// SPDX-FileCopyrightText: 2023 The Pion community <https://pion.ly>
// SPDX-License-Identifier: MIT

package main

import (
	"bytes"
	"context"
	"crypto/sha256"
	"crypto/tls"
	"encoding/base64"
	"encoding/hex"
	"encoding/json"
	"flag"
	"fmt"
	"io"
	"log"
	"math/rand"
	"net"
	"net/http"
	neturl "net/url"
	"os"
	"os/signal"
	"regexp"
	"strconv"
	"strings"
	"sync"
	"sync/atomic"
	"syscall"
	"time"

	"github.com/bschaatsbergen/dnsdialer"
	"github.com/cbeuw/connutil"
	"github.com/google/uuid"
	"github.com/gorilla/websocket"
	"github.com/pion/dtls/v3"
	"github.com/pion/dtls/v3/pkg/crypto/selfsign"
	"github.com/pion/logging"
	"github.com/pion/transport/v4"
	"github.com/pion/turn/v5"
)

type getCredsFunc func(ctx context.Context, link string, streamID int) (string, string, string, error)

type directNet struct{}

type directDialer struct {
	*net.Dialer
}

type directListenConfig struct {
	*net.ListenConfig
}

// globalClientWGAddr safely stores the UDP address of the local WireGuard client
var globalClientWGAddr atomic.Value

func newDirectNet() transport.Net {
	return directNet{}
}

func (directNet) ListenPacket(network string, address string) (net.PacketConn, error) {
	return net.ListenPacket(network, address) //nolint:noctx
}

func (directNet) ListenUDP(network string, locAddr *net.UDPAddr) (transport.UDPConn, error) {
	return net.ListenUDP(network, locAddr)
}

func (directNet) ListenTCP(network string, laddr *net.TCPAddr) (transport.TCPListener, error) {
	listener, err := net.ListenTCP(network, laddr)
	if err != nil {
		return nil, err
	}

	return directTCPListener{listener}, nil
}

func (directNet) Dial(network, address string) (net.Conn, error) {
	return net.Dial(network, address) //nolint:noctx
}

func (directNet) DialUDP(network string, laddr, raddr *net.UDPAddr) (transport.UDPConn, error) {
	return net.DialUDP(network, laddr, raddr)
}

func (directNet) DialTCP(network string, laddr, raddr *net.TCPAddr) (transport.TCPConn, error) {
	return net.DialTCP(network, laddr, raddr)
}

func (directNet) ResolveIPAddr(network, address string) (*net.IPAddr, error) {
	return net.ResolveIPAddr(network, address)
}

func (directNet) ResolveUDPAddr(network, address string) (*net.UDPAddr, error) {
	return net.ResolveUDPAddr(network, address)
}

func (directNet) ResolveTCPAddr(network, address string) (*net.TCPAddr, error) {
	return net.ResolveTCPAddr(network, address)
}

func (directNet) Interfaces() ([]*transport.Interface, error) {
	return nil, transport.ErrNotSupported
}

func (directNet) InterfaceByIndex(index int) (*transport.Interface, error) {
	return nil, fmt.Errorf("%w: index=%d", transport.ErrInterfaceNotFound, index)
}

func (directNet) InterfaceByName(name string) (*transport.Interface, error) {
	return nil, fmt.Errorf("%w: %s", transport.ErrInterfaceNotFound, name)
}

func (directNet) CreateDialer(dialer *net.Dialer) transport.Dialer {
	return directDialer{Dialer: dialer}
}

func (directNet) CreateListenConfig(listenerConfig *net.ListenConfig) transport.ListenConfig {
	return directListenConfig{ListenConfig: listenerConfig}
}

func (d directDialer) Dial(network, address string) (net.Conn, error) {
	return d.Dialer.Dial(network, address)
}

func (d directListenConfig) Listen(ctx context.Context, network, address string) (net.Listener, error) {
	return d.ListenConfig.Listen(ctx, network, address)
}

func (d directListenConfig) ListenPacket(ctx context.Context, network, address string) (net.PacketConn, error) {
	return d.ListenConfig.ListenPacket(ctx, network, address)
}

type directTCPListener struct {
	*net.TCPListener
}

func (l directTCPListener) AcceptTCP() (transport.TCPConn, error) {
	return l.TCPListener.AcceptTCP()
}

// region Helper: HTTP Headers Injection

// applyBrowserProfile applies consistent User-Agent and Client Hints to bypass WAFs
func applyBrowserProfile(req *http.Request, profile Profile) {
	req.Header.Set("User-Agent", profile.UserAgent)
	req.Header.Set("sec-ch-ua", profile.SecChUa)
	req.Header.Set("sec-ch-ua-mobile", profile.SecChUaMobile)
	req.Header.Set("sec-ch-ua-platform", profile.SecChUaPlatform)
	req.Header.Set("Accept-Language", "en-US,en;q=0.9")
	req.Header.Set("DNT", "1")
}

// endregion

// region Automatic Captcha Solver & Authentication

type VkCaptchaError struct {
	ErrorCode               int
	ErrorMsg                string
	CaptchaSid              string
	CaptchaImg              string
	RedirectUri             string
	IsSoundCaptchaAvailable bool
	SessionToken            string
	CaptchaTs               string
	CaptchaAttempt          string
}

func ParseVkCaptchaError(errData map[string]interface{}) *VkCaptchaError {
	codeFloat, _ := errData["error_code"].(float64)
	code := int(codeFloat)

	redirectUri, _ := errData["redirect_uri"].(string)
	captchaSid, _ := errData["captcha_sid"].(string)
	if captchaSid == "" {
		if sidNum, ok := errData["captcha_sid"].(float64); ok {
			captchaSid = fmt.Sprintf("%.0f", sidNum)
		}
	}

	captchaImg, _ := errData["captcha_img"].(string)
	errorMsg, _ := errData["error_msg"].(string)

	var sessionToken string
	if redirectUri != "" {
		if parsed, err := neturl.Parse(redirectUri); err == nil {
			sessionToken = parsed.Query().Get("session_token")
		}
	}

	isSound, _ := errData["is_sound_captcha_available"].(bool)

	var captchaTs string
	if tsFloat, ok := errData["captcha_ts"].(float64); ok {
		captchaTs = fmt.Sprintf("%.0f", tsFloat)
	} else if tsStr, ok := errData["captcha_ts"].(string); ok {
		captchaTs = tsStr
	}

	var captchaAttempt string
	if attFloat, ok := errData["captcha_attempt"].(float64); ok {
		captchaAttempt = fmt.Sprintf("%.0f", attFloat)
	} else if attStr, ok := errData["captcha_attempt"].(string); ok {
		captchaAttempt = attStr
	}

	return &VkCaptchaError{
		ErrorCode:               code,
		ErrorMsg:                errorMsg,
		CaptchaSid:              captchaSid,
		CaptchaImg:              captchaImg,
		RedirectUri:             redirectUri,
		IsSoundCaptchaAvailable: isSound,
		SessionToken:            sessionToken,
		CaptchaTs:               captchaTs,
		CaptchaAttempt:          captchaAttempt,
	}
}

func (e *VkCaptchaError) IsCaptchaError() bool {
	return e.ErrorCode == 14
}

func solveVkCaptcha(ctx context.Context, captchaErr *VkCaptchaError, streamID int, dialer *dnsdialer.Dialer, profile Profile) (string, error) {
	log.Printf("[STREAM %d] [Captcha] Solving Not Robot Captcha...", streamID)

	if captchaErr.SessionToken == "" {
		return "", fmt.Errorf("no session_token in redirect_uri for auto-solve")
	}
	if captchaErr.RedirectUri == "" {
		return "", fmt.Errorf("no redirect_uri for auto-solve")
	}

