func TestTypeSystem_DefinitionExample_StringifiesSimpleTypes(t *testing.T) {

	type Test struct {
		ttype    graphql.Type
		expected string
	}
	tests := []Test{
		{graphql.Int, "Int"},
		{blogArticle, "Article"},
		{interfaceType, "Interface"},
		{unionType, "Union"},
		{enumType, "Enum"},
		{inputObjectType, "InputObject"},
		{graphql.NewNonNull(graphql.Int), "Int!"},
		{graphql.NewList(graphql.Int), "[Int]"},
		{graphql.NewNonNull(graphql.NewList(graphql.Int)), "[Int]!"},
		{graphql.NewList(graphql.NewNonNull(graphql.Int)), "[Int!]"},
		{graphql.NewList(graphql.NewList(graphql.Int)), "[[Int]]"},
	}
	for _, test := range tests {
		ttypeStr := fmt.Sprintf("%v", test.ttype)
		if ttypeStr != test.expected {
			t.Fatalf(`expected %v , got: %v`, test.expected, ttypeStr)
		}
	}
}

func PluralIdentifyingRootField(config PluralIdentifyingRootFieldConfig) *graphql.FieldConfig {
	inputArgs := graphql.FieldConfigArgument{}
	if config.ArgName != "" {
		inputArgs[config.ArgName] = &graphql.ArgumentConfig{
			Type: graphql.NewNonNull(graphql.NewList(graphql.NewNonNull(config.InputType))),
		}
	}

	return &graphql.FieldConfig{
		Description: config.Description,
		Type:        graphql.NewList(config.OutputType),
		Args:        inputArgs,
		Resolve: func(p graphql.GQLFRParams) interface{} {
			inputs, ok := p.Args[config.ArgName]
			if !ok {
				return nil
			}

			if config.ResolveSingleInput == nil {
				return nil
			}
			switch inputs := inputs.(type) {
			case []interface{}:
				res := []interface{}{}
				for _, input := range inputs {
					r := config.ResolveSingleInput(input)
					res = append(res, r)
				}
				return res
			}
			return nil
		},
	}
}

func TestTypeSystem_ObjectsMustAdhereToInterfaceTheyImplement_AcceptsAnObjectWithAnEquivalentlyModifiedInterfaceField(t *testing.T) {
	anotherInterface := graphql.NewInterface(graphql.InterfaceConfig{
		Name: "AnotherInterface",
		ResolveType: func(value interface{}, info graphql.ResolveInfo) *graphql.Object {
			return nil
		},
		Fields: graphql.FieldConfigMap{
			"field": &graphql.FieldConfig{
				Type: graphql.NewNonNull(graphql.NewList(graphql.String)),
			},
		},
	})
	anotherObject := graphql.NewObject(graphql.ObjectConfig{
		Name:       "AnotherObject",
		Interfaces: []*graphql.Interface{anotherInterface},
		Fields: graphql.FieldConfigMap{
			"field": &graphql.FieldConfig{
				Type: graphql.NewNonNull(graphql.NewList(graphql.String)),
			},
		},
	})
	_, err := schemaWithObjectFieldOfType(anotherObject)
	if err != nil {
		t.Fatalf(`unexpected error: %v for type "%v"`, err, anotherObject)
	}
}

func PluralIdentifyingRootField(config PluralIdentifyingRootFieldConfig) *graphql.Field {
	inputArgs := graphql.FieldConfigArgument{}
	if config.ArgName != "" {
		inputArgs[config.ArgName] = &graphql.ArgumentConfig{
			Type: graphql.NewNonNull(graphql.NewList(graphql.NewNonNull(config.InputType))),
		}
	}

	return &graphql.Field{
		Description: config.Description,
		Type:        graphql.NewList(config.OutputType),
		Args:        inputArgs,
		Resolve: func(p graphql.ResolveParams) (interface{}, error) {
			inputs, ok := p.Args[config.ArgName]
			if !ok {
				return nil, fmt.Errorf("Missing arg %q", config.ArgName)
			}

