{-# LANGUAGE QuasiQuotes, OverloadedStrings, TemplateHaskell, RecordWildCards, ScopedTypeVariables, NamedFieldPuns, KindSignatures #-}

module TestBoilerplate where

import Control.Monad.Writer.Lazy hiding (Product)
import qualified Data.Aeson as A
import Data.Aeson.TH as A
import Data.Aeson.TypeScript.TH
import Data.Proxy
import Language.Haskell.TH
import Test.Hspec
import Util

data Unit = Unit
data OneFieldRecordless = OneFieldRecordless Int
data OneField = OneField { simpleString :: String }
data TwoFieldRecordless = TwoFieldRecordless Int String
data TwoField = TwoField { doubleInt :: Int, doubleString :: String }
data Hybrid = HybridSimple Int | HybridRecord { hybridString :: String }
data TwoConstructor = Con1 { con1String :: String } | Con2 { con2String :: String, con2Int :: Int }
data Complex a = Nullary | Unary Int | Product String Char a | Record { testOne :: Int, testTwo :: Bool, testThree :: Complex a} deriving Eq


testDeclarations :: String -> A.Options -> Q [Dec]
testDeclarations testName aesonOptions = do
  decls :: [Dec] <- execWriterT $ do
    deriveInstances ''Unit
    deriveInstances ''OneFieldRecordless
    deriveInstances ''OneField
    deriveInstances ''TwoFieldRecordless
    deriveInstances ''TwoField
    deriveInstances ''Hybrid
    deriveInstances ''TwoConstructor
    deriveInstances ''Complex

  typesAndValues :: Exp <- [e|[(getTypeScriptType (Proxy :: Proxy Unit), A.encode Unit)

                              , (getTypeScriptType (Proxy :: Proxy OneFieldRecordless), A.encode $ OneFieldRecordless 42)

                              , (getTypeScriptType (Proxy :: Proxy OneField), A.encode $ OneField "asdf")

                              , (getTypeScriptType (Proxy :: Proxy TwoFieldRecordless), A.encode $ TwoFieldRecordless 42 "asdf")

                              , (getTypeScriptType (Proxy :: Proxy TwoField), A.encode $ TwoField 42 "asdf")

                              , (getTypeScriptType (Proxy :: Proxy TwoConstructor), A.encode $ Con1 "asdf")
                              , (getTypeScriptType (Proxy :: Proxy TwoConstructor), A.encode $ Con2 "asdf" 42)

                              , (getTypeScriptType (Proxy :: Proxy Hybrid), A.encode $ HybridSimple 42)
                              , (getTypeScriptType (Proxy :: Proxy Hybrid), A.encode $ HybridRecord "asdf")

                              , (getTypeScriptType (Proxy :: Proxy (Complex Int)), A.encode (Nullary :: Complex Int))
                              , (getTypeScriptType (Proxy :: Proxy (Complex Int)), A.encode (Unary 42 :: Complex Int))
                              , (getTypeScriptType (Proxy :: Proxy (Complex Int)), A.encode (Product "asdf" 'g' 42 :: Complex Int))
                              , (getTypeScriptType (Proxy :: Proxy (Complex Int)), A.encode ((Record { testOne = 3, testTwo = True, testThree = Product "test" 'A' 123}) :: Complex Int))]
                           |]

  declarations :: Exp <- [e|getTypeScriptDeclarations (Proxy :: Proxy Unit)
                         <> getTypeScriptDeclarations (Proxy :: Proxy OneFieldRecordless)
                         <> getTypeScriptDeclarations (Proxy :: Proxy OneField)
                         <> getTypeScriptDeclarations (Proxy :: Proxy TwoFieldRecordless)
                         <> getTypeScriptDeclarations (Proxy :: Proxy TwoField)
                         <> getTypeScriptDeclarations (Proxy :: Proxy Hybrid)
                         <> getTypeScriptDeclarations (Proxy :: Proxy TwoConstructor)
                         <> getTypeScriptDeclarations (Proxy :: Proxy Complex)
                         |]

  tests <- [d|tests = describe $(return $ LitE $ StringL testName) $ it "type checks everything with tsc" $ testTypeCheckDeclarations $(return declarations) $(return typesAndValues)|]

  return $ decls ++ tests

  where deriveInstances :: Name -> WriterT [Dec] Q ()
        deriveInstances name = do
          writeM $ deriveJSON aesonOptions name
          writeM $ deriveTypeScript aesonOptions name

writeM :: (Monad m) => m w -> WriterT w m ()
writeM action = WriterT $ action >>= \w -> return ((), w)