	// HAR Timing: Browser page load & user perception
	time.Sleep(1500*time.Millisecond + time.Duration(rand.Intn(1000))*time.Millisecond)

	powInput, difficulty, cookies, err := fetchPowInput(ctx, captchaErr.RedirectUri, streamID, dialer, profile)
	if err != nil {
		return "", fmt.Errorf("failed to fetch PoW input: %w", err)
	}

	log.Printf("[STREAM %d] [Captcha] PoW input: %s, difficulty: %d", streamID, powInput, difficulty)

	hash := solvePoW(powInput, difficulty)
	log.Printf("[STREAM %d] [Captcha] PoW solved: hash=%s", streamID, hash)

	successToken, err := callCaptchaNotRobot(ctx, captchaErr.SessionToken, hash, cookies, streamID, dialer, profile)
	if err != nil {
		return "", fmt.Errorf("captchaNotRobot API failed: %w", err)
	}

	log.Printf("[STREAM %d] [Captcha] Success! Got success_token", streamID)
	return successToken, nil
}

func fetchPowInput(ctx context.Context, redirectUri string, streamID int, dialer *dnsdialer.Dialer, profile Profile) (string, int, string, error) {
	parsedURL, err := neturl.Parse(redirectUri)
	if err != nil {
		return "", 0, "", err
	}
	domain := parsedURL.Hostname()

	req, err := http.NewRequestWithContext(ctx, "GET", redirectUri, nil)
	if err != nil {
		return "", 0, "", err
	}

	req.Host = domain // Explicitly force Host header
	applyBrowserProfile(req, profile)
	req.Header.Set("Sec-Fetch-Site", "none")
	req.Header.Set("Sec-Fetch-Mode", "navigate")
	req.Header.Set("Sec-Fetch-Dest", "document")
	req.Header.Set("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8")

	client := &http.Client{
		Timeout: 20 * time.Second,
		Transport: &http.Transport{
			DialContext: dialer.DialContext,
			TLSClientConfig: &tls.Config{
				ServerName: domain, // Force SNI for DPI evasion
			},
		},
	}
	resp, err := client.Do(req)
	if err != nil {
		return "", 0, "", err
	}
	defer func(Body io.ReadCloser) {
		_ = Body.Close()
	}(resp.Body)

	var cookies []string
	for _, setCookie := range resp.Header.Values("Set-Cookie") {
		cookieParts := strings.Split(setCookie, ";")
		cookies = append(cookies, strings.TrimSpace(cookieParts[0]))
	}
	cookieHeader := strings.Join(cookies, "; ")
	if cookieHeader != "" {
		log.Printf("[STREAM %d] [Captcha] Captcha page set %d cookie(s)", streamID, len(cookies))
	}

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return "", 0, "", err
	}
	html := string(body)

	powInputRe := regexp.MustCompile(`const\s+powInput\s*=\s*"([^"]+)"`)
	powInputMatch := powInputRe.FindStringSubmatch(html)
	if len(powInputMatch) < 2 {
		return "", 0, "", fmt.Errorf("powInput not found in captcha HTML")
	}
	powInput := powInputMatch[1]

	diffRe := regexp.MustCompile(`startsWith\('0'\.repeat\((\d+)\)\)`)
	diffMatch := diffRe.FindStringSubmatch(html)
	difficulty := 2
	if len(diffMatch) >= 2 {
		if d, err := strconv.Atoi(diffMatch[1]); err == nil {
			difficulty = d
		}
	}
	return powInput, difficulty, cookieHeader, nil
}

func solvePoW(powInput string, difficulty int) string {
	target := strings.Repeat("0", difficulty)
	for nonce := 1; nonce <= 10000000; nonce++ {
		data := powInput + strconv.Itoa(nonce)
		hash := sha256.Sum256([]byte(data))
		hexHash := hex.EncodeToString(hash[:])
		if strings.HasPrefix(hexHash, target) {
			return hexHash
		}
	}
	return ""
}

func callCaptchaNotRobot(ctx context.Context, sessionToken, hash, cookies string, streamID int, dialer *dnsdialer.Dialer, profile Profile) (string, error) {
	vkReq := func(method string, postData string) (map[string]interface{}, error) {
		reqURL := "https://api.vk.ru/method/" + method + "?v=5.131"
		parsedURL, _ := neturl.Parse(reqURL)
		domain := parsedURL.Hostname()

		req, err := http.NewRequestWithContext(ctx, "POST", reqURL, strings.NewReader(postData))
		if err != nil {
			return nil, err
		}

		req.Host = domain
		applyBrowserProfile(req, profile)
		req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
		req.Header.Set("Accept", "*/*")
		req.Header.Set("Origin", "https://id.vk.ru")
		req.Header.Set("Referer", "https://id.vk.ru/")
		req.Header.Set("Sec-Fetch-Site", "same-site")
		req.Header.Set("Sec-Fetch-Mode", "cors")
		req.Header.Set("Sec-Fetch-Dest", "empty")
		req.Header.Set("Priority", "u=1, i")

		if cookies != "" {
			req.Header.Set("Cookie", cookies)
		}

		client := &http.Client{
			Timeout: 20 * time.Second,
			Transport: &http.Transport{
				DialContext: dialer.DialContext,
				TLSClientConfig: &tls.Config{
					ServerName: domain, // Enforce SNI for DPI evasion
				},
			},
		}

		httpResp, err := client.Do(req)
		if err != nil {
			return nil, err
		}
		defer func(Body io.ReadCloser) {
			_ = Body.Close()
		}(httpResp.Body)

		body, err := io.ReadAll(httpResp.Body)
		if err != nil {
			return nil, err
		}
		var resp map[string]interface{}
		if err := json.Unmarshal(body, &resp); err != nil {
			return nil, err
		}
		return resp, nil
	}

	baseParams := fmt.Sprintf("session_token=%s&domain=vk.com&adFp=&access_token=", neturl.QueryEscape(sessionToken))

	log.Printf("[STREAM %d] [Captcha] Step 1/4: settings", streamID)
	if _, err := vkReq("captchaNotRobot.settings", baseParams); err != nil {
		return "", fmt.Errorf("settings failed: %w", err)
	}

	// HAR Timing: settings -> componentDone
	time.Sleep(100*time.Millisecond + time.Duration(rand.Intn(100))*time.Millisecond)

	log.Printf("[STREAM %d] [Captcha] Step 2/4: componentDone", streamID)
	browserFp := fmt.Sprintf("%016x%016x", rand.Int63(), rand.Int63())
	deviceJSON := `{"screenWidth":1920,"screenHeight":1080,"screenAvailWidth":1920,"screenAvailHeight":1032,"innerWidth":1920,"innerHeight":945,"devicePixelRatio":1,"language":"en-US","languages":["en-US"],"webdriver":false,"hardwareConcurrency":16,"deviceMemory":8,"connectionEffectiveType":"4g","notificationsPermission":"denied"}`
	componentDoneData := baseParams + fmt.Sprintf("&browser_fp=%s&device=%s", browserFp, neturl.QueryEscape(deviceJSON))

	if _, err := vkReq("captchaNotRobot.componentDone", componentDoneData); err != nil {
		return "", fmt.Errorf("componentDone failed: %w", err)
	}

