package gateway

import (
	"bytes"
	"context"
	"crypto/aes"
	"crypto/cipher"
	"crypto/sha256"
	"crypto/tls"
	"crypto/x509"
	"encoding/binary"
	"encoding/hex"
	"encoding/pem"
	"errors"
	"fmt"
	"io"
	"net"
	"net/http"
	"net/http/httptest"
	"strconv"
	"strings"
	"testing"
	"time"

	protocol "git.sechmachine.io.vn/sechmachine/VerseVDI-Protocol/gen/go/protocol"
)

type nativeRoundTripFunc func(*http.Request) (*http.Response, error)

func (fn nativeRoundTripFunc) RoundTrip(request *http.Request) (*http.Response, error) {
	return fn(request)
}

func TestNativeApolloManagementUsesSessionScopedMTLS(t *testing.T) {
	serverTLS, clientTLS := testTLS(t)
	server := httptest.NewUnstartedServer(http.HandlerFunc(func(response http.ResponseWriter, request *http.Request) {
		if request.URL.Path != "/serverinfo" || request.TLS == nil || len(request.TLS.PeerCertificates) != 1 {
			http.Error(response, "mTLS required", http.StatusUnauthorized)
			return
		}
		_, _ = response.Write([]byte("<root><uniqueid>apollo-server</uniqueid></root>"))
	}))
	server.TLS = serverTLS
	server.StartTLS()
	defer server.Close()
	host, portText, err := net.SplitHostPort(server.Listener.Addr().String())
	if err != nil {
		t.Fatal(err)
	}
	port, err := strconv.ParseInt(portText, 10, 64)
	if err != nil {
		t.Fatal(err)
	}
	pinned := sha256.Sum256(serverTLS.Certificates[0].Certificate[0])
	work := protocol.ProviderSessionWork{
		Version: "1", SessionID: "session-1", GatewayID: "gateway-1", ReconnectSequence: 0,
		ExpiresAt: "2099-01-01T00:00:00Z", ProviderProfile: ProviderProfileApollo,
		ProviderIdentity: "apollo-server#sha256:" + hex.EncodeToString(pinned[:]), PolicyVersionID: "policy-1", ApplicationID: "1", ClientID: "paired-client",
		StreamPolicy:   protocol.ProviderStreamPolicy{ResolutionWidth: 1920, ResolutionHeight: 1080, Fps: 60, Codec: "H264", BitrateKbps: 8000, AudioEnabled: true},
		ManagementHost: host, ManagementPort: port, StreamHost: host, StreamPort: 47984,
		ClientCertificatePem: certificatePEM(t, clientTLS.Certificates[0]),
		ClientPrivateKeyPem:  privateKeyPEM(t, clientTLS.Certificates[0]),
		ServerCertificatePem: certificatePEM(t, tls.Certificate{Certificate: [][]byte{serverTLS.Certificates[0].Certificate[1]}}),
		ClipboardPolicy:      protocol.ClipboardPolicy{MaxTextBytes: 65536, MaxUpdatesPerMinute: 30},
	}
	data, err := NewNativeApolloBackend().Management(context.Background(), LaunchRequest{SessionID: "session-1", ProviderProfile: ProviderProfileApollo, ProviderWork: work})
	if err != nil {
		t.Fatalf("Management() error = %v", err)
	}
	if info, err := ParseManagementXML(data); err != nil || info.Identity.UniqueID != "apollo-server" {
		t.Fatalf("ParseManagementXML() = %+v, %v", info, err)
	}
}

func TestNativeApolloSetupRejectsUnsupportedStreamPolicyBeforeProviderReadiness(t *testing.T) {
	work := protocol.ProviderSessionWork{
		Version: "1", SessionID: "session-1", GatewayID: "gateway-1",
		ExpiresAt: "2099-01-01T00:00:00Z", ProviderProfile: ProviderProfileApollo,
		ProviderIdentity: "provider#sha256:00", PolicyVersionID: "policy-1",
		ApplicationID: "1", ClientID: "client-1", ManagementHost: "127.0.0.1", ManagementPort: 1,
		StreamHost: "127.0.0.1", StreamPort: 1, ClientCertificatePem: "invalid",
		ClientPrivateKeyPem: "invalid", ServerCertificatePem: "invalid",
		ClipboardPolicy: protocol.ClipboardPolicy{MaxTextBytes: 65536, MaxUpdatesPerMinute: 30},
	}
	for name, policy := range map[string]protocol.ProviderStreamPolicy{
		"audio-disabled":  {ResolutionWidth: 1920, ResolutionHeight: 1080, Fps: 60, Codec: "H264", BitrateKbps: 8000, AudioEnabled: false},
		"av1":             {ResolutionWidth: 3840, ResolutionHeight: 2160, Fps: 60, Codec: "AV1", BitrateKbps: 50000, AudioEnabled: true},
		"h264-resolution": {ResolutionWidth: 4097, ResolutionHeight: 2160, Fps: 60, Codec: "H264", BitrateKbps: 50000, AudioEnabled: true},
		"hevc-resolution": {ResolutionWidth: 8193, ResolutionHeight: 4320, Fps: 60, Codec: "HEVC", BitrateKbps: 80000, AudioEnabled: true},
		"fps":             {ResolutionWidth: 1920, ResolutionHeight: 1080, Fps: 241, Codec: "H264", BitrateKbps: 8000, AudioEnabled: true},
		"bitrate-cap":     {ResolutionWidth: 1920, ResolutionHeight: 1080, Fps: 60, Codec: "H264", BitrateKbps: 125001, AudioEnabled: true},
	} {
		t.Run(name, func(t *testing.T) {
			work.StreamPolicy = policy
			_, err := NewNativeApolloBackend().Setup(context.Background(), LaunchRequest{
				SessionID: "session-1", ProviderProfile: ProviderProfileApollo, ProviderWork: work,
			}, nil)
			if !errors.Is(err, ErrProviderMalformed) {
				t.Fatalf("Setup() error = %v, want ErrProviderMalformed before provider readiness", err)
			}
		})
	}
}

