mk6i-open-oscar-server/state/session_manager_test.go

package state

import (
	"context"
	"io"
	"log/slog"
	"math/rand"
	"sync"
	"testing"
	"testing/synctest"
	"time"

	"github.com/mk6i/open-oscar-server/wire"
	"github.com/stretchr/testify/require"

	"github.com/stretchr/testify/assert"
)

func TestInMemorySessionManager_AddSession(t *testing.T) {
	sm := NewInMemorySessionManager(slog.Default())

	ctx := context.Background()
	sess1, err := sm.AddSession(ctx, "user-screen-name", false)
	assert.NoError(t, err)
	sess1.SetSignonComplete()

	go func() {
		<-sess1.Closed()
		sm.RemoveSession(sess1.Session())
	}()

	sess2, err := sm.AddSession(ctx, "user-screen-name", false)
	assert.NoError(t, err)
	sess2.SetSignonComplete()

	assert.NotSame(t, sess1, sess2)
	assert.Contains(t, sm.AllSessions(), sess2.Session())
}

// A closed session lingers in the store until RemoveSession runs, which Signout
// only reaches at the END of onSessCloseFn. A sign-on landing in that window must
// neither attach to the dead session (its RunOnce is spent, so no rate limit
// monitor or warning decay) nor evict it and race ahead (the in-flight
// UnregisterBuddyList would land after the fresh session registered itself). It
// has to wait the teardown out, then build a fresh session.
func TestInMemorySessionManager_AddSession_WaitsForClosedSessionTeardown(t *testing.T) {
	for _, doMultiSess := range []bool{true, false} {
		name := "multi-session client"
		if !doMultiSess {
			name = "single-session client"
		}
		t.Run(name, func(t *testing.T) {
			synctest.Test(t, func(t *testing.T) {
				sm := NewInMemorySessionManager(slog.Default())
				ctx := context.Background()

				var mu sync.Mutex
				var events []string
				record := func(event string) {
					mu.Lock()
					defer mu.Unlock()
					events = append(events, event)
				}

				// Stands in for the servers' OnSessionClose: announce the
				// departure, tear the account's registrations down, and only
				// then Signout, whose last act is RemoveSession.
				teardown := func(sess *Session) {
					sess.OnSessionClose(func() {
						record("teardown begin")
						time.Sleep(time.Second) // BroadcastBuddyDeparted
						record("unregister buddy list")
						sm.RemoveSession(sess) // Signout
					})
				}

				inst1, err := sm.AddSession(ctx, "user-screen-name", doMultiSess, teardown)
				require.NoError(t, err)
				inst1.SetSignonComplete()
				dead := inst1.Session()

				// The account's last instance departs, running onSessCloseFn on
				// its own goroutine as a closing connection does.
				wg := &sync.WaitGroup{}
				wg.Add(1)
				go func() {
					defer wg.Done()
					inst1.CloseInstance()
				}()

				// Let the teardown get under way and park mid-flight. The
				// session is closed the moment its last instance departs, but
				// the store still holds it — the tombstone window. It is not
				// observable through AllSessions/RetrieveSession (both filter on
				// live instances), which is why AddSession checks IsClosed.
				synctest.Wait()
				require.True(t, dead.IsClosed())
				sm.mapMutex.RLock()
				require.NotNil(t, sm.findRec(dead.IdentScreenName()), "tombstone should still be in the store")
				sm.mapMutex.RUnlock()

				inst2, err := sm.AddSession(ctx, "user-screen-name", doMultiSess, teardown)
				record("signon complete")
				require.NoError(t, err)
				inst2.SetSignonComplete()
				wg.Wait()

				// The sign-on waited the whole teardown out. Without the wait,
				// "signon complete" lands before "unregister buddy list" and
				// that unregister wipes the buddy list the new session has
				// already registered.
				mu.Lock()
				assert.Equal(t, []string{
					"teardown begin",
					"unregister buddy list",
					"signon complete",
				}, events)
				mu.Unlock()

				// And it got a fresh session rather than the tombstone, so its
				// RunOnce is unspent and its per-account goroutines start.
				assert.NotSame(t, dead, inst2.Session(), "must not attach to the closed session")
				assert.False(t, inst2.Session().IsClosed())
				assert.Contains(t, sm.AllSessions(), inst2.Session())

				ran := false
				require.NoError(t, inst2.Session().RunOnce(func() error { ran = true; return nil }))
				assert.True(t, ran)
			})
		})
	}
}

// The tombstone gate reads IsClosed and then adds an instance to the session it
// just cleared, so a sign-on whose AddInstance lands as the last connection
// departs can pass the gate and have the session close underneath it. The
// instance is then live but orphaned: Closed() has fired, so the rate limit
// monitor has exited, and RunOnce is spent so nothing restarts it.
//
// AddSession must never return an instance on a closed session.
func TestInMemorySessionManager_AddSession_RacesLastInstanceDeparture(t *testing.T) {
	const iterations = 20_000

	logger := slog.New(slog.NewTextHandler(io.Discard, nil))

	for i := range iterations {
		sm := NewInMemorySessionManager(logger)

		ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)

		// Stands in for the servers' OnSessionClose, whose last act is
		// RemoveSession. Without it the tombstone wait has nothing to wake on.
		teardown := func(sess *Session) {
			sess.OnSessionClose(func() { sm.RemoveSession(sess) })
		}

		inst1, err := sm.AddSession(ctx, "user-screen-name", true, teardown)
		require.NoError(t, err)
		inst1.SetSignonComplete()
		departing := inst1.Session()

