{- This Source Code Form is subject to the terms of the Mozilla Public License,
   v. 2.0. If a copy of the MPL was not distributed with this file, You can
   obtain one at https://mozilla.org/MPL/2.0/. -}

{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE QuasiQuotes #-}
{-# LANGUAGE PackageImports #-}

module Language.GraphQL.FragmentSpec
    ( spec
    ) where

import qualified Data.HashMap.Strict as HashMap
import Data.Text (Text)
import Language.GraphQL.AST (Name)
import Data.HashMap.Strict (HashMap)
import Language.GraphQL.Type
import Language.GraphQL.Error
import qualified Language.GraphQL.Type.Out as Out
import "graphql-spice" Language.GraphQL.TH
import qualified Language.GraphQL as GraphQL
import Test.Hspec (Spec, describe, it)
import Test.Hspec.GraphQL

size :: (Text, Value)
size = ("size", String "L")

circumference :: (Text, Value)
circumference = ("circumference", Int 60)

garment :: Text -> (Text, Value)
garment typeName =
    ("garment",  Object $ HashMap.fromList
        [ if typeName == "Hat" then circumference else size
        , ("__typename", String typeName)
        ]
    )

inlineQuery :: Text
inlineQuery = [gql|
  {
    garment {
      ... on Hat {
        circumference
      }
      ... on Shirt {
        size
      }
    }
  }
|]

shirtType :: Out.ObjectType IO
shirtType = Out.ObjectType "Shirt" Nothing [] $ HashMap.fromList
    [ ("size", sizeFieldType)
    ]

hatType :: Out.ObjectType IO
hatType = Out.ObjectType "Hat" Nothing [] $ HashMap.fromList
    [ ("size", sizeFieldType)
    , ("circumference", circumferenceFieldType)
    ]

circumferenceFieldType :: Out.Resolver IO
circumferenceFieldType
    = Out.ValueResolver (Out.Field Nothing (Out.NamedScalarType int) mempty)
    $ pure $ snd circumference

sizeFieldType :: Out.Resolver IO
sizeFieldType
    = Out.ValueResolver (Out.Field Nothing (Out.NamedScalarType string) mempty)
    $ pure $ snd size

toSchema :: Text -> (Text, Value) -> Schema IO
toSchema t (_, resolve) = schema queryType Nothing Nothing mempty
  where
    garmentType = Out.UnionType "Garment" Nothing [hatType, shirtType]
    typeNameField = Out.Field Nothing (Out.NamedScalarType string) mempty
    garmentField = Out.Field Nothing (Out.NamedUnionType garmentType) mempty
    queryType =
        case t of
            "circumference" -> hatType
            "size" -> shirtType
            _ -> Out.ObjectType "Query" Nothing []
                $ HashMap.fromList
                    [ ("garment", ValueResolver garmentField (pure resolve))
                    , ("__typename", ValueResolver typeNameField (pure $ String "Shirt"))
                    ]

spec :: Spec
spec = do
    describe "Inline fragment executor" $ do
        it "chooses the first selection if the type matches" $ do
            let localSchema = toSchema "Hat" $ garment "Hat"
            actual <- GraphQL.graphql localSchema Nothing (mempty :: HashMap Name Value) inlineQuery
            let expected = Object
                    $ HashMap.singleton "garment"
                    $ Object
                    $ HashMap.singleton  "circumference"
                    $ Int 60
             in actual `shouldResolveTo` expected

        it "chooses the last selection if the type matches" $ do
            let localSchema = toSchema "Shirt" $ garment "Shirt"
            actual <- GraphQL.graphql localSchema Nothing (mempty :: HashMap Name Value) inlineQuery
            let expected = Object
                    $ HashMap.singleton "garment"
                    $ Object
                    $ HashMap.singleton "size"
                    $ String "L"
             in actual `shouldResolveTo` expected

        it "embeds inline fragments without type" $ do
            let sourceQuery = [gql|
              {
                circumference
                ... {
                  size
                }
              }
            |]
            let localSchema = toSchema "circumference" circumference
            actual <- GraphQL.graphql localSchema Nothing (mempty :: HashMap Name Value) sourceQuery
            let expected = Object $ HashMap.fromList
                    [ ("circumference", Int 60)
                    , ("size", String  "L")
                    ]
             in actual `shouldResolveTo` expected

        it "evaluates fragments on Query" $ do
            let sourceQuery = [gql|
              {
                ... {
                  size
                }
              }
            |]
                localSchema = toSchema "size" size
                actual :: Text -> IO (Either (ResponseEventStream IO Value) (Response Value))
                actual = GraphQL.graphql localSchema Nothing (mempty :: HashMap Name Value)
             in actual `shouldResolve` sourceQuery

    describe "Fragment spread executor" $ do
        it "evaluates fragment spreads" $ do
            let sourceQuery = [gql|
              {
                ...circumferenceFragment
              }

              fragment circumferenceFragment on Hat {
                circumference
              }
            |]
            let localSchema = toSchema "circumference" circumference
            actual <- GraphQL.graphql localSchema Nothing (mempty :: HashMap Name Value) sourceQuery
            let expected = Object
                    $ HashMap.singleton "circumference"
                    $ Int 60
             in actual `shouldResolveTo` expected

        it "evaluates nested fragments" $ do
            let sourceQuery = [gql|
              {
                garment {
                  ...circumferenceFragment
                }
              }

              fragment circumferenceFragment on Hat {
                ...hatFragment
              }

              fragment hatFragment on Hat {
                circumference
              }
            |]
            let localSchema = toSchema "Hat" $ garment "Hat"
            actual <- GraphQL.graphql localSchema Nothing (mempty :: HashMap Name Value) sourceQuery
            let expected = Object
                    $ HashMap.singleton "garment"
                    $ Object
                    $ HashMap.singleton "circumference"
                    $ Int 60
             in actual `shouldResolveTo` expected

        it "considers type condition" $ do
            let sourceQuery = [gql|
              {
                garment {
                  ...circumferenceFragment
                  ...sizeFragment
                }
              }
              fragment circumferenceFragment on Hat {
                circumference
              }
              fragment sizeFragment on Shirt {
                size
              }
            |]
                expected = Object
                    $ HashMap.singleton "garment"
                    $ Object
                    $ HashMap.singleton "circumference"
                    $ Int 60
            let localSchema = toSchema "Hat" $ garment "Hat"
            actual <- GraphQL.graphql localSchema Nothing (mempty :: HashMap Name Value) sourceQuery
            actual `shouldResolveTo` expected