func TestNativeApolloRejectsProviderCapabilityMismatchBeforeInventoryOrLaunch(t *testing.T) {
	serverTLS, clientTLS := testTLS(t)
	var paths []string
	management := httptest.NewUnstartedServer(http.HandlerFunc(func(response http.ResponseWriter, request *http.Request) {
		paths = append(paths, request.URL.Path)
		switch request.URL.Path {
		case "/serverinfo":
			_, _ = response.Write([]byte("<root><uniqueid>apollo-server</uniqueid><ServerCodecModeSupport>1</ServerCodecModeSupport><MaxLumaPixelsHEVC>0</MaxLumaPixelsHEVC></root>"))
		case "/applist":
			_, _ = response.Write([]byte("<root><App><ID>42</ID></App></root>"))
		default:
			http.Error(response, "unexpected provider request", http.StatusBadRequest)
		}
	}))
	management.TLS = serverTLS
	management.StartTLS()
	defer management.Close()
	host, portText, err := net.SplitHostPort(management.Listener.Addr().String())
	if err != nil {
		t.Fatal(err)
	}
	port, err := strconv.ParseInt(portText, 10, 64)
	if err != nil {
		t.Fatal(err)
	}
	pinned := sha256.Sum256(serverTLS.Certificates[0].Certificate[0])
	work := protocol.ProviderSessionWork{
		Version: "1", SessionID: "session-source-policy", GatewayID: "gateway-1",
		ExpiresAt: "2099-01-01T00:00:00Z", ProviderProfile: ProviderProfileApollo,
		ProviderIdentity: "apollo-server#sha256:" + hex.EncodeToString(pinned[:]), PolicyVersionID: "policy-1",
		ApplicationID: "42", ClientID: "paired-client",
		StreamPolicy: protocol.ProviderStreamPolicy{
			ResolutionWidth: 2560, ResolutionHeight: 1440, Fps: 120,
			Codec: "HEVC", BitrateKbps: 40000, AudioEnabled: true,
		},
		ManagementHost: host, ManagementPort: port, StreamHost: host, StreamPort: 47984,
		ClientCertificatePem: certificatePEM(t, clientTLS.Certificates[0]),
		ClientPrivateKeyPem:  privateKeyPEM(t, clientTLS.Certificates[0]),
		ServerCertificatePem: certificatePEM(t, tls.Certificate{Certificate: [][]byte{serverTLS.Certificates[0].Certificate[1]}}),
		ClipboardPolicy:      protocol.ClipboardPolicy{MaxTextBytes: 65536, MaxUpdatesPerMinute: 30},
	}
	adapter := NewApolloAdapter(NewNativeApolloBackend(), ProviderIdentity{UniqueID: "apollo-server", Fingerprint: "sha256:" + hex.EncodeToString(pinned[:])})
	if _, err := adapter.Start(context.Background(), LaunchRequest{
		SessionID: work.SessionID, ProviderProfile: ProviderProfileApollo,
		ProviderIdentity: work.ProviderIdentity, ProviderWork: work,
	}); err == nil {
		t.Fatal("Start() accepted a provider/source policy mismatch")
	}
	if got := strings.Join(paths, ","); got != "/serverinfo" {
		t.Fatalf("provider requests before capability rejection = %s", got)
	}
}

func TestApolloProviderCapabilityRejectsHEVCLumaDowngrade(t *testing.T) {
	info := ManagementInfo{
		ServerCodecModeSupport: 0x101, HasServerCodecModeSupport: true,
		MaxLumaPixelsHEVC: 1920 * 1080, HasMaxLumaPixelsHEVC: true,
	}
	policy := protocol.ProviderStreamPolicy{
		ResolutionWidth: 3840, ResolutionHeight: 2160, Fps: 60,
		Codec: "HEVC", BitrateKbps: 80000, AudioEnabled: true,
	}
	if err := validateApolloProviderStreamPolicy(info, policy); !errors.Is(err, ErrProviderMalformed) {
		t.Fatalf("provider HEVC luma downgrade error = %v", err)
	}
}

