// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
// SPDX-License-Identifier: MIT

package nfs4

import (
	"bytes"
	"errors"
	"testing"

	"sourcedock.dev/petrbalvin/nfs/internal/xdr"
)

func TestBitmapBits(t *testing.T) {
	m := OfBits(0, 31, 32, 55, 75)
	for _, n := range []uint32{0, 31, 32, 55, 75} {
		if !m.Has(n) {
			t.Fatalf("bit %d is not set", n)
		}
	}
	for _, n := range []uint32{1, 30, 33, 54, 76} {
		if m.Has(n) {
			t.Fatalf("bit %d is set but was never given", n)
		}
	}
}

func TestBitmapWireRoundTrip(t *testing.T) {
	want := OfBits(1, 3, 33, 55)
	d := xdr.NewDecoder(want.AppendTo(nil))
	got, err := ReadBitmap(d)
	if err != nil {
		t.Fatalf("read: %v", err)
	}
	for n := range uint32(80) {
		if want.Has(n) != got.Has(n) {
			t.Fatalf("bit %d: %v, want %v", n, got.Has(n), want.Has(n))
		}
	}
	if d.Remaining() != 0 {
		t.Fatalf("%d bytes left over", d.Remaining())
	}
}

func TestBitmapEmptyAndHuge(t *testing.T) {
	if len(OfBits().AppendTo(nil)) != 4 {
		t.Fatal("an empty bitmap encodes as exactly the zero word count")
	}
	huge := xdr.AppendUint32(nil, 101)
	if _, err := ReadBitmap(xdr.NewDecoder(huge)); !errors.Is(err, xdr.ErrBadLength) {
		t.Fatalf("a 101 word bitmap: %v", err)
	}
}

func TestStateidWire(t *testing.T) {
	b := AllZero.Append(nil)
	if len(b) != 16 || !bytes.Equal(b, make([]byte, 16)) {
		t.Fatalf("the anonymous stateid encodes as %x", b)
	}
	var s Stateid
	s[0] = 0x80
	if got := s.Append(nil); !bytes.Equal(got, s[:]) {
		t.Fatal("a stateid encodes in its own byte order")
	}
}

func TestFattrAllAdvertised(t *testing.T) {
	// The whole advertised set, every field set, in both directions.
	request := append(Bitmap{}, SupportedAttrs...)
	want := Attrs{
		Type:            NF4Dir,
		FHExpireType:    FH4Persistent,
		Change:          7,
		Size:            1,
		LinkSupport:     true,
		SymlinkSupport:  true,
		NamedAttr:       false,
		FSID:            [2]uint64{9, 0},
		UniqueHandles:   true,
		FileHandle:      []byte("h"),
		FileID:          3,
		Mode:            0o755,
		Numlinks:        2,
		SpaceUsed:       4096,
		TimeAccess:      NfsTime{1, 2},
		TimeMetadata:    NfsTime{3, 4},
		TimeModify:      NfsTime{5, 6},
		MountedOnFileID: 3,
		Limits:          DefaultLimits,
	}
	response, got, err := DecodeGetattrBody(AppendGetattrRes(nil, request, want))
	if err != nil {
		t.Fatalf("decode: %v", err)
	}
	for _, n := range []uint32{AttrSupportedAttrs, AttrType, AttrFHExpireType, AttrChange,
		AttrSize, AttrLinkSupport, AttrSymlinkSupport, AttrNamedAttr, AttrFSID,
		AttrUniqueHandles, AttrFileHandle, AttrFileID, AttrMaxName, AttrMaxRead,
		AttrMaxWrite, AttrMode, AttrNumlinks, AttrSpaceUsed, AttrTimeAccess,
		AttrTimeMetadata, AttrTimeModify, AttrMountedOnFileID} {
		if !response.Has(n) {
			t.Fatalf("attribute %d missing from the response bitmap", n)
		}
	}
	if got.Type != want.Type || got.FHExpireType != want.FHExpireType || got.Change != want.Change ||
		got.Size != want.Size || got.LinkSupport != want.LinkSupport ||
		got.SymlinkSupport != want.SymlinkSupport || got.NamedAttr != want.NamedAttr ||
		got.FSID != want.FSID || got.UniqueHandles != want.UniqueHandles ||
		!bytes.Equal(got.FileHandle, want.FileHandle) || got.FileID != want.FileID ||
		got.Mode != want.Mode || got.Numlinks != want.Numlinks ||
		got.SpaceUsed != want.SpaceUsed || got.TimeAccess != want.TimeAccess ||
		got.TimeMetadata != want.TimeMetadata || got.TimeModify != want.TimeModify ||
		got.MountedOnFileID != want.MountedOnFileID || got.Limits != want.Limits {
		t.Fatalf("round trip mismatch:\n got %+v\nwant %+v", got, want)
	}
}