	// HAR Timing: componentDone -> check ≈ 1.95s + statEvents delay ≈ 3.2s total
	time.Sleep(1950*time.Millisecond + time.Duration(rand.Intn(1250))*time.Millisecond)

	log.Printf("[STREAM %d] [Captcha] Step 3/4: check", streamID)
	cursorJSON := `[{"x":950,"y":500},{"x":945,"y":510},{"x":940,"y":520},{"x":938,"y":525},{"x":938,"y":525}]`
	answer := base64.StdEncoding.EncodeToString([]byte("{}"))
	debugInfo := "d44f534ce8deb56ba20be52e05c433309b49ee4d2a70602deeb17a1954257785"

	baseDownlink := 8.0 + rand.Float64()*4.0
	downlinkStr := fmt.Sprintf("%.1f", baseDownlink)
	connectionDownlink := "[" + downlinkStr + "," + downlinkStr + "," + downlinkStr + "," + downlinkStr + "," + downlinkStr + "," + downlinkStr + "," + downlinkStr + "]"

	checkData := baseParams + fmt.Sprintf(
		"&accelerometer=%s&gyroscope=%s&motion=%s&cursor=%s&taps=%s&connectionRtt=%s&connectionDownlink=%s&browser_fp=%s&hash=%s&answer=%s&debug_info=%s",
		neturl.QueryEscape("[]"), neturl.QueryEscape("[]"), neturl.QueryEscape("[]"),
		neturl.QueryEscape(cursorJSON), neturl.QueryEscape("[]"), neturl.QueryEscape("[]"),
		neturl.QueryEscape(connectionDownlink),
		browserFp, hash, answer, debugInfo,
	)

	checkResp, err := vkReq("captchaNotRobot.check", checkData)
	if err != nil {
		return "", fmt.Errorf("check failed: %w", err)
	}

	respObj, ok := checkResp["response"].(map[string]interface{})
	if !ok {
		return "", fmt.Errorf("invalid check response: %v", checkResp)
	}
	status, _ := respObj["status"].(string)
	if status != "OK" {
		return "", fmt.Errorf("check status: %s", status)
	}
	successToken, ok := respObj["success_token"].(string)
	if !ok || successToken == "" {
		return "", fmt.Errorf("success_token not found")
	}

	log.Printf("[STREAM %d] [Captcha] Step 4/4: endSession", streamID)
	_, err = vkReq("captchaNotRobot.endSession", baseParams)
	if err != nil {
		log.Printf("[STREAM %d] [Captcha] Warning: endSession failed: %v", streamID, err)
	}

	return successToken, nil
}

// endregion

// region VK Credentials & Caching Layer

type VKCredentials struct {
	ClientID     string
	ClientSecret string
}

var vkCredentialsList = []VKCredentials{
	{ClientID: "6287487", ClientSecret: "QbYic1K3lEV5kTGiqlq2"},  // VK_WEB_APP_ID
	{ClientID: "7879029", ClientSecret: "aR5NKGmm03GYrCiNKsaw"},  // VK_MVK_APP_ID
	{ClientID: "52461373", ClientSecret: "o557NLIkAErNhakXrQ7A"}, // VK_WEB_VKVIDEO_APP_ID
	{ClientID: "52649896", ClientSecret: "WStp4ihWG4l3nmXZgIbC"}, // VK_MVK_VKVIDEO_APP_ID
	{ClientID: "51781872", ClientSecret: "IjjCNl4L4Tf5QZEXIHKK"}, // VK_ID_AUTH_APP
}

type TurnCredentials struct {
	Username   string
	Password   string
	ServerAddr string
	ExpiresAt  time.Time
	Link       string
}

type StreamCredentialsCache struct {
	creds         TurnCredentials
	mutex         sync.RWMutex
	errorCount    atomic.Int32
	lastErrorTime atomic.Int64
}

const (
	credentialLifetime = 10 * time.Minute
	cacheSafetyMargin  = 60 * time.Second
	maxCacheErrors     = 3
	errorWindow        = 10 * time.Second
	streamsPerCache    = 10
)

func getCacheID(streamID int) int {
	return streamID / streamsPerCache
}

var vkRequestMu sync.Mutex

func vkDelayRandom(minMs, maxMs int) {
	ms := minMs + rand.Intn(maxMs-minMs+1)
	time.Sleep(time.Duration(ms) * time.Millisecond)
}

var credentialsStore = struct {
	mu     sync.RWMutex
	caches map[int]*StreamCredentialsCache
}{
	caches: make(map[int]*StreamCredentialsCache),
}

func getStreamCache(streamID int) *StreamCredentialsCache {
	cacheID := getCacheID(streamID)

	credentialsStore.mu.RLock()
	cache, exists := credentialsStore.caches[cacheID]
	credentialsStore.mu.RUnlock()

	if exists {
		return cache
	}

	credentialsStore.mu.Lock()
	defer credentialsStore.mu.Unlock()

	if cache, exists = credentialsStore.caches[cacheID]; exists {
		return cache
	}

	cache = &StreamCredentialsCache{}
	credentialsStore.caches[cacheID] = cache
	return cache
}

func isAuthError(err error) bool {
	if err == nil {
		return false
	}
	errStr := err.Error()
	return strings.Contains(errStr, "401") ||
		strings.Contains(errStr, "Unauthorized") ||
		strings.Contains(errStr, "authentication") ||
		strings.Contains(errStr, "invalid credential") ||
		strings.Contains(errStr, "stale nonce")
}

func handleAuthError(streamID int) bool {
	cache := getStreamCache(streamID)
	cacheID := getCacheID(streamID)

	now := time.Now().Unix()

	if now-cache.lastErrorTime.Load() > int64(errorWindow.Seconds()) {
		cache.errorCount.Store(0)
	}

	count := cache.errorCount.Add(1)
	cache.lastErrorTime.Store(now)

	log.Printf("[STREAM %d] Auth error (cache=%d, count=%d/%d)", streamID, cacheID, count, maxCacheErrors)

	if count >= maxCacheErrors {
		log.Printf("[VK Auth] Multiple auth errors detected (%d), invalidating cache %d for stream %d...", count, cacheID, streamID)
		cache.invalidate(streamID)
		return true
	}
	return false
}

func (c *StreamCredentialsCache) invalidate(streamID int) {
	c.mutex.Lock()
	c.creds = TurnCredentials{}
	c.mutex.Unlock()

	c.errorCount.Store(0)
	c.lastErrorTime.Store(0)

	log.Printf("[STREAM %d] [VK Auth] Credentials cache invalidated", streamID)
}

func getVkCredsCached(ctx context.Context, link string, streamID int, dialer *dnsdialer.Dialer) (string, string, string, error) {
	cache := getStreamCache(streamID)
	cacheID := getCacheID(streamID)

	cache.mutex.RLock()
	if cache.creds.Link == link && time.Now().Before(cache.creds.ExpiresAt) {
		expires := time.Until(cache.creds.ExpiresAt)
		u, p, a := cache.creds.Username, cache.creds.Password, cache.creds.ServerAddr
		cache.mutex.RUnlock()
		log.Printf("[STREAM %d] [VK Auth] Using cached credentials (cache=%d, expires in %v)", streamID, cacheID, expires)
		return u, p, a, nil
	}
	cache.mutex.RUnlock()

	cache.mutex.Lock()
	defer cache.mutex.Unlock()

