// 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"
)

// layoutStateidOf pulls the layout stateid out of a LAYOUTGET response
// body and checks the response shape.
func layoutStateidOf(t *testing.T, body []byte) nfs4.Stateid {
	t.Helper()
	d := xdr.NewDecoder(body)
	var st nfs4.Stateid
	raw, err := d.Raw(16)
	if err != nil {
		t.Fatalf("layout stateid: %v", err)
	}
	copy(st[:], raw)
	roc, err := d.Bool()
	if err != nil || roc {
		t.Fatalf("return on close %v: %v", roc, err)
	}
	n, err := d.Uint32()
	if err != nil || n != 1 {
		t.Fatalf("layout count %d: %v", n, err)
	}
	if _, err = d.Uint64(); err != nil { // offset
		t.Fatal(err)
	}
	if _, err = d.Uint64(); err != nil { // length
		t.Fatal(err)
	}
	if mode, err := d.Uint32(); err != nil || mode != nfs4.IoModeRW {
		t.Fatalf("iomode %d: %v", mode, err)
	}
	if typ, err := d.Uint32(); err != nil || typ != nfs4.LayoutTypeFlexfiles {
		t.Fatalf("type %d: %v", typ, err)
	}
	flex, err := d.VarOpaque()
	if err != nil {
		t.Fatal(err)
	}
	fd := xdr.NewDecoder(flex)
	if stripe, err := fd.Uint64(); err != nil || stripe != 0 {
		t.Fatalf("stripe unit: %v", err)
	}
	if mirrors, err := fd.Uint32(); err != nil || mirrors != 1 {
		t.Fatalf("mirrors %d: %v", mirrors, err)
	}
	if servers, err := fd.Uint32(); err != nil || servers != 1 {
		t.Fatalf("data servers %d: %v", servers, err)
	}
	var device [16]byte
	raw, rerr := fd.Raw(16)
	if rerr != nil {
		t.Fatal(rerr)
	}
	copy(device[:], raw)
	if device != layoutDeviceID {
		t.Fatalf("device id % x", device[:])
	}
	if _, err = fd.Uint32(); err != nil { // efficiency
		t.Fatal(err)
	}
	raw, rerr = fd.Raw(16)
	if rerr != nil {
		t.Fatal(rerr)
	}
	if !bytes.Equal(raw, st[:]) {
		t.Fatalf("data server stateid % x, want % x", raw, st[:])
	}
	fhCount, ferr := fd.Uint32()
	if ferr != nil || fhCount != 1 {
		t.Fatalf("file handle count %d: %v", fhCount, ferr)
	}
	if _, err = fd.VarOpaque(); err != nil { // the data server file handle
		t.Fatal(err)
	}
	return st
}

func TestPnfsLayoutLifecycle(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, "pnfs", 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)
		}
		if len(r.Ops) != len(all) {
			t.Fatalf("ops %d, want %d", len(r.Ops), len(all))
		}
		return r, bodies[1:]
	}

	// Open (create) the file the layout will hang from.
	res, bodies := run(seq, [][]byte{
		nfs4.AppendPutRootfh(nil),
		nfs4.AppendOpenArgs(nil, 0x2222, []byte("pnfs-owner"),
			nfs4.ShareAccessBoth, 0, true, 0o644, "lay.txt"),
		nfs4.AppendGetfh(nil),
	})
	if res.Status != nfs4.ErrOK {
		t.Fatalf("open: status %d", res.Status)
	}
	var openSt nfs4.Stateid
	copy(openSt[:], bodies[1])
	fh, err := xdr.NewDecoder(bodies[2]).VarOpaque()
	if err != nil || len(fh) == 0 {
		t.Fatalf("file handle: %v", err)
	}

	// LAYOUTGET grants one flexfiles segment naming this server as the
	// data server.
	seq++
	res, bodies = run(seq, [][]byte{
		nfs4.AppendPutfh(nil, fh),
		nfs4.AppendLayoutGetArgs(nil, false, nfs4.LayoutTypeFlexfiles,
			nfs4.IoModeRW, 0, ^uint64(0), 0, openSt, 1<<16),
	})
	wantStatus(t, "layout get", res.Status, nfs4.ErrOK)
	layoutSt := layoutStateidOf(t, bodies[1])
	if !bytes.HasPrefix(layoutSt[4:], []byte("LAYOUT")) {
		t.Fatalf("layout stateid other % x", layoutSt[4:])
	}
	if h.layouts().count() != 1 {
		t.Fatalf("layouts %d, want 1", h.layouts().count())
	}

