// This file is part of the happyDomain (R) project.
// Copyright (c) 2020-2026 happyDomain
// Authors: Pierre-Olivier Mercier, et al.
//
// This program is offered under a commercial and under the AGPL license.
// For commercial licensing, contact us at <contact@happydomain.org>.
//
// For AGPL licensing:
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

package checker

import (
	"encoding/json"

	"github.com/miekg/dns"
)

// Service type identifiers as exposed by happyDomain core.
const (
	serviceTypeOrigin       = "abstract.Origin"
	serviceTypeNSOnlyOrigin = "abstract.NSOnlyOrigin"
)

// originPayload is a minimal local copy of services/abstract.Origin keeping
// only the field this checker reads. The JSON tag matches the upstream wire
// format ("ns").
type originPayload struct {
	NameServers []*dns.NS `json:"ns"`
}

// nsOnlyOriginPayload is a minimal local copy of
// services/abstract.NSOnlyOrigin keeping only the field this checker reads.
type nsOnlyOriginPayload struct {
	NameServers []*dns.NS `json:"ns"`
}

// nsFromService extracts the list of NS records from an Origin or
// NSOnlyOrigin service payload.
func nsFromService(svc *serviceMessage) []*dns.NS {
	switch svc.Type {
	case serviceTypeOrigin:
		var o originPayload
		if err := json.Unmarshal(svc.Service, &o); err != nil {
			return nil
		}
		return o.NameServers
	case serviceTypeNSOnlyOrigin:
		var o nsOnlyOriginPayload
		if err := json.Unmarshal(svc.Service, &o); err != nil {
			return nil
		}
		return o.NameServers
	}
	return nil
}