	// Double-check
	if cache.creds.Link == link && time.Now().Before(cache.creds.ExpiresAt) {
		expires := time.Until(cache.creds.ExpiresAt)
		log.Printf("[STREAM %d] [VK Auth] Using cached credentials (cache=%d, expires in %v)", streamID, cacheID, expires)
		return cache.creds.Username, cache.creds.Password, cache.creds.ServerAddr, nil
	}

	log.Printf("[STREAM %d] [VK Auth] Cache miss (cache=%d), starting credential fetch...", streamID, cacheID)

	select {
	case <-ctx.Done():
		return "", "", "", ctx.Err()
	default:
	}

	user, pass, addr, err := fetchVkCredsSerialized(ctx, link, streamID, dialer)
	if err != nil {
		return "", "", "", err
	}

	cache.creds = TurnCredentials{
		Username:   user,
		Password:   pass,
		ServerAddr: addr,
		ExpiresAt:  time.Now().Add(credentialLifetime - cacheSafetyMargin),
		Link:       link,
	}

	log.Printf("[STREAM %d] [VK Auth] Success! Credentials cached until %v (cache=%d)", streamID, cache.creds.ExpiresAt, cacheID)
	return user, pass, addr, nil
}

func fetchVkCredsSerialized(ctx context.Context, link string, streamID int, dialer *dnsdialer.Dialer) (string, string, string, error) {
	vkRequestMu.Lock()
	defer vkRequestMu.Unlock()
	return fetchVkCreds(ctx, link, streamID, dialer)
}

func fetchVkCreds(ctx context.Context, link string, streamID int, dialer *dnsdialer.Dialer) (string, string, string, error) {
	var lastErr error

	for _, creds := range vkCredentialsList {
		log.Printf("[STREAM %d] [VK Auth] Trying credentials: client_id=%s", streamID, creds.ClientID)

		user, pass, addr, err := getTokenChain(ctx, link, streamID, creds, dialer)

		if err == nil {
			log.Printf("[STREAM %d] [VK Auth] Success with client_id=%s", streamID, creds.ClientID)
			return user, pass, addr, nil
		}

		lastErr = err
		log.Printf("[STREAM %d] [VK Auth] Failed with client_id=%s: %v", streamID, creds.ClientID, err)

		if strings.Contains(err.Error(), "error_code:29") || strings.Contains(err.Error(), "error_code: 29") || strings.Contains(err.Error(), "Rate limit") {
			log.Printf("[STREAM %d] [VK Auth] Rate limit detected, trying next credentials...", streamID)
		}
	}

	return "", "", "", fmt.Errorf("all VK credentials failed: %w", lastErr)
}

func getTokenChain(ctx context.Context, link string, streamID int, creds VKCredentials, dialer *dnsdialer.Dialer) (string, string, string, error) {
	profile := getRandomProfile()
	name := generateName()
	escapedName := neturl.QueryEscape(name)

	log.Printf("[STREAM %d] [VK Auth] Connecting Identity - Name: %s | User-Agent: %s", streamID, name, profile.UserAgent)

	doRequest := func(data string, url string) (resp map[string]interface{}, err error) {
		parsedURL, _ := neturl.Parse(url)
		domain := parsedURL.Hostname()

		client := &http.Client{
			Timeout: 20 * time.Second,
			Transport: &http.Transport{
				MaxIdleConns:        100,
				MaxIdleConnsPerHost: 100,
				IdleConnTimeout:     90 * time.Second,
				DialContext:         dialer.DialContext,
				TLSClientConfig: &tls.Config{
					ServerName: domain, // Force SNI for DPI evasion
				},
			},
		}
		defer client.CloseIdleConnections()

		req, err := http.NewRequestWithContext(ctx, "POST", url, bytes.NewBuffer([]byte(data)))
		if err != nil {
			return nil, err
		}

		req.Host = domain
		applyBrowserProfile(req, profile)
		req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
		req.Header.Set("Accept", "*/*")
		req.Header.Set("Origin", "https://vk.ru")
		req.Header.Set("Referer", "https://vk.ru/")
		req.Header.Set("Sec-Fetch-Site", "same-site")
		req.Header.Set("Sec-Fetch-Mode", "cors")
		req.Header.Set("Sec-Fetch-Dest", "empty")
		req.Header.Set("Priority", "u=1, i")

		httpResp, err := client.Do(req)
		if err != nil {
			return nil, err
		}
		defer func() {
			if closeErr := httpResp.Body.Close(); closeErr != nil {
				log.Printf("close response body: %s", closeErr)
			}
		}()

		body, err := io.ReadAll(httpResp.Body)
		if err != nil {
			return nil, err
		}

		err = json.Unmarshal(body, &resp)
		if err != nil {
			return nil, err
		}
		return resp, nil
	}

	// Token 1
	data := fmt.Sprintf("client_id=%s&token_type=messages&client_secret=%s&version=1&app_id=%s", creds.ClientID, creds.ClientSecret, creds.ClientID)
	resp, err := doRequest(data, "https://login.vk.ru/?act=get_anonym_token")
	if err != nil {
		return "", "", "", err
	}
	dataMap, ok := resp["data"].(map[string]interface{})
	if !ok {
		return "", "", "", fmt.Errorf("unexpected anon token response: %v", resp)
	}
	token1, ok := dataMap["access_token"].(string)
	if !ok {
		return "", "", "", fmt.Errorf("missing access_token in response: %v", resp)
	}

	vkDelayRandom(100, 200)

	// Token 1 -> getCallPreview
	data = fmt.Sprintf("vk_join_link=https://vk.com/call/join/%s&fields=photo_200&access_token=%s", link, token1)
	_, _ = doRequest(data, "https://api.vk.ru/method/calls.getCallPreview?v=5.275&client_id="+creds.ClientID)

	vkDelayRandom(500, 1000) // HAR: Delay updated

	// Token 2
	data = fmt.Sprintf("vk_join_link=https://vk.com/call/join/%s&name=%s&access_token=%s", link, escapedName, token1)
	urlAddr := fmt.Sprintf("https://api.vk.ru/method/calls.getAnonymousToken?v=5.275&client_id=%s", creds.ClientID)

	var token2 string
	const maxCaptchaAttempts = 3
	for attempt := 0; attempt <= maxCaptchaAttempts; attempt++ {
		resp, err = doRequest(data, urlAddr)
		if err != nil {
			return "", "", "", err
		}

		if errObj, hasErr := resp["error"].(map[string]interface{}); hasErr {
			captchaErr := ParseVkCaptchaError(errObj)
			if captchaErr != nil && captchaErr.IsCaptchaError() {
				var successToken string
				var captchaKey string
				var solveErr error

				// Try automatic if possible and attempts remain
				if attempt < maxCaptchaAttempts && captchaErr.SessionToken != "" && captchaErr.RedirectUri != "" {
					successToken, solveErr = solveVkCaptcha(ctx, captchaErr, streamID, dialer, profile)
					if solveErr != nil {
						log.Printf("[STREAM %d] [Captcha] Auto solve failed: %v. Falling back to manual...", streamID, solveErr)
					}
				} else if attempt >= maxCaptchaAttempts {
					log.Printf("[STREAM %d] [Captcha] Max auto attempts reached. Falling back to manual...", streamID)
					solveErr = fmt.Errorf("max attempts reached")
				} else {
					log.Printf("[STREAM %d] [Captcha] Missing fields for auto solve. Falling back to manual...", streamID)
					solveErr = fmt.Errorf("missing fields")
				}

