package link

import (
	"context"
	"sync"
	"testing"
	"time"
)

// listeningForAlive is a quiet link that also records anything said on an alive subject. The method
// is deliberately kept here: once the bus has no such method, this link can never be asked for it,
// and the test still holds the loop to saying nothing.
type listeningForAlive struct {
	*quietLink
	mu    sync.Mutex
	heard int
}

func (l *listeningForAlive) Alive(context.Context, string, []byte) error {
	l.mu.Lock()
	defer l.mu.Unlock()
	l.heard++
	return nil
}

func (l *listeningForAlive) count() int {
	l.mu.Lock()
	defer l.mu.Unlock()
	return l.heard
}

// 1158/AC1: the node-engine publishes nothing on its alive subject (novox/hq ADR 0429 §7, ADR 0433
// §3: presence replaces the alive message). The loop runs over a fake bus and no alive is published,
// neither at the start nor on a tick.
func TestTheLinkLoopPublishesNoAlive(t *testing.T) {
	m, _ := aMember(t)
	l := &listeningForAlive{quietLink: newQuietLink()}
	q := aQueue(m, nil, &keptInMemory{})

	ctx, stop := context.WithCancel(context.Background())
	done := make(chan error, 1)
	go func() { done <- serve(ctx, l, m, q, nil, time.Second) }()
	time.Sleep(300 * time.Millisecond)
	stop()
	select {
	case <-done:
	case <-time.After(5 * time.Second):
		t.Fatal("the loop did not end")
	}
	if n := l.count(); n != 0 {
		t.Fatalf("the node published %d alive messages (1158/AC1)", n)
	}
}