func TestNativeApolloSetupRequiresModernEncryptedRTSPOrder(t *testing.T) {
	serverTLS, clientTLS := testTLS(t)
	streamListener, err := net.Listen("tcp", "127.0.0.1:0")
	if err != nil {
		t.Fatal(err)
	}
	defer streamListener.Close()
	controlServer, err := net.ListenUDP("udp", &net.UDPAddr{IP: net.ParseIP("127.0.0.1")})
	if err != nil {
		t.Fatal(err)
	}
	defer controlServer.Close()
	audioServer, err := net.ListenUDP("udp", &net.UDPAddr{IP: net.ParseIP("127.0.0.1")})
	if err != nil {
		t.Fatal(err)
	}
	defer audioServer.Close()
	videoServer, err := net.ListenUDP("udp", &net.UDPAddr{IP: net.ParseIP("127.0.0.1")})
	if err != nil {
		t.Fatal(err)
	}
	defer videoServer.Close()
	streamHost, streamPortText, err := net.SplitHostPort(streamListener.Addr().String())
	if err != nil {
		t.Fatal(err)
	}
	streamPort, err := strconv.ParseInt(streamPortText, 10, 64)
	if err != nil {
		t.Fatal(err)
	}
	type fixtureKeyMaterial struct {
		key   []byte
		keyID uint32
	}
	keyReady := make(chan []byte, 1)
	keyMaterialReady := make(chan fixtureKeyMaterial, 1)
	clipboardWrites := make(chan string, 1)
	cancelCalls := make(chan struct{}, 1)
	streamDone := make(chan error, 1)
	go func() {
		key := <-keyReady
		codec, codecErr := newEncryptedRTSPCodec(key)
		if codecErr != nil {
			streamDone <- codecErr
			return
		}
		expectedMethods := []string{"OPTIONS", "DESCRIBE", "SETUP", "SETUP", "SETUP", "ANNOUNCE", "PLAY"}
		expectedTargets := []string{"rtspenc://" + streamListener.Addr().String(), "rtspenc://" + streamListener.Addr().String(), "streamid=audio/0/0", "streamid=video/0/0", "streamid=control/13/0", "streamid=control/13/0", "/"}
		describeBody := "a=x-ss-general.featureFlags:1\r\na=x-ss-general.encryptionSupported:7\r\na=x-ss-general.encryptionRequested:1\r\na=fmtp:97 surround-params=21101\r\n"
		responses := []string{
			"RTSP/1.0 200 OK\r\nCSeq: 1\r\n\r\n",
			fmt.Sprintf("RTSP/1.0 200 OK\r\nCSeq: 2\r\nContent-Type: application/sdp\r\nContent-Length: %d\r\n\r\n%s", len(describeBody), describeBody),
			fmt.Sprintf("RTSP/1.0 200 OK\r\nCSeq: 3\r\nSession: fixture-session;timeout=90\r\nTransport: unicast;server_port=%d\r\nX-SS-Ping-Payload: 0123456789abcdef\r\n\r\n", audioServer.LocalAddr().(*net.UDPAddr).Port),
			fmt.Sprintf("RTSP/1.0 200 OK\r\nCSeq: 4\r\nSession: fixture-session\r\nTransport: unicast;server_port=%d\r\nX-SS-Ping-Payload: fedcba9876543210\r\n\r\n", videoServer.LocalAddr().(*net.UDPAddr).Port),
			fmt.Sprintf("RTSP/1.0 200 OK\r\nCSeq: 5\r\nSession: fixture-session\r\nTransport: unicast;server_port=%d\r\nX-SS-Connect-Data: 305419896\r\n\r\n", controlServer.LocalAddr().(*net.UDPAddr).Port),
			"RTSP/1.0 200 OK\r\nCSeq: 6\r\nSession: fixture-session\r\n\r\n",
			"RTSP/1.0 200 OK\r\nCSeq: 7\r\nSession: fixture-session\r\n\r\n",
		}
		for index, method := range expectedMethods {
			connection, acceptErr := streamListener.Accept()
			if acceptErr != nil {
				streamDone <- acceptErr
				return
			}
			header := make([]byte, encryptedRTSPHeaderSize)
			if _, readErr := io.ReadFull(connection, header); readErr != nil {
				_ = connection.Close()
				streamDone <- readErr
				return
			}
			length := binary.BigEndian.Uint32(header[:4]) & 0x7fffffff
			frame := make([]byte, encryptedRTSPHeaderSize+int(length))
			copy(frame, header)
			if _, readErr := io.ReadFull(connection, frame[encryptedRTSPHeaderSize:]); readErr != nil {
				_ = connection.Close()
				streamDone <- readErr
				return
			}
			plaintext, decryptErr := codec.OpenClient(frame)
			firstLine, _, _ := strings.Cut(string(plaintext), "\r\n")
			if decryptErr != nil || firstLine != method+" "+expectedTargets[index]+" RTSP/1.0" || !strings.Contains(string(plaintext), "CSeq: "+strconv.Itoa(index+1)+"\r\n") {
				_, _ = connection.Write(hostEncryptedRTSPFrame(t, key, uint32(index+1), []byte("RTSP/1.0 400 Bad Request\r\nCSeq: "+strconv.Itoa(index+1)+"\r\n\r\n")))
				_ = connection.Close()
				streamDone <- ErrProviderMalformed
				return
			}
			if method == "ANNOUNCE" {
				for _, required := range []string{
					"a=x-nv-video[0].clientViewportWd:2560", "a=x-nv-video[0].clientViewportHt:1440", "a=x-nv-video[0].maxFPS:120",
					"a=x-nv-video[0].packetSize:1024", "a=x-nv-clientSupportHevc:1", "a=x-nv-vqos[0].bitStreamFormat:1",
					"a=x-nv-vqos[0].bw.maximumBitrateKbps:32000", "a=x-ml-video.configuredBitrateKbps:40000", "a=x-nv-audio.surround.numChannels:2",
					"a=x-nv-general.useReliableUdp:13", "a=x-ss-general.encryptionEnabled:7",
				} {
					if !strings.Contains(string(plaintext), required+"\r\n") {
						_ = connection.Close()
						streamDone <- ErrProviderMalformed
						return
					}
				}
			}
			_, writeErr := connection.Write(hostEncryptedRTSPFrame(t, key, uint32(index+1), []byte(responses[index])))
			_ = connection.Close()
			if writeErr != nil {
				streamDone <- writeErr
				return
			}
		}
		streamDone <- nil
	}()
	management := httptest.NewUnstartedServer(http.HandlerFunc(func(response http.ResponseWriter, request *http.Request) {
		if request.TLS == nil || len(request.TLS.PeerCertificates) != 1 {
			http.Error(response, "mTLS required", http.StatusUnauthorized)
			return
		}
		switch request.URL.Path {
		case "/serverinfo":
			_, _ = response.Write([]byte("<root><uniqueid>apollo-server</uniqueid><ServerCodecModeSupport>257</ServerCodecModeSupport><MaxLumaPixelsHEVC>1869449984</MaxLumaPixelsHEVC></root>"))
		case "/applist":
			if request.URL.Query().Get("uniqueid") != "paired-client" {
				http.Error(response, "wrong client", http.StatusBadRequest)
				return
			}
			_, _ = response.Write([]byte("<root><App><ID>42</ID></App></root>"))
		case "/launch":
			query := request.URL.Query()
			if query.Get("uniqueid") != "paired-client" || query.Get("appid") != "42" || query.Get("corever") != "1" || query.Get("localAudioPlayMode") != "0" {
				http.Error(response, "wrong launch", http.StatusBadRequest)
				return
			}
			key, decodeErr := hex.DecodeString(query.Get("rikey"))
			if decodeErr != nil || len(key) != 16 || query.Get("rikeyid") == "" {
				http.Error(response, "bad key", http.StatusBadRequest)
				return
			}
			keyID, keyIDErr := strconv.ParseUint(query.Get("rikeyid"), 10, 32)
			if keyIDErr != nil {
				http.Error(response, "bad key id", http.StatusBadRequest)
				return
			}
			keyReady <- key
			keyMaterialReady <- fixtureKeyMaterial{key: append([]byte(nil), key...), keyID: uint32(keyID)}
			_, _ = response.Write([]byte("<root status_code=\"200\"><sessionUrl0>rtspenc://" + streamListener.Addr().String() + "</sessionUrl0></root>"))
		case "/resume":
			_, _ = response.Write([]byte("<root status_code=\"200\"/>"))
		case "/cancel":
			if request.Method != http.MethodGet {
				http.Error(response, "cancel must be GET", http.StatusMethodNotAllowed)
				return
			}
			cancelCalls <- struct{}{}
			_, _ = response.Write([]byte("<root status_code=\"200\"><cancel>1</cancel></root>"))
		case "/actions/clipboard":
			if request.URL.Query().Get("type") != "text" || (request.Method != http.MethodGet && request.Method != http.MethodPost) {
				http.Error(response, "bad clipboard request", http.StatusBadRequest)
				return
			}
			if request.Method == http.MethodPost {
				body, readErr := io.ReadAll(request.Body)
				if readErr != nil || string(body) != "client clipboard" {
					http.Error(response, "bad clipboard body", http.StatusBadRequest)
					return
				}
				clipboardWrites <- string(body)
				return
			}
			_, _ = response.Write([]byte("fixture clipboard"))
		default:
			http.NotFound(response, request)
		}
	}))
	management.TLS = serverTLS
	management.StartTLS()
	defer management.Close()
	managementHost, managementPortText, err := net.SplitHostPort(management.Listener.Addr().String())
	if err != nil {
		t.Fatal(err)
	}
	managementPort, err := strconv.ParseInt(managementPortText, 10, 64)
	if err != nil {
		t.Fatal(err)
	}
	pinned := sha256.Sum256(serverTLS.Certificates[0].Certificate[0])
	work := protocol.ProviderSessionWork{
		Version: "1", SessionID: "session-1", GatewayID: "gateway-1", ReconnectSequence: 0,
		ExpiresAt: "2099-01-01T00:00:00Z", ProviderProfile: ProviderProfileApollo,
		ProviderIdentity: "apollo-server#sha256:" + hex.EncodeToString(pinned[:]), PolicyVersionID: "policy-1", ApplicationID: "42", ClientID: "paired-client",
		StreamPolicy:   protocol.ProviderStreamPolicy{ResolutionWidth: 2560, ResolutionHeight: 1440, Fps: 120, Codec: "HEVC", BitrateKbps: 40000, AudioEnabled: true},
		ManagementHost: managementHost, ManagementPort: managementPort, StreamHost: streamHost, StreamPort: streamPort,
