package bus_test

import (
	"context"
	"errors"
	"strings"
	"testing"
	"time"

	"github.com/nats-io/nats-server/v2/server"
	"github.com/nats-io/nats.go"

	"github.com/novox/mesh-tools/node-tools/internal/bus"
	mt "github.com/novox/mesh-tools/node-tools/internal/meshtest"
)

// novox/hq ADR 0670 §1 (design 34 every-event §12, §16): a subscription the bus refuses is noted and the others go on
// waiting, a heard event carries its own time; a wait whose every subscription is refused answers only after its
// timeout, in words naming the grants part's grant of every event subject, never a wait grant (E-2).
func TestTheBusRefusesAWaitOutsideTheGrant(t *testing.T) {
	granted := "mesh.seat.operator-channel.event.decided.claude-code"
	other := "mesh.seat.operator-channel.event.decided.shop"
	s, err := server.NewServer(&server.Options{Host: "127.0.0.1", Port: server.RANDOM_PORT, NoLog: true, NoSigs: true,
		Users: []*server.User{{Username: "desk.node-tools", Password: "pw", Permissions: &server.Permissions{
			Publish:   &server.SubjectPermission{Allow: []string{"$JS.API.DIRECT.GET.>", "mesh.>"}},
			Subscribe: &server.SubjectPermission{Allow: []string{granted, "_INBOX.desk.node-tools.>", "mesh.assignment.desk.*"}},
		}}}})
	if err != nil {
		t.Fatal(err)
	}
	go s.Start()
	if !s.ReadyForConnections(10 * time.Second) {
		t.Fatal("the bus did not come up")
	}
	t.Cleanup(s.Shutdown)
	c := dial(t, s.ClientURL(), "node-tools", "desk", "desk.node-tools")

	// Every subscription refused: answered after the timeout, never at once, in §16's words.
	start := time.Now()
	_, ok, refused, err := c.HearFirst(context.Background(), []string{other}, 300*time.Millisecond, nil)
	if took := time.Since(start); took < 300*time.Millisecond || took > 3*time.Second {
		t.Errorf("a wait refused whole answered after %s, want its timeout of 300ms", took)
	}
	if ok || err == nil || !strings.Contains(err.Error(), "the bus refused this account a subscription on "+other) ||
		!strings.Contains(err.Error(), "every event subject (novox/hq ADR 0670 §1)") ||
		strings.Contains(err.Error(), "wait grant") || strings.Contains(err.Error(), "0367") ||
		len(refused) != 1 || refused[0] != other {
		t.Errorf("a wait on another asker's decided: heard %v, refused %v, %v", ok, refused, err)
	}

	// One refused beside one granted: the granted one hears, with the event's own time, and the refused one is listed.
	pub, err := nats.Connect(s.ClientURL(), nats.UserInfo("desk.node-tools", "pw"))
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(pub.Close)
	for _, published := range []string{"2026-11-12T03:00:00.5Z", ""} {
		type result struct {
			h       bus.Heard
			refused []string
			err     error
		}
		done := make(chan result, 1)
		go func() {
			h, ok, refused, err := c.HearFirst(context.Background(), []string{other, granted}, 5*time.Second, nil)
			if !ok && err == nil {
				err = errors.New("timed out")
			}
			done <- result{h, refused, err}
		}()
		// The event is said again until the wait, subscribed in its own time, hears it.
		say := time.NewTicker(20 * time.Millisecond)
		var r result
	heard:
		for {
			select {
			case r = <-done:
				break heard
			case <-say.C:
				msg := nats.NewMsg(granted)
				msg.Data = []byte(`{"ask":"a1"}`)
				if published != "" {
					msg.Header.Set("x-time", published)
				}
				if err := pub.PublishMsg(msg); err != nil {
					t.Fatal(err)
				}
			}
		}
		say.Stop()
		if r.err != nil || r.h.Subject != granted || string(r.h.Body) != `{"ask":"a1"}` || r.h.Published != published {
			t.Errorf("heard %+v, %v; want published %q", r.h, r.err, published)
		}
		if len(r.refused) > 1 || len(r.refused) == 1 && r.refused[0] != other {
			t.Errorf("refused %v, want at most %s", r.refused, other)
		}
	}
}

// A wait whose caller is gone ends at once, its subscription closed (the review of issue 745).
func TestAWaitEndsWhenItsCallerIsGone(t *testing.T) {
	c := dial(t, mt.URL(t), "node-tools", "desk", "")
	before := c.Subscriptions()
	ctx, cancel := context.WithCancel(context.Background())
	time.AfterFunc(200*time.Millisecond, cancel)
	start := time.Now()
	_, ok, _, err := c.HearFirst(ctx, []string{"mesh.mod.mesh-knowledge.event.reviewed"}, time.Minute, nil)
	if ok || !errors.Is(err, context.Canceled) {
		t.Errorf("a cancelled wait answered %v, %v", ok, err)
	}
	if took := time.Since(start); took > 2*time.Second {
		t.Errorf("a cancelled wait ended after %s", took)
	}
	if after := c.Subscriptions(); after != before {
		t.Errorf("%d subscriptions before, %d after", before, after)
	}
}