func TestGetattrTruncatedBody(t *testing.T) {
	// A successful GETATTR whose blob is cut short is a decoding error at
	// the exact attribute, not a silent misread.
	request := OfBits(AttrType, AttrSize)
	full := AppendGetattrRes(nil, request, Attrs{Type: NF4Reg, Size: 5})
	// The fattr4 is a bitmap then a length prefixed blob; cut the last
	// byte off the whole result and the blob no longer holds the size.
	truncated := full[:len(full)-1]
	if _, _, err := DecodeGetattrBody(truncated); err == nil {
		t.Fatal("a truncated attribute list decoded")
	}
}

func TestBitmapWithAndWords(t *testing.T) {
	m := OfBits(3).With(70)
	if !m.Has(3) || !m.Has(70) {
		t.Fatalf("With lost a bit: %v", m.Words())
	}
	if len(OfBits(3, 32, 64).Words()) != 3 {
		t.Fatal("Words trimmed a live word")
	}
	if len(Bitmap{5, 0}.Words()) != 1 {
		t.Fatal("Words kept a trailing zero word")
	}
}

func TestCompoundResUnknownOpBody(t *testing.T) {
	// A successful result of an operation this client cannot measure is a
	// decoding error, not a silent misread. WANT_DELEGATION fits: this
	// build neither asks for delegations nor understands their answer.
	payload := AppendCompoundRes(nil, ErrOK, "", [][]byte{
		AppendOpHeader(nil, OpWantDelegation, ErrOK),
	})
	if _, _, err := DecodeCompoundResBodies(payload); !errors.Is(err, ErrUnknownOp) {
		t.Fatalf("a WANT_DELEGATION result decoded as %v", err)
	}
}

func TestAccessResRoundTrip(t *testing.T) {
	supported, access, err := DecodeAccessBody(AppendAccessRes(nil, 0x3f, 0x21))
	if err != nil || supported != 0x3f || access != 0x21 {
		t.Fatalf("access body: %x %x, %v", supported, access, err)
	}
}

func TestArgopBuilders(t *testing.T) {
	// Every builder writes the operation number first, then its arguments.
	cases := []struct {
		name string
		arg  []byte
		op   uint32
	}{
		{"putrootfh", AppendPutRootfh(nil), OpPutRootfh},
		{"savefh", AppendSavefh(nil), OpSavefh},
		{"restorefh", AppendRestorefh(nil), OpRestorefh},
		{"getfh", AppendGetfh(nil), OpGetfh},
		{"putfh", AppendPutfh(nil, []byte("h")), OpPutfh},
		{"lookup", AppendLookup(nil, "n"), OpLookup},
		{"getattr", AppendGetattr(nil, OfBits(AttrType)), OpGetattr},
		{"access", AppendAccess(nil, AccessRead), OpAccess},
		{"read", AppendRead(nil, AllZero, 1, 2), OpRead},
		{"readdir", AppendReaddir(nil, 1, [8]byte{}, 8, 4096, OfBits(AttrType)), OpReaddir},
	}
	for _, tc := range cases {
		d := xdr.NewDecoder(tc.arg)
		op, err := d.Uint32()
		if err != nil || op != tc.op {
			t.Fatalf("%s: op %d, %v; want %d", tc.name, op, err, tc.op)
		}
	}
	// Spot check the argument shapes the tests rely on.
	if fh, err := xdr.NewDecoder(AppendPutfh(nil, []byte("h"))[4:]).VarOpaque(); err != nil || string(fh) != "h" {
		t.Fatalf("putfh argument: %q, %v", fh, err)
	}
	if n, err := xdr.NewDecoder(AppendLookup(nil, "n")[4:]).String(); err != nil || n != "n" {
		t.Fatalf("lookup argument: %q, %v", n, err)
	}
}

func TestResBodyLen(t *testing.T) {
	getattr := AppendGetattrRes(nil, OfBits(AttrType), Attrs{Type: NF4Reg})
	readdir := AppendReadDirRes(nil, [8]byte{}, []DirEntryRes{{Cookie: 1, Name: "x", Attrs: Attrs{Type: NF4Reg}}}, OfBits(AttrType), true)
	cases := []struct {
		name   string
		op     uint32
		status uint32
		body   []byte
		want   int
	}{
		{"error has no body", OpGetfh, ErrNoEnt, []byte{9, 9, 9, 9}, 0},
		{"putfh", OpPutfh, ErrOK, nil, 0},
		{"getfh", OpGetfh, ErrOK, AppendGetfhRes(nil, []byte("handle")), 4 + 8},
		{"open", OpOpen, ErrOK, AppendOpenRes(nil, AllZero), 16 + 20 + 4 + 4 + 4},
		{"getattr", OpGetattr, ErrOK, getattr, len(getattr)},
		{"access", OpAccess, ErrOK, AppendAccessRes(nil, 3, 1), 8},
		{"read", OpRead, ErrOK, AppendReadRes(nil, false, []byte("ab")), 4 + 4 + 2 + 2},
		{"readdir", OpReaddir, ErrOK, readdir, len(readdir)},
	}
	for _, tc := range cases {
		got, err := resBodyLen(tc.op, tc.status, tc.body)
		if err != nil || got != tc.want {
			t.Fatalf("%s: %d, %v; want %d", tc.name, got, err, tc.want)
		}
	}
	if _, err := resBodyLen(OpWantDelegation, ErrOK, nil); !errors.Is(err, ErrUnknownOp) {
		t.Fatalf("an unmeasurable result: %v", err)
	}
	if n, err := resBodyLen(OpGetfh, ErrOK, []byte{0, 0, 0, 9, 1}); err == nil || n != 0 {
		t.Fatalf("a truncated getfh body measured as %d, %v", n, err)
	}
}