		ClientCertificatePem: certificatePEM(t, clientTLS.Certificates[0]), ClientPrivateKeyPem: privateKeyPEM(t, clientTLS.Certificates[0]),
		ServerCertificatePem:                  certificatePEM(t, tls.Certificate{Certificate: [][]byte{serverTLS.Certificates[0].Certificate[1]}}),
		ClipboardPolicy:                       protocol.ClipboardPolicy{MaxTextBytes: 65536, MaxUpdatesPerMinute: 30},
		ProviderApplicationTerminationAllowed: true,
	}
	backend := NewNativeApolloBackend()
	response, err := backend.Setup(context.Background(), LaunchRequest{SessionID: "session-1", ProviderProfile: ProviderProfileApollo, ProviderWork: work}, []byte("<root><uniqueid>apollo-server</uniqueid><ServerCodecModeSupport>257</ServerCodecModeSupport><MaxLumaPixelsHEVC>1869449984</MaxLumaPixelsHEVC></root>"))
	if err != nil {
		t.Fatalf("Setup() error = %v", err)
	}
	if parsed, err := ParseRTSPResponse(response); err != nil || parsed.Session != "fixture-session" {
		t.Fatalf("ParseRTSPResponse() = %+v, %v", parsed, err)
	}
	if err := <-streamDone; err != nil {
		t.Fatalf("stream transaction error = %v", err)
	}
	material := <-keyMaterialReady
	videoData, videoParity := sourceShapedEncryptedVideoFEC(t, material.key)
	audioPackets := make([][]byte, 0, apolloAudioDataShards)
	for index, payload := range [][]byte{{'A'}, {'B'}, {'C'}, {'D'}} {
		audioPackets = append(audioPackets, sourceShapedEncryptedAudioPacket(t, material.key, material.keyID, uint16(index), payload))
	}
	mediaDone := make(chan error, 2)
	serveMedia := func(server *net.UDPConn, ping string, packets [][]byte) {
		buffer := make([]byte, apolloMediaMaximumPacket)
		count, remote, readErr := server.ReadFromUDP(buffer)
		if readErr != nil || count != 20 || string(buffer[:16]) != ping {
			if readErr != nil {
				mediaDone <- readErr
			} else {
				mediaDone <- ErrProviderMalformed
			}
			return
		}
		for _, packet := range packets {
			if _, writeErr := server.WriteToUDP(packet, remote); writeErr != nil {
				mediaDone <- writeErr
				return
			}
		}
		mediaDone <- nil
	}
	go serveMedia(audioServer, "0123456789abcdef", audioPackets)
	go serveMedia(videoServer, "fedcba9876543210", [][]byte{videoData, videoParity})
	type observedControl struct {
		typeID   uint16
		reliable bool
	}
	controls := make(chan observedControl, 16)
	controlRemote := make(chan *net.UDPAddr, 1)
	controlDone := make(chan error, 1)
	go func() {
		buffer := make([]byte, apolloENetMaximumPacket)
		count, remote, readErr := controlServer.ReadFromUDP(buffer)
		if readErr != nil {
			controlDone <- readErr
			return
		}
		connect := buffer[:count]
		if count != 52 || connect[4] != apolloENetConnect|apolloENetAcknowledged || connect[5] != 0xff || binary.BigEndian.Uint32(connect[20:24]) != apolloENetChannels || binary.BigEndian.Uint32(connect[48:52]) != 305419896 {
			controlDone <- ErrProviderMalformed
			return
		}
		verify := make([]byte, 48)
		apolloENetHeader(verify, 0, 0, time.Now())
		verify[4] = apolloENetVerifyConnect | apolloENetAcknowledged
		verify[5] = 0xff
		binary.BigEndian.PutUint16(verify[6:8], 1)
		binary.BigEndian.PutUint16(verify[8:10], 7)
		verify[10], verify[11] = 2, 3
		binary.BigEndian.PutUint32(verify[12:16], 1400)
		binary.BigEndian.PutUint32(verify[16:20], 32768)
		binary.BigEndian.PutUint32(verify[20:24], apolloENetChannels)
		binary.BigEndian.PutUint32(verify[44:48], binary.BigEndian.Uint32(connect[44:48]))
		if _, writeErr := controlServer.WriteToUDP(verify, remote); writeErr != nil {
			controlDone <- writeErr
			return
		}
		controlRemote <- remote
		for {
			count, _, readErr = controlServer.ReadFromUDP(buffer)
			if readErr != nil {
				controlDone <- readErr
				return
			}
			packet := buffer[:count]
			if len(packet) < 8 {
				controlDone <- ErrProviderMalformed
				return
			}
			command, channel := packet[4]&apolloENetCommandMask, packet[5]
			sequence := binary.BigEndian.Uint16(packet[6:8])
			switch command {
			case 1:
				continue
			case apolloENetSendReliable:
				if len(packet) < 10 || int(binary.BigEndian.Uint16(packet[8:10])) != len(packet)-10 {
					controlDone <- ErrProviderMalformed
					return
				}
				typeID, _ := sourceOpenClientControl(t, material.key, packet[10:])
				controls <- observedControl{typeID: typeID, reliable: true}
				if _, writeErr := controlServer.WriteToUDP(sourceShapedENetAcknowledgePacket(7, 2, channel, sequence), remote); writeErr != nil {
					controlDone <- writeErr
					return
				}
			case apolloENetSendUnsequenced:
				if len(packet) < 12 || int(binary.BigEndian.Uint16(packet[10:12])) != len(packet)-12 {
					controlDone <- ErrProviderMalformed
					return
				}
				typeID, _ := sourceOpenClientControl(t, material.key, packet[12:])
				controls <- observedControl{typeID: typeID}
			case apolloENetPing:
				if _, writeErr := controlServer.WriteToUDP(sourceShapedENetAcknowledgePacket(7, 2, channel, sequence), remote); writeErr != nil {
					controlDone <- writeErr
					return
				}
			case apolloENetDisconnect:
				_, writeErr := controlServer.WriteToUDP(sourceShapedENetAcknowledgePacket(7, 2, channel, sequence), remote)
				controlDone <- writeErr
				return
			default:
				controlDone <- ErrProviderMalformed
				return
			}
		}
	}()
	request := LaunchRequest{SessionID: "session-1", ProviderProfile: ProviderProfileApollo, ProviderWork: work}
	parsed, err := ParseRTSPResponse(response)
	if err != nil {
		t.Fatal(err)
	}
	session, err := backend.Open(context.Background(), request, parsed)
	if err != nil {
		t.Fatalf("Open() error = %v", err)
	}
	if err := session.Ready(context.Background()); err != nil {
		t.Fatalf("Ready() error = %v", err)
	}
	if clipboard, clipboardErr := session.ReadClipboard(context.Background()); clipboardErr != nil || clipboard != "fixture clipboard" {
		t.Fatalf("ReadClipboard() = %q, %v", clipboard, clipboardErr)
	}
	if err := session.WriteClipboard(context.Background(), "client clipboard"); err != nil {
		t.Fatalf("WriteClipboard() error = %v", err)
	}
	select {
	case <-clipboardWrites:
	case <-time.After(time.Second):
		t.Fatal("provider did not receive authenticated clipboard write")
	}
	awaitControl := func(want uint16, reliable bool) {
		deadline := time.NewTimer(time.Second)
		defer deadline.Stop()
		for {
			select {
			case observed := <-controls:
				if observed.typeID == want && observed.reliable == reliable {
					return
				}
			case <-deadline.C:
				t.Fatalf("provider did not receive control %#x", want)
			}
		}
	}
	awaitControl(apolloControlTypeIDR, true)
	awaitControl(apolloControlTypeStart, true)
	if err := session.Input(context.Background(), InputEvent{Device: "keyboard", Code: 7, Pressed: true}); err != nil {
		t.Fatal(err)
	}
	awaitControl(apolloControlTypeInput, true)
	if err := session.Feedback(context.Background(), Feedback{Kind: FeedbackFEC, Payload: []byte{0, 0, 0, 42, 0, 5, 0, 3, 0, 2, 0, 10, 0, 2, 0, 8, 0, 2, 20, 0, 1}}); err != nil {
		t.Fatal(err)
	}
	awaitControl(apolloControlTypeFEC, false)
	select {
	case media := <-session.Video():
		payload := media.Payload
		if len(payload) != 1001 || payload[0] != 'A' || payload[1000] != 'B' {
			t.Fatalf("source-shaped video relay = %x", payload)
		}
	case <-time.After(time.Second):
		t.Fatal("source-shaped video was not relayed")
	}
	select {
	case media := <-session.Audio():
		payload := media.Payload
		if string(payload) != "A" {
			t.Fatalf("source-shaped audio relay = %x", payload)
		}
	case <-time.After(time.Second):
		t.Fatal("source-shaped audio was not relayed")
	}
	remote := <-controlRemote
	hostTermination := sourceSealHostControl(t, material.key, 0, apolloControlTypeTerm, []byte{1, 2, 3, 4})
	if _, err := controlServer.WriteToUDP(sourceShapedENetReliablePacketOn(7, 2, apolloChannelGeneric, 1, hostTermination), remote); err != nil {
		t.Fatal(err)
	}
	select {
	case event := <-session.Events():
		if event.Kind != ProviderEventTerminated || string(event.Payload) != string([]byte{1, 2, 3, 4}) {
			t.Fatalf("provider termination event = %#v", event)
		}
	case <-time.After(time.Second):
		t.Fatal("encrypted host termination was not forwarded")
	}
	terminateCtx, cancel := context.WithTimeout(context.Background(), time.Second)
	defer cancel()
	if err := session.Terminate(terminateCtx); err != nil {
		t.Fatalf("Terminate() error = %v", err)
	}
	select {
	case <-cancelCalls:
	case <-time.After(time.Second):
		t.Fatal("authorized provider application cancellation was not sent")
	}
	if err := <-controlDone; err != nil {
		t.Fatalf("control fake = %v", err)
	}
	for range 2 {
		if err := <-mediaDone; err != nil {
			t.Fatalf("media fake = %v", err)
		}
	}
}