		// The account's last connection drops at the same moment a new one signs
		// on. Neither path takes a lock the other holds: CloseInstance runs on a
		// connection goroutine, AddSession under the per-user lock.
		start := make(chan struct{})
		var wg sync.WaitGroup
		wg.Add(2)

		go func() {
			defer wg.Done()
			<-start
			inst1.CloseInstance()
		}()

		var inst2 *SessionInstance
		var addErr error
		go func() {
			defer wg.Done()
			<-start
			inst2, addErr = sm.AddSession(ctx, "user-screen-name", true, teardown)
		}()

		close(start)
		wg.Wait()
		cancel()

		require.NoError(t, addErr, "iteration %d", i)
		require.False(t, inst2.Session().IsClosed(),
			"iteration %d: sign-on returned an instance on a closed session "+
				"(same session as the departing connection: %t) — its rate limit "+
				"monitor has already exited and RunOnce is spent",
			i, inst2.Session() == departing)
	}
}

// A teardown that never reaches RemoveSession must not wedge the sign-on
// forever; the wait is bounded by the caller's context, as the single-session
// displacement path already was.
func TestInMemorySessionManager_AddSession_ClosedSessionTeardownTimesOut(t *testing.T) {
	synctest.Test(t, func(t *testing.T) {
		sm := NewInMemorySessionManager(slog.Default())

		inst1, err := sm.AddSession(context.Background(), "user-screen-name", true)
		require.NoError(t, err)
		inst1.SetSignonComplete()

		// No OnSessionClose is registered, so RemoveSession is never called and
		// the tombstone stays in the store for good.
		inst1.CloseInstance()

		ctx, cancel := context.WithTimeout(context.Background(), time.Second)
		defer cancel()

		_, err = sm.AddSession(ctx, "user-screen-name", true)
		assert.ErrorIs(t, err, context.DeadlineExceeded)
	})
}

func TestInMemorySessionManager_AddSession_AppliesCfgToSession(t *testing.T) {
	sm := NewInMemorySessionManager(slog.Default())
	wantUIN := uint32(424242)
	wantCookie := "cfg-test-cookie"

	instance, err := sm.AddSession(context.Background(), "user-screen-name", false,
		func(sess *Session) {
			sess.SetUIN(wantUIN)
			sess.SetChatRoomCookie(wantCookie)
		},
	)
	assert.NoError(t, err)

	s := instance.Session()
	assert.Equal(t, wantUIN, s.UIN(), "cfg mutates Session before AddInstance / store insert")
	assert.Equal(t, wantCookie, s.ChatRoomCookie())
}

func TestInMemorySessionManager_AddSession_Timeout(t *testing.T) {
	sm := NewInMemorySessionManager(slog.Default())

	ctx, cancel := context.WithCancel(context.Background())
	sess1, err := sm.AddSession(ctx, "user-screen-name", false)
	assert.NoError(t, err)
	sess1.SetSignonComplete()

	go func() {
		<-sess1.Closed()
		cancel()
	}()

	sess2, err := sm.AddSession(ctx, "user-screen-name", false)
	assert.Nil(t, sess2)
	assert.ErrorIs(t, err, context.Canceled)
}

func TestInMemorySessionManager_Remove_Existing(t *testing.T) {
	sm := NewInMemorySessionManager(slog.Default())

	user1Old, err := sm.AddSession(context.Background(), "user-screen-name-1", false)
	assert.NoError(t, err)

	// Verify the old session is in the store
	rec, ok := sm.store[user1Old.IdentScreenName()]
	assert.True(t, ok)
	assert.Equal(t, user1Old.Session(), rec.session)

	// Remove the session
	sm.RemoveSession(user1Old.Session())

	// Verify the session is no longer in the store
	_, ok = sm.store[user1Old.IdentScreenName()]
	assert.False(t, ok)

	// Verify the removed channel was closed
	select {
	case <-rec.removed:
		// Channel was closed, as expected
	default:
		assert.Fail(t, "removed channel should be closed")
	}

	user1New, err := sm.AddSession(context.Background(), "user-screen-name-1", false)
	assert.NoError(t, err)
	user1New.SetSignonComplete()

	user2, err := sm.AddSession(context.Background(), "user-screen-name-2", false)
	assert.NoError(t, err)
	user2.SetSignonComplete()

	// Remove user1New and verify it's gone
	sm.RemoveSession(user1New.Session())
	_, ok = sm.store[user1New.IdentScreenName()]
	assert.False(t, ok)

	if assert.Len(t, sm.AllSessions(), 1) {
		assert.NotContains(t, sm.AllSessions(), user1Old.Session())
		assert.NotContains(t, sm.AllSessions(), user1New.Session())
		assert.Contains(t, sm.AllSessions(), user2.Session())
	}
}

func TestInMemorySessionManager_Remove_MissingSameScreenName(t *testing.T) {
	sm := NewInMemorySessionManager(slog.Default())

	user1Old, err := sm.AddSession(context.Background(), "user-screen-name-1", false)
	assert.NoError(t, err)

	// Verify the old session is in the store
	recOld, ok := sm.store[user1Old.IdentScreenName()]
	assert.True(t, ok)
	assert.Equal(t, user1Old.Session(), recOld.session)

	// Remove the old session
	sm.RemoveSession(user1Old.Session())
	_, ok = sm.store[user1Old.IdentScreenName()]
	assert.False(t, ok)

	// Create a new session with the same screen name but different Session
	user1New, err := sm.AddSession(context.Background(), "user-screen-name-1", false)
	assert.NoError(t, err)
	user1New.SetSignonComplete()

	// Verify the new session is in the store with a different Session
	recNew, ok := sm.store[user1New.IdentScreenName()]
	assert.True(t, ok)
	assert.Equal(t, user1New.Session(), recNew.session)
	assert.NotEqual(t, user1Old.Session(), user1New.Session())

	user2, err := sm.AddSession(context.Background(), "user-screen-name-2", false)
	assert.NoError(t, err)
	user2.SetSignonComplete()

