package broker

import (
	"errors"
	"os"
	"path/filepath"
	"strings"
	"testing"
	"time"

	"github.com/nats-io/nats-server/v2/server"
	"github.com/nats-io/nats.go"
	"golang.org/x/crypto/bcrypt"
)

// vaultRecords is a mesh of two machines: anchor, a desk whose runtime carries the desk's prompt (rofi holding
// node-launcher) beside an issuing provider (plex) and a module with a tool of its own; and novox, where the vault
// runs in a runtime of its own on its own account (ADR 0259 §8's runs-as).
func vaultRecords() Records {
	launcher := Seat{Name: "node-launcher", Scope: "node", Serves: []string{"menu", "secret"}}
	vault := Seat{Name: VaultSeat, Scope: "mesh", Serves: []string{"get", "accept", "secret-ask", "issued", "rotate"}}
	return Records{Nodes: []string{"anchor", "novox"}, Assigned: map[string][]Declared{
		"anchor": {{Module: RuntimeModule}, {Module: "rofi", Holds: []Seat{launcher}, NoAccount: true},
			{Module: "plex", Serves: []string{"plex_issued_credential", "plex_status"},
				Issued: []string{"plex_issued_credential"}, NoAccount: true},
			{Module: "other", Serves: []string{"tool"}, NoAccount: true}},
		"novox": {{Module: RuntimeModule}, {Module: "mesh-vault", Holds: []Seat{vault}, RunsAs: "mesh-vault"}},
	}}
}

// The vault's holder may ask the desk's prompt and each issuing tool in its own name, and nothing else outside its
// seat; no other module and no runtime is granted it (issue 723).
func TestTheVaultAsksTheDeskAndTheIssuingToolsInItsOwnNameAlone(t *testing.T) {
	users, err := Users(vaultRecords())
	if err != nil {
		t.Fatal(err)
	}
	perms := map[string]Permissions{}
	for _, u := range users {
		p, err := PermissionsFor(u)
		if err != nil {
			t.Fatal(err)
		}
		perms[u.Username()] = p
	}
	vault, ok := perms["novox.mesh-vault"]
	if !ok {
		t.Fatal("the vault has no account of its own")
	}
	token := CallerToken("novox.mesh-vault")
	for _, s := range []string{
		"mesh.seat.node-launcher.call.secret.anchor." + token,
		"mesh.mod.plex.call.plex_issued_credential.anchor." + token,
	} {
		if !MayPublish(vault, s) {
			t.Errorf("the vault may not ask %s", s)
		}
	}
	for _, s := range []string{
		"mesh.seat.node-launcher.tool.secret.anchor",
		"mesh.seat.node-launcher.call.secret.anchor.controller",
		"mesh.seat.node-launcher.call.menu.anchor." + token,
		"mesh.mod.rofi.call.node-launcher.secret.anchor." + token,
		"mesh.mod.plex.call.plex_status.anchor." + token,
		"mesh.mod.plex.tool.plex_issued_credential.anchor",
		"mesh.mod.other.call.tool.anchor." + token,
		"mesh.mod.other.tool.tool.anchor",
		"mesh.seat.mesh-controller.call.status." + token,
	} {
		if MayPublish(vault, s) {
			t.Errorf("the vault may publish %s", s)
		}
	}
	// Outside its own namespace and its own seat, the vault publishes nothing but those two calls, its inbox's
	// answers and the stream API's reads of what it keeps.
	for _, s := range vault.Publish {
		switch {
		case strings.HasPrefix(s, "mesh.mod.mesh-vault."), strings.HasPrefix(s, "mesh.seat."+VaultSeat+"."),
			s == "mesh.seat.node-launcher.call.secret.*."+token,
			s == "mesh.mod.plex.call.plex_issued_credential.*."+token,
			strings.HasPrefix(s, "$JS."), strings.HasPrefix(s, "$KV."), strings.HasPrefix(s, "_INBOX."),
			strings.HasPrefix(s, "mesh.discover."), strings.HasPrefix(s, "$SRV."):
		default:
			t.Errorf("the vault is granted %s, outside its seat", s)
		}
	}
	// Nobody else is granted the vault's calls; the controller keeps today's path until R1 (issue 682).
	for name, p := range perms {
		if name == "novox.mesh-vault" {
			continue
		}
		for _, s := range []string{"mesh.seat.node-launcher.call.secret.anchor." + token,
			"mesh.mod.plex.call.plex_issued_credential.anchor." + token} {
			if MayPublish(p, s) {
				t.Errorf("%s may call in the vault's name: %s", name, s)
			}
		}
	}
	controller := perms["controller"]
	for _, s := range []string{"mesh.seat.node-launcher.tool.secret.anchor",
		"mesh.mod.plex.call.plex_issued_credential.anchor.controller"} {
		if !MayPublish(controller, s) {
			t.Errorf("the controller lost today's path %s before R1", s)
		}
	}
	if MayPublish(perms["anchor.node-tools"], "mesh.seat.node-launcher.call.secret.anchor."+CallerToken("anchor.node-tools")) {
		t.Error("a machine's runtime may ask the desk's prompt")
	}
}

