// RemoveSnapFiles removes the snap files from the disk after unmounting the snap.
func (b Backend) RemoveSnapFiles(s snap.PlaceInfo, typ snap.Type, meter progress.Meter) error {
	mountDir := s.MountDir()

	// this also ensures that the mount unit stops
	if err := removeMountUnit(mountDir, meter); err != nil {
		return err
	}

	if err := os.RemoveAll(mountDir); err != nil {
		return err
	}

	// try to remove parent dir, failure is ok, means some other
	// revisions are still in there
	os.Remove(filepath.Dir(mountDir))

	// snapPath may either be a file or a (broken) symlink to a dir
	snapPath := s.MountFile()
	if _, err := os.Lstat(snapPath); err == nil {
		// remove the kernel assets (if any)
		if typ == snap.TypeKernel {
			if err := boot.RemoveKernelAssets(s); err != nil {
				return err
			}
		}

		// remove the snap
		if err := os.RemoveAll(snapPath); err != nil {
			return err
		}
	}

	return nil
}

func removeCurrentSymlinks(info snap.PlaceInfo) error {
	var err1, err2 error

	// the snap "current" symlink
	currentActiveSymlink := filepath.Join(info.MountDir(), "..", "current")
	err1 = os.Remove(currentActiveSymlink)
	if err1 != nil && !os.IsNotExist(err1) {
		logger.Noticef("Cannot remove %q: %v", currentActiveSymlink, err1)
	} else {
		err1 = nil
	}

	// the data "current" symlink
	currentDataSymlink := filepath.Join(info.DataDir(), "..", "current")
	err2 = os.Remove(currentDataSymlink)
	if err2 != nil && !os.IsNotExist(err2) {
		logger.Noticef("Cannot remove %q: %v", currentDataSymlink, err2)
	} else {
		err2 = nil
	}

	if err1 != nil && err2 != nil {
		return fmt.Errorf("cannot remove snap current symlink: %v and %v", err1, err2)
	} else if err1 != nil {
		return fmt.Errorf("cannot remove snap current symlink: %v", err1)
	} else if err2 != nil {
		return fmt.Errorf("cannot remove snap current symlink: %v", err2)
	}

	return nil
}

func (f *fakeSnappyBackend) RemoveSnapFiles(s snap.PlaceInfo, typ snap.Type, meter progress.Meter) error {
	meter.Notify("remove-snap-files")
	f.ops = append(f.ops, fakeOp{
		op:    "remove-snap-files",
		name:  s.MountDir(),
		stype: typ,
	})
	return nil
}

func (f *fakeSnappyBackend) UndoSetupSnap(s snap.PlaceInfo, typ snap.Type, p progress.Meter) error {
	p.Notify("setup-snap")
	f.ops = append(f.ops, fakeOp{
		op:    "undo-setup-snap",
		name:  s.MountDir(),
		stype: typ,
	})
	return nil
}

// RemoveKernelAssets removes the unpacked kernel/initrd for the given
// kernel snap.
func RemoveKernelAssets(s snap.PlaceInfo) error {
	bootloader, err := partition.FindBootloader()
	if err != nil {
		return fmt.Errorf("no not remove kernel assets: %s", err)
	}

	// remove the kernel blob
	blobName := filepath.Base(s.MountFile())
	dstDir := filepath.Join(bootloader.Dir(), blobName)
	if err := os.RemoveAll(dstDir); err != nil {
		return err
	}

	return nil
}