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

package nfs4server

import (
	"bytes"
	"testing"

	"sourcedock.dev/petrbalvin/nfs/internal/nfs4"
	"sourcedock.dev/petrbalvin/nfs/internal/xdr"
)

// GETDEVICELIST answers the one device of this build for any layout
// type; LAYOUTGET accepts the emulated families and returns their wire
// bodies.
func TestEmulatedLayoutFamilies(t *testing.T) {
	h := testTree(t)
	sid, seq := newSession(t, h)
	run := func(s uint32, ops [][]byte) (nfs4.CompoundRes, [][]byte) {
		t.Helper()
		all := append([][]byte{nfs4.AppendSequenceArgs(nil, sid, s, 0, defaultSlots-1, true)}, ops...)
		payload := nfs4.AppendCompoundArgs(nil, "fam", nfs4.MinorVersion, all)
		body, ok := h.compound(payload, cred{uid: 0, gid: 0})
		if !ok {
			t.Fatal("garbage")
		}
		r, bodies, derr := nfs4.DecodeCompoundResBodies(body)
		if derr != nil {
			t.Fatalf("decode: %v", derr)
		}
		return r, bodies[1:]
	}

	seq++
	res, bodies := run(seq, [][]byte{
		nfs4.AppendPutRootfh(nil),
		nfs4.AppendGetattr(nil, nfs4.OfBits(nfs4.AttrType)),
		nfs4.AppendGetDeviceListArgs(nil, nfs4.LayoutTypeFlexfiles, 8, 0, [8]byte{}),
	})
	wantStatus(t, "open", res.Status, nfs4.ErrOK)
	seq++
	res, bodies = run(seq, [][]byte{
		nfs4.AppendGetDeviceListArgs(nil, nfs4.LayoutTypeFlexfiles, 8, 0, [8]byte{}),
	})
	wantStatus(t, "device list", res.Status, nfs4.ErrOK)
	gd := xdr.NewDecoder(bodies[0])
	if cookie, cerr := gd.Uint64(); cerr != nil || cookie != 0 {
		t.Fatalf("cookie %d", cookie)
	}
	if _, cerr := gd.Raw(8); cerr != nil { // verifier
		t.Fatal(cerr)
	}
	n, cerr := gd.Uint32()
	if cerr != nil || n != 1 {
		t.Fatalf("devices %d: %v", n, cerr)
	}
	raw, _ := gd.Raw(16)
	if !bytes.Equal(raw, layoutDeviceID[:]) {
		t.Fatalf("device % x", raw)
	}
	if eof, _ := gd.Bool(); !eof {
		t.Fatal("eof false")
	}

