// UserTypeUnmarshalerImpl returns the code implementing the user type unmarshaler function.
func UserTypeUnmarshalerImpl(u *design.UserTypeDefinition, context string) string {
	var required []string
	for _, v := range u.Validations {
		if r, ok := v.(*design.RequiredValidationDefinition); ok {
			required = r.Names
			break
		}
	}
	var impl string
	switch {
	case u.IsObject():
		impl = objectUnmarshalerR(u, required, context, "source", "target", 1)
	case u.IsArray():
		impl = arrayUnmarshalerR(u.ToArray(), context, "source", "target", 1)
	case u.IsHash():
		impl = hashUnmarshalerR(u.ToHash(), context, "source", "target", 1)
	default:
		return "" // No function for primitive types - they just get casted
	}
	data := map[string]interface{}{
		"Name": userTypeUnmarshalerFuncName(u),
		"Type": u,
		"Impl": impl,
	}
	return RunTemplate(unmUserImplT, data)
}

// Type implements the type definition DSL. A type definition describes a data structure consisting
// of attributes. Each attribute has a type which can also refer to a type definition (or use a
// primitive type or nested attibutes). The DSL syntax for define a type definition is the
// Attribute DSL, see Attribute.
//
// On top of specifying any attribute type, type definitions can also be used to describe the data
// structure of a request payload. They can also be used by media type definitions as reference, see
// Reference. Here is an example:
//
//	Type("createPayload", func() {
//		Description("Type of create and upload action payloads")
//		APIVersion("1.0")
//		Attribute("name", String, "name of bottle")
//		Attribute("origin", Origin, "Details on wine origin")  // See Origin definition below
//		Required("name")
//	})
//
//	var Origin = Type("origin", func() {
//		Description("Origin of bottle")
//		Attribute("Country")
//	})
//
// This function returns the newly defined type so the value can be used throughout the DSL.
func Type(name string, dsl func()) *design.UserTypeDefinition {
	if design.Design.Types == nil {
		design.Design.Types = make(map[string]*design.UserTypeDefinition)
	} else if _, ok := design.Design.Types[name]; ok {
		ReportError("type %#v defined twice", name)
		return nil
	}
	var t *design.UserTypeDefinition
	if topLevelDefinition(true) {
		t = &design.UserTypeDefinition{
			TypeName:            name,
			AttributeDefinition: &design.AttributeDefinition{DSLFunc: dsl},
		}
		if dsl == nil {
			t.Type = design.String
		}
		design.Design.Types[name] = t
	}
	return t
}

// userTypeUnmarshalerFuncName returns the name for the given user type unmarshaler function.
func userTypeUnmarshalerFuncName(u *design.UserTypeDefinition) string {
	return fmt.Sprintf("Unmarshal%s", GoTypeName(u, u.AllRequired(), 0))
}

// UserTypeUnmarshalerImpl returns the code implementing the user type unmarshaler function.
func UserTypeUnmarshalerImpl(u *design.UserTypeDefinition, versioned bool, defaultPkg, context string) string {
	validation := RecursiveChecker(u.AttributeDefinition, false, false, "source", context, 1)
	var impl string
	switch {
	case u.IsObject():
		impl = objectUnmarshalerR(u, u.AllRequired(), u.AllNonZero(), versioned, defaultPkg, context, "source", "target", 1)
	case u.IsArray():
		impl = arrayUnmarshalerR(u.ToArray(), versioned, defaultPkg, context, "source", "target", 1)
	case u.IsHash():
		impl = hashUnmarshalerR(u.ToHash(), versioned, defaultPkg, context, "source", "target", 1)
	default:
		return "" // No function for primitive types - they just get casted
	}
	data := map[string]interface{}{
		"Name":         userTypeUnmarshalerFuncName(u),
		"Type":         u,
		"Impl":         impl,
		"MustValidate": strings.TrimSpace(validation) != "",
	}
	return RunTemplate(unmUserImplT, data)
}