				// If auto failed, or we skipped it, drop to manual fallback
				if solveErr != nil {
					if captchaErr.RedirectUri != "" {
						successToken, solveErr = solveCaptchaViaProxy(captchaErr.RedirectUri, dialer)
						if solveErr != nil {
							return "", "", "", fmt.Errorf("manual proxy captcha solve error: %w", solveErr)
						}
					} else if captchaErr.CaptchaImg != "" {
						captchaKey, solveErr = solveCaptchaViaHTTP(captchaErr.CaptchaImg)
						if solveErr != nil {
							return "", "", "", fmt.Errorf("manual HTTP captcha solve error: %w", solveErr)
						}
					} else {
						return "", "", "", fmt.Errorf("cannot solve captcha manually: no redirect_uri or captcha_img")
					}
				}

				if captchaErr.CaptchaAttempt == "0" || captchaErr.CaptchaAttempt == "" {
					captchaErr.CaptchaAttempt = "1"
				}

				if captchaKey != "" {
					data = fmt.Sprintf("vk_join_link=https://vk.com/call/join/%s&name=%s&captcha_key=%s&captcha_sid=%s&access_token=%s",
						link, escapedName, neturl.QueryEscape(captchaKey), captchaErr.CaptchaSid, token1)
				} else {
					data = fmt.Sprintf("vk_join_link=https://vk.com/call/join/%s&name=%s&captcha_key=&captcha_sid=%s&is_sound_captcha=0&success_token=%s&captcha_ts=%s&captcha_attempt=%s&access_token=%s",
						link, escapedName, captchaErr.CaptchaSid, neturl.QueryEscape(successToken), captchaErr.CaptchaTs, captchaErr.CaptchaAttempt, token1)
				}
				continue
			}
			return "", "", "", fmt.Errorf("VK API error: %v", errObj)
		}

		respMap, ok := resp["response"].(map[string]interface{})
		if !ok {
			return "", "", "", fmt.Errorf("unexpected getAnonymousToken response: %v", resp)
		}
		token2, ok = respMap["token"].(string)
		if !ok {
			return "", "", "", fmt.Errorf("missing token in response: %v", resp)
		}
		break
	}

	vkDelayRandom(100, 200)

	// Token 3
	sessionData := fmt.Sprintf(`{"version":2,"device_id":"%s","client_version":1.1,"client_type":"SDK_JS"}`, uuid.New())
	data = fmt.Sprintf("session_data=%s&method=auth.anonymLogin&format=JSON&application_key=CGMMEJLGDIHBABABA", neturl.QueryEscape(sessionData))
	resp, err = doRequest(data, "https://calls.okcdn.ru/fb.do")
	if err != nil {
		return "", "", "", err
	}
	token3 := resp["session_key"].(string)

	vkDelayRandom(100, 200)

	// Token 4 -> TURN Creds
	data = fmt.Sprintf("joinLink=%s&isVideo=false&protocolVersion=5&capabilities=2F7F&anonymToken=%s&method=vchat.joinConversationByLink&format=JSON&application_key=CGMMEJLGDIHBABABA&session_key=%s", link, token2, token3)
	resp, err = doRequest(data, "https://calls.okcdn.ru/fb.do")
	if err != nil {
		return "", "", "", err
	}

	ts := resp["turn_server"].(map[string]interface{})
	user := ts["username"].(string)
	pass := ts["credential"].(string)
	urls := ts["urls"].([]interface{})
	urlStr := urls[0].(string)

	clean := strings.Split(urlStr, "?")[0]
	address := strings.TrimPrefix(strings.TrimPrefix(clean, "turn:"), "turns:")

	vkDelayRandom(4000, 5000) // HAR: Final matching delay

	return user, pass, address, nil
}

// endregion

func getYandexCreds(link string) (string, string, string, error) {
	const debug = false
	const telemostConfHost = "cloud-api.yandex.ru"
	telemostConfPath := fmt.Sprintf("%s%s%s", "/telemost_front/v2/telemost/conferences/https%3A%2F%2Ftelemost.yandex.ru%2Fj%2F", link, "/connection?next_gen_media_platform_allowed=false")

	profile := getRandomProfile()
	name := generateName()

	type ConferenceResponse struct {
		URI                 string `json:"uri"`
		RoomID              string `json:"room_id"`
		PeerID              string `json:"peer_id"`
		ClientConfiguration struct {
			MediaServerURL string `json:"media_server_url"`
		} `json:"client_configuration"`
		Credentials string `json:"credentials"`
	}

	type PartMeta struct {
		Name        string `json:"name"`
		Role        string `json:"role"`
		Description string `json:"description"`
		SendAudio   bool   `json:"sendAudio"`
		SendVideo   bool   `json:"sendVideo"`
	}

	type PartAttrs struct {
		Name        string `json:"name"`
		Role        string `json:"role"`
		Description string `json:"description"`
	}

	type SdkInfo struct {
		Implementation string `json:"implementation"`
		Version        string `json:"version"`
		UserAgent      string `json:"userAgent"`
		HwConcurrency  int    `json:"hwConcurrency"`
	}

	type Capabilities struct {
		OfferAnswerMode             []string `json:"offerAnswerMode"`
		InitialSubscriberOffer      []string `json:"initialSubscriberOffer"`
		SlotsMode                   []string `json:"slotsMode"`
		SimulcastMode               []string `json:"simulcastMode"`
		SelfVadStatus               []string `json:"selfVadStatus"`
		DataChannelSharing          []string `json:"dataChannelSharing"`
		VideoEncoderConfig          []string `json:"videoEncoderConfig"`
		DataChannelVideoCodec       []string `json:"dataChannelVideoCodec"`
		BandwidthLimitationReason   []string `json:"bandwidthLimitationReason"`
		SdkDefaultDeviceManagement  []string `json:"sdkDefaultDeviceManagement"`
		JoinOrderLayout             []string `json:"joinOrderLayout"`
		PinLayout                   []string `json:"pinLayout"`
		SendSelfViewVideoSlot       []string `json:"sendSelfViewVideoSlot"`
		ServerLayoutTransition      []string `json:"serverLayoutTransition"`
		SdkPublisherOptimizeBitrate []string `json:"sdkPublisherOptimizeBitrate"`
		SdkNetworkLostDetection     []string `json:"sdkNetworkLostDetection"`
		SdkNetworkPathMonitor       []string `json:"sdkNetworkPathMonitor"`
		PublisherVp9                []string `json:"publisherVp9"`
		SvcMode                     []string `json:"svcMode"`
		SubscriberOfferAsyncAck     []string `json:"subscriberOfferAsyncAck"`
		SvcModes                    []string `json:"svcModes"`
		ReportTelemetryModes        []string `json:"reportTelemetryModes"`
		KeepDefaultDevicesModes     []string `json:"keepDefaultDevicesModes"`
	}

	type HelloPayload struct {
		ParticipantMeta        PartMeta     `json:"participantMeta"`
		ParticipantAttributes  PartAttrs    `json:"participantAttributes"`
		SendAudio              bool         `json:"sendAudio"`
		SendVideo              bool         `json:"sendVideo"`
		SendSharing            bool         `json:"sendSharing"`
		ParticipantID          string       `json:"participantId"`
		RoomID                 string       `json:"roomId"`
		ServiceName            string       `json:"serviceName"`
		Credentials            string       `json:"credentials"`
		CapabilitiesOffer      Capabilities `json:"capabilitiesOffer"`
		SdkInfo                SdkInfo      `json:"sdkInfo"`
		SdkInitializationID    string       `json:"sdkInitializationId"`
		DisablePublisher       bool         `json:"disablePublisher"`
		DisableSubscriber      bool         `json:"disableSubscriber"`
		DisableSubscriberAudio bool         `json:"disableSubscriberAudio"`
	}

	type HelloRequest struct {
		UID   string       `json:"uid"`
		Hello HelloPayload `json:"hello"`
	}

	type FlexUrls []string

	type WSSResponse struct {
		UID         string `json:"uid"`
		ServerHello struct {
			RtcConfiguration struct {
				IceServers []struct {
					Urls       FlexUrls `json:"urls"`
					Username   string   `json:"username,omitempty"`
					Credential string   `json:"credential,omitempty"`
				} `json:"iceServers"`
			} `json:"rtcConfiguration"`
		} `json:"serverHello"`
	}

	type WSSAck struct {
		Uid string `json:"uid"`
		Ack struct {
			Status struct {
				Code string `json:"code"`
			} `json:"status"`
		} `json:"ack"`
	}

