package annotation

import (
	"fmt"
	"reflect"

	cur "git.loafle.net/commons/util-go/reflect"
)

var annotationRegistry map[string]*AnnotationDefinition

func init() {
	annotationRegistry = make(map[string]*AnnotationDefinition, 0)
}

func RegisterAnnotation(t reflect.Type) error {
	rt, _, _ := cur.GetTypeInfo(t)

	f := getTypeAnnotationField(t)
	if nil == f {
		return fmt.Errorf("DI: This type[%s] is not Annotation", rt.Name())
	}

	name, _ := parseAnnotationMeta(f.Tag)

	if _, ok := annotationRegistry[name]; ok {
		return fmt.Errorf("DI: name[%s] of annotation exist already", name)
	}

	def := &AnnotationDefinition{
		t:  t,
		rt: rt,
	}

	annotationRegistry[name] = def

	return nil
}

type AnnotationDefinition struct {
	t  reflect.Type
	rt reflect.Type
}

func getTypeAnnotationField(t reflect.Type) *reflect.StructField {
	rt, _, _ := cur.GetTypeInfo(t)
	if reflect.Struct != rt.Kind() {
		return nil
	}

	for i := 0; i < rt.NumField(); i++ {
		f := rt.Field(i)

		if f.Anonymous {
			if f.Type == TypeAnnotationType {
				return &f
			}
		}
	}
	return nil
}