			if config.ResolveSingleInput == nil {
				return nil, nil
			}
			switch inputs := inputs.(type) {
			case []interface{}:
				res := []interface{}{}
				for _, input := range inputs {
					r := config.ResolveSingleInput(input)
					res = append(res, r)
				}
				return res, nil
			}
			return nil, fmt.Errorf("Can't handle %T", inputs)
		},
	}
}

func withModifiers(ttypes []graphql.Type) []graphql.Type {
	res := ttypes
	for _, ttype := range ttypes {
		res = append(res, graphql.NewList(ttype))
	}
	for _, ttype := range ttypes {
		res = append(res, graphql.NewNonNull(ttype))
	}
	for _, ttype := range ttypes {
		res = append(res, graphql.NewNonNull(graphql.NewList(ttype)))
	}
	return res
}

func TestLists_NullableListOfNonNullObjects_ContainsNull(t *testing.T) {
	ttype := graphql.NewList(graphql.NewNonNull(graphql.Int))
	data := []interface{}{
		1, nil, 2,
	}
	expected := &graphql.Result{
		Data: map[string]interface{}{
			"nest": map[string]interface{}{
				"test": nil,
			},
		},
		Errors: []gqlerrors.FormattedError{
			gqlerrors.FormattedError{
				Message: "Cannot return null for non-nullable field DataType.test.",
				Locations: []location.SourceLocation{
					location.SourceLocation{
						Line:   1,
						Column: 10,
					},
				},
			},
		},
	}
	checkList(t, ttype, data, expected)
}

func TestLists_NonNullListOfNonNullFunc_ReturnsNull(t *testing.T) {
	ttype := graphql.NewNonNull(graphql.NewList(graphql.NewNonNull(graphql.Int)))

	// `data` is a function that return values
	// Note that its uses the expected signature `func() interface{} {...}`
	data := func() interface{} {
		return nil
	}
	expected := &graphql.Result{
		Data: map[string]interface{}{
			"nest": nil,
		},
		Errors: []gqlerrors.FormattedError{
			gqlerrors.FormattedError{
				Message: "Cannot return null for non-nullable field DataType.test.",
				Locations: []location.SourceLocation{
					location.SourceLocation{
						Line:   1,
						Column: 10,
					},
				},
			},
		},
	}
	checkList(t, ttype, data, expected)
}

func TestTypeSystem_ObjectsMustAdhereToInterfaceTheyImplement_RejectsAnObjectWithAListInterfaceFieldNonListType(t *testing.T) {
	anotherInterface := graphql.NewInterface(graphql.InterfaceConfig{
		Name: "AnotherInterface",
		ResolveType: func(p graphql.ResolveTypeParams) *graphql.Object {
			return nil
		},
		Fields: graphql.Fields{
			"field": &graphql.Field{
				Type: graphql.String,
			},
		},
	})
	anotherObject := graphql.NewObject(graphql.ObjectConfig{
		Name:       "AnotherObject",
		Interfaces: []*graphql.Interface{anotherInterface},
		Fields: graphql.Fields{
			"field": &graphql.Field{
				Type: graphql.NewList(graphql.String),
			},
		},
	})
	_, err := schemaWithFieldType(anotherObject)
	expectedError := `AnotherInterface.field expects type "String" but AnotherObject.field provides type "[String]".`
	if err == nil || err.Error() != expectedError {
		t.Fatalf("Expected error: %v, got %v", expectedError, err)
	}
}