func TestWriteWire(t *testing.T) {
	args := AppendWriteArgs(nil, AllZero, 512, StableDataSync, []byte("data"))
	stateid, off, stable, data, err := DecodeWriteArgs(args[4:])
	if err != nil {
		t.Fatalf("decode: %v", err)
	}
	if stateid != AllZero || off != 512 || stable != StableDataSync || string(data) != "data" {
		t.Fatalf("write args: %+v %d %d %q", stateid, off, stable, data)
	}

	verf := [8]byte{1, 2, 3, 4, 5, 6, 7, 8}
	res := AppendWriteRes(nil, 4, StableFileSync, verf)
	count, committed, gotVerf, err := DecodeWriteRes(res)
	if err != nil || count != 4 || committed != StableFileSync || gotVerf != verf {
		t.Fatalf("write res: %d %d %x, %v", count, committed, gotVerf, err)
	}
	// The measured body length matches what was written.
	n, err := resBodyLen(OpWrite, ErrOK, res)
	if err != nil || n != len(res) {
		t.Fatalf("measure: %d of %d, %v", n, len(res), err)
	}
}

func TestCreateWire(t *testing.T) {
	cases := []struct {
		name     string
		kind     uint32
		linkdata string
		major    uint32
		minor    uint32
		perm     uint32
	}{
		{"dir", NF4Dir, "", 0, 0, 0o750},
		{"symlink", NF4Lnk, "target.txt", 0, 0, 0o644},
		{"fifo", NF4Fifo, "", 0, 0, 0o600},
		{"chrdev", NF4Chr, "", 4, 64, 0o600},
		{"nomode", NF4Sock, "", 0, 0, 0},
	}
	for _, tc := range cases {
		arg := AppendCreateArgs(nil, tc.kind, "obj", tc.linkdata, tc.major, tc.minor, tc.perm)
		kind, name, linkdata, major, minor, perm, err := DecodeCreateArgs(arg[4:])
		if err != nil {
			t.Fatalf("%s: %v", tc.name, err)
		}
		if kind != tc.kind || name != "obj" || linkdata != tc.linkdata ||
			major != tc.major || minor != tc.minor || perm != tc.perm {
			t.Fatalf("%s: kind %d name %q linkdata %q major %d minor %d perm %o",
				tc.name, kind, name, linkdata, major, minor, perm)
		}
	}
}

func TestCreateResMeasure(t *testing.T) {
	res := AppendCreateRes(nil)
	n, err := resBodyLen(OpCreate, ErrOK, res)
	if err != nil || n != len(res) {
		t.Fatalf("measure: %d of %d, %v", n, len(res), err)
	}
}

func TestFattrRoundTrip(t *testing.T) {
	request := OfBits(AttrType, AttrChange, AttrSize, AttrFSID, AttrMode,
		AttrNumlinks, AttrTimeModify, AttrMountedOnFileID, AttrFileHandle)
	a := Attrs{
		Type:            NF4Reg,
		FHExpireType:    FH4Persistent,
		Change:          0x1234,
		Size:            9,
		LinkSupport:     true,
		SymlinkSupport:  true,
		NamedAttr:       false,
		FSID:            [2]uint64{0x700, 0},
		UniqueHandles:   true,
		FileHandle:      []byte("handle-bytes"),
		FileID:          42,
		Mode:            0o644,
		Numlinks:        1,
		SpaceUsed:       4096,
		TimeModify:      NfsTime{1700000000, 500},
		MountedOnFileID: 42,
	}
	response, got, err := DecodeGetattrBody(AppendGetattrRes(nil, request, a))
	if err != nil {
		t.Fatalf("decode: %v", err)
	}
	for _, n := range []uint32{AttrType, AttrChange, AttrSize, AttrFSID, AttrMode,
		AttrNumlinks, AttrTimeModify, AttrMountedOnFileID, AttrFileHandle} {
		if !response.Has(n) {
			t.Fatalf("attribute %d is missing from the response bitmap", n)
		}
	}
	if got.Type != NF4Reg || got.Change != a.Change || got.Size != 9 ||
		got.FSID != a.FSID || got.Mode != 0o644 || got.Numlinks != 1 ||
		got.TimeModify != a.TimeModify || got.MountedOnFileID != 42 ||
		!bytes.Equal(got.FileHandle, a.FileHandle) {
		t.Fatalf("round trip mismatch: %+v", got)
	}
}