func TestValidateApolloDescribeRejectsUnknownLines(t *testing.T) {
	message := apolloRTSPMessage{
		headers: map[string]string{"content-type": "application/sdp"},
		body: []byte("a=x-ss-general.featureFlags:1\r\n" +
			"a=x-ss-general.encryptionSupported:7\r\n" +
			"a=x-ss-general.encryptionRequested:1\r\n" +
			"a=fmtp:97 surround-params=21101\r\n" +
			"unexpected-source-line\r\n"),
	}
	if err := validateApolloDescribe(message); err == nil {
		t.Fatal("validateApolloDescribe() accepted an unknown source line")
	}
}

func TestNativeApolloTerminateSkipsProviderCancelWithoutServerPolicy(t *testing.T) {
	session := newNativeApolloSession("session-1")
	close(session.readDone)
	session.managementClient = &http.Client{Transport: nativeRoundTripFunc(func(request *http.Request) (*http.Response, error) {
		t.Fatalf("unauthorized provider cancellation request: %s %s", request.Method, request.URL)
		return nil, fmt.Errorf("unexpected provider cancellation")
	})}
	session.managementHost = "provider.invalid"
	session.managementPort = 47984
	if err := session.Terminate(context.Background()); err != nil {
		t.Fatalf("Terminate() error = %v", err)
	}
}

func TestNativeApolloTerminateRetainsCleanupPendingAfterFailure(t *testing.T) {
	session := newNativeApolloSession("session-1")
	failed, cancel := context.WithCancel(context.Background())
	cancel()
	if err := session.Terminate(failed); !errors.Is(err, context.Canceled) {
		t.Fatalf("first Terminate() error = %v", err)
	}
	if state := session.State(); state.State != ProviderStateCleanup || !state.CleanupPending {
		t.Fatalf("failed cleanup state = %#v", state)
	}
	if err := session.Terminate(context.Background()); !errors.Is(err, context.Canceled) {
		t.Fatalf("second Terminate() error = %v", err)
	}
	if state := session.State(); state.State != ProviderStateCleanup || !state.CleanupPending {
		t.Fatalf("repeated cleanup state = %#v", state)
	}
}

func TestApolloReconnectUsesResumeWithFreshRIK(t *testing.T) {
	work := protocol.ProviderSessionWork{ReconnectSequence: 1, ApplicationID: "42", ClientID: "paired-client"}
	path, values := apolloSessionRequest(work, []byte("0123456789abcdef"), 0x01020304)
	if path != "/resume" || values.Get("rikey") != "30313233343536373839616263646566" || values.Get("rikeyid") != "16909060" || values.Get("localAudioPlayMode") != "0" {
		t.Fatalf("resume request = path %q values %#v", path, values)
	}
	if values.Get("appid") != "" || values.Get("uniqueid") != "" || values.Get("corever") != "" {
		t.Fatalf("resume request leaked launch-only values %#v", values)
	}
}

func TestNativeApolloSessionRelaysOnlyAuthenticatedEncodedUDPMedia(t *testing.T) {
	key := []byte("0123456789abcdef")
	audioServer, err := net.ListenUDP("udp", &net.UDPAddr{IP: net.ParseIP("127.0.0.1")})
	if err != nil {
		t.Fatal(err)
	}
	defer audioServer.Close()
	videoServer, err := net.ListenUDP("udp", &net.UDPAddr{IP: net.ParseIP("127.0.0.1")})
	if err != nil {
		t.Fatal(err)
	}
	defer videoServer.Close()
	audioClient, err := net.DialUDP("udp", nil, audioServer.LocalAddr().(*net.UDPAddr))
	if err != nil {
		t.Fatal(err)
	}
	videoClient, err := net.DialUDP("udp", nil, videoServer.LocalAddr().(*net.UDPAddr))
	if err != nil {
		t.Fatal(err)
	}
	session := newNativeApolloSession("session-media")
	const keyID = 0x01020304
	session.media, err = newApolloMediaCodec(key, keyID)
	if err != nil {
		t.Fatal(err)
	}
	session.audioConn, session.videoConn = audioClient, videoClient
	go session.readUDPMedia()

	videoPacket := sourceShapedEncryptedVideoPacket(t, key, []byte{0x01, 0x02, 0x03})
	if _, err := videoServer.WriteToUDP(videoPacket, videoClient.LocalAddr().(*net.UDPAddr)); err != nil {
		t.Fatal(err)
	}
	wantAudio := [][]byte{{0xf8, 0x08}, {0xf8, 0x09}, {0xf8, 0x0a}, {0xf8, 0x0b}}
	for index, payload := range wantAudio {
		packet := sourceShapedEncryptedAudioPacket(t, key, keyID, uint16(8+index), payload)
		if _, err := audioServer.WriteToUDP(packet, audioClient.LocalAddr().(*net.UDPAddr)); err != nil {
			t.Fatal(err)
		}
	}