// addConnections adds connections fields to the object afterward to prevent from dead loops
func (t types) addConnections(o *graphql.Object, idx resource.Index, r *resource.Resource) {
	// Add sub field references
	for name, def := range r.Schema().Fields {
		if ref, ok := def.Validator.(*schema.Reference); ok {
			sr, found := idx.GetResource(ref.Path, nil)
			if !found {
				log.Panicf("resource reference not found: %s", ref.Path)
			}
			o.AddFieldConfig(name, &graphql.Field{
				Description: def.Description,
				Type:        t.getObjectType(idx, sr),
				Args:        getFArgs(def.Params),
				Resolve:     getSubFieldResolver(name, sr, def),
			})
		}
	}
	// Add sub resources
	for _, sr := range r.GetResources() {
		name := sr.Name()
		o.AddFieldConfig(name, &graphql.Field{
			Description: fmt.Sprintf("Connection to %s", name),
			Type:        graphql.NewList(t.getObjectType(idx, sr)),
			Args:        listArgs,
			Resolve:     getSubResourceResolver(sr),
		})
	}
}

func TestTypeSystem_ListMustAcceptGraphQLTypes_RejectsANilTypeAsItemTypeOfList(t *testing.T) {
	result := graphql.NewList(nil)
	expectedError := `Can only create List of a Type but got: <nil>.`
	if result.GetError() == nil || result.GetError().Error() != expectedError {
		t.Fatalf("Expected error: %v, got %v", expectedError, result.GetError())
	}
}

func TestLists_NonNullListOfNonNullArrayOfFunc_ContainsNulls(t *testing.T) {
	ttype := graphql.NewNonNull(graphql.NewList(graphql.NewNonNull(graphql.Int)))

	// `data` is a slice of functions that return values
	// Note that its uses the expected signature `func() interface{} {...}`
	data := []interface{}{
		func() interface{} {
			return 1
		},
		func() interface{} {
			return nil
		},
		func() interface{} {
			return 2
		},
	}
	expected := &graphql.Result{
		Data: map[string]interface{}{
			"nest": map[string]interface{}{
				"test": []interface{}{
					1, nil, 2,
				},
			},
		},
	}
	checkList(t, ttype, data, expected)
}

func TestTypeSystem_DefinitionExample_IdentifiesOutputTypes(t *testing.T) {
	type Test struct {
		ttype    graphql.Type
		expected bool
	}
	tests := []Test{
		{graphql.Int, true},
		{objectType, true},
		{interfaceType, true},
		{unionType, true},
		{enumType, true},
		{inputObjectType, false},
	}
	for _, test := range tests {
		ttypeStr := fmt.Sprintf("%v", test.ttype)
		if graphql.IsOutputType(test.ttype) != test.expected {
			t.Fatalf(`expected %v , got: %v`, test.expected, ttypeStr)
		}
		if graphql.IsOutputType(graphql.NewList(test.ttype)) != test.expected {
			t.Fatalf(`expected %v , got: %v`, test.expected, ttypeStr)
		}
		if graphql.IsOutputType(graphql.NewNonNull(test.ttype)) != test.expected {
			t.Fatalf(`expected %v , got: %v`, test.expected, ttypeStr)
		}
	}
}

func TestTypeSystem_NonNullMustAcceptGraphQLTypes_AcceptsAnTypeAsNullableTypeOfNonNull(t *testing.T) {
	nullableTypes := []graphql.Type{
		graphql.String,
		someScalarType,
		someObjectType,
		someUnionType,
		someInterfaceType,
		someEnumType,
		someInputObject,
		graphql.NewList(graphql.String),
		graphql.NewList(graphql.NewNonNull(graphql.String)),
	}
	for _, ttype := range nullableTypes {
		result := graphql.NewNonNull(ttype)
		if result.GetError() != nil {
			t.Fatalf(`unexpected error: %v for type "%v"`, result.GetError(), ttype)
		}
	}
}

func TestLists_ListOfNullableObjects_ReturnsNull(t *testing.T) {
	ttype := graphql.NewList(graphql.Int)
	expected := &graphql.Result{
		Data: map[string]interface{}{
			"nest": map[string]interface{}{
				"test": nil,
			},
		},
	}
	checkList(t, ttype, nil, expected)
}

