import { getErrorMessage } from "../../utils/error-message.js";
import { type Response } from "express";
import {
  createServer as createTcpServer,
  Socket as TcpSocket,
  type Server as TcpServer,
} from "net";
import { Client, type ClientChannel } from "ssh2";
import { SSH_ALGORITHMS } from "../../utils/ssh-algorithms.js";
import { ChildProcess } from "child_process";
import axios from "axios";
import { createCurrentHostResolutionRepository } from "../../database/repositories/factory.js";
import type {
  SSHHost,
  TunnelConfig,
  TunnelStatus,
  VerificationData,
} from "../../../types/index.js";
import { CONNECTION_STATES } from "../../../types/index.js";
import { tunnelLogger } from "../../utils/logger.js";
import { logAudit } from "../../utils/audit-logger.js";
import { SystemCrypto } from "../../utils/system-crypto.js";
import { DataCrypto } from "../../utils/data-crypto.js";
import { createSocks5Connection } from "../../utils/socks5-helper.js";
import { withConnection } from "../ssh-connection-pool.js";
import { preparePrivateKeyForSSH2 } from "../../utils/ssh-key-utils.js";
import {
  applyAuthOptions,
  bindForwardIn,
  connectClient,
  forwardOut,
  getManagedTunnelAlgorithms,
  pipeTunnelStreams,
  unbindForwardIn,
} from "./ssh-primitives.js";
import {
  classifyTunnelError,
  getTunnelBindHost,
  getTunnelMarker,
  getTunnelMode,
  getTunnelScope,
  normalizeTunnelName,
} from "./utils.js";

import { resolveSshConnectConfigHost } from "../ssh-dns.js";
import { PermissionManager } from "../../utils/permission-manager.js";
import { handleSocks5Connect } from "./socks5-relay.js";
import { notifyAutomationInternalEvent } from "../metrics/automation-bridge.js";

export const activeTunnels = new Map<string, Client>();
export const retryCounters = new Map<string, number>();
export const connectionStatus = new Map<string, TunnelStatus>();
export const tunnelVerifications = new Map<string, VerificationData>();
export const manualDisconnects = new Set<string>();
export const verificationTimers = new Map<string, NodeJS.Timeout>();
export const activeRetryTimers = new Map<string, NodeJS.Timeout>();
export const countdownIntervals = new Map<string, NodeJS.Timeout>();
export const retryExhaustedTunnels = new Set<string>();
export const cleanupInProgress = new Set<string>();
export const tunnelConnecting = new Set<string>();
export const lastTunnelErrors = new Map<string, string>();
export const lastTunnelErrorTypes = new Map<
  string,
  TunnelStatus["errorType"]
>();

export const tunnelConfigs = new Map<string, TunnelConfig>();
export const activeTunnelProcesses = new Map<string, ChildProcess>();
export const pendingTunnelOperations = new Map<string, Promise<void>>();
// SSE clients mapped to the user they belong to, so snapshots can be
// filtered to tunnels that user can actually reach.
export const tunnelStatusClients = new Map<Response, string>();

export const INTERNAL_HOST_API_BASE_URL = "http://localhost:30001/host/db/host";
export const AUTOSTART_FETCH_RETRIES = 6;

export function sleep(ms: number): Promise<void> {
  return new Promise((resolve) => setTimeout(resolve, ms));
}

export function describeAxiosError(error: unknown): string {
  if (axios.isAxiosError(error)) {
    return error.response
      ? `${error.response.status} ${error.response.statusText}`
      : error.message;
  }

  return getErrorMessage(error);
}

export async function fetchInternalHosts(
  path: "internal" | "internal/all",
  internalAuthToken: string,
): Promise<SSHHost[]> {
  let lastError: unknown;

  for (let attempt = 1; attempt <= AUTOSTART_FETCH_RETRIES; attempt++) {
    try {
      const response = await axios.get(
        `${INTERNAL_HOST_API_BASE_URL}/${path}`,
        {
          headers: {
            "Content-Type": "application/json",
            "X-Internal-Auth-Token": internalAuthToken,
          },
          timeout: 5000,
        },
      );
      return response.data || [];
    } catch (error) {
      lastError = error;
      if (attempt === AUTOSTART_FETCH_RETRIES) {
        break;
      }