	select {
	case media := <-session.Video():
		payload := media.Payload
		if string(payload) != string([]byte{0x01, 0x02, 0x03}) {
			t.Fatalf("video relay = %x, want encoded payload", payload)
		}
	case <-time.After(time.Second):
		t.Fatal("encrypted video was not relayed")
	}
	for _, want := range wantAudio {
		select {
		case media := <-session.Audio():
			payload := media.Payload
			if string(payload) != string(want) {
				t.Fatalf("audio relay = %x, want %x", payload, want)
			}
		case <-time.After(time.Second):
			t.Fatal("encrypted audio was not relayed")
		}
	}
	dataPacket, parityPacket := sourceShapedEncryptedVideoFEC(t, key)
	for _, packet := range [][]byte{dataPacket, parityPacket} {
		if _, err := videoServer.WriteToUDP(packet, videoClient.LocalAddr().(*net.UDPAddr)); err != nil {
			t.Fatal(err)
		}
	}
	select {
	case media := <-session.Video():
		payload := media.Payload
		if len(payload) != 1001 || payload[0] != 'A' || payload[999] != 'A' || payload[1000] != 'B' {
			t.Fatalf("FEC video relay = %x", payload)
		}
	case <-time.After(time.Second):
		t.Fatal("encrypted FEC video was not recovered")
	}
	for _, packet := range sourceShapedEncryptedAudioFEC(t, key, keyID) {
		if _, err := audioServer.WriteToUDP(packet, audioClient.LocalAddr().(*net.UDPAddr)); err != nil {
			t.Fatal(err)
		}
	}
	for _, want := range [][]byte{{'A'}, {'B'}, {'C'}, {'D'}} {
		select {
		case media := <-session.Audio():
			payload := media.Payload
			if string(payload) != string(want) {
				t.Fatalf("FEC audio relay = %x, want %x", payload, want)
			}
		case <-time.After(time.Second):
			t.Fatal("encrypted FEC audio was not recovered")
		}
	}
	for block := 0; block < apolloAudioMaximumBlocks+1; block++ {
		sequence := uint16(100 + block*apolloAudioDataShards)
		packet := sourceShapedEncryptedAudioPacketWithHeaders(t, key, keyID, sequence, uint32(sequence)*5, 1, []byte{byte(block)})
		if _, err := audioServer.WriteToUDP(packet, audioClient.LocalAddr().(*net.UDPAddr)); err != nil {
			t.Fatal(err)
		}
	}
	for index, want := range [][]byte{{0xa0}, {0xa1}, {0xa2}, {0xa3}} {
		sequence := uint16(124 + index)
		packet := sourceShapedEncryptedAudioPacketWithHeaders(t, key, keyID, sequence, uint32(sequence)*5, 1, want)
		if _, err := audioServer.WriteToUDP(packet, audioClient.LocalAddr().(*net.UDPAddr)); err != nil {
			t.Fatal(err)
		}
	}
	for _, want := range [][]byte{{0xa0}, {0xa1}, {0xa2}, {0xa3}} {
		select {
		case media := <-session.Audio():
			payload := media.Payload
			if string(payload) != string(want) {
				t.Fatalf("post-loss audio relay = %x, want %x", payload, want)
			}
		case <-time.After(time.Second):
			t.Fatal("sustained loss permanently stalled newer audio")
		}
	}
	if drops := session.Telemetry().MediaDrops; drops < 2 {
		t.Fatalf("stale FEC eviction drops = %d, want at least 2", drops)
	}
	terminateCtx, cancel := context.WithTimeout(context.Background(), time.Second)
	defer cancel()
	if err := session.Terminate(terminateCtx); err != nil {
		t.Fatalf("Terminate() error = %v", err)
	}
}

func TestNativeApolloTerminateReleasesPressedProviderInput(t *testing.T) {
	server, err := net.ListenUDP("udp", &net.UDPAddr{IP: net.ParseIP("127.0.0.1")})
	if err != nil {
		t.Fatal(err)
	}
	defer server.Close()
	client, err := net.DialUDP("udp", nil, server.LocalAddr().(*net.UDPAddr))
	if err != nil {
		t.Fatal(err)
	}
	peer, err := newApolloENetPeer(client, time.Now)
	if err != nil {
		t.Fatal(err)
	}
	peer.state, peer.peerID, peer.outboundSession = apolloENetConnected, 1, 1
	codecKey := []byte("0123456789abcdef")
	codec, err := newApolloControlCodec(codecKey)
	if err != nil {
		t.Fatal(err)
	}
	session := newNativeApolloSession("session-terminate")
	session.enet, session.control = peer, codec
	close(session.readDone)
	packets := make(chan []byte, 3)
	go func() {
		defer close(packets)
		buffer := make([]byte, apolloENetMaximumPacket)
		for {
			_ = server.SetReadDeadline(time.Now().Add(time.Second))
			count, _, readErr := server.ReadFromUDP(buffer)
			if readErr != nil {
				return
			}
			packet := append([]byte(nil), buffer[:count]...)
			packets <- packet
			if len(packet) >= 5 && packet[4]&apolloENetCommandMask == apolloENetDisconnect {
				peer.close(nil)
				return
			}
		}
	}()
	if err := session.Input(context.Background(), InputEvent{Device: "keyboard", Code: 7, Pressed: true}); err != nil {
		t.Fatal(err)
	}
	terminateCtx, cancel := context.WithTimeout(context.Background(), time.Second)
	defer cancel()
	if err := session.Terminate(terminateCtx); err != nil {
		t.Fatalf("Terminate() error = %v", err)
	}
	var observed [][]byte
	for packet := range packets {
		observed = append(observed, packet)
	}
	if len(observed) != 3 {
		t.Fatalf("provider packets = %d, want pressed input, release, disconnect", len(observed))
	}
	typeID, payload := sourceOpenClientControl(t, codecKey, observed[1][10:])
	if typeID != apolloControlTypeInput || len(payload) < 8 || binary.LittleEndian.Uint32(payload[4:8]) != 4 {
		t.Fatalf("release packet = type %#x payload %x", typeID, payload)
	}
}

func TestNativeApolloSessionForwardsEncryptedHostFeedback(t *testing.T) {
	key := []byte("0123456789abcdef")
	codec, err := newApolloControlCodec(key)
	if err != nil {
		t.Fatal(err)
	}
	session := newNativeApolloSession("session-feedback")
	session.control = codec
	messages := []struct {
		typeID  uint16
		payload []byte
		want    ProviderEvent
	}{
		{apolloControlTypeRumble, []byte{0, 0, 0, 0, 1, 0, 0x34, 0x12, 0x78, 0x56}, ProviderEvent{Kind: ProviderEventRumble, Payload: []byte{1, 0x12, 0x34, 0x56, 0x78}}},
		{apolloControlTypeHDR, append([]byte{1}, make([]byte, 26)...), ProviderEvent{Kind: ProviderEventHDR, Payload: []byte{1}}},
		{apolloControlTypeTerm, []byte{1, 2, 3, 4}, ProviderEvent{Kind: ProviderEventTerminated, Payload: []byte{1, 2, 3, 4}}},
	}
	for sequence, message := range messages {
		session.handleApolloControlPayload(apolloChannelGeneric, true, sourceSealHostControl(t, key, uint32(sequence), message.typeID, message.payload))
		select {
		case event := <-session.Events():
			if event.Kind != message.want.Kind || string(event.Payload) != string(message.want.Payload) {
				t.Fatalf("provider event = %#v, want %#v", event, message.want)
			}
		case <-time.After(time.Second):
			t.Fatalf("host event %#x was not forwarded", message.typeID)
		}
	}
}

