// 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"
)

func TestOps41Matrix(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, "ops41", 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:]
	}

	// LOOKUPP walks to the parent: the root is its own parent.
	var rootFH []byte
	res, bodies := run(seq, [][]byte{
		nfs4.AppendPutRootfh(nil),
		nfs4.AppendGetfh(nil),
	})
	rootFH, err := xdr.NewDecoder(bodies[1]).VarOpaque()
	if err != nil {
		t.Fatal(err)
	}
	seq++
	res, bodies = run(seq, [][]byte{
		nfs4.AppendPutRootfh(nil),
		nfs4.AppendLookup(nil, "sub"),
		nfs4.AppendLookupp(nil),
		nfs4.AppendGetfh(nil),
	})
	if res.Status != nfs4.ErrOK {
		t.Fatalf("lookupp: status %d", res.Status)
	}
	got, derr := xdr.NewDecoder(bodies[3]).VarOpaque()
	if derr != nil || !bytes.Equal(got, rootFH) {
		t.Fatalf("lookupp landed outside the root: % x %v", got, derr)
	}

	// PUTPUBFH answers the same handle as PUTROOTFH.
	seq++
	res, bodies = run(seq, [][]byte{
		nfs4.AppendPutPubfh(nil),
		nfs4.AppendGetfh(nil),
	})
	wantStatus(t, "putpubfh", res.Status, nfs4.ErrOK)
	pub, derr := xdr.NewDecoder(bodies[1]).VarOpaque()
	if derr != nil || !bytes.Equal(pub, rootFH) {
		t.Fatalf("public handle differs from the root")
	}

	// VERIFY passes when the file matches and fails with NOT_SAME when it
	// does not; NVERIFY is the exact opposite.
	seq++
	res, _ = run(seq, [][]byte{
		nfs4.AppendPutRootfh(nil),
		nfs4.AppendLookup(nil, "a.txt"),
		nfs4.AppendVerifyArgs(nil, nfs4.OfBits(nfs4.AttrMode, nfs4.AttrSize),
			nfs4.Attrs{Mode: 0o644, Size: 9}),
	})
	wantStatus(t, "verify pass", res.Status, nfs4.ErrOK)
	seq++
	res, _ = run(seq, [][]byte{
		nfs4.AppendPutRootfh(nil),
		nfs4.AppendLookup(nil, "a.txt"),
		nfs4.AppendVerifyArgs(nil, nfs4.OfBits(nfs4.AttrSize), nfs4.Attrs{Size: 8}),
	})
	wantStatus(t, "verify mismatch", res.Status, nfs4.ErrNotSame)
	seq++
	res, _ = run(seq, [][]byte{
		nfs4.AppendPutRootfh(nil),
		nfs4.AppendLookup(nil, "a.txt"),
		nfs4.AppendNverifyArgs(nil, nfs4.OfBits(nfs4.AttrSize), nfs4.Attrs{Size: 8}),
	})
	wantStatus(t, "nverify pass", res.Status, nfs4.ErrOK)
	seq++
	res, _ = run(seq, [][]byte{
		nfs4.AppendPutRootfh(nil),
		nfs4.AppendLookup(nil, "a.txt"),
		nfs4.AppendNverifyArgs(nil, nfs4.OfBits(nfs4.AttrSize), nfs4.Attrs{Size: 9}),
	})
	wantStatus(t, "nverify match", res.Status, nfs4.ErrSame)

	// Open the file for the stateful half of the matrix.
	seq++
	res, bodies = run(seq, [][]byte{
		nfs4.AppendPutRootfh(nil),
		nfs4.AppendOpenArgs(nil, 0x3333, []byte("ops41-owner"),
			nfs4.ShareAccessBoth, 0, false, 0, "a.txt"),
	})
	wantStatus(t, "open", res.Status, nfs4.ErrOK)
	var openSt nfs4.Stateid
	copy(openSt[:], bodies[1])
	var delegSt nfs4.Stateid
	if len(bodies[1]) >= 68 {
		copy(delegSt[:], bodies[1][52:68])
	}

	// DELEGRETURN hands the delegation back; a second return is answered
	// OK the same way, the release of nothing is already done.
	seq++
	res, _ = run(seq, [][]byte{
		nfs4.AppendPutfh(nil, []byte("ignored")),
		nfs4.AppendDelegReturnArgs(nil, delegSt),
	})
	if res.Status != nfs4.ErrOK && res.Status != nfs4.ErrBadStateid {
		t.Fatalf("deleg return: status %d", res.Status)
	}
	if res.Status == nfs4.ErrOK {
		seq++
		res, _ = run(seq, [][]byte{
			nfs4.AppendDelegReturnArgs(nil, delegSt),
		})
		wantStatus(t, "deleg return again", res.Status, nfs4.ErrOK)
	}

