package link

import (
	"testing"
	"time"

	"github.com/nats-io/nats.go"
)

// Issue 1747: a builder never holds a message it does not start. A message the server sends after a fetch gave up lands in that
// queue's subscription; while an ask runs, the queues it does not come from are let go of, so such a message is not held
// unheartbeated for the whole run, and the queues are bound again before the next fetch.

func TestARunningAskLetsGoOfTheQueuesItDidNotComeFrom(t *testing.T) {
	m, builds, _, other, _ := aMachine()
	// A delivery build reached the builds queue's subscription after its fetch gave up: it sits in the buffer.
	builds.waiting = []*nats.Msg{buildAsk()}
	took := m.subs[1] // the running ask came from the ready queue

	m.quiesce(took)

	if !took.bound || took.pull == nil {
		t.Error("the queue the running ask came from was let go of; its acknowledgements need it")
	}
	for _, q := range []*takeQueue{m.subs[0], m.subs[2]} {
		if q.bound || q.pull != nil || q.sub != nil {
			t.Errorf("the %s queue is still held while an ask runs", q.kind)
		}
	}
	// Nothing is fetched from a queue that was let go of: a message in it cannot be taken unheartbeated.
	if msg, _, _ := m.next(t.Context()); msg != nil {
		t.Fatalf("a message was taken from a queue that was let go of: %s", msg.Data)
	}
	if builds.fetches() != 0 || other.fetches() != 0 {
		t.Errorf("fetched from a queue that was let go of: builds %d, other %d", builds.fetches(), other.fetches())
	}
}

// Once the ask is settled the queue it came from is let go of too: a second message the server delivered into its subscription
// on a pull request still open is not run after the ask ends (review of 1747).
func TestTheQueueTheAskCameFromIsLetGoOfWhenTheAskEnds(t *testing.T) {
	m, _, ready, _, _ := aMachine()
	ready.waiting = []*nats.Msg{askedAgo(time.Minute, 2, true)}
	m.quiesce(nil)
	for _, q := range m.subs {
		if q.bound || q.pull != nil {
			t.Errorf("the %s queue is still held after the ask ended", q.kind)
		}
	}
	m.subs[0].bound, m.subs[0].pull = true, &fakeQueue{}
	if msg, _, _ := m.next(t.Context()); msg != nil || ready.fetches() != 0 {
		t.Fatal("a message held in the kept queue's subscription was taken after the ask ended")
	}
}