{-# LANGUAGE QuasiQuotes #-}
{-# LANGUAGE ViewPatterns #-}

{-# OPTIONS -Wno-redundant-constraints #-}

-- | MySQL helpers.
module Harness.Backend.Mysql
  ( livenessCheck,
    run_,
    defaultSourceMetadata,
    createTable,
    insertTable,
    trackTable,
    dropTable,
    untrackTable,
    setup,
    teardown,
    setupTablesAction,
    setupPermissionsAction,
  )
where

import Control.Concurrent.Extended (sleep)
import Control.Monad.Reader
import Data.Aeson (Value)
import Data.String (fromString)
import Data.Text qualified as T
import Data.Text.Extended (commaSeparated)
import Data.Time (defaultTimeLocale, formatTime)
import Database.MySQL.Simple as Mysql
import Harness.Constants as Constants
import Harness.Exceptions
import Harness.GraphqlEngine qualified as GraphqlEngine
import Harness.Quoter.Yaml (yaml)
import Harness.Test.BackendType (BackendType (MySQL), defaultBackendTypeString, defaultSource)
import Harness.Test.Fixture (SetupAction (..))
import Harness.Test.Permissions qualified as Permissions
import Harness.Test.Schema (BackendScalarType (..), BackendScalarValue (..), ScalarValue (..))
import Harness.Test.Schema qualified as Schema
import Harness.TestEnvironment (TestEnvironment)
import Hasura.Prelude
import System.Process.Typed

-- | Check that the MySQL service is live and ready to accept connections.
livenessCheck :: HasCallStack => IO ()
livenessCheck = loop Constants.mysqlLivenessCheckAttempts
  where
    loop 0 = error ("Liveness check failed for MySQL.")
    loop attempts =
      catch
        ( bracket
            (Mysql.connect Constants.mysqlConnectInfo)
            Mysql.close
            (const (pure ()))
        )
        ( \(_failure :: ExitCodeException) -> do
            sleep Constants.httpHealthCheckIntervalSeconds
            loop (attempts - 1)
        )

-- | Run a plain SQL string against the server, ignore the
-- result. Just checks for errors.
run_ :: HasCallStack => String -> IO ()
run_ query' =
  catch
    ( bracket
        (Mysql.connect Constants.mysqlConnectInfo)
        Mysql.close
        (\conn -> void (Mysql.execute_ conn (fromString query')))
    )
    ( \(e :: SomeException) ->
        error
          ( unlines
              [ "MySQL query error:",
                show e,
                "SQL was:",
                query'
              ]
          )
    )

-- | Metadata source information for the default Mysql instance.
defaultSourceMetadata :: Value
defaultSourceMetadata =
  let source = defaultSource MySQL
      backendType = defaultBackendTypeString MySQL
   in [yaml|
name: *source
kind: *backendType
tables: []
configuration:
  database: *mysqlDb
  user: *mysqlUser
  password: *mysqlPassword
  host: *mysqlHost
  port: *mysqlPort
  pool_settings: {}
  |]

-- | Serialize Table into a SQL statement, as needed, and execute it on the MySQL backend
createTable :: Schema.Table -> IO ()
createTable Schema.Table {tableUniqueConstraints = _ : _} = error "Not Implemented: MySql test harness support for Unique constraints"
createTable Schema.Table {tableName, tableColumns, tablePrimaryKey = pk, tableReferences} = do
  run_ $
    T.unpack $
      T.unwords
        [ "CREATE TABLE",
          T.pack Constants.mysqlDb <> "." <> tableName,
          "(",
          commaSeparated $
            (mkColumn <$> tableColumns)
              <> (bool [mkPrimaryKey pk] [] (null pk))
              <> (mkReference <$> tableReferences),
          ");"
        ]

scalarType :: HasCallStack => Schema.ScalarType -> Text
scalarType = \case
  Schema.TInt -> "INT UNSIGNED"
  Schema.TStr -> "TEXT"
  Schema.TUTCTime -> "DATETIME"
  Schema.TBool -> "BIT"
  Schema.TCustomType txt -> Schema.getBackendScalarType txt bstMysql

mkColumn :: Schema.Column -> Text
mkColumn Schema.Column {columnName, columnType, columnNullable, columnDefault} =
  T.unwords
    [ columnName,
      scalarType columnType,
      bool "NOT NULL" "DEFAULT NULL" columnNullable,
      maybe "" ("DEFAULT " <>) columnDefault
    ]

mkPrimaryKey :: [Text] -> Text
mkPrimaryKey key =
  T.unwords
    [ "PRIMARY KEY",
      "(",
      commaSeparated key,
      ")"
    ]

mkReference :: Schema.Reference -> Text
mkReference Schema.Reference {referenceLocalColumn, referenceTargetTable, referenceTargetColumn} =
  T.unwords
    [ "FOREIGN KEY",
      "(",
      referenceLocalColumn,
      ")",
      "REFERENCES",
      referenceTargetTable,
      "(",
      referenceTargetColumn,
      ")",
      "ON DELETE CASCADE",
      "ON UPDATE CASCADE"
    ]

