package broker

import (
	"slices"
	"testing"
)

// The bus's own module copies the bus and does nothing else on it (novox/hq ADR 0235): its whole
// authority is the snapshot API and its own inbox, whatever else it declared — its tools are the
// node's runtime's to serve.
func TestTheBussOwnModuleMaySnapshotAndNothingElse(t *testing.T) {
	p := Principal{Kind: KindModule, Node: "anchor", Module: "nats", SnapshotsTheBus: true,
		Serves: []string{"nats_streams"}, PasswordHash: "x"}
	perms, err := PermissionsFor(p)
	if err != nil {
		t.Fatal(err)
	}
	want := []string{"$JS.API.STREAM.INFO.*", "$JS.API.STREAM.NAMES", "$JS.API.STREAM.SNAPSHOT.*", "$JS.SNAPSHOT.ACK.>"}
	if !slices.Equal(perms.Publish, want) {
		t.Errorf("it may publish %v, want exactly %v", perms.Publish, want)
	}
	if !slices.Equal(perms.Subscribe, []string{"_INBOX.anchor.nats.>"}) {
		t.Errorf("it may subscribe %v, want its own inbox alone", perms.Subscribe)
	}
	if perms.AllowResponses {
		t.Error("nothing is asked of it, and it may answer")
	}
}

// Read-only, by the writers table: no grant of it overlaps a subject a write of the mesh's state is a
// publish to — a stream's definition, a bucket, a message.
func TestTheSnapshotGrantsWriteNothing(t *testing.T) {
	p := Principal{Kind: KindModule, Node: "anchor", Module: "nats"}
	if err := CheckWriters(p, BusSnapshotGrants.Publish); err != nil {
		t.Fatal(err)
	}
	for _, grant := range BusSnapshotGrants.Publish {
		for _, write := range []string{"$JS.API.STREAM.CREATE.X", "$JS.API.STREAM.UPDATE.X", "$JS.API.STREAM.DELETE.X",
			"$JS.API.STREAM.PURGE.X", "$JS.API.STREAM.MSG.DELETE.X", "$JS.API.STREAM.RESTORE.X",
			"$JS.API.CONSUMER.CREATE.X", "$JS.API.CONSUMER.DURABLE.CREATE.X.y", "$KV.b.k", "mesh.mod.m.event.e"} {
			if SubjectsOverlap(grant, write) {
				t.Errorf("%s would let the bus's own module publish %s", grant, write)
			}
		}
	}
}

// A module that is not the bus gets nothing of it, and the flag travels from the records to the user.
func TestOnlyTheBussOwnModuleIsGrantedTheSnapshot(t *testing.T) {
	users, err := Users(Records{Nodes: []string{"anchor"}, Assigned: map[string][]Declared{"anchor": {
		{Module: "nats", SnapshotsTheBus: true},
		{Module: "shop", Emits: []string{"order.placed"}},
	}}})
	if err != nil {
		t.Fatal(err)
	}
	for _, u := range users {
		perms, err := PermissionsFor(u)
		if err != nil {
			t.Fatal(err)
		}
		snapshots := slices.Contains(perms.Publish, "$JS.API.STREAM.SNAPSHOT.*")
		switch u.Username() {
		case "anchor.nats":
			if !snapshots {
				t.Error("the bus's own module is not granted the snapshot")
			}
		case "controller":
		default:
			if snapshots {
				t.Errorf("%s may snapshot the bus", u.Username())
			}
		}
	}
}