	// A byte range lock gives the lock owner a stateid; LOCKT of a second
	// owner sees it, RELEASE_LOCKOWNER removes it.
	seq++
	res, bodies = run(seq, [][]byte{
		nfs4.AppendPutRootfh(nil),
		nfs4.AppendLookup(nil, "a.txt"),
		nfs4.AppendLockArgsNew(nil, openSt, 0x3333, []byte("ops41-locker"),
			nfs4.LockTypeWrite, false, 0, 10),
	})
	wantStatus(t, "lock", res.Status, nfs4.ErrOK)
	var lockSt nfs4.Stateid
	copy(lockSt[:], bodies[2])
	seq++
	res, _ = run(seq, [][]byte{
		nfs4.AppendPutRootfh(nil),
		nfs4.AppendLookup(nil, "a.txt"),
		nfs4.AppendLocktArgs(nil, nfs4.LockTypeWrite, 0, 10, 0x9999, []byte("other")),
	})
	wantStatus(t, "lockt sees the lock", res.Status, nfs4.ErrDenied)
	seq++
	res, _ = run(seq, [][]byte{
		nfs4.AppendReleaseLockOwnerArgs(nil, sid.ClientIDOf(), []byte("ops41-locker")),
	})
	wantStatus(t, "release lock owner", res.Status, nfs4.ErrOK)
	seq++
	res, _ = run(seq, [][]byte{
		nfs4.AppendPutRootfh(nil),
		nfs4.AppendLookup(nil, "a.txt"),
		nfs4.AppendLocktArgs(nil, nfs4.LockTypeWrite, 0, 10, 0x9999, []byte("other")),
	})
	wantStatus(t, "lockt after release", res.Status, nfs4.ErrOK)

	// FREE_STATEID refuses a stateid that never existed and the one that
	// was just dropped.
	seq++
	res, _ = run(seq, [][]byte{nfs4.AppendFreeStateidArgs(nil, lockSt)})
	if res.Status != nfs4.ErrOK && res.Status != nfs4.ErrBadStateid {
		t.Fatalf("free stateid: status %d", res.Status)
	}
	seq++
	res, _ = run(seq, [][]byte{nfs4.AppendFreeStateidArgs(nil, lockSt)})
	wantStatus(t, "free stateid again", res.Status, nfs4.ErrBadStateid)

	// TEST_STATEID answers one status per stateid: the live open, a dead
	// stateid and the anonymous form.
	seq++
	res, bodies = run(seq, [][]byte{
		nfs4.AppendTestStateidArgs(nil, []nfs4.Stateid{openSt, lockSt, {}}),
	})
	wantStatus(t, "test stateid", res.Status, nfs4.ErrOK)
	td := xdr.NewDecoder(bodies[0])
	count, terr := td.Uint32()
	if terr != nil || count != 3 {
		t.Fatalf("statuses %d: %v", count, terr)
	}
	s0, _ := td.Uint32()
	s1, _ := td.Uint32()
	s2, _ := td.Uint32()
	if s0 != nfs4.ErrOK || s1 != nfs4.ErrBadStateid || s2 != nfs4.ErrOK {
		t.Fatalf("statuses %d %d %d", s0, s1, s2)
	}

	// BIND_CONN_TO_SESSION refuses a session that does not exist.
	seq++
	badSID := nfs4.SessionID{}
	res, _ = run(seq, [][]byte{
		nfs4.AppendBindConnToSessionArgs(nil, badSID, nfs4.Cdfc4Fore, false),
	})
	wantStatus(t, "bind unknown session", res.Status, nfs4.ErrBadSession)
	seq++
	res, bodies = run(seq, [][]byte{
		nfs4.AppendBindConnToSessionArgs(nil, sid, nfs4.Cdfc4Fore, false),
	})
	wantStatus(t, "bind fore", res.Status, nfs4.ErrOK)
	bd := xdr.NewDecoder(bodies[0])
	var echoed nfs4.SessionID
	raw, rerr := bd.Raw(16)
	if rerr != nil {
		t.Fatal(rerr)
	}
	copy(echoed[:], raw)
	if echoed != sid {
		t.Fatal("bind echoed another session")
	}
	if dir, _ := bd.Uint32(); dir != nfs4.Cdfs4Fore {
		t.Fatalf("dir %d", dir)
	}
	if bd.Remaining() != 0 {
		t.Fatalf("%d bytes left in the bind result", bd.Remaining())
	}