      const retryDelayMs = Math.min(500 * 2 ** (attempt - 1), 5000);
      tunnelLogger.warn("Internal host API unavailable, retrying", {
        operation: "tunnel_autostart_fetch_retry",
        path,
        attempt,
        maxAttempts: AUTOSTART_FETCH_RETRIES,
        retryDelayMs,
        error: describeAxiosError(error),
      });
      await sleep(retryDelayMs);
    }
  }

  throw new Error(
    `Failed to fetch ${path} hosts after ${AUTOSTART_FETCH_RETRIES} attempts: ${describeAxiosError(lastError)}`,
  );
}

export type ActiveTunnelRuntime = {
  sourceClient: Client;
  endpointClient?: Client;
  bindClient?: Client;
  bindHost?: string;
  bindPort?: number;
  tcpServer?: TcpServer;
  close: () => void;
};

export const activeTunnelRuntimes = new Map<string, ActiveTunnelRuntime>();

export function findHostByTunnelEndpoint(
  hosts: SSHHost[],
  endpointHost?: string,
): SSHHost | undefined {
  const value = endpointHost?.trim();
  if (!value) return undefined;

  return hosts.find((host) => {
    const userAtIp = `${host.username}@${host.ip}`;
    return (
      String(host.id) === value ||
      host.name === value ||
      host.ip === value ||
      userAtIp === value
    );
  });
}

export function broadcastTunnelStatus(
  tunnelName: string,
  status: TunnelStatus,
): void {
  if (
    status.status === CONNECTION_STATES.CONNECTED &&
    activeRetryTimers.has(tunnelName)
  ) {
    return;
  }

  const nextStatus = { ...status };

  if (
    retryExhaustedTunnels.has(tunnelName) &&
    nextStatus.status === CONNECTION_STATES.FAILED
  ) {
    const previousReason = lastTunnelErrors.get(tunnelName);
    nextStatus.reason = previousReason
      ? `Max retries exhausted: ${previousReason}`
      : "Max retries exhausted";
  }

  if (nextStatus.status === CONNECTION_STATES.FAILED && nextStatus.reason) {
    lastTunnelErrors.set(tunnelName, nextStatus.reason);
    if (nextStatus.errorType) {
      lastTunnelErrorTypes.set(tunnelName, nextStatus.errorType);
    }
  } else if (
    (nextStatus.status === CONNECTION_STATES.CONNECTING ||
      nextStatus.status === CONNECTION_STATES.RETRYING ||
      nextStatus.status === CONNECTION_STATES.WAITING) &&
    !nextStatus.reason
  ) {
    nextStatus.reason = lastTunnelErrors.get(tunnelName);
    nextStatus.errorType = lastTunnelErrorTypes.get(tunnelName);
  } else if (
    nextStatus.status === CONNECTION_STATES.CONNECTED ||
    (nextStatus.status === CONNECTION_STATES.DISCONNECTED &&
      nextStatus.manualDisconnect)
  ) {
    lastTunnelErrors.delete(tunnelName);
    lastTunnelErrorTypes.delete(tunnelName);
  }

  connectionStatus.set(tunnelName, nextStatus);
  broadcastTunnelStatusSnapshot();
}

export function getAllTunnelStatus(): Record<string, TunnelStatus> {
  const tunnelStatus: Record<string, TunnelStatus> = {};
  connectionStatus.forEach((status, key) => {
    tunnelStatus[key] = status;
  });
  return tunnelStatus;
}

// Tunnel names embed host labels and destination endpoints, and error text
// can leak internal hostnames -- so visibility is scoped to tunnels whose
// source host the requesting user can access (owner, share grant, admin),
// mirroring the ownership model of the connect/disconnect routes.
export async function getTunnelStatusForUser(
  userId: string,
): Promise<Record<string, TunnelStatus>> {
  const permissionManager = PermissionManager.getInstance();
  const accessibleHostIds = await permissionManager.filterAccessibleHostIds(
    userId,
    [...tunnelConfigs.values()]
      .map((config) => config.sourceHostId)
      .filter((id) => Number.isInteger(id)),
  );

  const tunnelStatus: Record<string, TunnelStatus> = {};
  connectionStatus.forEach((status, name) => {
    const sourceHostId = tunnelConfigs.get(name)?.sourceHostId;
    if (sourceHostId !== undefined && accessibleHostIds.has(sourceHostId)) {
      tunnelStatus[name] = status;
    }
  });
  return tunnelStatus;
}