func TestFattrSkipsUnsupported(t *testing.T) {
	// Owner is encoded when the attributes carry it: a request that
	// asks gets the decimal uid string in the blob and the response
	// bitmap keeps it.
	request := OfBits(AttrType, AttrOwner)
	response, got, err := DecodeGetattrBody(AppendGetattrRes(nil, request, Attrs{Type: NF4Dir, Owner: "0"}))
	if err != nil {
		t.Fatalf("decode: %v", err)
	}
	if !response.Has(AttrType) || !response.Has(AttrOwner) {
		t.Fatalf("response bitmap %v drops the owner", response.Words())
	}
	if got.Type != NF4Dir || got.Owner != "0" {
		t.Fatalf("type %d owner %q", got.Type, got.Owner)
	}
}

func TestFattrEmptyRequest(t *testing.T) {
	response, _, err := DecodeGetattrBody(AppendGetattrRes(nil, Bitmap{}, Attrs{}))
	if err != nil || len(response.Words()) != 0 {
		t.Fatalf("an empty request: %v, %v", response, err)
	}
}

func TestCompoundArgsRoundTrip(t *testing.T) {
	var ops [][]byte
	ops = append(ops, AppendPutRootfh(nil))
	ops = append(ops, AppendPutfh(nil, []byte{1, 2, 3}))
	ops = append(ops, AppendLookup(nil, "a.txt"))
	payload := AppendCompoundArgs(nil, "probe", 2, ops)

	h, d, err := DecodeCompoundArgs(payload)
	if err != nil {
		t.Fatalf("decode: %v", err)
	}
	if h.Tag != "probe" || h.Minor != 2 || h.OpCount != 3 {
		t.Fatalf("header %+v", h)
	}
	for i, want := range []uint32{OpPutRootfh, OpPutfh, OpLookup} {
		got, err := d.Uint32()
		if err != nil || got != want {
			t.Fatalf("op %d: got %d, %v; want %d", i, got, err, want)
		}
		if want == OpPutfh {
			if fh, err := d.VarOpaque(); err != nil || !bytes.Equal(fh, []byte{1, 2, 3}) {
				t.Fatalf("putfh argument: %x, %v", fh, err)
			}
		}
		if want == OpLookup {
			if name, err := d.String(); err != nil || name != "a.txt" {
				t.Fatalf("lookup component: %q, %v", name, err)
			}
		}
	}
}

func TestCompoundResBodies(t *testing.T) {
	var results [][]byte
	results = append(results, AppendOpHeader(nil, OpPutRootfh, ErrOK))
	fh := AppendGetfhRes(AppendOpHeader(nil, OpGetfh, ErrOK), []byte("the-handle"))
	results = append(results, fh)
	results = append(results, AppendOpHeader(nil, OpLookup, ErrNoEnt))
	payload := AppendCompoundRes(nil, ErrNoEnt, "tag", results)

	res, bodies, err := DecodeCompoundResBodies(payload)
	if err != nil {
		t.Fatalf("decode: %v", err)
	}
	if res.Status != ErrNoEnt || res.Tag != "tag" || len(res.Ops) != 3 {
		t.Fatalf("res: status %d tag %q ops %d", res.Status, res.Tag, len(res.Ops))
	}
	wantStatus := []uint32{ErrOK, ErrOK, ErrNoEnt}
	for i, op := range res.Ops {
		if op.Status != wantStatus[i] {
			t.Fatalf("op %d status %d", i, op.Status)
		}
	}
	if len(bodies[0]) != 0 || len(bodies[2]) != 0 {
		t.Fatalf("a bodyless result carried bytes: %x %x", bodies[0], bodies[2])
	}
	gotFH, err := xdr.NewDecoder(bodies[1]).VarOpaque()
	if err != nil || !bytes.Equal(gotFH, []byte("the-handle")) {
		t.Fatalf("getfh body: %q, %v", gotFH, err)
	}
}

func TestReadAndReaddirWire(t *testing.T) {
	read := AppendRead(nil, AllZero, 512, 4096)
	// The arguments follow the operation number.
	d := xdr.NewDecoder(read[4:])
	var st Stateid
	raw, err := d.Raw(16)
	if err != nil {
		t.Fatalf("stateid: %v", err)
	}
	copy(st[:], raw)
	off, err := d.Uint64()
	count, err := d.Uint32()
	if err != nil || off != 512 || count != 4096 {
		t.Fatalf("read args: off %d count %d, %v", off, count, err)
	}

	res := AppendReadRes(nil, true, []byte("chunk"))
	eof, data, err := DecodeReadBody(res)
	if err != nil || !eof || string(data) != "chunk" {
		t.Fatalf("read res: %v %q, %v", eof, data, err)
	}

	entries := []DirEntryRes{
		{Cookie: 1, Name: "one", Attrs: Attrs{Type: NF4Reg}},
		{Cookie: 2, Name: "two", Attrs: Attrs{Type: NF4Dir}},
	}
	req := OfBits(AttrType)
	dir := AppendReadDirRes(nil, [8]byte{1, 2, 3, 4, 5, 6, 7, 8}, entries, req, true)
	verf, got, eof, err := DecodeReadDirBody(dir)
	if err != nil || !eof {
		t.Fatalf("readdir: eof %v, %v", eof, err)
	}
	if verf != [8]byte{1, 2, 3, 4, 5, 6, 7, 8} {
		t.Fatalf("verifier %x", verf)
	}
	if len(got) != 2 || got[0].Name != "one" || got[0].Cookie != 1 ||
		got[1].Attrs.Type != NF4Dir {
		t.Fatalf("entries %+v", got)
	}
}