	// The files layout body decodes with its device and fh list.
	openSt := nfs4.Stateid{}
	seq++
	res, bodies = run(seq, [][]byte{
		nfs4.AppendPutRootfh(nil),
		nfs4.AppendOpenArgs(nil, 0x8888, []byte("fam"), nfs4.ShareAccessRead, 0, false, 0, "a.txt"),
		nfs4.AppendGetfh(nil),
	})
	wantStatus(t, "open", res.Status, nfs4.ErrOK)
	copy(openSt[:], bodies[1])
	fh, _ := xdr.NewDecoder(bodies[2]).VarOpaque()
	seq++
	res, bodies = run(seq, [][]byte{
		nfs4.AppendPutfh(nil, fh),
		nfs4.AppendLayoutGetArgs(nil, false, nfs4.LayoutTypeFiles, nfs4.IoModeRead, 0, ^uint64(0), 0, openSt, 1<<16),
	})
	wantStatus(t, "files layoutget", res.Status, nfs4.ErrOK)
	ld := xdr.NewDecoder(bodies[1])
	var st nfs4.Stateid
	raw, _ = ld.Raw(16)
	copy(st[:], raw)
	if !bytes.HasPrefix(st[4:], []byte("LAYOUT")) {
		t.Fatalf("stateid % x", st[4:])
	}
	if _, _ = ld.Bool(); ld.Remaining() == 0 {
		t.Fatal("no layout segments")
	}
	if n, _ := ld.Uint32(); n != 1 { // the segment count
		t.Fatalf("segment count %d", n)
	}
	if _, _ = ld.Uint64(); ld.Remaining() == 0 { // offset
		t.Fatal("short segment")
	}
	if _, _ = ld.Uint64(); ld.Remaining() == 0 { // length
		t.Fatal("short segment")
	}
	if _, _ = ld.Uint32(); ld.Remaining() == 0 { // iomode
		t.Fatal("short segment")
	}
	if _, _ = ld.Uint32(); ld.Remaining() == 0 { // type
		t.Fatal("short segment")
	}
	flex, ferr := ld.VarOpaque()
	if ferr != nil {
		t.Fatal(ferr)
	}
	// The files layout body: device, util, first stripe, pattern offset,
	// the fh list with the file's own handle.
	fd := xdr.NewDecoder(flex)
	dev, _ := fd.Raw(16)
	if !bytes.Equal(dev, layoutDeviceID[:]) {
		t.Fatalf("body device % x len %d", dev, len(flex))
	}
	if _, _ = fd.Uint32(); fd.Remaining() == 0 { // util
		t.Fatal("short files body")
	}
	if _, _ = fd.Uint32(); fd.Remaining() == 0 { // first stripe
		t.Fatal("short files body")
	}
	if _, _ = fd.Uint64(); fd.Remaining() == 0 { // pattern offset
		t.Fatal("short files body")
	}
	fn, _ := fd.Uint32()
	if fn != 1 {
		t.Fatalf("fh list %d", fn)
	}
	if got, _ := fd.VarOpaque(); !bytes.Equal(got, fh) {
		t.Fatalf("fh % x", got)
	}

	// The block, objects and SCSI families answer the same way with
	// their own bodies; the emulated device is always this server.
	for _, typ := range []uint32{nfs4.LayoutTypeFlexFilesV2, nfs4.LayoutTypeBlock, nfs4.LayoutTypeObjects, nfs4.LayoutTypeScsi} {
		seq++
		res, bodies = run(seq, [][]byte{
			nfs4.AppendPutfh(nil, fh),
			nfs4.AppendLayoutGetArgs(nil, false, typ, nfs4.IoModeRead, 0, ^uint64(0), 0, openSt, 1<<16),
		})
		if res.Status != nfs4.ErrOK {
			t.Fatalf("family %d: status %d", typ, res.Status)
		}
	}
}

// LAYOUTGET of the flexfiles version 2 type answers the version two
// body: the data server with its stateid array, the file handle and the
// AUTH_NONE credential of tight coupling.
func TestFlexFilesV2LayoutGet(t *testing.T) {
	h := testTree(t)
	sid, seq := newSession(t, h)
	run := func(s uint32, ops [][]byte) (nfs4.CompoundRes, [][]byte) {
		t.Helper()
		all := append([][]byte{nfs4.AppendSequenceArgs(nil, sid, s, 0, defaultSlots-1, true)}, ops...)
		payload := nfs4.AppendCompoundArgs(nil, "ffv2", nfs4.MinorVersion, all)
		body, ok := h.compound(payload, cred{uid: 0, gid: 0})
		if !ok {
			t.Fatal("garbage")
		}
		r, bodies, derr := nfs4.DecodeCompoundResBodies(body)
		if derr != nil {
			t.Fatalf("decode: %v", derr)
		}
		return r, bodies[1:]
	}

	seq++
	res, bodies := run(seq, [][]byte{
		nfs4.AppendPutRootfh(nil),
		nfs4.AppendOpenArgs(nil, 0x9999, []byte("ffv2"), nfs4.ShareAccessRead, 0, false, 0, "a.txt"),
		nfs4.AppendGetfh(nil),
	})
	wantStatus(t, "open", res.Status, nfs4.ErrOK)
	var openSt nfs4.Stateid
	copy(openSt[:], bodies[1])
	fh, _ := xdr.NewDecoder(bodies[2]).VarOpaque()