export async function canAccessTunnel(
  userId: string,
  tunnelName: string,
): Promise<boolean> {
  const sourceHostId = tunnelConfigs.get(tunnelName)?.sourceHostId;
  if (sourceHostId === undefined) return false;
  const permissionManager = PermissionManager.getInstance();
  const access = await permissionManager.canAccessHost(
    userId,
    sourceHostId,
    "connect",
  );
  return access.hasAccess;
}

export function sendTunnelStatusSnapshot(res: Response): void {
  const userId = tunnelStatusClients.get(res);
  if (userId === undefined) {
    tunnelStatusClients.delete(res);
    return;
  }
  void getTunnelStatusForUser(userId)
    .then((statuses) => {
      res.write(`event: statuses\ndata: ${JSON.stringify(statuses)}\n\n`);
    })
    .catch(() => {
      tunnelStatusClients.delete(res);
    });
}

export function broadcastTunnelStatusSnapshot(): void {
  for (const client of tunnelStatusClients.keys()) {
    sendTunnelStatusSnapshot(client);
  }
}

export async function cleanupTunnelResources(
  tunnelName: string,
  forceCleanup = false,
): Promise<void> {
  if (cleanupInProgress.has(tunnelName)) {
    return;
  }

  if (!forceCleanup && tunnelConnecting.has(tunnelName)) {
    return;
  }

  cleanupInProgress.add(tunnelName);

  const tunnelConfig = tunnelConfigs.get(tunnelName);
  const runtime = activeTunnelRuntimes.get(tunnelName);
  if (runtime) {
    try {
      runtime.close();
    } catch (error) {
      tunnelLogger.error("Error while closing managed tunnel runtime", error, {
        operation: "managed_tunnel_cleanup",
        tunnelName,
      });
    }
    activeTunnelRuntimes.delete(tunnelName);
    cleanupInProgress.delete(tunnelName);
  } else if (tunnelConfig) {
    await new Promise<void>((resolve) => {
      killRemoteTunnelByMarker(tunnelConfig, tunnelName, (err) => {
        cleanupInProgress.delete(tunnelName);
        if (err) {
          tunnelLogger.error(
            `Failed to kill remote tunnel for '${tunnelName}': ${err.message}`,
          );
        }
        resolve();
      });
    });
  } else {
    cleanupInProgress.delete(tunnelName);
  }

  if (activeTunnelProcesses.has(tunnelName)) {
    try {
      const proc = activeTunnelProcesses.get(tunnelName);
      if (proc) {
        proc.kill("SIGTERM");
      }
    } catch (e) {
      tunnelLogger.error(
        `Error while killing local ssh process for tunnel '${tunnelName}'`,
        e,
      );
    }
    activeTunnelProcesses.delete(tunnelName);
  }

  if (activeTunnels.has(tunnelName)) {
    try {
      const conn = activeTunnels.get(tunnelName);
      if (conn) {
        conn.end();
      }
    } catch (e) {
      tunnelLogger.error(
        `Error while closing SSH2 Client for tunnel '${tunnelName}'`,
        e,
      );
    }
    activeTunnels.delete(tunnelName);
  }

  if (tunnelVerifications.has(tunnelName)) {
    const verification = tunnelVerifications.get(tunnelName);
    if (verification?.timeout) clearTimeout(verification.timeout);
    try {
      verification?.conn.end();
    } catch (error) {
      tunnelLogger.error("Error during tunnel cleanup", error, {
        operation: "tunnel_cleanup_error",
        tunnelName,
      });
    }
    tunnelVerifications.delete(tunnelName);
  }

  const timerKeys = [
    tunnelName,
    `${tunnelName}_confirm`,
    `${tunnelName}_retry`,
    `${tunnelName}_verify_retry`,
    `${tunnelName}_ping`,
  ];

  timerKeys.forEach((key) => {
    if (verificationTimers.has(key)) {
      clearTimeout(verificationTimers.get(key)!);
      verificationTimers.delete(key);
    }
  });

  if (activeRetryTimers.has(tunnelName)) {
    clearTimeout(activeRetryTimers.get(tunnelName)!);
    activeRetryTimers.delete(tunnelName);
  }

