemoteSchemaCtx
addRemoteSchemaP2Setup env (AddRemoteSchemaQuery name def _) = do
  httpMgr <- askHttpManager
  rsi <- validateRemoteSchemaDef env def
  fetchRemoteSchema env httpMgr name rsi

runRemoveRemoteSchema ::
  (QErrM m, UserInfoM m, CacheRWM m, MetadataM m) =>
  RemoteSchemaNameQuery ->
  m EncJSON
runRemoveRemoteSchema (RemoteSchemaNameQuery rsn) = do
  void $ removeRemoteSchemaP1 rsn
  withNewInconsistentObjsCheck $
    buildSchemaCache $
      dropRemoteSchemaInMetadata rsn
  pure successMsg

removeRemoteSchemaP1 ::
  (UserInfoM m, QErrM m, CacheRM m) =>
  RemoteSchemaName ->
  m [RoleName]
removeRemoteSchemaP1 rsn = do
  sc <- askSchemaCache
  let rmSchemas = scRemoteSchemas sc
  void $
    onNothing (Map.lookup rsn rmSchemas) $
      throw400 NotExists "no such remote schema"
  let depObjs = getDependentObjs sc remoteSchemaDepId
      roles = mapMaybe getRole depObjs
      nonPermDependentObjs = filter nonPermDependentObjPredicate depObjs
  -- report non permission dependencies (if any), this happens
  -- mostly when a remote relationship is defined with
  -- the current remote schema

  -- we only report the non permission dependencies because we
  -- drop the related permissions
  unless (null nonPermDependentObjs) $ reportDependentObjectsExist nonPermDependentObjs
  pure roles
  where
    remoteSchemaDepId = SORemoteSchema rsn

    getRole depObj =
      case depObj of
        SORemoteSchemaPermission _ role -> Just role
        _ -> Nothing

    nonPermDependentObjPredicate (SORemoteSchemaPermission _ _) = False
    nonPermDependentObjPredicate _ = True

runReloadRemoteSchema ::
  (QErrM m, CacheRWM m, MetadataM m) =>
  RemoteSchemaNameQuery ->
  m EncJSON
runReloadRemoteSchema (RemoteSchemaNameQuery name) = do
  remoteSchemas <- getAllRemoteSchemas <$> askSchemaCache
  unless (name `elem` remoteSchemas) $
    throw400 NotExists $
      "remote schema with name " <> name <<> " does not exist"

  let invalidations = mempty {ciRemoteSchemas = S.singleton name}
  metadata <- getMetadata
  withNewInconsistentObjsCheck $
    buildSchemaCacheWithOptions (CatalogUpdate Nothing) invalidations metadata
  pure successMsg

dropRemoteSchemaInMetadata :: RemoteSchemaName -> MetadataModifier
dropRemoteSchemaInMetadata name =
  MetadataModifier $ metaRemoteSchemas %~ OMap.delete name

dropRemoteSchemaPermissionInMetadata :: RemoteSchemaName -> RoleName -> MetadataModifier
dropRemoteSchemaPermissionInMetadata remoteSchemaName roleName =
  MetadataModifier $ metaRemoteSchemas . ix remoteSchemaName . rsmPermissions %~ filter ((/=) roleName . _rspmRole)

runIntrospectRemoteSchema ::
  (CacheRM m, QErrM m) => RemoteSchemaNameQuery -> m EncJSON
runIntrospectRemoteSchema (RemoteSchemaNameQuery rsName) = do
  sc <- askSchemaCache
  RemoteSchemaCtx {..} <-
    Map.lookup rsName (scRemoteSchemas sc) `onNothing` throw400 NotExists ("remote schema: " <> rsName <<> " not found")
  pure $ encJFromLBS _rscRawIntrospectionResult

runUpdateRemoteSchema ::
  ( QErrM m,
    CacheRWM m,
    MonadIO m,
    MonadUnique m,
    HasHttpManagerM m,
    MetadataM m,
    Tracing.MonadTrace m
  ) =>
  Env.Environment ->
  AddRemoteSchemaQuery ->
  m EncJSON
runUpdateRemoteSchema env (AddRemoteSchemaQuery name defn comment) = do
  remoteSchemaNames <- getAllRemoteSchemas <$> askSchemaCache
  remoteSchemaMap <- _metaRemoteSchemas <$> getMetadata

  let metadataRMSchema = OMap.lookup name remoteSchemaMap
      metadataRMSchemaPerms = maybe mempty _rsmPermissions metadataRMSchema
      -- `metadataRMSchemaURL` and `metadataRMSchemaURLFromEnv` represent
      -- details that were stored within the metadata
      metadataRMSchemaURL = (_rsdUrl . _rsmDefinition) =<< metadataRMSchema
      metadataRMSchemaURLFromEnv = (_rsdUrlFromEnv . _rsmDefinition) =<< metadataRMSchema
      -- `currentRMSchemaURL` and `currentRMSchemaURLFromEnv` represent
      -- the details that were provided in the request
      currentRMSchemaURL = _rsdUrl defn
      currentRMSchemaURLFromEnv = _rsdUrlFromEnv defn

  unless (name `elem` remoteSchemaNames) $
    throw400 NotExists $ "remote schema with name " <> name <<> " doesn't exist"

  rsi <- validateRemoteSchemaDef env defn

  -- we only proceed to fetch the remote schema if the url has been updated
  unless
    ( (isJust metadataRMSchemaURL && isJust currentRMSchemaURL && metadataRMSchemaURL == currentRMSchemaURL)
        || (isJust metadataRMSchemaURLFromEnv && isJust currentRMSchemaURLFromEnv && metadataRMSchemaURLFromEnv == currentRMSchemaURLFromEnv)
    )
    $ do
      httpMgr <- askHttpManager
      void $ fetchRemoteSchema env httpMgr name rsi

  -- This will throw an error if the new schema fetched in incompatible
  -- with the existing permissions and relations
  withNewInconsistentObjsCheck $
    buildSchemaCacheFor (MORemoteSchema name) $
      MetadataModifier $ metaRemoteSchemas %~ OMap.insert name (remoteSchemaMeta metadataRMSchemaPerms)

  pure successMsg
  where
    remoteSchemaMeta perms = RemoteSchemaMetadata name defn comment perms