package layout

import (
	"github.com/carlosframework/platform/internal/hostbox"
	"github.com/carlosframework/platform/internal/provision"
	"os"
	"path/filepath"
)

func InstanceCensusName(rel string) (string, bool) {
	parent := filepath.Dir(rel)
	if parent != "instances" && parent != ".instances" {
		return "", false
	}
	name := filepath.Base(rel)
	if rel != filepath.Join(parent, name) || name == "." || name == ".." {
		return "", false
	}
	return name, true
}

func VerifyInstanceCensusAlias(root, alias, host string) error {
	public := filepath.Join("instances", provision.InstanceID(host))
	if alias != filepath.Join(".instances", provision.InstanceID(host)) {
		return os.ErrPermission
	}
	a, err := hostbox.CaptureInventoryIdentity(root, alias)
	if err != nil {
		return err
	}
	b, err := hostbox.CaptureInventoryIdentity(root, public)
	if err != nil {
		return err
	}
	ar, err := filepath.Rel(a.MountPoint, filepath.Join(root, alias))
	if err != nil || !filepath.IsLocal(ar) {
		return os.ErrPermission
	}
	br, err := filepath.Rel(b.MountPoint, filepath.Join(root, public))
	if err != nil || !filepath.IsLocal(br) {
		return os.ErrPermission
	}
	if !a.SameMountNamespace(b) || a.Device != b.Device || filepath.Join(a.MountRoot, ar) != filepath.Join(b.MountRoot, br) {
		return os.ErrPermission
	}
	b.MountRoot, b.MountPoint, b.Mount, b.MountLineage = a.MountRoot, a.MountPoint, a.Mount, a.MountLineage
	b.MountUnique = a.MountUnique
	if !a.Same(b) {
		return os.ErrPermission
	}
	return nil
}