package app

import (
	"strings"

	"git.k8s-git-k6n.net/mats/fancy-dns/internal/api"
	"git.k8s-git-k6n.net/mats/fancy-dns/internal/localzone"
)

// The resolver only reads zones. Master files from blocklist.local_zones and the
// rendered DNSZone objects are compiled into one store; editing is the
// console's job and happens on the objects.

// listZones renders the compiled store for the console.
func (a *App) listZones() (any, error) {
	// The zones that can be edited are the DNSZone objects, which the Kubernetes
	// source renders into a directory of its own. The resolver itself writes
	// nothing; the console, which can, reports the zones writable.
	dir := a.kubeZoneDir()
	store := a.local.Get()
	// The slices are never nil: the console reads lengths and maps without
	// a null check, and an empty list is a list.
	res := api.ZonesResponse{
		Zones:      []api.Zone{},
		Files:      []string{},
		ManagedDir: dir,
		Writable:   false,
		Types:      localzone.EditableTypes(),
	}
	if store != nil {
		res.Files = store.Files()
		res.BuiltAt = store.BuiltAt()
		for _, zone := range store.SnapshotAll(dir) {
			res.Zones = append(res.Zones, *zone)
			res.Records += zone.RecordCount
		}
	}
	res.Error = a.localZoneError()
	return res, nil
}

// localZoneError is the reason the store is stale, or "" when it is current.
// It comes from the degraded list, so the console and /healthz agree.
func (a *App) localZoneError() string {
	for _, d := range a.Degraded() {
		if rest, ok := strings.CutPrefix(d, "local zones: "); ok {
			return rest
		}
	}
	return ""
}