// Describe [T!]! Array<T>
func TestLists_NonNullListOfNonNullObjects_ContainsValues(t *testing.T) {
	ttype := graphql.NewNonNull(graphql.NewList(graphql.NewNonNull(graphql.Int)))
	data := []interface{}{
		1, 2,
	}
	expected := &graphql.Result{
		Data: map[string]interface{}{
			"nest": map[string]interface{}{
				"test": []interface{}{
					1, 2,
				},
			},
		},
	}
	checkList(t, ttype, data, expected)
}

func TestLists_ListOfNullableObjects_ContainsNull(t *testing.T) {
	ttype := graphql.NewList(graphql.Int)
	data := []interface{}{
		1, nil, 2,
	}
	expected := &graphql.Result{
		Data: map[string]interface{}{
			"nest": map[string]interface{}{
				"test": []interface{}{
					1, nil, 2,
				},
			},
		},
	}
	checkList(t, ttype, data, expected)
}

func TestTypeSystem_ListMustAcceptGraphQLTypes_AcceptsAnTypeAsItemTypeOfList(t *testing.T) {
	testTypes := withModifiers([]graphql.Type{
		graphql.String,
		someScalarType,
		someEnumType,
		someObjectType,
		someUnionType,
		someInterfaceType,
	})
	for _, ttype := range testTypes {
		result := graphql.NewList(ttype)
		if result.GetError() != nil {
			t.Fatalf(`unexpected error: %v for type "%v"`, result.GetError(), ttype)
		}
	}
}

func TestLists_NullableListOfNonNullFunc_ReturnsNull(t *testing.T) {
	ttype := graphql.NewList(graphql.NewNonNull(graphql.Int))

	// `data` is a function that return values
	// Note that its uses the expected signature `func() interface{} {...}`
	data := func() interface{} {
		return nil
	}
	expected := &graphql.Result{
		Data: map[string]interface{}{
			"nest": map[string]interface{}{
				"test": nil,
			},
		},
	}
	checkList(t, ttype, data, expected)
}

func ConnectionDefinitions(config ConnectionConfig) *GraphQLConnectionDefinitions {

	edgeType := graphql.NewObject(graphql.ObjectConfig{
		Name:        config.Name + "Edge",
		Description: "An edge in a connection",
		Fields: graphql.Fields{
			"node": &graphql.Field{
				Type:        config.NodeType,
				Description: "The item at the end of the edge",
			},
			"cursor": &graphql.Field{
				Type:        graphql.NewNonNull(graphql.String),
				Description: " cursor for use in pagination",
			},
		},
	})
	for fieldName, fieldConfig := range config.EdgeFields {
		edgeType.AddFieldConfig(fieldName, fieldConfig)
	}

	connectionType := graphql.NewObject(graphql.ObjectConfig{
		Name:        config.Name + "Connection",
		Description: "A connection to a list of items.",

		Fields: graphql.Fields{
			"pageInfo": &graphql.Field{
				Type:        graphql.NewNonNull(pageInfoType),
				Description: "Information to aid in pagination.",
			},
			"edges": &graphql.Field{
				Type:        graphql.NewList(edgeType),
				Description: "Information to aid in pagination.",
			},
		},
	})
	for fieldName, fieldConfig := range config.ConnectionFields {
		connectionType.AddFieldConfig(fieldName, fieldConfig)
	}

	return &GraphQLConnectionDefinitions{
		EdgeType:       edgeType,
		ConnectionType: connectionType,
	}
}

// Describe [T] Func()Array<T> // equivalent to Promise<Array<T>>
func TestLists_ListOfNullableFunc_ContainsValues(t *testing.T) {
	ttype := graphql.NewList(graphql.Int)

	// `data` is a function that return values
	// Note that its uses the expected signature `func() interface{} {...}`
	data := func() interface{} {
		return []interface{}{
			1, 2,
		}
	}
	expected := &graphql.Result{
		Data: map[string]interface{}{
			"nest": map[string]interface{}{
				"test": []interface{}{
					1, 2,
				},
			},
		},
	}
	checkList(t, ttype, data, expected)
}