func TestWriteAndCreateTruncated(t *testing.T) {
	full := AppendWriteArgs(nil, AllZero, 8, StableFileSync, []byte("abc"))
	// The args without the data length fail: the data is length prefixed
	// and the cut lands inside it.
	if _, _, _, _, err := DecodeWriteArgs(full[4 : len(full)-1]); err == nil {
		t.Fatal("a truncated write body decoded")
	}
	if _, _, _, _, err := DecodeWriteArgs(full[4 : 4+16+8+4]); err == nil {
		t.Fatal("write args without data decoded")
	}
	// A CREATE whose attribute list is cut short fails.
	cre := AppendCreateArgs(nil, NF4Fifo, "p", "", 0, 0, 0o644)
	if _, _, _, _, _, _, err := DecodeCreateArgs(cre[4 : len(cre)-1]); err == nil {
		t.Fatal("a truncated attribute list decoded")
	}
}

func TestNfsTimeOf(t *testing.T) {
	if got := NfsTimeOf(5, 6); got != (NfsTime{5, 6}) {
		t.Fatalf("NfsTimeOf: %+v", got)
	}
}

func TestRemoveAndRenameWire(t *testing.T) {
	remove := AppendRemoveArgs(nil, "victim")
	if op, err := xdr.NewDecoder(remove).Uint32(); err != nil || op != OpRemove {
		t.Fatalf("remove op: %d, %v", op, err)
	}
	if name, err := xdr.NewDecoder(remove[4:]).String(); err != nil || name != "victim" {
		t.Fatalf("remove name: %q, %v", name, err)
	}

	rename := AppendRenameArgs(nil, "old", "new")
	d := xdr.NewDecoder(rename)
	if op, err := d.Uint32(); err != nil || op != OpRename {
		t.Fatalf("rename op: %d, %v", op, err)
	}
	oldName, err := d.String()
	newName, err := d.String()
	if err != nil || oldName != "old" || newName != "new" {
		t.Fatalf("rename names: %q %q, %v", oldName, newName, err)
	}

	// The change info is twenty bytes, the rename result carries two of
	// them, and the measurement walks the wire forms.
	if n, err := resBodyLen(OpRemove, ErrOK, AppendRemoveRes(nil)); err != nil || n != 20 {
		t.Fatalf("remove measure: %d, %v", n, err)
	}
	renameRes := AppendRenameRes(nil)
	if n, err := resBodyLen(OpRename, ErrOK, renameRes); err != nil || n != len(renameRes) {
		t.Fatalf("rename measure: %d of %d, %v", n, len(renameRes), err)
	}
}

func TestDecodeSetattrBlob(t *testing.T) {
	// mode, size, both times, owner and group in one walk.
	request := OfBits(AttrMode, AttrSize, AttrTimeAccessSet, AttrTimeModifySet,
		AttrOwner, AttrOwnerGroup)
	// The values walk the blob in ascending attribute order.
	var blob []byte
	blob = xdr.AppendUint64(blob, 4096)           // size
	blob = xdr.AppendUint32(blob, 0o640)          // mode
	blob = xdr.AppendString(blob, "1000@EXAMPLE") // owner
	blob = xdr.AppendString(blob, "100@EXAMPLE")  // owner group
	blob = xdr.AppendBool(blob, false)            // access: explicit time
	blob = xdr.AppendInt64(blob, 100)
	blob = xdr.AppendUint32(blob, 5)
	blob = xdr.AppendBool(blob, true) // modify: server time

	u, err := DecodeSetattrBlob(blob, request)
	if err != nil {
		t.Fatalf("decode: %v", err)
	}
	if !u.HasMode || u.Mode != 0o640 || !u.HasSize || u.Size != 4096 {
		t.Fatalf("mode and size: %+v", u)
	}
	if u.Atime == nil || u.Atime.Server || u.Atime.Time != (NfsTime{100, 5}) {
		t.Fatalf("atime: %+v", u.Atime)
	}
	if u.Mtime == nil || !u.Mtime.Server {
		t.Fatalf("mtime: %+v", u.Mtime)
	}
	if u.UID == nil || *u.UID != 1000 || u.GID == nil || *u.GID != 100 {
		t.Fatalf("owner: uid %v gid %v", u.UID, u.GID)
	}

