"path"
	"slices"
	"strings"
	"time"
)

// Writer provides sequential writing of a tar archive.
// [Writer.WriteHeader] begins a new file with the provided [Header],
// and then Writer can be treated as an io.Writer to supply that file's data.
type Writer struct {
	w    io.Writer
	pad  int64      // Amount of padding to write after current file entry
	curr fileWriter // Writer for current file entry

// for the file metadata. [Writer] takes ownership of fh and may mutate
// its fields. The caller must not modify fh after calling [Writer.CreateHeader].
//
// This returns a [Writer] to which the file contents should be written.
// The file's contents must be written to the io.Writer before the next
// call to [Writer.Create], [Writer.CreateHeader], [Writer.CreateRaw], or [Writer.Close].

		}
	}
}

// testNonEmptyWriter wraps an io.Writer and ensures that
// Write is never called with an empty buffer.
type testNonEmptyWriter struct{ io.Writer }

func (w testNonEmptyWriter) Write(b []byte) (int, error) {
	if len(b) == 0 {
		return 0, errors.New("unexpected empty Write call")
	}
	return w.Writer.Write(b)
}

func TestFileWriter(t *testing.T) {
	type (

pkg archive/zip, method (*Writer) Copy(*File) error
pkg archive/zip, method (*Writer) CreateRaw(*FileHeader) (io.Writer, error)
pkg compress/lzw, method (*Reader) Close() error
pkg compress/lzw, method (*Reader) Read([]uint8) (int, error)
pkg compress/lzw, method (*Reader) Reset(io.Reader, Order, int)
pkg compress/lzw, method (*Writer) Close() error
pkg compress/lzw, method (*Writer) Reset(io.Writer, Order, int)

	w := NewWriter(io.Discard)
	dw, err := w.Create("dir/")
	if err != nil {
		t.Fatal(err)
	}
	if _, err := dw.Write(nil); err != nil {
		t.Errorf("Write(nil) to directory: got %v, want nil", err)
	}
	if _, err := dw.Write([]byte("hello")); err == nil {
		t.Error(`Write("hello") to directory: got nil error, want non-nil`)
	}
}

func TestWriterDirAttributes(t *testing.T) {
	var buf bytes.Buffer

// size. If the argument io.Writer is already a [Writer] with large enough
// size, it returns the underlying [Writer].
func NewWriterSize(w io.Writer, size int) *Writer {
	// Is it already a Writer?
	b, ok := w.(*Writer)
	if ok && len(b.buf) >= size {
		return b
	}
	if size <= 0 {
		size = defaultBufSize
	}
	return &Writer{
		buf: make([]byte, size),
		wr:  w,
	}
}

pkg bufio, method (*Writer) AvailableBuffer() []uint8
pkg bufio, method (ReadWriter) AvailableBuffer() []uint8
pkg bytes, func Cut([]uint8, []uint8) ([]uint8, []uint8, bool)
pkg bytes, func Title //deprecated
pkg crypto/tls, method (*Conn) NetConn() net.Conn
pkg crypto/tls, type Config struct, PreferServerCipherSuites //deprecated
pkg crypto/x509, method (*CertPool) Subjects //deprecated
pkg debug/buildinfo, func Read(io.ReaderAt) (*debug.BuildInfo, error)

var (
	ErrHeader          = errors.New("archive/tar: invalid tar header")
	ErrWriteTooLong    = errors.New("archive/tar: write too long")
	ErrFieldTooLong    = errors.New("archive/tar: header field too long")
	ErrWriteAfterClose = errors.New("archive/tar: write after close")
	ErrInsecurePath    = errors.New("archive/tar: insecure file path")

	}
	for i := 0; i < chunks; i++ {
		_, err := f.Write(chunk)
		if err != nil {
			t.Fatal("write chunk:", err)
		}
	}
	if frag := int(size % chunkSize); frag > 0 {
		_, err := f.Write(chunk[:frag])
		if err != nil {
			t.Fatal("write chunk:", err)
		}
	}
	end := []byte("END\n")
	_, err = f.Write(end)
	if err != nil {
		t.Fatal("write end:", err)
	}
	if err := w.Close(); err != nil {

	return n, nil
}

func (f *testFile) Write(b []byte) (int, error) {
	if len(b) == 0 {
		return 0, nil
	}
	if len(f.ops) == 0 {
		return 0, errors.New("unexpected Write operation")
	}
	s, ok := f.ops[0].(string)
	if !ok {
		return 0, errors.New("unexpected Write operation")
	}

	if !strings.HasPrefix(s, string(b)) {
		return 0, testError{fmt.Errorf("got Write(%q), want Write(%q)", b, s)}
	}
	if len(s) > len(b) {