	// Try to remove the old session again - should do nothing because Session doesn't match
	sm.RemoveSession(user1Old.Session())

	// Verify the new session is still in the store (not removed)
	recNewAfter, ok := sm.store[user1New.IdentScreenName()]
	assert.True(t, ok, "new session should still be in store")
	assert.Equal(t, user1New.Session(), recNewAfter.session)

	if assert.Len(t, sm.AllSessions(), 2) {
		assert.NotContains(t, sm.AllSessions(), user1Old.Session())
		assert.Contains(t, sm.AllSessions(), user1New.Session())
		assert.Contains(t, sm.AllSessions(), user2.Session())
	}
}

func TestInMemorySessionManager_Empty(t *testing.T) {
	tests := []struct {
		name  string
		given []DisplayScreenName
		want  bool
	}{
		{
			name: "session manager is not empty",
			given: []DisplayScreenName{
				"user-screen-name-1",
			},
			want: false,
		},
		{
			name:  "session manager is empty",
			given: []DisplayScreenName{},
			want:  true,
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			sm := NewInMemorySessionManager(slog.Default())

			for _, screenName := range tt.given {
				sess, err := sm.AddSession(context.Background(), screenName, false)
				assert.NoError(t, err)
				sess.SetSignonComplete()
			}

			have := sm.Empty()
			assert.Equal(t, tt.want, have)
		})
	}
}

func TestInMemorySessionManager_Retrieve(t *testing.T) {
	tests := []struct {
		name             string
		given            []DisplayScreenName
		lookupScreenName IdentScreenName
		wantScreenName   IdentScreenName
	}{
		{
			name: "lookup finds match",
			given: []DisplayScreenName{
				"user-screen-name-1",
				"user-screen-name-2",
			},
			lookupScreenName: NewIdentScreenName("user-screen-name-2"),
			wantScreenName:   NewIdentScreenName("user-screen-name-2"),
		},
		{
			name:             "lookup does not find match",
			given:            []DisplayScreenName{},
			lookupScreenName: NewIdentScreenName("user-screen-name-3"),
			wantScreenName:   NewIdentScreenName(""),
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			sm := NewInMemorySessionManager(slog.Default())

			for _, screenName := range tt.given {
				sess, err := sm.AddSession(context.Background(), screenName, false)
				assert.NoError(t, err)
				sess.SetSignonComplete()
			}

			have := sm.RetrieveSession(tt.lookupScreenName)
			if have == nil {
				assert.Empty(t, tt.wantScreenName)
			} else {
				assert.Equal(t, tt.wantScreenName, have.IdentScreenName())
			}
		})
	}
}

func TestInMemorySessionManager_RelayToScreenNames(t *testing.T) {
	sm := NewInMemorySessionManager(slog.Default())

	user1, err := sm.AddSession(context.Background(), "user-screen-name-1", false)
	assert.NoError(t, err)
	user1.SetSignonComplete()
	user2, err := sm.AddSession(context.Background(), "user-screen-name-2", false)
	assert.NoError(t, err)
	user2.SetSignonComplete()
	user3, err := sm.AddSession(context.Background(), "user-screen-name-3", false)
	assert.NoError(t, err)
	user3.SetSignonComplete()

	want := wire.SNACMessage{Frame: wire.SNACFrame{FoodGroup: wire.ICBM}}

	recips := []IdentScreenName{
		NewIdentScreenName("user-screen-name-1"),
		NewIdentScreenName("user-screen-name-2"),
	}
	sm.RelayToScreenNames(context.Background(), recips, want)

	have := <-user1.ReceiveMessage()
	assert.Equal(t, want, have)

	have = <-user2.ReceiveMessage()
	assert.Equal(t, want, have)

	select {
	case <-user3.ReceiveMessage():
		assert.Fail(t, "user 3 should not receive a message")
	default:
	}
}

func TestInMemorySessionManager_Broadcast(t *testing.T) {
	sm := NewInMemorySessionManager(slog.Default())

	user1, err := sm.AddSession(context.Background(), "user-screen-name-1", false)
	assert.NoError(t, err)
	user1.SetSignonComplete()
	user2, err := sm.AddSession(context.Background(), "user-screen-name-2", false)
	assert.NoError(t, err)
	user2.SetSignonComplete()

	want := wire.SNACMessage{Frame: wire.SNACFrame{FoodGroup: wire.ICBM}}

	sm.RelayToAll(context.Background(), want)

	have := <-user1.ReceiveMessage()
	assert.Equal(t, want, have)

	have = <-user2.ReceiveMessage()
	assert.Equal(t, want, have)
}

func TestInMemorySessionManager_Broadcast_SkipClosedSession(t *testing.T) {
	sm := NewInMemorySessionManager(slog.Default())

	user1, err := sm.AddSession(context.Background(), "user-screen-name-1", false)
	assert.NoError(t, err)
	user1.SetSignonComplete()
	user2, err := sm.AddSession(context.Background(), "user-screen-name-2", false)
	assert.NoError(t, err)
	user2.SetSignonComplete()
	user2.CloseInstance()

	want := wire.SNACMessage{Frame: wire.SNACFrame{FoodGroup: wire.ICBM}}

	sm.RelayToAll(context.Background(), want)

	have := <-user1.ReceiveMessage()
	assert.Equal(t, want, have)

	select {
	case <-user2.ReceiveMessage():
		assert.Fail(t, "user 2 should not receive a message")
	default:
	}
}

func TestInMemorySessionManager_RelayToScreenName_SessionExists(t *testing.T) {
	sm := NewInMemorySessionManager(slog.Default())

