package locode

import (
	"errors"
	"fmt"

	"github.com/nspcc-dev/neofs-node/pkg/util/locode"
	"github.com/nspcc-dev/neofs-sdk-go/netmap"
)

var errMissingRequiredAttr = errors.New("missing required attribute in DB record")

// VerifyAndUpdate validates UN-LOCODE attribute of n
// and adds a group of related attributes.
//
// If n contains at least one of the LOCODE-derived attributes,
// an error returns.
//
// If n contains UN-LOCODE attribute and its value does not
// match the UN/LOCODE format, an error returns.
//
// New attributes are formed from the record of DB instance (Prm).
// If DB entry R was found w/o errors, then new attributes are:
//  * CountryCode: R.CountryCode().String();
//  * Country: R.CountryName();
//  * Location: Record.LocationName();
//  * SubDivCode: R.SubDivCode();
//  * SubDiv: R.SubDivName();
//  * Continent: R.Continent().String().
//
// UN-LOCODE attribute remains untouched.
func (v *Validator) VerifyAndUpdate(n *netmap.NodeInfo) error {
	mAttr := uniqueAttributes(n.Attributes())

	// check if derived attributes are presented
	for attrKey := range v.mAttr {
		if _, ok := mAttr[attrKey]; ok {
			return fmt.Errorf("attribute derived from %s is presented: %s",
				netmap.AttrUNLOCODE,
				attrKey,
			)
		}
	}

	attrLocode, ok := mAttr[netmap.AttrUNLOCODE]
	if !ok {
		return nil
	}

	lc, err := locode.FromString(attrLocode.Value())
	if err != nil {
		return fmt.Errorf("invalid locode value: %w", err)
	}

	record, err := v.db.Get(lc)
	if err != nil {
		return fmt.Errorf("could not get locode record from DB: %w", err)
	}

	for attrKey, attrDesc := range v.mAttr {
		attrVal := attrDesc.converter(record)
		if attrVal == "" {
			if !attrDesc.optional {
				return errMissingRequiredAttr
			}

			continue
		}

		a := netmap.NewNodeAttribute()
		a.SetKey(attrKey)
		a.SetValue(attrVal)

		mAttr[attrKey] = a
	}

	as := n.Attributes()
	as = as[:0]

	for _, attr := range mAttr {
		as = append(as, attr)
	}

	n.SetAttributes(as...)

	return nil
}

func uniqueAttributes(as []*netmap.NodeAttribute) map[string]*netmap.NodeAttribute {
	mAttr := make(map[string]*netmap.NodeAttribute, len(as))

	for _, attr := range as {
		mAttr[attr.Key()] = attr
	}

	return mAttr
}