	// A non numeric owner is refused, not silently dropped.
	blob = xdr.AppendString(OfBits(AttrOwner).AppendTo(nil), "petr@EXAMPLE")
	if _, err := DecodeSetattrBlob(blob, OfBits(AttrOwner)); err == nil {
		t.Fatal("a non numeric owner decoded")
	}
	// An attribute the server cannot set stops the walk.
	blob = append(xdr.AppendUint32(nil, 0), xdr.AppendUint32(nil, 0)...)
	if _, err := DecodeSetattrBlob(blob, OfBits(AttrRawDev)); !errors.Is(err, ErrAttrNotSettable) {
		t.Fatalf("rawdev: %v", err)
	}
}

func TestSetattrAndLinkWire(t *testing.T) {
	args := AppendSetattrArgs(nil, AllZero, OfBits(AttrMode), Attrs{Mode: 0o600})
	// stateid first, then the fattr4: bitmap then length prefixed blob.
	d := xdr.NewDecoder(args[4:])
	if _, err := d.Raw(16); err != nil {
		t.Fatalf("stateid: %v", err)
	}
	if _, err := ReadBitmap(d); err != nil {
		t.Fatalf("bitmap: %v", err)
	}
	if _, err := d.VarOpaque(); err != nil {
		t.Fatalf("blob: %v", err)
	}

	res := AppendSetattrRes(nil, OfBits(AttrMode, AttrSize))
	attrsset, err := ReadBitmap(xdr.NewDecoder(res))
	if err != nil || !attrsset.Has(AttrMode) || !attrsset.Has(AttrSize) {
		t.Fatalf("attrsset: %v, %v", attrsset.Words(), err)
	}
	if n, err := resBodyLen(OpSetattr, ErrOK, res); err != nil || n != len(res) {
		t.Fatalf("setattr measure: %d of %d, %v", n, len(res), err)
	}

	link := AppendLinkArgs(nil, "newname")
	if op, err := xdr.NewDecoder(link).Uint32(); err != nil || op != OpLink {
		t.Fatalf("link op: %d, %v", op, err)
	}
	if name, err := xdr.NewDecoder(link[4:]).String(); err != nil || name != "newname" {
		t.Fatalf("link name: %q, %v", name, err)
	}
	linkRes := AppendLinkRes(nil)
	if n, err := resBodyLen(OpLink, ErrOK, linkRes); err != nil || n != len(linkRes) {
		t.Fatalf("link measure: %d of %d, %v", n, len(linkRes), err)
	}
}

func TestSetattrUpdatesWire(t *testing.T) {
	uid, gid := uint32(1000), uint32(100)
	u := SetAttrUpdates{
		HasMode: true, Mode: 0o640,
		HasSize: true, Size: 8192,
		UID:   &uid,
		GID:   &gid,
		Atime: &NfsTimeSet{Server: true},
		Mtime: &NfsTimeSet{Time: NfsTime{1_000_000_000, 7}},
	}
	arg := AppendSetattrArgsUpdates(nil, AllZero, u)

	d := xdr.NewDecoder(arg)
	if op, err := d.Uint32(); err != nil || op != OpSetattr {
		t.Fatalf("op: %d, %v", op, err)
	}
	raw, err := d.Raw(16)
	if err != nil || !bytes.Equal(raw, AllZero[:]) {
		t.Fatalf("stateid: %x, %v", raw, err)
	}
	request, err := ReadBitmap(d)
	blob, err := d.VarOpaque()
	if err != nil {
		t.Fatalf("fattr: %v", err)
	}
	for _, want := range []uint32{AttrMode, AttrSize, AttrOwner, AttrOwnerGroup,
		AttrTimeAccessSet, AttrTimeModifySet} {
		if !request.Has(want) {
			t.Fatalf("the bitmap misses attribute %d", want)
		}
	}
	got, err := DecodeSetattrBlob(blob, request)
	if err != nil {
		t.Fatalf("decode: %v", err)
	}
	if !got.HasMode || got.Mode != u.Mode || !got.HasSize || got.Size != u.Size {
		t.Fatalf("mode and size: %+v", got)
	}
	if got.UID == nil || *got.UID != uid || got.GID == nil || *got.GID != gid {
		t.Fatalf("owner: %v %v", got.UID, got.GID)
	}
	if got.Atime == nil || !got.Atime.Server {
		t.Fatalf("atime: %+v", got.Atime)
	}
	if got.Mtime == nil || got.Mtime.Server || got.Mtime.Time != u.Mtime.Time {
		t.Fatalf("mtime: %+v", got.Mtime)
	}
}

func TestReadlinkAndCommitWire(t *testing.T) {
	link := AppendReadlinkArgs(nil)
	if op, err := xdr.NewDecoder(link).Uint32(); err != nil || op != OpReadlink {
		t.Fatalf("readlink op: %d, %v", op, err)
	}
	res := AppendReadlinkRes(nil, "target.txt")
	got, err := xdr.NewDecoder(res).String()
	if err != nil || got != "target.txt" {
		t.Fatalf("readlink res: %q, %v", got, err)
	}
	if n, err := resBodyLen(OpReadlink, ErrOK, res); err != nil || n != len(res) {
		t.Fatalf("readlink measure: %d of %d, %v", n, len(res), err)
	}