	user1, err := sm.AddSession(context.Background(), "user-screen-name-1", false)
	assert.NoError(t, err)
	user1.SetSignonComplete()
	user2, err := sm.AddSession(context.Background(), "user-screen-name-2", false)
	assert.NoError(t, err)
	user2.SetSignonComplete()

	want := wire.SNACMessage{Frame: wire.SNACFrame{FoodGroup: wire.ICBM}}

	recip := NewIdentScreenName("user-screen-name-1")
	sm.RelayToScreenName(context.Background(), recip, want)

	have := <-user1.ReceiveMessage()
	assert.Equal(t, want, have)

	select {
	case <-user2.ReceiveMessage():
		assert.Fail(t, "user 2 should not receive a message")
	default:
	}
}

func TestInMemorySessionManager_RelayToScreenName_SessionNotExist(t *testing.T) {
	sm := NewInMemorySessionManager(slog.Default())

	user1, err := sm.AddSession(context.Background(), "user-screen-name-1", false)
	assert.NoError(t, err)
	user1.SetSignonComplete()

	want := wire.SNACMessage{Frame: wire.SNACFrame{FoodGroup: wire.ICBM}}

	recip := NewIdentScreenName("user-screen-name-2")
	sm.RelayToScreenName(context.Background(), recip, want)

	select {
	case <-user1.ReceiveMessage():
		assert.Fail(t, "user 1 should not receive a message")
	default:
	}
}

func TestInMemorySessionManager_RelayToScreenName_SkipFullSession(t *testing.T) {
	sm := NewInMemorySessionManager(slog.Default())

	user1, err := sm.AddSession(context.Background(), "user-screen-name-1", false)
	assert.NoError(t, err)
	user1.SetSignonComplete()
	msg := wire.SNACMessage{Frame: wire.SNACFrame{FoodGroup: wire.ICBM}}

	wantCount := 0
	for user1.RelayMessageToInstance(msg) != SessQueueFull {
		wantCount++
	}

	recip := NewIdentScreenName("user-screen-name-1")
	sm.RelayToScreenName(context.Background(), recip, msg)

	haveCount := 0
loop:
	for {
		select {
		case <-user1.ReceiveMessage():
			haveCount++
		default:
			break loop
		}
	}

	assert.Equal(t, wantCount, haveCount)
}

func TestInMemorySessionManager_SessionReplacement_NoMultiSess_NoMultiSess(t *testing.T) {
	synctest.Test(t, func(t *testing.T) {
		sm := NewInMemorySessionManager(slog.Default())

		sess1, err := sm.AddSession(context.Background(), "user-screen-name-1", false)
		assert.NoError(t, err)
		sess1.SetSignonComplete()

		wg := &sync.WaitGroup{}
		wg.Add(1)

		go func() {
			defer wg.Done()
			// add the session again. this call blocks until RemoveSession makes
			// room for the new session
			sess2, err := sm.AddSession(context.Background(), "user-screen-name-1", false)
			assert.NoError(t, err)
			if assert.NotNil(t, sess2) {
				sess2.SetSignonComplete()
				assert.Equal(t, sess1.DisplayScreenName(), sess2.DisplayScreenName())
			}
		}()

		// wait for second call to AddSession() to block
		synctest.Wait()

		// AddSession() is blocked waiting for the lock, now unblock it
		sm.RemoveSession(sess1.Session())

		wg.Wait()

		// make sure we got a brand new session
		got := sm.RetrieveSession(NewIdentScreenName("user-screen-name-1"))
		assert.NotEqual(t, sess1, got)
		assert.Equal(t, 1, got.InstanceCount())
	})
}

func TestInMemorySessionManager_SessionReplacement_MultiSess_NoMultiSess(t *testing.T) {
	synctest.Test(t, func(t *testing.T) {
		sm := NewInMemorySessionManager(slog.Default())
		sm.maxConcurrentSessions = 5

		var sessList []*SessionInstance
		for i := 0; i < sm.maxConcurrentSessions; i++ {
			sess, err := sm.AddSession(context.Background(), "user-screen-name-1", true)
			assert.NoError(t, err)
			sess.SetSignonComplete()
			sessList = append(sessList, sess)
		}

		assert.Equal(t, len(sessList), sessList[0].Session().InstanceCount())

		wg := &sync.WaitGroup{}
		wg.Add(1)

		go func() {
			defer wg.Done()
			// add the session again. this call blocks until RemoveSession makes
			// room for the new session
			sess, err := sm.AddSession(context.Background(), "user-screen-name-1", false)
			assert.NoError(t, err)
			assert.NotNil(t, sess)
			sess.SetSignonComplete()
			assert.Equal(t, "user-screen-name-1", sess.DisplayScreenName().String())
			assert.Equal(t, 1, sess.Session().InstanceCount())
		}()

		// wait for the last call to AddSession() to block
		synctest.Wait()

		// AddSession() is blocked waiting for the lock, now unblock it
		for _, sess := range sessList {
			sm.RemoveSession(sess.Session())
		}

		wg.Wait()

		got := sm.RetrieveSession(NewIdentScreenName("user-screen-name-1"))

		for _, sess := range sessList {
			assert.NotSame(t, sess, got)
		}
		assert.Equal(t, 1, got.InstanceCount())
	})
}

func TestInMemorySessionManager_SessionReplacement_NoMultiSess_MultiSess(t *testing.T) {
	synctest.Test(t, func(t *testing.T) {
		sm := NewInMemorySessionManager(slog.Default())

		sess1, err := sm.AddSession(context.Background(), "user-screen-name-1", false)
		assert.NoError(t, err)
		sess1.SetSignonComplete()

		wg := &sync.WaitGroup{}
		wg.Add(1)

		go func() {
			defer wg.Done()
			// add the session again. this call blocks until RemoveSession makes
			// room for the new session
			sess2, err := sm.AddSession(context.Background(), "user-screen-name-1", true)
			assert.NoError(t, err)
			assert.NotNil(t, sess2)
			assert.Equal(t, sess1.DisplayScreenName(), sess2.DisplayScreenName())
			sess2.SetSignonComplete()
		}()