func TestApolloTerminalEventSurvivesFullFeedbackQueue(t *testing.T) {
	session := newNativeApolloSession("session-full-feedback")
	key := []byte("0123456789abcdef")
	codec, err := newApolloControlCodec(key)
	if err != nil {
		t.Fatal(err)
	}
	session.control = codec
	for range cap(session.events) {
		session.events <- ProviderEvent{Kind: ProviderEventRumble, Payload: []byte{1, 0, 0, 0, 0}}
	}

	session.handleApolloControlPayload(
		apolloChannelGeneric,
		true,
		sourceSealHostControl(t, key, 0, apolloControlTypeTerm, []byte{1, 2, 3, 4}),
	)

	foundTerminal := false
	for range cap(session.events) {
		event := <-session.events
		foundTerminal = foundTerminal || event.Kind == ProviderEventTerminated
	}
	if !foundTerminal {
		t.Fatal("encrypted host termination was lost behind a full feedback queue")
	}
}

func TestPushLatestDropsExactlyOneOldPayload(t *testing.T) {
	queue := make(chan []byte, 1)
	if dropped := pushLatest(queue, []byte("old")); dropped {
		t.Fatal("first media payload dropped")
	}
	if dropped := pushLatest(queue, []byte("new")); !dropped {
		t.Fatal("bounded media queue did not report a drop")
	}
	if got := string(<-queue); got != "new" {
		t.Fatalf("bounded media queue payload = %q", got)
	}
}

func TestNativeProviderVideoQueueBoundsRealFrames(t *testing.T) {
	const maximumQueuedVideoBytes = 4 << 20
	session := newNativeApolloSession("bounded-video")
	frame := bytes.Repeat([]byte{0x65}, 768<<10)
	for index := 0; index < 12; index++ {
		if !session.enqueueMedia(session.video, append([]byte(nil), frame...), time.Now()) {
			t.Fatalf("frame %d was not accepted", index)
		}
	}

	var queuedBytes int
	for {
		select {
		case media := <-session.Video():
			queuedBytes += len(media.Payload)
		default:
			if queuedBytes > maximumQueuedVideoBytes {
				t.Fatalf("video queue retained %d bytes, limit %d", queuedBytes, maximumQueuedVideoBytes)
			}
			if drops := session.Telemetry().MediaDrops; drops != 7 {
				t.Fatalf("latest-frame replacements = %d, want 7", drops)
			}
			if maximum := session.mediaQueueMaximum.Load(); maximum > nativeApolloVideoQueuePackets {
				t.Fatalf("maximum video queue entries = %d", maximum)
			}
			if maximum := session.mediaQueueMaximumBytes.Load(); maximum > maximumQueuedVideoBytes {
				t.Fatalf("maximum video queue bytes = %d", maximum)
			}
			return
		}
	}
}

func TestNativeProviderVideoQueueExpiresResidence(t *testing.T) {
	session := newNativeApolloSession("expiring-video")
	if !session.enqueueMedia(session.video, []byte("stale-frame"), time.Now()) {
		t.Fatal("video frame was not accepted")
	}
	time.Sleep(nativeApolloVideoQueueLatency + 25*time.Millisecond)
	select {
	case media := <-session.Video():
		t.Fatalf("expired video remained queued: %#v", media)
	default:
	}
	if drops := session.Telemetry().MediaDrops; drops != 1 {
		t.Fatalf("expired video drops = %d, want 1", drops)
	}
}

func sourceShapedEncryptedVideoPacket(t *testing.T, key, encoded []byte) []byte {
	t.Helper()
	payload := make([]byte, apolloVideoShardPayloadSize)
	payload[0], payload[3] = 0x01, 0x01
	binary.LittleEndian.PutUint16(payload[4:6], uint16(8+len(encoded)))
	copy(payload[8:], encoded)
	plaintext := sourceShapedVideoRaw(42, 7, 1, 0x07, 1, 0, 0, payload)
	return sourceEncryptVideoRaw(t, key, plaintext, "0123456789aV")
}

func sourceShapedEncryptedVideoFEC(t *testing.T, key []byte) ([]byte, []byte) {
	t.Helper()
	firstPayload := make([]byte, apolloVideoShardPayloadSize)
	firstPayload[0], firstPayload[3] = 0x01, 0x01
	binary.LittleEndian.PutUint16(firstPayload[4:6], 1)
	for index := 8; index < len(firstPayload); index++ {
		firstPayload[index] = 'A'
	}
	secondPayload := make([]byte, apolloVideoShardPayloadSize)
	secondPayload[0] = 'B'
	first := sourceShapedVideoRaw(43, 100, 100, 0x05, 2, 50, 0, firstPayload)
	second := sourceShapedVideoRaw(43, 101, 101, 0x03, 2, 50, 1, secondPayload)
	parity := make([]byte, len(first))
	for index := range parity {
		parity[index] = first[index] ^ sourceGFMultiply(second[index], 142)
	}
	sourceConfigureVideoShard(first, 43, 100, 0, 2, 50, 0)
	sourceConfigureVideoShard(second, 43, 101, 1, 2, 50, 1)
	sourceConfigureVideoShard(parity, 43, 102, 2, 2, 50, 2)
	return sourceEncryptVideoRaw(t, key, second, "0123456789bV"), sourceEncryptVideoRaw(t, key, parity, "0123456789cV")
}

func sourceShapedVideoRaw(frame uint32, sequence uint16, streamIndex uint32, flags byte, dataShards, percentage, shardIndex int, payload []byte) []byte {
	raw := make([]byte, apolloVideoRawPacketSize)
	binary.LittleEndian.PutUint32(raw[16:20], streamIndex<<8)
	binary.LittleEndian.PutUint32(raw[20:24], frame)
	raw[24], raw[26] = flags, 0x10
	binary.LittleEndian.PutUint32(raw[28:32], uint32(shardIndex<<12|dataShards<<22|percentage<<4))
	copy(raw[32:], payload)
	sourceConfigureVideoShard(raw, frame, sequence, streamIndex, dataShards, percentage, shardIndex)
	return raw
}

func sourceConfigureVideoShard(raw []byte, frame uint32, sequence uint16, streamIndex uint32, dataShards, percentage, shardIndex int) {
	raw[0] = 0x90
	binary.BigEndian.PutUint16(raw[2:4], sequence)
	binary.BigEndian.PutUint32(raw[4:8], 99)
	binary.LittleEndian.PutUint32(raw[20:24], frame)
	raw[27] = 0
	binary.LittleEndian.PutUint32(raw[28:32], uint32(shardIndex<<12|dataShards<<22|percentage<<4))
}