// **On a real server, as composed** (issue 723): the vault's account asks the desk's prompt and an issuing tool
// and is answered, naming itself; the server refuses it any other call; and the controller is still answered on
// today's path. That only sealed values cross is the vault's test (mesh-catalog, mesh-vault intake_test.go).
func TestOnARealBusTheVaultsAccountIsAnsweredByTheDeskAndTheProviderAndNothingElse(t *testing.T) {
	users, err := Users(vaultRecords())
	if err != nil {
		t.Fatal(err)
	}
	hash, err := bcrypt.GenerateFromPassword([]byte("pw"), bcrypt.MinCost)
	if err != nil {
		t.Fatal(err)
	}
	for i := range users {
		users[i].PasswordHash = string(hash)
	}
	accounts, err := ComposeAccounts(users)
	if err != nil {
		t.Fatal(err)
	}
	conf := filepath.Join(t.TempDir(), "bus.conf")
	if err := os.WriteFile(conf, []byte("listen: 127.0.0.1:-1\njetstream { store_dir: "+
		`"`+t.TempDir()+`"`+" }\n"+accounts), 0o600); err != nil {
		t.Fatal(err)
	}
	opts, err := server.ProcessConfigFile(conf)
	if err != nil {
		t.Fatalf("the composed accounts do not parse: %v", err)
	}
	opts.NoLog, opts.NoSigs = true, true
	s, err := server.NewServer(opts)
	if err != nil {
		t.Fatal(err)
	}
	go s.Start()
	if !s.ReadyForConnections(10 * time.Second) {
		t.Fatal("the bus did not come up")
	}
	defer s.Shutdown()

	// anchor's runtime serves the desk's prompt and plex's issuing tool, on every subject it is granted, and says
	// which subject it heard.
	holder, err := nats.Connect(s.ClientURL(), nats.UserInfo("anchor.node-tools", "pw"))
	if err != nil {
		t.Fatal(err)
	}
	defer holder.Close()
	heard := make(chan string, 8)
	answer := func(m *nats.Msg) {
		heard <- m.Subject
		_ = m.Respond([]byte(`{"result":{"sealed":"c2VhbGVkLXRvLXRoZS1jYWxs"}}`))
	}
	for _, subject := range []string{"mesh.seat.node-launcher.call.secret.anchor.*",
		"mesh.seat.node-launcher.tool.secret.anchor", "mesh.mod.plex.call.plex_issued_credential.anchor.*",
		"mesh.mod.other.call.tool.anchor.*", "mesh.seat.node-launcher.call.menu.anchor.*"} {
		sub, err := holder.Subscribe(subject, answer)
		if err != nil {
			t.Fatal(err)
		}
		_ = holder.Flush()
		if !sub.IsValid() {
			t.Fatalf("the desk's runtime may not hear %s", subject)
		}
	}

	refusals := make(chan error, 16)
	vault, err := nats.Connect(s.ClientURL(), nats.UserInfo("novox.mesh-vault", "pw"),
		nats.CustomInboxPrefix("_INBOX.novox.mesh-vault"),
		nats.ErrorHandler(func(_ *nats.Conn, _ *nats.Subscription, err error) { refusals <- err }))
	if err != nil {
		t.Fatalf("the vault's own account cannot connect: %v", err)
	}
	defer vault.Close()
	token := CallerToken("novox.mesh-vault")
	for _, subject := range []string{"mesh.seat.node-launcher.call.secret.anchor." + token,
		"mesh.mod.plex.call.plex_issued_credential.anchor." + token} {
		if _, err := vault.Request(subject, []byte(`{"seal_to":"a2V5LW9mLXRoZS1jYWxs"}`), 3*time.Second); err != nil {
			t.Fatalf("the vault's call %s was not answered: %v", subject, err)
		}
		if got := <-heard; got != subject {
			t.Fatalf("the holder heard %s, want %s", got, subject)
		}
	}
	for _, subject := range []string{"mesh.seat.node-launcher.tool.secret.anchor",
		"mesh.seat.node-launcher.call.secret.anchor.controller",
		"mesh.seat.node-launcher.call.menu.anchor." + token,
		"mesh.mod.other.call.tool.anchor." + token} {
		if err := vault.Publish(subject, []byte(`{}`)); err != nil {
			t.Fatal(err)
		}
		_ = vault.Flush()
		select {
		case err := <-refusals:
			if !errors.Is(err, nats.ErrPermissionViolation) {
				t.Errorf("%s: the server said %v, want a permissions violation", subject, err)
			}
		case <-time.After(3 * time.Second):
			t.Errorf("the server did not refuse the vault %s", subject)
		}
	}
	select {
	case got := <-heard:
		t.Errorf("a call the vault may not make reached the holder: %s", got)
	case <-time.After(200 * time.Millisecond):
	}

	// The controller is still answered on today's path, for the modules filled the old way (until R1).
	controller, err := nats.Connect(s.ClientURL(), nats.UserInfo("controller", "pw"),
		nats.CustomInboxPrefix("_INBOX.controller"))
	if err != nil {
		t.Fatal(err)
	}
	defer controller.Close()
	if _, err := controller.Request("mesh.seat.node-launcher.tool.secret.anchor", []byte(`{}`), 3*time.Second); err != nil {
		t.Errorf("the controller's call to the desk on today's path: %v", err)
	}
	<-heard
}