package assign

import (
	"git.sxidc.com/go-tools/utils/reflectutils"
	"github.com/pkg/errors"
	"reflect"
)

type OnParsedFieldTagCallback func(fromFieldName string, fromFieldElemValue reflect.Value, toFieldElementValue reflect.Value, tag *Tag) error

func UseTag(from any, to any, onParsedFieldTagFunc OnParsedFieldTagCallback) error {
	if from == nil || to == nil {
		return nil
	}

	fromValue := reflect.ValueOf(from)
	toValue := reflect.ValueOf(to)

	// 类型校验
	if !reflectutils.IsValueStructOrStructPointer(fromValue) {
		return errors.New("参数不是结构或结构指针")
	}

	if !reflectutils.IsValueStructPointer(toValue) {
		return errors.New("返回类型不是结构指针")
	}

	fromElemValue := reflectutils.PointerValueElem(fromValue)
	toElemValue := reflectutils.PointerValueElem(toValue)

	for i := 0; i < toElemValue.NumField(); i++ {
		toField := toElemValue.Field(i)
		if !toField.IsValid() {
			return errors.New("被赋值的结构存在无效字段")
		}

		// 初始化空值指针
		if toField.Kind() == reflect.Ptr && toField.IsNil() {
			toField.Set(reflect.New(toField.Type().Elem()))
		}
	}

	err := parseTag(fromElemValue, &toElemValue, onParsedFieldTagFunc)
	if err != nil {
		return err
	}

	return nil
}