	// GETDEVICEINFO refuses an unknown device and answers the address of
	// the one device this server carries.
	seq++
	res, _ = run(seq, [][]byte{
		nfs4.AppendPutfh(nil, fh),
		nfs4.AppendGetDeviceInfoArgs(nil, [16]byte{7}, nfs4.LayoutTypeFlexfiles, 1<<16, nfs4.Bitmap{}),
	})
	wantStatus(t, "unknown device", res.Status, nfs4.ErrNoEnt)
	seq++
	res, bodies = run(seq, [][]byte{
		nfs4.AppendPutfh(nil, fh),
		nfs4.AppendGetDeviceInfoArgs(nil, layoutDeviceID, nfs4.LayoutTypeFlexfiles, 1<<16, nfs4.Bitmap{}),
	})
	wantStatus(t, "device info", res.Status, nfs4.ErrOK)
	d := xdr.NewDecoder(bodies[1])
	if typ, derr := d.Uint32(); derr != nil || typ != nfs4.LayoutTypeFlexfiles {
		t.Fatalf("address type %d: %v", typ, derr)
	}
	blob, derr := d.VarOpaque()
	if derr != nil {
		t.Fatal(derr)
	}
	addr, derr := nfs4.DecodeFlexDeviceAddr(blob)
	if derr != nil {
		t.Fatalf("decode address: %v", derr)
	}
	if len(addr.NetAddrs) != 1 || addr.NetAddrs[0].Netid != "tcp" || addr.NetAddrs[0].Uaddr == "" {
		t.Fatalf("net addresses %+v", addr.NetAddrs)
	}
	if len(addr.Versions) != 1 || addr.Versions[0].Version != 4 || addr.Versions[0].MinorVersion != nfs4.MinorVersion {
		t.Fatalf("versions %+v", addr.Versions)
	}

	// LAYOUTCOMMIT with a last write beyond the size grows the file.
	seq++
	res, bodies = run(seq, [][]byte{
		nfs4.AppendPutfh(nil, fh),
		nfs4.AppendLayoutCommitArgs(nil, 0, ^uint64(0), false, layoutSt, true, 100, false, 0, 0, 0, nil),
	})
	wantStatus(t, "layout commit", res.Status, nfs4.ErrOK)
	cd := xdr.NewDecoder(bodies[1])
	if changed, cerr := cd.Bool(); cerr != nil || !changed {
		t.Fatalf("size changed %v: %v", changed, cerr)
	}
	if size, cerr := cd.Uint64(); cerr != nil || size != 101 {
		t.Fatalf("new size %d: %v", size, cerr)
	}
	info, gerr := h.FS.Getattr(fh)
	if gerr != nil || info.Size != 101 {
		t.Fatalf("backend size %d: %v", info.Size, gerr)
	}

	// A layout get with an anonymous stateid has no open behind it.
	allOnes := nfs4.Stateid{}
	for i := range allOnes {
		allOnes[i] = 0xff
	}
	seq++
	res, _ = run(seq, [][]byte{
		nfs4.AppendPutfh(nil, fh),
		nfs4.AppendLayoutGetArgs(nil, false, nfs4.LayoutTypeFlexfiles,
			nfs4.IoModeRW, 0, ^uint64(0), 0, allOnes, 1<<16),
	})
	wantStatus(t, "layout get without open", res.Status, nfs4.ErrBadStateid)

	// An unknown layout type and a bogus IO mode are refused before any
	// state is touched. The block layout is one of the emulated families,
	// so the probe uses a type nothing supports.
	seq++
	res, _ = run(seq, [][]byte{
		nfs4.AppendPutfh(nil, fh),
		nfs4.AppendLayoutGetArgs(nil, false, 99,
			nfs4.IoModeRW, 0, ^uint64(0), 0, openSt, 1<<16),
	})
	wantStatus(t, "unknown layout type", res.Status, nfs4.ErrUnknownLayoutType)
	seq++
	res, _ = run(seq, [][]byte{
		nfs4.AppendPutfh(nil, fh),
		nfs4.AppendLayoutGetArgs(nil, false, nfs4.LayoutTypeFlexfiles,
			0, 0, ^uint64(0), 0, openSt, 1<<16),
	})
	wantStatus(t, "bad iomode", res.Status, nfs4.ErrBadIOMode)