		// wait for second call to AddSession() to block
		synctest.Wait()

		// AddSession() is blocked waiting for the lock, now unblock it
		sm.RemoveSession(sess1.Session())

		wg.Wait()

		got := sm.RetrieveSession(NewIdentScreenName("user-screen-name-1"))

		if assert.NotNil(t, got) {
			assert.NotSame(t, sess1, got)
			assert.Equal(t, 1, got.InstanceCount())
		}
	})
}

func TestInMemorySessionManager_RemoveSession_DoubleLogin_NoMultiSess_Chaos(t *testing.T) {
	wg := &sync.WaitGroup{}
	sm := NewInMemorySessionManager(slog.Default())

	for i := 0; i < 1000; i++ { // shake out race conditions
		wg.Add(1)

		time.Sleep(time.Duration(rand.Intn(1000)) * time.Microsecond)
		go func() {
			defer wg.Done()
			sess1, err := sm.AddSession(context.Background(), "user-screen-name-1", false)
			assert.NoError(t, err)
			time.Sleep(time.Duration(rand.Intn(1000)) * time.Microsecond)
			sm.RemoveSession(sess1.Session())
		}()
	}

	wg.Wait()
}

func TestInMemoryChatSessionManager_AddSession_AppliesCfgToSession(t *testing.T) {
	sm := NewInMemoryChatSessionManager(slog.Default())
	chatCookie := "chat-room-cfg"
	wantUIN := uint32(777001)

	instance, err := sm.AddSession(context.Background(), chatCookie, "user-screen-name",
		func(sess *Session) {
			sess.SetUIN(wantUIN)
		},
	)
	assert.NoError(t, err)

	s := instance.Session()
	assert.Equal(t, wantUIN, s.UIN(), "cfg mutates Session via inner AddSession before instance is returned")
	assert.Equal(t, chatCookie, s.ChatRoomCookie())
}

func TestInMemoryChatSessionManager_RelayToAllExcept_HappyPath(t *testing.T) {
	sm := NewInMemoryChatSessionManager(slog.Default())

	cookie := "the-cookie"
	user1, err := sm.AddSession(context.Background(), cookie, "user-screen-name-1")
	assert.NoError(t, err)
	user1.SetSignonComplete()
	user2, err := sm.AddSession(context.Background(), cookie, "user-screen-name-2")
	assert.NoError(t, err)
	user2.SetSignonComplete()
	user3, err := sm.AddSession(context.Background(), cookie, "user-screen-name-3")
	assert.NoError(t, err)
	user3.SetSignonComplete()

	want := wire.SNACMessage{Frame: wire.SNACFrame{FoodGroup: wire.ICBM}}

	sm.RelayToAllExcept(context.Background(), cookie, user2.IdentScreenName(), want)

	have := <-user1.ReceiveMessage()
	assert.Equal(t, want, have)

	select {
	case <-user2.ReceiveMessage():
		assert.Fail(t, "user 2 should not receive a message")
	default:
	}

	have = <-user3.ReceiveMessage()
	assert.Equal(t, want, have)
}

//func TestInMemoryChatSessionManager_AllSessions_RoomExists(t *testing.T) {
//	sm := NewInMemoryChatSessionManager(slog.Default())
//
//	user1, err := sm.AddSession(context.Background(), "the-cookie", "user-screen-name-1")
//	assert.NoError(t, err)
//	user1.SetSignonComplete()
//	user2, err := sm.AddSession(context.Background(), "the-cookie", "user-screen-name-2")
//	assert.NoError(t, err)
//	user2.SetSignonComplete()
//
//	sessions := sm.AllSessions("the-cookie")
//	assert.Len(t, sessions, 2)
//
//	lookup := make(map[*SessionInstance]bool)
//	for _, session := range sessions {
//		lookup[session] = true
//	}
//
//	assert.True(t, lookup[user1])
//	assert.True(t, lookup[user2])
//}

func TestInMemoryChatSessionManager_RelayToScreenName_SessionAndChatRoomExist(t *testing.T) {
	sm := NewInMemoryChatSessionManager(slog.Default())

	user1, err := sm.AddSession(context.Background(), "chat-room-1", "user-screen-name-1")
	assert.NoError(t, err)
	user1.SetSignonComplete()
	user2, err := sm.AddSession(context.Background(), "chat-room-1", "user-screen-name-2")
	assert.NoError(t, err)
	user2.SetSignonComplete()

	want := wire.SNACMessage{Frame: wire.SNACFrame{FoodGroup: wire.ICBM}}

	recip := NewIdentScreenName("user-screen-name-1")
	sm.RelayToScreenName(context.Background(), "chat-room-1", recip, want)

	have := <-user1.ReceiveMessage()
	assert.Equal(t, want, have)

	select {
	case <-user2.ReceiveMessage():
		assert.Fail(t, "user 2 should not receive a message")
	default:
	}
}

func TestInMemoryChatSessionManager_RemoveSession(t *testing.T) {
	sm := NewInMemoryChatSessionManager(slog.Default())

	user1, err := sm.AddSession(context.Background(), "chat-room-1", "user-screen-name-1")
	assert.NoError(t, err)
	user1.SetSignonComplete()
	user2, err := sm.AddSession(context.Background(), "chat-room-1", "user-screen-name-2")
	assert.NoError(t, err)
	user2.SetSignonComplete()

	assert.Len(t, sm.AllSessions("chat-room-1"), 2)

	sm.RemoveSession(user1.Session())
	sm.RemoveSession(user2.Session())