	// BACKCHANNEL_CTL records the future back channel program.
	seq++
	res, _ = run(seq, [][]byte{nfs4.AppendBackchannelCtlArgs(nil, 0x40000001)})
	wantStatus(t, "backchannel ctl", res.Status, nfs4.ErrOK)
}

func TestVerifyTimeAndBareLookupp(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, "verify", 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:]
	}

	// LOOKUPP without a current handle answers NOFILE_HANDLE.
	seq++
	res, _ := run(seq, [][]byte{nfs4.AppendLookupp(nil)})
	wantStatus(t, "lookupp bare", res.Status, nfs4.ErrNoFileHandle)

	// The modify time of a.txt asserts against itself: VERIFY passes,
	// NVERIFY answers SAME; a wrong time flips both answers.
	info, err := h.FS.Getattr(mustLookup(t, h, "a.txt"))
	if err != nil {
		t.Fatal(err)
	}
	modified := nfs4.NfsTime{Seconds: info.ModTime.Unix(), Nseconds: uint32(info.ModTime.Nanosecond())}
	seq++
	res, _ = run(seq, [][]byte{
		nfs4.AppendPutRootfh(nil),
		nfs4.AppendLookup(nil, "a.txt"),
		nfs4.AppendVerifyArgs(nil, nfs4.OfBits(nfs4.AttrTimeModify),
			nfs4.Attrs{TimeModify: modified}),
	})
	wantStatus(t, "verify time", res.Status, nfs4.ErrOK)
	seq++
	res, _ = run(seq, [][]byte{
		nfs4.AppendPutRootfh(nil),
		nfs4.AppendLookup(nil, "a.txt"),
		nfs4.AppendNverifyArgs(nil, nfs4.OfBits(nfs4.AttrTimeModify),
			nfs4.Attrs{TimeModify: modified}),
	})
	wantStatus(t, "nverify time match", res.Status, nfs4.ErrSame)
	modified.Nseconds++
	seq++
	res, _ = run(seq, [][]byte{
		nfs4.AppendPutRootfh(nil),
		nfs4.AppendLookup(nil, "a.txt"),
		nfs4.AppendVerifyArgs(nil, nfs4.OfBits(nfs4.AttrTimeModify),
			nfs4.Attrs{TimeModify: modified}),
	})
	wantStatus(t, "verify time mismatch", res.Status, nfs4.ErrNotSame)
}

func TestOps41EdgeBranches(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, "edge", 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:]
	}

	// A VERIFY of an attribute this server refuses to compare answers
	// ATTRNOTSUPP.
	seq++
	res, _ := run(seq, [][]byte{
		nfs4.AppendPutRootfh(nil),
		nfs4.AppendLookup(nil, "a.txt"),
		nfs4.AppendVerifyArgs(nil, nfs4.OfBits(nfs4.AttrMountedOnFileID),
			nfs4.Attrs{MountedOnFileID: 1}),
	})
	wantStatus(t, "verify unsupported attr", res.Status, nfs4.ErrAttrNotSupp)

	// A nonsense connection direction answers INVAL.
	seq++
	res, _ = run(seq, [][]byte{
		nfs4.AppendBindConnToSessionArgs(nil, sid, 9, false),
	})
	wantStatus(t, "bind direction", res.Status, nfs4.ErrInval)

	// FREE_STATEID of a lock owner that still holds ranges answers
	// LOCKS_HELD.
	seq++
	res, bodies := run(seq, [][]byte{
		nfs4.AppendPutRootfh(nil),
		nfs4.AppendOpenArgs(nil, 0x4444, []byte("edge-owner"),
			nfs4.ShareAccessBoth, 0, false, 0, "a.txt"),
	})
	wantStatus(t, "open", res.Status, nfs4.ErrOK)
	openSt := bodyStateid(bodies[1])
	seq++
	res, bodies = run(seq, [][]byte{
		nfs4.AppendPutfh(nil, mustLookup(t, h, "a.txt")),
		nfs4.AppendLockArgsNew(nil, openSt, 0x4444,
			[]byte("edge-locker"), nfs4.LockTypeWrite, false, 0, 10),
	})
	wantStatus(t, "lock", res.Status, nfs4.ErrOK)
	lockSt := bodyStateid(bodies[1])
	seq++
	res, _ = run(seq, [][]byte{
		nfs4.AppendFreeStateidArgs(nil, lockSt),
	})
	wantStatus(t, "free with locks held", res.Status, nfs4.ErrLocksHeld)
}

// bodyStateid reads the stateid that opens every stateful result body.
func bodyStateid(body []byte) nfs4.Stateid {
	var st nfs4.Stateid
	copy(st[:], body)
	return st
}