	// LAYOUTRETURN of the file drops the layout; the commit under the
	// returned stateid is refused afterwards.
	seq++
	res, bodies = run(seq, [][]byte{
		nfs4.AppendPutfh(nil, fh),
		nfs4.AppendLayoutReturnFileArgs(nil, false, nfs4.LayoutTypeFlexfiles,
			nfs4.IoModeRW, 0, ^uint64(0), layoutSt),
	})
	wantStatus(t, "layout return", res.Status, nfs4.ErrOK)
	rd := xdr.NewDecoder(bodies[1])
	if returned, rerr := rd.Bool(); rerr != nil || !returned {
		t.Fatalf("returned %v: %v", returned, rerr)
	}
	if h.layouts().count() != 0 {
		t.Fatalf("layouts %d after return, want 0", h.layouts().count())
	}
	seq++
	res, _ = run(seq, [][]byte{
		nfs4.AppendPutfh(nil, fh),
		nfs4.AppendLayoutCommitArgs(nil, 0, ^uint64(0), false, layoutSt, false, 0, false, 0, 0, 0, nil),
	})
	wantStatus(t, "layout commit after return", res.Status, nfs4.ErrBadStateid)

	// A whole client return drops every layout of the session.
	seq++
	res, _ = run(seq, [][]byte{
		nfs4.AppendPutfh(nil, fh),
		nfs4.AppendLayoutGetArgs(nil, false, nfs4.LayoutTypeFlexfiles,
			nfs4.IoModeRW, 0, ^uint64(0), 0, openSt, 1<<16),
	})
	wantStatus(t, "layout get again", res.Status, nfs4.ErrOK)
	seq++
	res, _ = run(seq, [][]byte{
		nfs4.AppendPutfh(nil, fh),
		nfs4.AppendLayoutReturnArgs(nil, false, nfs4.LayoutTypeFlexfiles,
			nfs4.IoModeRW, nfs4.ReturnAll),
	})
	wantStatus(t, "layout return all", res.Status, nfs4.ErrOK)
	if h.layouts().count() != 0 {
		t.Fatalf("layouts %d after whole client return, want 0", h.layouts().count())
	}

	// DESTROY_SESSION drops the layouts the session still holds.
	seq++
	res, _ = run(seq, [][]byte{
		nfs4.AppendPutfh(nil, fh),
		nfs4.AppendLayoutGetArgs(nil, false, nfs4.LayoutTypeFlexfiles,
			nfs4.IoModeRW, 0, ^uint64(0), 0, openSt, 1<<16),
	})
	wantStatus(t, "layout get before destroy", res.Status, nfs4.ErrOK)
	if h.layouts().count() != 1 {
		t.Fatalf("layouts %d, want 1", h.layouts().count())
	}
	payload := nfs4.AppendCompoundArgs(nil, "pnfs", nfs4.MinorVersion,
		[][]byte{nfs4.AppendDestroySessionArgs(nil, sid)})
	body, ok := h.compound(payload, cred{uid: 0, gid: 0})
	if !ok {
		t.Fatal("garbage destroy")
	}
	dres, _, derr := nfs4.DecodeCompoundResBodies(body)
	if derr != nil || dres.Status != nfs4.ErrOK {
		t.Fatalf("destroy session: status %d %v", dres.Status, derr)
	}
	if h.layouts().count() != 0 {
		t.Fatalf("layouts %d after destroy, want 0", h.layouts().count())
	}
}

func TestUaddrOf(t *testing.T) {
	t.Parallel()
	cases := []struct {
		in   string
		want string
	}{
		{"127.0.0.1:2049", "127.0.0.1.8.1"},
		{"192.168.1.5:65535", "192.168.1.5.255.255"},
		{"0.0.0.0:1", "0.0.0.0.0.1"},
		{"[::1]:2049", "00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.01.8.1"},
		{"no-host", ""},
		{"host:notaport", ""},
		{"host.example.com:80", ""},
		{"1.2.3.4:99999", ""},
		{"1.2.3.4:", ""},
	}
	for _, c := range cases {
		if got := uaddrOf(c.in); got != c.want {
			t.Errorf("uaddrOf(%q) = %q, want %q", c.in, got, c.want)
		}
	}
}

func TestDeviceAddrPreference(t *testing.T) {
	t.Parallel()
	h := &Handler{DeviceAddr: "10.0.0.1.8.1"}
	if got := h.deviceAddr(nil); got != "10.0.0.1.8.1" {
		t.Fatalf("configured address ignored: %q", got)
	}
	h2 := &Handler{}
	if got := h2.deviceAddr(nil); got != "127.0.0.1.8.1" {
		t.Fatalf("loopback default: %q", got)
	}
}