package resolver

import (
	"context"
	"regexp"
	"strings"

	"git.zb-server.de/Sebi/ssh-netbox-wrapper/internal/netbox"
)

var validHostname = regexp.MustCompile(`^[A-Za-z0-9]([A-Za-z0-9-]*[A-Za-z0-9])?(\.[A-Za-z0-9]([A-Za-z0-9-]*[A-Za-z0-9])?)*$`)

// HostnameStrategy connects by the NetBox name instead of an IP, so DNS or
// ~/.ssh/config resolves it. Names without a dot get the optional domain.
// Names that are no valid hostname fall through to the next strategy.
type HostnameStrategy struct {
	domain string
}

func (s *HostnameStrategy) Name() string { return "hostname" }

func (s *HostnameStrategy) Resolve(_ context.Context, entry *netbox.HostEntry, _ *netbox.Client) (string, error) {
	name := strings.ToLower(entry.Name)
	if domain := strings.Trim(s.domain, "."); domain != "" && !strings.Contains(name, ".") {
		name += "." + strings.ToLower(domain)
	}
	if !validHostname.MatchString(name) {
		return "", ErrNoIP
	}
	return name, nil
}