	assert.Empty(t, sm.AllSessions("chat-room-1"))
}

func TestInMemoryChatSessionManager_RemoveSession_DoubleLogin(t *testing.T) {
	for i := 0; i < 50; i++ { // shake out race conditions

		synctest.Test(t, func(t *testing.T) {
			sm := NewInMemoryChatSessionManager(slog.Default())

			chatSess1, err := sm.AddSession(context.Background(), "chat-room-1", "user-screen-name-1")
			assert.NoError(t, err)
			chatSess1.SetSignonComplete()

			wg := &sync.WaitGroup{}
			wg.Add(1)

			go func() {
				// add the session again. this call blocks until RemoveSession makes
				// room for the new session
				chatSess2, err := sm.AddSession(context.Background(), "chat-room-1", "user-screen-name-1")
				assert.NoError(t, err)
				assert.NotNil(t, chatSess2)
				chatSess2.SetSignonComplete()
				assert.Equal(t, chatSess1.DisplayScreenName(), chatSess2.DisplayScreenName())
				wg.Done()
			}()

			// wait for second call to AddSession() to block
			synctest.Wait()

			// AddSession() is blocked waiting for the lock, now unblock it
			sm.RemoveSession(chatSess1.Session())

			wg.Wait()
		})
	}
}

func TestInMemoryChatSessionManager_RemoveUserFromAllChats(t *testing.T) {
	sm := NewInMemoryChatSessionManager(slog.Default())

	user1 := NewIdentScreenName("user-screen-name-1")
	user1sess, err := sm.AddSession(context.Background(), "chat-room-1", "user-screen-name-1")
	assert.NoError(t, err)
	user1sess.SetSignonComplete()
	user2sess, err := sm.AddSession(context.Background(), "chat-room-1", "user-screen-name-2")
	assert.NoError(t, err)
	user2sess.SetSignonComplete()

	assert.Len(t, sm.AllSessions("chat-room-1"), 2)

	sm.RemoveUserFromAllChats(user1)

	lookup := make(map[*Session]bool)
	for _, session := range sm.AllSessions("chat-room-1") {
		lookup[session] = true
	}

	assert.False(t, lookup[user1sess.Session()])
	assert.True(t, lookup[user2sess.Session()])

}

// TestInMemoryChatSessionManager_NoDeadlockOnCloseHookReentry verifies that
// session close hooks don't deadlock when they re-enter
// InMemoryChatSessionManager.
//
// The deadlock scenario under test:
//
//  1. BOS session closes, triggering its close hook.
//  2. The close hook calls RemoveUserFromAllChats, which iterates chat rooms
//     and calls CloseSession on the user's chat session.
//  3. The chat session's close hook calls AllSessions, which acquires
//     mapMutex.RLock.
//
// If RemoveUserFromAllChats naively held mapMutex.RLock while calling
// CloseSession in step 2, the AllSessions call in step 3 would attempt a
// recursive read lock on the same goroutine—something sync.RWMutex forbids—and
// deadlock. The production code avoids this by copying the session managers and
// releasing the lock before calling CloseSession.
func TestInMemoryChatSessionManager_NoDeadlockOnCloseHookReentry(t *testing.T) {
	user := DisplayScreenName("user-screen-name-1")
	cookie := "chat-room-1"

	bosSM := NewInMemorySessionManager(slog.Default())
	chatSM := NewInMemoryChatSessionManager(slog.Default())

	bosSess, err := bosSM.AddSession(context.Background(), user, false)
	require.NoError(t, err)
	bosSess.Session().SetIdentScreenName(user.IdentScreenName())
	bosSess.SetSignonComplete()

	chatSess, err := chatSM.AddSession(context.Background(), cookie, user)
	require.NoError(t, err)
	chatSess.SetSignonComplete()

	// Simulate the real signoff flow: when the BOS session closes, remove
	// the user from all chat rooms.
	bosSess.Session().OnSessionClose(func() {
		chatSM.RemoveUserFromAllChats(user.IdentScreenName())
	})
	// When the chat session closes, re-enter the chat session manager to
	// simulate some cleanup operations, which would deadlock if the manager's
	// lock were still held.
	chatSess.Session().OnSessionClose(func() {
		chatSM.AllSessions(cookie)
	})

	done := make(chan struct{})
	go func() {
		defer close(done)
		bosSess.Session().CloseSession()
	}()

	select {
	case <-done:
	case <-time.After(5 * time.Second):
		t.Fatal("timed out waiting for session close — probable deadlock in close hook chain")
	}
}

func TestInMemorySessionManager_RelayToAll_SkipIncompleteSignon(t *testing.T) {
	sm := NewInMemorySessionManager(slog.Default())

	user1, err := sm.AddSession(context.Background(), "user-screen-name-1", false)
	assert.NoError(t, err)
	user1.SetSignonComplete()

	user2, err := sm.AddSession(context.Background(), "user-screen-name-2", false)
	assert.NoError(t, err)
	// user2 has not completed signon

	want := wire.SNACMessage{Frame: wire.SNACFrame{FoodGroup: wire.ICBM}}

	sm.RelayToAll(context.Background(), want)

	have := <-user1.ReceiveMessage()
	assert.Equal(t, want, have)

	select {
	case <-user2.ReceiveMessage():
		assert.Fail(t, "user 2 should not receive a message because signon is incomplete")
	default:
	}
}

func TestInMemorySessionManager_RetrieveSession_IncompleteSignon(t *testing.T) {
	sm := NewInMemorySessionManager(slog.Default())

	user1, err := sm.AddSession(context.Background(), "user-screen-name-1", false)
	assert.NoError(t, err)
	// user1 has not completed signon