func sourceEncryptVideoRaw(t *testing.T, key, plaintext []byte, iv string) []byte {
	t.Helper()
	if len(plaintext) != apolloVideoRawPacketSize || len(iv) != 12 {
		t.Fatal("invalid source video fixture")
	}
	block, err := aes.NewCipher(key)
	if err != nil {
		t.Fatal(err)
	}
	aead, err := cipher.NewGCM(block)
	if err != nil {
		t.Fatal(err)
	}
	sealed := aead.Seal(nil, []byte(iv), plaintext, nil)
	packet := make([]byte, 32+len(plaintext))
	copy(packet[:12], iv)
	binary.LittleEndian.PutUint32(packet[12:16], binary.LittleEndian.Uint32(plaintext[20:24]))
	copy(packet[16:32], sealed[len(plaintext):])
	copy(packet[32:], sealed[:len(plaintext)])
	return packet
}

func sourceOpenClientControl(t *testing.T, key, packet []byte) (uint16, []byte) {
	t.Helper()
	if len(packet) < apolloControlHeaderSize+apolloControlTagSize+apolloControlInnerSize || binary.LittleEndian.Uint16(packet[:2]) != apolloControlOuterType || int(binary.LittleEndian.Uint16(packet[2:4])) != len(packet)-4 {
		t.Fatalf("control packet = %x", packet)
	}
	block, err := aes.NewCipher(key)
	if err != nil {
		t.Fatal(err)
	}
	aead, err := cipher.NewGCM(block)
	if err != nil {
		t.Fatal(err)
	}
	nonce := make([]byte, 12)
	binary.LittleEndian.PutUint32(nonce, binary.LittleEndian.Uint32(packet[4:8]))
	nonce[10], nonce[11] = 'C', 'C'
	sealed := append([]byte(nil), packet[24:]...)
	sealed = append(sealed, packet[8:24]...)
	plaintext, err := aead.Open(nil, nonce, sealed, nil)
	if err != nil || len(plaintext) < apolloControlInnerSize || int(binary.LittleEndian.Uint16(plaintext[2:4])) != len(plaintext)-apolloControlInnerSize {
		t.Fatalf("control open = %x, %v", packet, err)
	}
	return binary.LittleEndian.Uint16(plaintext[:2]), append([]byte(nil), plaintext[4:]...)
}

func sourceSealHostControl(t *testing.T, key []byte, sequence uint32, typeID uint16, payload []byte) []byte {
	t.Helper()
	block, err := aes.NewCipher(key)
	if err != nil {
		t.Fatal(err)
	}
	aead, err := cipher.NewGCM(block)
	if err != nil {
		t.Fatal(err)
	}
	inner := make([]byte, apolloControlInnerSize+len(payload))
	binary.LittleEndian.PutUint16(inner[:2], typeID)
	binary.LittleEndian.PutUint16(inner[2:4], uint16(len(payload)))
	copy(inner[4:], payload)
	nonce := make([]byte, 12)
	binary.LittleEndian.PutUint32(nonce, sequence)
	nonce[10], nonce[11] = 'H', 'C'
	sealed := aead.Seal(nil, nonce, inner, nil)
	packet := make([]byte, apolloControlHeaderSize+len(sealed))
	binary.LittleEndian.PutUint16(packet[:2], apolloControlOuterType)
	binary.LittleEndian.PutUint16(packet[2:4], uint16(4+len(sealed)))
	binary.LittleEndian.PutUint32(packet[4:8], sequence)
	copy(packet[8:24], sealed[len(inner):])
	copy(packet[24:], sealed[:len(inner)])
	return packet
}

func sourceGFMultiply(first, second byte) byte {
	var product byte
	for second != 0 {
		if second&1 != 0 {
			product ^= first
		}
		high := first & 0x80
		first <<= 1
		if high != 0 {
			first ^= 0x1d
		}
		second >>= 1
	}
	return product
}

func sourceShapedEncryptedAudioPacket(t *testing.T, key []byte, keyID uint32, sequence uint16, encoded []byte) []byte {
	return sourceShapedEncryptedAudioPacketWithHeaders(t, key, keyID, sequence, 99, 1, encoded)
}

func sourceShapedEncryptedAudioPacketWithHeaders(t *testing.T, key []byte, keyID uint32, sequence uint16, timestamp, ssrc uint32, encoded []byte) []byte {
	t.Helper()
	packet := make([]byte, 12)
	packet[0], packet[1] = 0x80, 97
	binary.BigEndian.PutUint16(packet[2:4], sequence)
	binary.BigEndian.PutUint32(packet[4:8], timestamp)
	binary.BigEndian.PutUint32(packet[8:12], ssrc)
	padded := append([]byte(nil), encoded...)
	padding := aes.BlockSize - len(padded)%aes.BlockSize
	for range padding {
		padded = append(padded, byte(padding))
	}
	iv := make([]byte, aes.BlockSize)
	binary.BigEndian.PutUint32(iv, keyID+uint32(sequence))
	block, err := aes.NewCipher(key)
	if err != nil {
		t.Fatal(err)
	}
	cipher.NewCBCEncrypter(block, iv).CryptBlocks(padded, padded)
	return append(packet, padded...)
}

func sourceShapedEncryptedAudioFEC(t *testing.T, key []byte, keyID uint32) [][]byte {
	t.Helper()
	const base = uint16(12)
	const timestamp = uint32(100)
	data := make([][]byte, apolloAudioDataShards)
	for index, payload := range [][]byte{{'A'}, {'B'}, {'C'}, {'D'}} {
		data[index] = sourceShapedEncryptedAudioPacketWithHeaders(t, key, keyID, base+uint16(index), timestamp+uint32(index*5), 0, payload)
	}
	parity := make([]byte, len(data[0])-apolloRTPHeaderSize)
	for index, coefficient := range sourceAudioFECRow() {
		for offset, value := range data[index][apolloRTPHeaderSize:] {
			parity[offset] ^= sourceGFMultiply(value, coefficient)
		}
	}
	fec := make([]byte, apolloRTPHeaderSize+12+len(parity))
	fec[0], fec[1] = 0x80, 127
	binary.BigEndian.PutUint16(fec[2:4], base+apolloAudioDataShards)
	fec[apolloRTPHeaderSize+1] = 97
	binary.BigEndian.PutUint16(fec[apolloRTPHeaderSize+2:apolloRTPHeaderSize+4], base)
	binary.BigEndian.PutUint32(fec[apolloRTPHeaderSize+4:apolloRTPHeaderSize+8], timestamp)
	binary.BigEndian.PutUint32(fec[apolloRTPHeaderSize+8:apolloRTPHeaderSize+12], 0)
	copy(fec[apolloRTPHeaderSize+12:], parity)
	return [][]byte{data[1], data[2], data[3], fec}
}

func sourceAudioFECRow() []byte {
	return []byte{0x77, 0x40, 0x38, 0x0e}
}

func certificatePEM(t *testing.T, certificate tls.Certificate) string {
	t.Helper()
	if len(certificate.Certificate) == 0 {
		t.Fatal("expected certificate")
	}
	return string(pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: certificate.Certificate[0]}))
}

func privateKeyPEM(t *testing.T, certificate tls.Certificate) string {
	t.Helper()
	encoded, err := x509.MarshalPKCS8PrivateKey(certificate.PrivateKey)
	if err != nil {
		t.Fatal(err)
	}
	return string(pem.EncodeToMemory(&pem.Block{Type: "PRIVATE KEY", Bytes: encoded}))
}