package busdedup

import (
	"context"
	"testing"
	"time"

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

// **The same announcement published twice with one message id is stored once** (novox/hq ADR 0406 §6, issue 976). The
// forge module announces a merge, a head and a close with a deterministic `x-event-id` (announce.ts); the runtime makes
// that header the bus's message id (mesh-tools node-tools/internal/bus/bus.go, `nats.MsgId`), and the events stream's
// message de-duplication keeps the second. The publish here is the runtime's own: the headers the module stamps, the id
// as the message id. A real JetStream server is linked into the test and started for it alone (the TypeScript harness
// has none, so this is the Go half of the module's tests).

const subject = "mesh.mod.gitea.event.pull.merged"

func publish(t *testing.T, js nats.JetStreamContext, id string) *nats.PubAck {
	t.Helper()
	msg := nats.NewMsg(subject)
	msg.Header.Set("x-event-id", id)
	msg.Header.Set("x-source", "gitea")
	msg.Header.Set("content-type", "application/json")
	msg.Data = []byte(`{"owner":"novox","repo":"app","number":7,"merge_commit_sha":"mmm222"}`)
	ack, err := js.PublishMsg(msg, nats.MsgId(id))
	if err != nil {
		t.Fatal(err)
	}
	return ack
}

func TestTheSameAnnouncementPublishedTwiceWithOneMessageIdIsStoredOnce(t *testing.T) {
	s, err := server.NewServer(&server.Options{Host: "127.0.0.1", Port: server.RANDOM_PORT, JetStream: true,
		StoreDir: t.TempDir(), NoLog: true, NoSigs: true})
	if err != nil {
		t.Fatal(err)
	}
	go s.Start()
	if !s.ReadyForConnections(30 * time.Second) {
		t.Fatal("a bus for this test did not come up within 30s")
	}
	t.Cleanup(func() { s.Shutdown(); s.WaitForShutdown() })
	nc, err := nats.Connect(s.ClientURL())
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(nc.Close)
	js, err := nc.JetStream()
	if err != nil {
		t.Fatal(err)
	}
	// The events stream as the controller makes it: two minutes of message de-duplication.
	if _, err := js.AddStream(&nats.StreamConfig{Name: "EVENTS", Subjects: []string{"mesh.mod.>"}, Duplicates: 2 * time.Minute}); err != nil {
		t.Fatal(err)
	}
	const id = "merged:novox/app#7@mmm222"
	first := publish(t, js, id)
	second := publish(t, js, id) // the poll and the forge's event both announced it
	if first.Duplicate || !second.Duplicate {
		t.Fatalf("the first publish was a duplicate: %v; the second: %v (wanted false, true)", first.Duplicate, second.Duplicate)
	}
	publish(t, js, "merged:novox/app#8@nnn333") // another merge is another message
	jsNew, err := jetstream.New(nc)
	if err != nil {
		t.Fatal(err)
	}
	stream, err := jsNew.Stream(context.Background(), "EVENTS")
	if err != nil {
		t.Fatal(err)
	}
	info, err := stream.Info(context.Background())
	if err != nil {
		t.Fatal(err)
	}
	if info.State.Msgs != 2 {
		t.Fatalf("the stream stores %d messages for two announcements published three times; wanted 2", info.State.Msgs)
	}
}