// Package secondary implements a secondary plugin.
package secondary

import (
	"sync"

	"github.com/coredns/coredns/plugin/file"
	"github.com/coredns/coredns/plugin/pkg/catalog"
)

// Secondary implements a secondary plugin that allows CoreDNS to retrieve (via AXFR)
// zone information from a primary server.
type Secondary struct {
	file.File

	zoneMu       sync.RWMutex
	zoneNames    map[*file.Zone]string
	dynamicZones map[string]*dynamicZone

	catalogMu          sync.RWMutex
	catalogs           map[string]*catalog.Catalog
	catalogZones       map[string]struct{}
	catalogMemberZones map[string]map[string]struct{}
}

type dynamicZone struct {
	catalog  string
	shutdown chan bool
	stopOnce sync.Once
}

// Name implements the Handler interface.
func (s *Secondary) Name() string { return "secondary" }