	type WSSData struct {
		ParticipantId string
		RoomId        string
		Credentials   string
		Wss           string
	}

	endpoint := "https://" + telemostConfHost + telemostConfPath
	tr := &http.Transport{
		MaxIdleConns:        100,
		MaxIdleConnsPerHost: 100,
		IdleConnTimeout:     90 * time.Second,
	}
	client := &http.Client{
		Timeout:   20 * time.Second,
		Transport: tr,
	}
	defer client.CloseIdleConnections()
	req, err := http.NewRequest("GET", endpoint, nil)
	if err != nil {
		return "", "", "", err
	}

	applyBrowserProfile(req, profile)
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Referer", "https://telemost.yandex.ru/")
	req.Header.Set("Origin", "https://telemost.yandex.ru")
	req.Header.Set("Client-Instance-Id", uuid.New().String())

	resp, err := client.Do(req)
	if err != nil {
		return "", "", "", err
	}
	defer func() {
		if closeErr := resp.Body.Close(); closeErr != nil {
			log.Printf("close response body: %s", closeErr)
		}
	}()
	if resp.StatusCode != http.StatusOK {
		body, _ := io.ReadAll(resp.Body)
		return "", "", "", fmt.Errorf("GetConference: status=%s body=%s", resp.Status, string(body))
	}

	var result ConferenceResponse
	if err = json.NewDecoder(resp.Body).Decode(&result); err != nil {
		return "", "", "", fmt.Errorf("decode conf: %v", err)
	}
	data := WSSData{
		ParticipantId: result.PeerID,
		RoomId:        result.RoomID,
		Credentials:   result.Credentials,
		Wss:           result.ClientConfiguration.MediaServerURL,
	}
	h := http.Header{}
	h.Set("Origin", "https://telemost.yandex.ru")
	h.Set("User-Agent", profile.UserAgent)

	ctx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
	defer cancel()

	dialer := websocket.Dialer{}
	conn, _, err := dialer.DialContext(ctx, data.Wss, h)
	if err != nil {
		return "", "", "", fmt.Errorf("ws dial: %w", err)
	}
	defer func() {
		if closeErr := conn.Close(); closeErr != nil {
			log.Printf("close websocket: %s", closeErr)
		}
	}()

	req1 := HelloRequest{
		UID: uuid.New().String(),
		Hello: HelloPayload{
			ParticipantMeta: PartMeta{
				Name:        name,
				Role:        "SPEAKER",
				Description: "",
				SendAudio:   false,
				SendVideo:   false,
			},
			ParticipantAttributes: PartAttrs{
				Name:        name,
				Role:        "SPEAKER",
				Description: "",
			},
			SendAudio:   false,
			SendVideo:   false,
			SendSharing: false,

			ParticipantID: data.ParticipantId,
			RoomID:        data.RoomId,
			ServiceName:   "telemost",
			Credentials:   data.Credentials,
			SdkInfo: SdkInfo{
				Implementation: "browser",
				Version:        "5.15.0",
				UserAgent:      profile.UserAgent,
				HwConcurrency:  4,
			},
			SdkInitializationID:    uuid.New().String(),
			DisablePublisher:       false,
			DisableSubscriber:      false,
			DisableSubscriberAudio: false,
			CapabilitiesOffer: Capabilities{
				OfferAnswerMode:             []string{"SEPARATE"},
				InitialSubscriberOffer:      []string{"ON_HELLO"},
				SlotsMode:                   []string{"FROM_CONTROLLER"},
				SimulcastMode:               []string{"DISABLED"},
				SelfVadStatus:               []string{"FROM_SERVER"},
				DataChannelSharing:          []string{"TO_RTP"},
				VideoEncoderConfig:          []string{"NO_CONFIG"},
				DataChannelVideoCodec:       []string{"VP8"},
				BandwidthLimitationReason:   []string{"BANDWIDTH_REASON_DISABLED"},
				SdkDefaultDeviceManagement:  []string{"SDK_DEFAULT_DEVICE_MANAGEMENT_DISABLED"},
				JoinOrderLayout:             []string{"JOIN_ORDER_LAYOUT_DISABLED"},
				PinLayout:                   []string{"PIN_LAYOUT_DISABLED"},
				SendSelfViewVideoSlot:       []string{"SEND_SELF_VIEW_VIDEO_SLOT_DISABLED"},
				ServerLayoutTransition:      []string{"SERVER_LAYOUT_TRANSITION_DISABLED"},
				SdkPublisherOptimizeBitrate: []string{"SDK_PUBLISHER_OPTIMIZE_BITRATE_DISABLED"},
				SdkNetworkLostDetection:     []string{"SDK_NETWORK_LOST_DETECTION_DISABLED"},
				SdkNetworkPathMonitor:       []string{"SDK_NETWORK_PATH_MONITOR_DISABLED"},
				PublisherVp9:                []string{"PUBLISH_VP9_DISABLED"},
				SvcMode:                     []string{"SVC_MODE_DISABLED"},
				SubscriberOfferAsyncAck:     []string{"SUBSCRIBER_OFFER_ASYNC_ACK_DISABLED"},
				SvcModes:                    []string{"FALSE"},
				ReportTelemetryModes:        []string{"TRUE"},
				KeepDefaultDevicesModes:     []string{"TRUE"},
			},
		},
	}

	if debug {
		b, _ := json.MarshalIndent(req1, "", "  ")
		log.Printf("Sending HELLO:\n%s", string(b))
	}

	if err := conn.WriteJSON(req1); err != nil {
		return "", "", "", fmt.Errorf("ws write: %w", err)
	}

	if err := conn.SetReadDeadline(time.Now().Add(15 * time.Second)); err != nil {
		return "", "", "", fmt.Errorf("ws set read deadline: %w", err)
	}

	for {
		_, msg, err := conn.ReadMessage()
		if err != nil {
			return "", "", "", fmt.Errorf("ws read: %w", err)
		}
		if debug {
			s := string(msg)
			if len(s) > 800 {
				s = s[:800] + "...(truncated)"
			}
			log.Printf("WSS recv: %s", s)
		}

		var ack WSSAck
		if err := json.Unmarshal(msg, &ack); err == nil && ack.Ack.Status.Code != "" {
			continue
		}

		var resp WSSResponse
		if err := json.Unmarshal(msg, &resp); err == nil {
			ice := resp.ServerHello.RtcConfiguration.IceServers
			for _, s := range ice {
				for _, u := range s.Urls {
					if !strings.HasPrefix(u, "turn:") && !strings.HasPrefix(u, "turns:") {
						continue
					}
					if strings.Contains(u, "transport=tcp") {
						continue
					}
					clean := strings.Split(u, "?")[0]
					address := strings.TrimPrefix(strings.TrimPrefix(clean, "turn:"), "turns:")

					return s.Username, s.Credential, address, nil
				}
			}
		}
	}
}

func dtlsFunc(ctx context.Context, conn net.PacketConn, peer *net.UDPAddr) (net.Conn, error) {
	certificate, err := selfsign.GenerateSelfSigned()
	if err != nil {
		return nil, err
	}
	config := &dtls.Config{
		Certificates:          []tls.Certificate{certificate},
		InsecureSkipVerify:    true,
		ExtendedMasterSecret:  dtls.RequireExtendedMasterSecret,
		CipherSuites:          []dtls.CipherSuiteID{dtls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256},
		ConnectionIDGenerator: dtls.OnlySendCIDGenerator(),
	}
	ctx1, cancel := context.WithTimeout(ctx, 30*time.Second)
	defer cancel()
	dtlsConn, err := dtls.Client(conn, peer, config)
	if err != nil {
		return nil, err
	}