	sess := sm.RetrieveSession(NewIdentScreenName("user-screen-name-1"))
	assert.Nil(t, sess, "should return nil for session with incomplete signon")

	user1.SetSignonComplete()
	sess = sm.RetrieveSession(NewIdentScreenName("user-screen-name-1"))
	assert.NotNil(t, sess, "should return session after signon is complete")
	assert.Equal(t, user1.Session(), sess)
}

func TestInMemorySessionManager_RetrieveSession_CompleteSignon(t *testing.T) {
	sm := NewInMemorySessionManager(slog.Default())

	user1, err := sm.AddSession(context.Background(), "user-screen-name-1", false)
	assert.NoError(t, err)
	user1.SetSignonComplete()

	sess := sm.RetrieveSession(NewIdentScreenName("user-screen-name-1"))
	assert.NotNil(t, sess)
	assert.Equal(t, user1.Session(), sess)
}

func TestInMemorySessionManager_RelayToScreenNames_SkipIncompleteSignon(t *testing.T) {
	sm := NewInMemorySessionManager(slog.Default())

	user1, err := sm.AddSession(context.Background(), "user-screen-name-1", false)
	assert.NoError(t, err)
	user1.SetSignonComplete()

	user2, err := sm.AddSession(context.Background(), "user-screen-name-2", false)
	assert.NoError(t, err)
	// user2 has not completed signon

	user3, err := sm.AddSession(context.Background(), "user-screen-name-3", false)
	assert.NoError(t, err)
	user3.SetSignonComplete()

	want := wire.SNACMessage{Frame: wire.SNACFrame{FoodGroup: wire.ICBM}}

	recips := []IdentScreenName{
		NewIdentScreenName("user-screen-name-1"),
		NewIdentScreenName("user-screen-name-2"), // incomplete signon
		NewIdentScreenName("user-screen-name-3"),
	}
	sm.RelayToScreenNames(context.Background(), recips, want)

	have := <-user1.ReceiveMessage()
	assert.Equal(t, want, have)

	select {
	case <-user2.ReceiveMessage():
		assert.Fail(t, "user 2 should not receive a message because signon is incomplete")
	default:
	}

	have = <-user3.ReceiveMessage()
	assert.Equal(t, want, have)
}

func TestInMemorySessionManager_AllSessions_SkipIncompleteSignon(t *testing.T) {
	sm := NewInMemorySessionManager(slog.Default())

	user1, err := sm.AddSession(context.Background(), "user-screen-name-1", false)
	assert.NoError(t, err)
	user1.SetSignonComplete()

	user2, err := sm.AddSession(context.Background(), "user-screen-name-2", false)
	assert.NoError(t, err)
	// user2 has not completed signon

	user3, err := sm.AddSession(context.Background(), "user-screen-name-3", false)
	assert.NoError(t, err)
	user3.SetSignonComplete()

	sessions := sm.AllSessions()
	assert.Len(t, sessions, 2, "should only return sessions with complete signon")

	// Check that we have sessions for user1 and user3 (by checking Session identity)
	user1Found := false
	user3Found := false
	user2Found := false

	for _, session := range sessions {
		if session == user1.Session() {
			user1Found = true
		}
		if session == user2.Session() {
			user2Found = true
		}
		if session == user3.Session() {
			user3Found = true
		}
	}

	assert.True(t, user1Found, "user1 should be included (complete signon)")
	assert.False(t, user2Found, "user2 should not be included (incomplete signon)")
	assert.True(t, user3Found, "user3 should be included (complete signon)")
}

func TestInMemorySessionManager_RelayToScreenName_IncompleteSignon(t *testing.T) {
	sm := NewInMemorySessionManager(slog.Default())

	user1, err := sm.AddSession(context.Background(), "user-screen-name-1", false)
	assert.NoError(t, err)
	// user1 has not completed signon

	want := wire.SNACMessage{Frame: wire.SNACFrame{FoodGroup: wire.ICBM}}

	recip := NewIdentScreenName("user-screen-name-1")
	sm.RelayToScreenName(context.Background(), recip, want)

	select {
	case <-user1.ReceiveMessage():
		assert.Fail(t, "user 1 should not receive a message because signon is incomplete")
	default:
	}
}

func TestInMemorySessionManager_RelayToOtherInstances_SkipsNonLiveInstances(t *testing.T) {
	sm := NewInMemorySessionManager(slog.Default())

	// Create a session with multiple instances
	user1, err := sm.AddSession(context.Background(), "user-screen-name-1", true)
	assert.NoError(t, err)
	user1.SetSignonComplete()

	// Add a second instance that hasn't completed signon
	user1Instance2, err := sm.AddSession(context.Background(), "user-screen-name-1", true)
	assert.NoError(t, err)
	// user1Instance2 has not completed signon, so this instance is not live

	// Add a third instance that has completed signon
	user1Instance3, err := sm.AddSession(context.Background(), "user-screen-name-1", true)
	assert.NoError(t, err)
	user1Instance3.SetSignonComplete()

	// Verify instance-level live() behavior
	assert.True(t, user1.live(), "user1 should be live (not closed and signon complete)")
	assert.False(t, user1Instance2.live(), "user1Instance2 should not be live (signon not complete)")
	assert.True(t, user1Instance3.live(), "user1Instance3 should be live (not closed and signon complete)")

	want := wire.SNACMessage{Frame: wire.SNACFrame{FoodGroup: wire.ICBM}}

	// Relay to other instances from user1
	sm.RelayToOtherInstances(context.Background(), user1, want)

	// user1 should not receive the message (it's the sender)
	select {
	case <-user1.ReceiveMessage():
		assert.Fail(t, "user1 should not receive a message relayed from itself")
	default:
	}