	commit := AppendCommitArgs(nil, 512, 1024, [8]byte{7, 7, 7, 7, 7, 7, 7, 7})
	d := xdr.NewDecoder(commit)
	if op, err := d.Uint32(); err != nil || op != OpCommit {
		t.Fatalf("commit op: %d, %v", op, err)
	}
	d = xdr.NewDecoder(commit[4:])
	off, err := d.Uint64()
	count, err := d.Uint32()
	verf, err := d.Raw(8)
	if err != nil || off != 512 || count != 1024 || verf[0] != 7 {
		t.Fatalf("commit args: %d %d %x, %v", off, count, verf, err)
	}
	commitRes := AppendCommitRes(nil, [8]byte{1, 2, 3, 4, 5, 6, 7, 8})
	if n, err := resBodyLen(OpCommit, ErrOK, commitRes); err != nil || n != 8 {
		t.Fatalf("commit measure: %d, %v", n, err)
	}
	gotVerf, err := xdr.NewDecoder(commitRes).Raw(8)
	if err != nil || gotVerf[7] != 8 {
		t.Fatalf("commit res: %x, %v", gotVerf, err)
	}
}

func TestSecinfoWire(t *testing.T) {
	args := AppendSecinfoArgs(nil, "a.txt")
	if op, err := xdr.NewDecoder(args).Uint32(); err != nil || op != OpSecinfo {
		t.Fatalf("secinfo op: %d, %v", op, err)
	}
	if name, err := xdr.NewDecoder(args[4:]).String(); err != nil || name != "a.txt" {
		t.Fatalf("secinfo name: %q, %v", name, err)
	}

	// The no name argument is the style enum alone: four bytes and
	// nothing after them, RFC 7863.
	noname := AppendSecinfoNoNameArgs(nil, StyleCurrentFH)
	if len(noname) != 8 {
		t.Fatalf("no name args of %d bytes, want 8", len(noname))
	}
	d := xdr.NewDecoder(noname)
	if op, err := d.Uint32(); err != nil || op != OpSecinfoNoName {
		t.Fatalf("no name op: %d, %v", op, err)
	}
	style, err := DecodeSecinfoNoNameArgs(d)
	if err != nil || style != StyleCurrentFH || d.Remaining() != 0 {
		t.Fatalf("no name style %d, %v", style, err)
	}
	if _, err := DecodeSecinfoNoNameArgs(xdr.NewDecoder(xdr.AppendUint32(nil, 5))); err == nil {
		t.Fatal("an unknown style accepted")
	}

	// The result: one word per flavour, the rpcsec_gss_info body only on
	// the RPCSEC_GSS branch, RFC 7863.
	res := AppendSecinfoRes(nil, []SecinfoEntry{{Flavor: SecFlavorSys}})
	if len(res) != 8 {
		t.Fatalf("auth_sys entry of %d bytes, want 8", len(res))
	}
	entries, err := DecodeSecinfoRes(res)
	if err != nil || len(entries) != 1 || entries[0].Flavor != SecFlavorSys ||
		entries[0].GSS != nil {
		t.Fatalf("secinfo res: %+v, %v", entries, err)
	}
	if n, err := resBodyLen(OpSecinfo, ErrOK, res); err != nil || n != len(res) {
		t.Fatalf("secinfo measure: %d of %d, %v", n, len(res), err)
	}
	gssRes := AppendSecinfoRes(nil, []SecinfoEntry{
		{Flavor: SecFlavorSys},
		{Flavor: SecFlavorGSS, GSS: &GSSInfo{OID: []byte{0x2a}, QOP: 0, Service: 1}},
	})
	entries, err = DecodeSecinfoRes(gssRes)
	if err != nil || len(entries) != 2 || entries[1].GSS == nil ||
		len(entries[1].GSS.OID) != 1 || entries[1].GSS.Service != 1 {
		t.Fatalf("gss entry: %+v, %v", entries, err)
	}
	if n, err := resBodyLen(OpSecinfoNoName, ErrOK, gssRes); err != nil || n != len(gssRes) {
		t.Fatalf("no name measure: %d of %d, %v", n, len(gssRes), err)
	}
}

func TestDecodeLocktDeniedCompound(t *testing.T) {
	var ops [][]byte
	ops = append(ops, append(AppendOpHeader(nil, OpSequence, ErrOK), make([]byte, 36)...))
	ops = append(ops, AppendOpHeader(nil, OpPutRootfh, ErrOK))
	deniedBody := AppendLocktResDenied(AppendOpHeader(nil, OpLockt, ErrDenied),
		0, 100, LockTypeWrite, 0x1111, []byte("locker-a"))
	ops = append(ops, deniedBody)