	if err := dtlsConn.HandshakeContext(ctx1); err != nil {
		return nil, err
	}
	return dtlsConn, nil
}

func oneDtlsConnection(ctx context.Context, peer *net.UDPAddr, listenConn net.PacketConn, connchan chan<- net.PacketConn, okchan chan<- struct{}, c chan<- error) {
	time.Sleep(time.Duration(rand.Intn(400)+100) * time.Millisecond)
	var err error = nil
	defer func() { c <- err }()
	dtlsctx, dtlscancel := context.WithCancel(ctx)
	defer dtlscancel()
	var conn1, conn2 net.PacketConn
	conn1, conn2 = connutil.AsyncPacketPipe()
	go func() {
		for {
			select {
			case <-dtlsctx.Done():
				return
			case connchan <- conn2:
			}
		}
	}()
	dtlsConn, err1 := dtlsFunc(dtlsctx, conn1, peer)
	if err1 != nil {
		err = fmt.Errorf("failed to connect DTLS: %s", err1)
		return
	}
	defer func() {
		if closeErr := dtlsConn.Close(); closeErr != nil {
			err = fmt.Errorf("failed to close DTLS connection: %s", closeErr)
			return
		}
		log.Printf("Closed DTLS connection\n")
	}()
	log.Printf("Established DTLS connection!\n")

	if okchan != nil {
		go func() {
			select {
			case okchan <- struct{}{}:
			case <-dtlsctx.Done():
			}
		}()
	}

	wg := sync.WaitGroup{}
	wg.Add(2)
	context.AfterFunc(dtlsctx, func() {
		if err := listenConn.SetDeadline(time.Now()); err != nil {
			log.Printf("Failed to set listener deadline: %s", err)
		}
		if err := dtlsConn.SetDeadline(time.Now()); err != nil {
			log.Printf("Failed to set DTLS deadline: %s", err)
		}
	})

	go func() {
		defer wg.Done()
		defer dtlscancel()
		buf := make([]byte, 1600)
		for {
			select {
			case <-dtlsctx.Done():
				return
			default:
			}
			n, addr1, err1 := listenConn.ReadFrom(buf)
			if err1 != nil {
				log.Printf("Failed: %s", err1)
				return
			}

			globalClientWGAddr.Store(addr1)

			_, err1 = dtlsConn.Write(buf[:n])
			if err1 != nil {
				log.Printf("Failed: %s", err1)
				return
			}
		}
	}()

	go func() {
		defer wg.Done()
		defer dtlscancel()
		buf := make([]byte, 1600)
		for {
			select {
			case <-dtlsctx.Done():
				return
			default:
			}
			n, err1 := dtlsConn.Read(buf)
			if err1 != nil {
				log.Printf("Failed: %s", err1)
				return
			}

			addr1, ok := globalClientWGAddr.Load().(net.Addr)
			if !ok {
				continue
			}

			_, err1 = listenConn.WriteTo(buf[:n], addr1)
			if err1 != nil {
				log.Printf("Failed: %s", err1)
				return
			}
		}
	}()

	wg.Wait()
	if err := listenConn.SetDeadline(time.Time{}); err != nil {
		log.Printf("Failed to clear listener deadline: %s", err)
	}
	if err := dtlsConn.SetDeadline(time.Time{}); err != nil {
		log.Printf("Failed to clear DTLS deadline: %s", err)
	}
}

type connectedUDPConn struct {
	*net.UDPConn
}

func (c *connectedUDPConn) WriteTo(p []byte, _ net.Addr) (int, error) {
	return c.Write(p)
}

type turnParams struct {
	host     string
	port     string
	link     string
	udp      bool
	getCreds getCredsFunc
}

func oneTurnConnection(ctx context.Context, turnParams *turnParams, peer *net.UDPAddr, conn2 net.PacketConn, streamID int, c chan<- error) {
	time.Sleep(time.Duration(rand.Intn(400)+100) * time.Millisecond)
	var err error = nil
	defer func() { c <- err }()
	user, pass, urlTarget, err1 := turnParams.getCreds(ctx, turnParams.link, streamID)
	if err1 != nil {
		err = fmt.Errorf("failed to get TURN credentials: %s", err1)
		return
	}
	urlhost, urlport, err1 := net.SplitHostPort(urlTarget)
	if err1 != nil {
		err = fmt.Errorf("failed to parse TURN server address: %s", err1)
		return
	}
	if turnParams.host != "" {
		urlhost = turnParams.host
	}
	if turnParams.port != "" {
		urlport = turnParams.port
	}
	var turnServerAddr string
	turnServerAddr = net.JoinHostPort(urlhost, urlport)
	turnServerUdpAddr, err1 := net.ResolveUDPAddr("udp", turnServerAddr)
	if err1 != nil {
		err = fmt.Errorf("failed to resolve TURN server address: %s", err1)
		return
	}
	turnServerAddr = turnServerUdpAddr.String()

	var cfg *turn.ClientConfig
	var turnConn net.PacketConn
	var d net.Dialer
	ctx1, cancel := context.WithTimeout(ctx, 5*time.Second)
	defer cancel()
	if turnParams.udp {
		conn, err2 := net.DialUDP("udp", nil, turnServerUdpAddr) // nolint: noctx
		if err2 != nil {
			err = fmt.Errorf("failed to connect to TURN server: %s", err2)
			return
		}
		defer func() {
			if err1 = conn.Close(); err1 != nil {
				err = fmt.Errorf("failed to close TURN server connection: %s", err1)
				return
			}
		}()
		turnConn = &connectedUDPConn{conn}
	} else {
		conn, err2 := d.DialContext(ctx1, "tcp", turnServerAddr) // nolint: noctx
		if err2 != nil {
			err = fmt.Errorf("failed to connect to TURN server: %s", err2)
			return
		}
		defer func() {
			if err1 = conn.Close(); err1 != nil {
				err = fmt.Errorf("failed to close TURN server connection: %s", err1)
				return
			}
		}()
		turnConn = turn.NewSTUNConn(conn)
	}
	var addrFamily turn.RequestedAddressFamily
	if peer.IP.To4() != nil {
		addrFamily = turn.RequestedAddressFamilyIPv4
	} else {
		addrFamily = turn.RequestedAddressFamilyIPv6
	}

	cfg = &turn.ClientConfig{
		STUNServerAddr:         turnServerAddr,
		TURNServerAddr:         turnServerAddr,
		Conn:                   turnConn,
		Net:                    newDirectNet(),
		Username:               user,
		Password:               pass,
		RequestedAddressFamily: addrFamily,
		LoggerFactory:          logging.NewDefaultLoggerFactory(),
	}

	client, err1 := turn.NewClient(cfg)
	if err1 != nil {
		err = fmt.Errorf("failed to create TURN client: %s", err1)
		return
	}
	defer client.Close()

	err1 = client.Listen()
	if err1 != nil {
		err = fmt.Errorf("failed to listen: %s", err1)
		return
	}

	relayConn, err1 := client.Allocate()
	if err1 != nil {
		if isAuthError(err1) {
			handleAuthError(streamID)
		}
		err = fmt.Errorf("failed to allocate: %s", err1)
		return
	}
	defer func() {
		if err1 := relayConn.Close(); err1 != nil {
			err = fmt.Errorf("failed to close TURN allocated connection: %s", err1)
		}
	}()