	// user1Instance2 should not receive the message (not live - signon incomplete)
	select {
	case <-user1Instance2.ReceiveMessage():
		assert.Fail(t, "user1Instance2 should not receive a message because it's not live")
	default:
	}

	// user1Instance3 should receive the message (is live)
	select {
	case have := <-user1Instance3.ReceiveMessage():
		assert.Equal(t, want, have)
	default:
		assert.Fail(t, "user1Instance3 should receive the message")
	}
}

func TestInMemorySessionManager_MaybeRelayMessage_SkipsNonLiveInstances(t *testing.T) {
	sm := NewInMemorySessionManager(slog.Default())

	// Create a session with multiple instances
	user1, err := sm.AddSession(context.Background(), "user-screen-name-1", true)
	assert.NoError(t, err)
	user1.SetSignonComplete()

	// Add a third instance that has completed signon
	user1Instance3, err := sm.AddSession(context.Background(), "user-screen-name-1", true)
	assert.NoError(t, err)
	user1Instance3.SetSignonComplete()

	// Create a separate session with incomplete signon to test that non-live instances are skipped
	user2, err := sm.AddSession(context.Background(), "user-screen-name-2", false)
	assert.NoError(t, err)
	// user2 has not completed signon, so this instance is not live
	assert.False(t, user2.live(), "instance should not be live when signon is incomplete")

	want := wire.SNACMessage{Frame: wire.SNACFrame{FoodGroup: wire.ICBM}}

	// Use maybeRelayMessage (called internally by RelayToScreenName)
	// This should relay to all live instances in the session
	sm.RelayToScreenName(context.Background(), user1.IdentScreenName(), want)

	// user1 should receive the message
	select {
	case have := <-user1.ReceiveMessage():
		assert.Equal(t, want, have)
	default:
		assert.Fail(t, "user1 should receive the message")
	}

	// user1Instance3 should receive the message (session is live)
	select {
	case have := <-user1Instance3.ReceiveMessage():
		assert.Equal(t, want, have)
	default:
		assert.Fail(t, "user1Instance3 should receive the message")
	}

	// Test that non-live instances are skipped in RelayToAll (which calls maybeRelayMessage)
	sm.RelayToAll(context.Background(), want)

	// user2 should not receive the message (instance is not live, so maybeRelayMessage skips it)
	select {
	case <-user2.ReceiveMessage():
		assert.Fail(t, "user2 should not receive a message because the instance is not live")
	default:
	}
}

func TestInMemorySessionManager_AddSession_MaxConcurrentSessions(t *testing.T) {
	t.Run("enforces limit", func(t *testing.T) {
		sm := NewInMemorySessionManager(slog.Default())
		sm.maxConcurrentSessions = 5

		// Create sessions up to the limit (5)
		var sessList []*SessionInstance
		for i := 0; i < sm.maxConcurrentSessions; i++ {
			sess, err := sm.AddSession(context.Background(), "user-screen-name-1", true)
			assert.NoError(t, err)
			sess.SetSignonComplete()
			sessList = append(sessList, sess)
		}

		// Verify we have exactly 5 instances
		assert.Equal(t, sm.maxConcurrentSessions, sessList[0].Session().InstanceCount())

		// Try to add one more session - should fail with ErrMaxConcurrentSessionsReached
		sess, err := sm.AddSession(context.Background(), "user-screen-name-1", true)
		assert.Nil(t, sess)
		assert.ErrorIs(t, err, ErrMaxConcurrentSessionsReached)

		// Verify we still have exactly 5 instances
		assert.Equal(t, sm.maxConcurrentSessions, sessList[0].Session().InstanceCount())
	})

	t.Run("allows new session after removal", func(t *testing.T) {
		sm := NewInMemorySessionManager(slog.Default())
		sm.maxConcurrentSessions = 5

		// Create sessions up to the limit (5)
		var sessList []*SessionInstance
		for i := 0; i < sm.maxConcurrentSessions; i++ {
			sess, err := sm.AddSession(context.Background(), "user-screen-name-1", true)
			assert.NoError(t, err)
			sess.SetSignonComplete()
			sessList = append(sessList, sess)
		}

		// Verify we have exactly 5 instances
		assert.Equal(t, sm.maxConcurrentSessions, sessList[0].Session().InstanceCount())

		// Try to add one more session - should fail
		sess, err := sm.AddSession(context.Background(), "user-screen-name-1", true)
		assert.Nil(t, sess)
		assert.ErrorIs(t, err, ErrMaxConcurrentSessionsReached)

		// Close one instance (this removes it from the Session)
		sessList[0].CloseInstance()

		// Now we should be able to add a new instance to the same session
		newSess, err := sm.AddSession(context.Background(), "user-screen-name-1", true)
		assert.NoError(t, err)
		assert.NotNil(t, newSess)
		newSess.SetSignonComplete()

		// Verify we have exactly 5 instances again (4 remaining + 1 new = 5)
		assert.Equal(t, sm.maxConcurrentSessions, newSess.Session().InstanceCount())
	})

	t.Run("no limit for non-multi-session", func(t *testing.T) {
		sm := NewInMemorySessionManager(slog.Default())

		// Create multiple non-multi-session sessions - should not be limited
		// (though they will replace each other, but that's expected behavior)
		sess1, err := sm.AddSession(context.Background(), "user-screen-name-1", false)
		assert.NoError(t, err)
		sess1.SetSignonComplete()

		// Close and remove the first session to allow a new one
		go func() {
			<-sess1.Closed()
			sm.RemoveSession(sess1.Session())
		}()

		sess2, err := sm.AddSession(context.Background(), "user-screen-name-1", false)
		assert.NoError(t, err)
		sess2.SetSignonComplete()

		// Verify the limit doesn't apply to non-multi-session
		assert.Equal(t, 1, sess2.Session().InstanceCount())
	})
}