//go:build integration

package link

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

	"github.com/nats-io/nats.go"
	"github.com/novox/mesh-controller/internal/testbus"
)

// Against a real bus whose largest message is small: the limit is read from the connection, the one that fits goes
// through, the one over is refused by us with its size and the limit, not by the client's bare error (issue 1689).
func TestADeclarationIsMeasuredAgainstTheRealBusLimit(t *testing.T) {
	s := testbus.StartWithMaxPayload(t, 2048)
	conn, err := nats.Connect(s.ClientURL())
	if err != nil {
		t.Fatal(err)
	}
	defer conn.Close()
	js, err := conn.JetStream()
	if err != nil {
		t.Fatal(err)
	}
	if _, err := js.AddStream(&nats.StreamConfig{Name: "NODES", Subjects: []string{"mesh.node.*.declare"}}); err != nil {
		t.Fatal(err)
	}
	bus := OverNATS{Conn: conn, JS: js}
	if bus.MaxPayload() != 2048 {
		t.Fatalf("the limit read from the connection is %d, expected 2048", bus.MaxPayload())
	}
	var told []int64
	was := DeclarationMeasured
	DeclarationMeasured = func(_ context.Context, _ string, size, limit int64) { told = append(told, size, limit) }
	t.Cleanup(func() { DeclarationMeasured = was })

	fits := []byte(`{"a":"` + strings.Repeat("x", 600) + `"}`)
	if err := Declare(t.Context(), bus, fixedSigner{}, "novox", fits, 5*time.Second); err != nil {
		t.Fatalf("a declaration under the limit: %v", err)
	}
	over := []byte(`{"a":"` + strings.Repeat("x", 1600) + `"}`)
	err = Declare(t.Context(), bus, fixedSigner{}, "novox", over, 5*time.Second)
	if err == nil || !strings.Contains(err.Error(), "2048 bytes") || strings.Contains(err.Error(), "maximum payload exceeded") {
		t.Fatalf("a declaration over the limit: %v", err)
	}
	if len(told) != 4 || told[1] != 2048 || told[2] <= 2048 {
		t.Fatalf("measured %v", told)
	}
}