	// Reset error count on successful allocation
	getStreamCache(streamID).errorCount.Store(0)

	log.Printf("[STREAM %d] relayed-address=%s", streamID, relayConn.LocalAddr().String())

	wg := sync.WaitGroup{}
	wg.Add(2)
	turnctx, turncancel := context.WithCancel(context.Background())
	context.AfterFunc(turnctx, func() {
		if err := relayConn.SetDeadline(time.Now()); err != nil {
			log.Printf("Failed to set relay deadline: %s", err)
		}
		if err := conn2.SetDeadline(time.Now()); err != nil {
			log.Printf("Failed to set upstream deadline: %s", err)
		}
	})
	var internalPipeAddr atomic.Value

	go func() {
		defer wg.Done()
		defer turncancel()
		buf := make([]byte, 1600)
		for {
			select {
			case <-turnctx.Done():
				return
			default:
			}
			n, addr1, err1 := conn2.ReadFrom(buf)
			if err1 != nil {
				log.Printf("Failed: %s", err1)
				return
			}

			internalPipeAddr.Store(addr1)

			_, err1 = relayConn.WriteTo(buf[:n], peer)
			if err1 != nil {
				log.Printf("Failed: %s", err1)
				return
			}
		}
	}()

	go func() {
		defer wg.Done()
		defer turncancel()
		buf := make([]byte, 1600)
		for {
			select {
			case <-turnctx.Done():
				return
			default:
			}
			n, _, err1 := relayConn.ReadFrom(buf)
			if err1 != nil {
				log.Printf("Failed: %s", err1)
				return
			}
			addr1, ok := internalPipeAddr.Load().(net.Addr)
			if !ok {
				log.Printf("Failed: no listener ip")
				return
			}

			_, err1 = conn2.WriteTo(buf[:n], addr1)
			if err1 != nil {
				log.Printf("Failed: %s", err1)
				return
			}
		}
	}()

	wg.Wait()
	if err := relayConn.SetDeadline(time.Time{}); err != nil {
		log.Printf("Failed to clear relay deadline: %s", err)
	}
	if err := conn2.SetDeadline(time.Time{}); err != nil {
		log.Printf("Failed to clear upstream deadline: %s", err)
	}
}

func oneDtlsConnectionLoop(ctx context.Context, peer *net.UDPAddr, listenConnChan <-chan net.PacketConn, connchan chan<- net.PacketConn, okchan chan<- struct{}) {
	for {
		select {
		case <-ctx.Done():
			return
		case listenConn := <-listenConnChan:
			c := make(chan error)
			go oneDtlsConnection(ctx, peer, listenConn, connchan, okchan, c)
			if err := <-c; err != nil {
				log.Printf("%s", err)
			}
		}
	}
}

func oneTurnConnectionLoop(ctx context.Context, turnParams *turnParams, peer *net.UDPAddr, connchan <-chan net.PacketConn, t <-chan time.Time, streamID int) {
	for {
		select {
		case <-ctx.Done():
			return
		case conn2 := <-connchan:
			select {
			case <-t:
			case <-ctx.Done():
				return
			}
			c := make(chan error)
			go oneTurnConnection(ctx, turnParams, peer, conn2, streamID, c)
			if err := <-c; err != nil {
				log.Printf("[STREAM %d] %s", streamID, err)
			}
		}
	}
}

func main() {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()
	signalChan := make(chan os.Signal, 1)
	signal.Notify(signalChan, syscall.SIGTERM, syscall.SIGINT)
	go func() {
		<-signalChan
		log.Printf("Terminating...\n")
		cancel()
		select {
		case <-signalChan:
		case <-time.After(5 * time.Second):
		}
		log.Fatalf("Exit...\n")
	}()

	host := flag.String("turn", "", "override TURN server ip")
	port := flag.String("port", "", "override TURN port")
	listen := flag.String("listen", "127.0.0.1:9000", "listen on ip:port")
	vklink := flag.String("vk-link", "", "VK calls invite link \"https://vk.com/call/join/...\"")
	yalink := flag.String("yandex-link", "", "Yandex telemost invite link \"https://telemost.yandex.ru/j/...\"")
	peerAddr := flag.String("peer", "", "peer server address (host:port)")
	n := flag.Int("n", 0, "connections to TURN (default 10 for VK, 1 for Yandex)")
	udp := flag.Bool("udp", false, "connect to TURN with UDP")
	direct := flag.Bool("no-dtls", false, "connect without obfuscation. DO NOT USE")
	flag.Parse()
	if *peerAddr == "" {
		log.Panicf("Need peer address!")
	}
	peer, err := net.ResolveUDPAddr("udp", *peerAddr)
	if err != nil {
		panic(err)
	}
	if (*vklink == "") == (*yalink == "") {
		log.Panicf("Need either vk-link or yandex-link!")
	}

	var link string
	var getCreds getCredsFunc
	if *vklink != "" {
		parts := strings.Split(*vklink, "join/")
		link = parts[len(parts)-1]

		dialer := dnsdialer.New(
			dnsdialer.WithResolvers("77.88.8.8:53", "77.88.8.1:53", "8.8.8.8:53", "8.8.4.4:53", "1.1.1.1:53", "1.0.0.1:53"),
			dnsdialer.WithStrategy(dnsdialer.Fallback{}),
			dnsdialer.WithCache(100, 10*time.Hour, 10*time.Hour),
		)

		getCreds = func(ctx context.Context, s string, streamID int) (string, string, string, error) {
			return getVkCredsCached(ctx, s, streamID, dialer)
		}
		if *n <= 0 {
			*n = 10
		}
	} else {
		parts := strings.Split(*yalink, "j/")
		link = parts[len(parts)-1]
		getCreds = func(ctx context.Context, s string, streamID int) (string, string, string, error) {
			return getYandexCreds(s)
		}
		if *n <= 0 {
			*n = 1
		}
	}
	if idx := strings.IndexAny(link, "/?#"); idx != -1 {
		link = link[:idx]
	}

	params := &turnParams{
		host:     *host,
		port:     *port,
		link:     link,
		udp:      *udp,
		getCreds: getCreds,
	}

	listenConnChan := make(chan net.PacketConn)
	listenConn, err := net.ListenPacket("udp", *listen) // nolint: noctx
	if err != nil {
		log.Panicf("Failed to listen: %s", err)
	}
	context.AfterFunc(ctx, func() {
		if closeErr := listenConn.Close(); closeErr != nil {
			log.Panicf("Failed to close local connection: %s", closeErr)
		}
	})
	go func() {
		for {
			select {
			case <-ctx.Done():
				return
			case listenConnChan <- listenConn:
			}
		}
	}()

	wg1 := sync.WaitGroup{}
	t := time.Tick(200 * time.Millisecond)
	if *direct {
		for i := 0; i < *n; i++ {
			wg1.Add(1)
			go func(streamID int) {
				defer wg1.Done()
				oneTurnConnectionLoop(ctx, params, peer, listenConnChan, t, streamID)
			}(i)
		}
	} else {
		okchan := make(chan struct{})
		connchan := make(chan net.PacketConn)

		wg1.Add(1)
		go func() {
			defer wg1.Done()
			oneDtlsConnectionLoop(ctx, peer, listenConnChan, connchan, okchan)
		}()

		wg1.Add(1)
		go func() {
			defer wg1.Done()
			oneTurnConnectionLoop(ctx, params, peer, connchan, t, 0)
		}()

		select {
		case <-okchan:
		case <-ctx.Done():
		}
		for i := 0; i < *n-1; i++ {
			connchan := make(chan net.PacketConn)
			wg1.Add(1)
			go func() {
				defer wg1.Done()
				oneDtlsConnectionLoop(ctx, peer, listenConnChan, connchan, nil)
			}()
			wg1.Add(1)
			go func(streamID int) {
				defer wg1.Done()
				oneTurnConnectionLoop(ctx, params, peer, connchan, t, streamID)
			}(i + 1)
		}
	}

	wg1.Wait()
}