//go:build integration

package process

import (
	"crypto/ecdsa"
	"crypto/elliptic"
	"crypto/rand"
	"crypto/sha256"
	"crypto/tls"
	"crypto/x509"
	"crypto/x509/pkix"
	"encoding/hex"
	"math/big"
	"testing"
	"time"

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

// selfSignedServer is a nats-server with JetStream and TLS, self-signed, for this test alone (mirroring
// go/internal/testbus.Start, with a certificate added since testbus has none): a mesh's bus presents its own
// certificate in no public trust store, which is exactly what a process pins to (ADR 0436 clause 4).
func selfSignedServer(t *testing.T) (url, fingerprint string) {
	t.Helper()
	key, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
	if err != nil {
		t.Fatal(err)
	}
	tmpl := &x509.Certificate{
		SerialNumber: big.NewInt(1),
		Subject:      pkix.Name{CommonName: "mesh-sdk-test-bus"},
		NotBefore:    time.Now().Add(-time.Hour),
		NotAfter:     time.Now().Add(time.Hour),
		KeyUsage:     x509.KeyUsageDigitalSignature | x509.KeyUsageKeyEncipherment,
		ExtKeyUsage:  []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
	}
	der, err := x509.CreateCertificate(rand.Reader, tmpl, tmpl, &key.PublicKey, key)
	if err != nil {
		t.Fatal(err)
	}
	sum := sha256.Sum256(der)
	fingerprint = "sha256:" + hex.EncodeToString(sum[:])
	cert := tls.Certificate{Certificate: [][]byte{der}, PrivateKey: key}
	opts := &server.Options{Host: "127.0.0.1", Port: server.RANDOM_PORT, JetStream: true, StoreDir: t.TempDir(),
		NoLog: true, NoSigs: true, TLSConfig: &tls.Config{Certificates: []tls.Certificate{cert}},
		Username: "novox.mesh-mail.send", Password: "the-pw"}
	s, err := server.NewServer(opts)
	if err != nil {
		t.Fatalf("a TLS bus for this test could not be made: %v", err)
	}
	go s.Start()
	if !s.ReadyForConnections(10 * time.Second) {
		s.Shutdown()
		t.Fatal("a TLS bus for this test did not come up within 10s")
	}
	t.Cleanup(func() {
		s.Shutdown()
		s.WaitForShutdown()
	})
	return s.ClientURL(), fingerprint
}

func mailSenderAccount(url, fingerprint string) Account {
	return Account{URL: url, Fingerprint: fingerprint, Node: "novox", Module: "mesh-mail",
		User: "novox.mesh-mail.send", Password: "the-pw"}
}

// 1171/AC3: given a test bus with TLS and the account composed for novox.mesh-mail.send, when the package
// connects with the file, then it connects with the inbox prefix _INBOX.novox.mesh-mail.send.
func TestConnectPinsTheFingerprintAndSetsTheInboxPrefix(t *testing.T) {
	url, fingerprint := selfSignedServer(t)
	account := mailSenderAccount(url, fingerprint)
	conn, err := Connect(account)
	if err != nil {
		t.Fatalf("connecting with the right fingerprint was refused: %v", err)
	}
	defer conn.Close()
	if !conn.nc.IsConnected() {
		t.Fatal("the connection did not come up")
	}
	if got := conn.nc.Opts.InboxPrefix; got != "_INBOX.novox.mesh-mail.send" {
		t.Errorf("inbox prefix: %q, want %q", got, "_INBOX.novox.mesh-mail.send")
	}
}

// 1171/AC3: connecting with a fingerprint that is not the bus's own leaf certificate is refused.
func TestConnectRefusesTheWrongFingerprint(t *testing.T) {
	url, _ := selfSignedServer(t)
	account := mailSenderAccount(url, "sha256:0000000000000000000000000000000000000000000000000000000000000000")
	if _, err := Connect(account); err == nil {
		t.Fatal("connecting with the wrong fingerprint was not refused")
	}
}