package annotation

import (
	"fmt"
	"reflect"
	"strings"

	"git.loafle.net/commons_go/di"
)

const (
	AnnotationStartChar        = "("
	AnnotationEndChar          = ")"
	AnnotationAttributeSpliter = ","
	AnnotationKeyValueSpliter  = "="
)

type Annotation interface {
}

// @Inject(name? string)
// @Resource(name? string)
func ParseAnnotation(tag reflect.StructTag) (map[string]Annotation, error) {
	a := strings.Trim(tag.Get(di.AnnotationTag), " ")
	if "" == a {
		return nil, nil
	}

	rKVs := make(map[string]Annotation)

	inject, err := ParseInject(a)
	if nil != err {
		return nil, err
	}
	rKVs[InjectTag] = inject

	resource, err := ParseResource(a)
	if nil != err {
		return nil, err
	}
	rKVs[ResourceTag] = resource

	return rKVs, nil
}

func ParseAttribute(a string, startIndex int) (map[string]string, error) {
	if startIndex >= len(a) {
		return nil, nil
	}

	if AnnotationStartChar != string([]rune(a)[startIndex]) {
		return nil, nil
	}

	endIndex := strings.Index(a[startIndex+1:], AnnotationEndChar)
	if -1 == endIndex {
		return nil, fmt.Errorf("DI: Syntax error - annotation(%s) has '%s', but '%s' is not exist", a, AnnotationStartChar, AnnotationEndChar)
	}
	endIndex = endIndex + startIndex + 1

	body := a[startIndex+1 : endIndex]
	kvs := strings.Split(body, AnnotationAttributeSpliter)
	if 0 == len(kvs) {
		return nil, nil
	}

	rKVs := make(map[string]string)
	for i := 0; i < len(kvs); i++ {
		s := strings.Trim(kvs[i], " ")
		if "" == s {
			continue
		}
		kv := strings.Split(s, AnnotationKeyValueSpliter)
		k := strings.Trim(kv[0], " ")
		v := strings.Trim(kv[1], " ")
		rKVs[k] = v
	}

	return rKVs, nil
}