	payload := AppendCompoundRes(nil, ErrDenied, "t", ops)
	res, bodies, err := DecodeCompoundResBodies(payload)
	if err != nil {
		t.Fatalf("decode: %v", err)
	}
	if res.Status != ErrDenied || len(res.Ops) != 3 {
		t.Fatalf("res: status %d ops %d", res.Status, len(res.Ops))
	}
	for i, op := range res.Ops {
		t.Logf("op %d: op=%d status=%d bodylen=%d", i, op.Op, op.Status, len(bodies[i]))
	}
	if len(bodies[2]) == 0 {
		t.Fatal("the denied body is empty")
	}
	got, err := DecodeLocktResBody(res.Status, bodies[2])
	if err != nil {
		t.Fatalf("denied decode: %v", err)
	}
	if got.ClientID != 0x1111 || got.LockType != LockTypeWrite || got.Length != 100 {
		t.Fatalf("denied: %+v", got)
	}
}

func TestLockWire(t *testing.T) {
	openSt := AllZero
	arg := AppendLockArgsNew(nil, openSt, 0x1111, []byte("owner"), LockTypeWrite, false, 8, 16)
	d := xdr.NewDecoder(arg)
	if op, err := d.Uint32(); err != nil || op != OpLock {
		t.Fatalf("op: %d, %v", op, err)
	}
	if lt, err := d.Uint32(); err != nil || lt != LockTypeWrite {
		t.Fatalf("locktype: %v", err)
	}
	if reclaim, err := d.Bool(); err != nil || reclaim {
		t.Fatal("reclaim set")
	}
	if off, err := d.Uint64(); err != nil || off != 8 {
		t.Fatalf("offset: %v", err)
	}
	if length, err := d.Uint64(); err != nil || length != 16 {
		t.Fatalf("length: %v", err)
	}
	if newOwner, err := d.Bool(); err != nil || !newOwner {
		t.Fatal("new owner flag missing")
	}
	if _, err := d.Uint32(); err != nil { // open seqid
		t.Fatal(err)
	}
	if raw, err := d.Raw(16); err != nil || !bytes.Equal(raw, openSt[:]) {
		t.Fatal("open stateid mismatch")
	}
	if _, err := d.Uint32(); err != nil { // lock seqid
		t.Fatal(err)
	}
	if clientid, err := d.Uint64(); err != nil || clientid != 0x1111 {
		t.Fatalf("clientid: %v", err)
	}
	if owner, err := d.VarOpaque(); err != nil || string(owner) != "owner" {
		t.Fatalf("owner: %q, %v", owner, err)
	}

	existing := AppendLockArgsExisting(nil, AllZero, LockTypeRead, 0, 32)
	d = xdr.NewDecoder(existing[4:])
	if _, err := d.Uint32(); err != nil { // lock type
		t.Fatal(err)
	}
	if reclaim, err := d.Bool(); err != nil || reclaim {
		t.Fatal("existing lock marked as reclaim")
	}
	if off, err := d.Uint64(); err != nil || off != 0 {
		t.Fatalf("offset: %v", err)
	}
	if length, err := d.Uint64(); err != nil || length != 32 {
		t.Fatalf("length: %v", err)
	}
	if newOwner, err := d.Bool(); err != nil || newOwner {
		t.Fatal("existing lock carried the new owner form")
	}
	if _, err := d.Raw(16); err != nil {
		t.Fatal(err)
	}
	if _, err := d.Uint32(); err != nil { // lock seqid
		t.Fatal(err)
	}

	var lockSt Stateid
	lockSt[4], lockSt[5], lockSt[6], lockSt[7] = 'L', 'O', 'C', 'K'
	lockRes := AppendLockRes(nil, lockSt)
	if n, err := resBodyLen(OpLock, ErrOK, lockRes); err != nil || n != 16 {
		t.Fatalf("lock measure: %d, %v", n, err)
	}

	lockt := AppendLocktArgs(nil, LockTypeRead, 0, 64, 0x2222, []byte("prober"))
	d = xdr.NewDecoder(lockt[4:])
	if lt, err := d.Uint32(); err != nil || lt != LockTypeRead {
		t.Fatalf("lockt type: %v", err)
	}
	if _, err := d.Uint64(); err != nil {
		t.Fatal(err)
	}
	if _, err := d.Uint64(); err != nil {
		t.Fatal(err)
	}
	if cid, err := d.Uint64(); err != nil || cid != 0x2222 {
		t.Fatalf("lockt clientid: %v", err)
	}
	if owner, err := d.VarOpaque(); err != nil || string(owner) != "prober" {
		t.Fatalf("lockt owner: %q, %v", owner, err)
	}

	denied := AppendLocktResDenied(nil, 0, 100, LockTypeWrite, 0x3333, []byte("holder"))
	got, err := DecodeLocktResBody(ErrDenied, denied)
	if err != nil || got.Offset != 0 || got.Length != 100 ||
		got.LockType != LockTypeWrite || got.ClientID != 0x3333 ||
		string(got.Owner) != "holder" {
		t.Fatalf("denied: %+v, %v", got, err)
	}
	if n, err := resBodyLenLockt(ErrDenied, denied); err != nil || n != len(denied) {
		t.Fatalf("lockt measure: %d of %d, %v", n, len(denied), err)
	}
	if _, err := resBodyLenLockt(ErrDenied, []byte{0, 0, 0, 0, 0, 0, 0, 0}); err == nil {
		t.Fatal("a truncated denied body measured without error")
	}
}