package guest

import (
	"archive/tar"
	"bytes"
	"io"
	"os"
	"path/filepath"
	"testing"
)

func TestWriteTarArchiveKeepsTopLevelDirectory(t *testing.T) {
	t.Parallel()

	sourceDir := filepath.Join(t.TempDir(), "6.8.0-test")
	if err := os.MkdirAll(filepath.Join(sourceDir, "kernel"), 0o755); err != nil {
		t.Fatalf("MkdirAll: %v", err)
	}
	if err := os.WriteFile(filepath.Join(sourceDir, "modules.dep"), []byte("deps"), 0o644); err != nil {
		t.Fatalf("WriteFile modules.dep: %v", err)
	}
	if err := os.WriteFile(filepath.Join(sourceDir, "kernel", "module.ko"), []byte("ko"), 0o644); err != nil {
		t.Fatalf("WriteFile module.ko: %v", err)
	}

	var buf bytes.Buffer
	if err := writeTarArchive(&buf, sourceDir); err != nil {
		t.Fatalf("writeTarArchive: %v", err)
	}

	tr := tar.NewReader(bytes.NewReader(buf.Bytes()))
	var names []string
	for {
		header, err := tr.Next()
		if err == io.EOF {
			break
		}
		if err != nil {
			t.Fatalf("tar.Next: %v", err)
		}
		names = append(names, header.Name)
	}

	want := map[string]struct{}{
		"6.8.0-test":                  {},
		"6.8.0-test/modules.dep":      {},
		"6.8.0-test/kernel":           {},
		"6.8.0-test/kernel/module.ko": {},
	}
	if len(names) != len(want) {
		t.Fatalf("archive names = %v, want %d entries", names, len(want))
	}
	for _, name := range names {
		if _, ok := want[name]; !ok {
			t.Fatalf("unexpected archive entry %q in %v", name, names)
		}
	}
}