-- | Serialize tableData into an SQL insert statement and execute it.
insertTable :: Schema.Table -> IO ()
insertTable Schema.Table {tableName, tableColumns, tableData}
  | null tableData = pure ()
  | otherwise = do
    run_ $
      T.unpack $
        T.unwords
          [ "INSERT INTO",
            T.pack Constants.mysqlDb <> "." <> tableName,
            "(",
            commaSeparated (Schema.columnName <$> tableColumns),
            ")",
            "VALUES",
            commaSeparated $ mkRow <$> tableData,
            ";"
          ]

-- | 'ScalarValue' serializer for Mysql
serialize :: ScalarValue -> Text
serialize = \case
  VInt i -> tshow i
  VStr s -> "'" <> T.replace "'" "\'" s <> "'"
  VUTCTime t -> T.pack $ formatTime defaultTimeLocale "'%F %T'" t
  VBool b -> tshow @Int $ if b then 1 else 0
  VNull -> "NULL"
  VCustomValue bsv -> Schema.formatBackendScalarValueType $ Schema.backendScalarValue bsv bsvMysql

mkRow :: [Schema.ScalarValue] -> Text
mkRow row =
  T.unwords
    [ "(",
      commaSeparated $ serialize <$> row,
      ")"
    ]

-- | Serialize Table into an SQL DROP statement and execute it
dropTable :: Schema.Table -> IO ()
dropTable Schema.Table {tableName} = do
  run_ $
    T.unpack $
      T.unwords
        [ "DROP TABLE", -- we don't want @IF EXISTS@ here, because we don't want this to fail silently
          T.pack Constants.mysqlDb <> "." <> tableName,
          ";"
        ]

-- | Post an http request to start tracking the table
trackTable :: TestEnvironment -> Schema.Table -> IO ()
trackTable testEnvironment table =
  Schema.trackTable MySQL (defaultSource MySQL) table testEnvironment

-- | Post an http request to stop tracking the table
untrackTable :: TestEnvironment -> Schema.Table -> IO ()
untrackTable testEnvironment table =
  Schema.untrackTable MySQL (defaultSource MySQL) table testEnvironment

-- | Setup the schema in the most expected way.
-- NOTE: Certain test modules may warrant having their own local version.
setup :: [Schema.Table] -> (TestEnvironment, ()) -> IO ()
setup tables (testEnvironment, _) = do
  -- Clear and reconfigure the metadata
  GraphqlEngine.setSource testEnvironment defaultSourceMetadata Nothing
  -- Setup and track tables
  for_ tables $ \table -> do
    createTable table
    insertTable table
    trackTable testEnvironment table
  -- Setup relationships
  for_ tables $ \table -> do
    Schema.trackObjectRelationships MySQL table testEnvironment
    Schema.trackArrayRelationships MySQL table testEnvironment

-- | Teardown the schema and tracking in the most expected way.
-- NOTE: Certain test modules may warrant having their own version.
teardown :: [Schema.Table] -> (TestEnvironment, ()) -> IO ()
teardown (reverse -> tables) (testEnvironment, _) = do
  finally
    -- Teardown relationships first
    ( forFinally_ tables $ \table ->
        Schema.untrackRelationships MySQL table testEnvironment
    )
    -- Then teardown tables
    ( forFinally_ tables $ \table ->
        finally
          (untrackTable testEnvironment table)
          (dropTable table)
    )

setupTablesAction :: [Schema.Table] -> TestEnvironment -> SetupAction
setupTablesAction ts env =
  SetupAction
    (setup ts (env, ()))
    (const $ teardown ts (env, ()))

setupPermissionsAction :: [Permissions.Permission] -> TestEnvironment -> SetupAction
setupPermissionsAction permissions env =
  SetupAction
    (setupPermissions permissions env)
    (const $ teardownPermissions permissions env)

-- | Setup the given permissions to the graphql engine in a TestEnvironment.
setupPermissions :: [Permissions.Permission] -> TestEnvironment -> IO ()
setupPermissions permissions env = Permissions.setup "mysql" permissions env

-- | Remove the given permissions from the graphql engine in a TestEnvironment.
teardownPermissions :: [Permissions.Permission] -> TestEnvironment -> IO ()
teardownPermissions permissions env = Permissions.teardown "mysql" permissions env