	seq++
	res, bodies = run(seq, [][]byte{
		nfs4.AppendPutfh(nil, fh),
		nfs4.AppendLayoutGetArgs(nil, false, nfs4.LayoutTypeFlexFilesV2,
			nfs4.IoModeRead, 0, ^uint64(0), 0, openSt, 1<<16),
	})
	wantStatus(t, "ffv2 layoutget", res.Status, nfs4.ErrOK)
	ld := xdr.NewDecoder(bodies[1])
	var st nfs4.Stateid
	raw, _ := ld.Raw(16)
	copy(st[:], raw)
	if !bytes.HasPrefix(st[4:], []byte("LAYOUT")) {
		t.Fatalf("stateid % x", st[4:])
	}
	if _, _ = ld.Bool(); ld.Remaining() == 0 {
		t.Fatal("no segments")
	}
	if n, _ := ld.Uint32(); n != 1 {
		t.Fatalf("segments %d", n)
	}
	if _, _ = ld.Uint64(); ld.Remaining() == 0 { // offset
		t.Fatal("short segment")
	}
	if _, _ = ld.Uint64(); ld.Remaining() == 0 { // length
		t.Fatal("short segment")
	}
	if _, _ = ld.Uint32(); ld.Remaining() == 0 { // iomode
		t.Fatal("short segment")
	}
	if typ, _ := ld.Uint32(); typ != nfs4.LayoutTypeFlexFilesV2 {
		t.Fatalf("segment type %d", typ)
	}
	v2, verr := ld.VarOpaque()
	if verr != nil {
		t.Fatal(verr)
	}
	fd := xdr.NewDecoder(v2)
	if su, err := fd.Uint64(); err != nil || su != 0 {
		t.Fatalf("stripe unit %d: %v", su, err)
	}
	if n, err := fd.Uint32(); err != nil || n != 1 {
		t.Fatalf("mirrors %d: %v", n, err)
	}
	if n, err := fd.Uint32(); err != nil || n != 1 {
		t.Fatalf("servers %d: %v", n, err)
	}
	raw, _ = fd.Raw(16)
	if !bytes.Equal(raw, layoutDeviceID[:]) {
		t.Fatalf("device % x", raw)
	}
	if eff, err := fd.Uint32(); err != nil || eff != 0 {
		t.Fatalf("efficiency %d: %v", eff, err)
	}
	if n, err := fd.Uint32(); err != nil || n != 1 {
		t.Fatalf("stateids %d: %v", n, err)
	}
	raw, _ = fd.Raw(16)
	if !bytes.Equal(raw, st[:]) {
		t.Fatalf("v2 stateid % x want % x", raw, st[:])
	}
	if n, err := fd.Uint32(); err != nil || n != 1 {
		t.Fatalf("fhs %d: %v", n, err)
	}
	if v2fh, err := fd.VarOpaque(); err != nil || !bytes.Equal(v2fh, fh) {
		t.Fatalf("v2 fh % x", v2fh)
	}
	if _, _ = fd.String(); fd.Remaining() == 0 { // user
		t.Fatal("short v2 body")
	}
	if _, _ = fd.String(); fd.Remaining() == 0 { // group
		t.Fatal("short v2 body")
	}
	if flavor, err := fd.Uint32(); err != nil || flavor != 0 {
		t.Fatalf("auth flavor %d: %v", flavor, err)
	}
	if authBody, err := fd.VarOpaque(); err != nil || len(authBody) != 0 {
		t.Fatalf("auth body % x", authBody)
	}

	// GETDEVICEINFO and GETDEVICELIST accept the version two type.
	seq++
	res, _ = run(seq, [][]byte{
		nfs4.AppendPutfh(nil, fh),
		nfs4.AppendGetDeviceInfoArgs(nil, layoutDeviceID,
			nfs4.LayoutTypeFlexFilesV2, 1<<16, nfs4.Bitmap{}),
	})
	wantStatus(t, "ffv2 deviceinfo", res.Status, nfs4.ErrOK)
	seq++
	res, _ = run(seq, [][]byte{
		nfs4.AppendGetDeviceListArgs(nil, nfs4.LayoutTypeFlexFilesV2, 8, 0, [8]byte{}),
	})
	wantStatus(t, "ffv2 devicelist", res.Status, nfs4.ErrOK)
}