  if (countdownIntervals.has(tunnelName)) {
    clearInterval(countdownIntervals.get(tunnelName)!);
    countdownIntervals.delete(tunnelName);
  }
}

export function resetRetryState(tunnelName: string): void {
  retryCounters.delete(tunnelName);
  retryExhaustedTunnels.delete(tunnelName);
  lastTunnelErrors.delete(tunnelName);
  lastTunnelErrorTypes.delete(tunnelName);
  cleanupInProgress.delete(tunnelName);
  tunnelConnecting.delete(tunnelName);

  if (activeRetryTimers.has(tunnelName)) {
    clearTimeout(activeRetryTimers.get(tunnelName)!);
    activeRetryTimers.delete(tunnelName);
  }

  if (countdownIntervals.has(tunnelName)) {
    clearInterval(countdownIntervals.get(tunnelName)!);
    countdownIntervals.delete(tunnelName);
  }

  ["", "_confirm", "_retry", "_verify_retry", "_ping"].forEach((suffix) => {
    const timerKey = `${tunnelName}${suffix}`;
    if (verificationTimers.has(timerKey)) {
      clearTimeout(verificationTimers.get(timerKey)!);
      verificationTimers.delete(timerKey);
    }
  });
}

export async function handleDisconnect(
  tunnelName: string,
  tunnelConfig: TunnelConfig | null,
  shouldRetry = true,
): Promise<void> {
  if (tunnelVerifications.has(tunnelName)) {
    try {
      const verification = tunnelVerifications.get(tunnelName);
      if (verification?.timeout) clearTimeout(verification.timeout);
      verification?.conn.end();
    } catch (error) {
      tunnelLogger.error("Error during tunnel cleanup", error, {
        operation: "tunnel_cleanup_error",
        tunnelName,
      });
    }
    tunnelVerifications.delete(tunnelName);
  }

  while (cleanupInProgress.has(tunnelName)) {
    await new Promise((resolve) => setTimeout(resolve, 100));
  }

  await cleanupTunnelResources(tunnelName);

  if (manualDisconnects.has(tunnelName)) {
    resetRetryState(tunnelName);

    broadcastTunnelStatus(tunnelName, {
      connected: false,
      status: CONNECTION_STATES.DISCONNECTED,
      manualDisconnect: true,
    });
    return;
  }

  // Past the manual branch, so this is a drop the user did not ask for.
  const ownerUserId =
    tunnelConfig?.sourceUserId ?? tunnelConfig?.requestingUserId;
  if (ownerUserId) {
    notifyAutomationInternalEvent(
      "tunnel_disconnected",
      ownerUserId,
      tunnelConfig?.sourceHostId,
      { tunnelName },
    );
  }

  if (retryExhaustedTunnels.has(tunnelName)) {
    broadcastTunnelStatus(tunnelName, {
      connected: false,
      status: CONNECTION_STATES.FAILED,
      reason: "Max retries already exhausted",
    });
    return;
  }

  if (activeRetryTimers.has(tunnelName)) {
    return;
  }

  if (shouldRetry && tunnelConfig) {
    const maxRetries = tunnelConfig.maxRetries || 3;
    const retryInterval = tunnelConfig.retryInterval || 5000;

    let retryCount = retryCounters.get(tunnelName) || 0;
    retryCount = retryCount + 1;

    if (retryCount > maxRetries) {
      tunnelLogger.error(`All ${maxRetries} retries failed for ${tunnelName}`);

      retryExhaustedTunnels.add(tunnelName);
      activeTunnels.delete(tunnelName);
      retryCounters.delete(tunnelName);

      broadcastTunnelStatus(tunnelName, {
        connected: false,
        status: CONNECTION_STATES.FAILED,
        retryExhausted: true,
        reason: `Max retries exhausted`,
      });
      return;
    }

    retryCounters.set(tunnelName, retryCount);

    if (retryCount <= maxRetries) {
      broadcastTunnelStatus(tunnelName, {
        connected: false,
        status: CONNECTION_STATES.RETRYING,
        retryCount: retryCount,
        maxRetries: maxRetries,
        nextRetryIn: retryInterval / 1000,
      });

      if (activeRetryTimers.has(tunnelName)) {
        clearTimeout(activeRetryTimers.get(tunnelName)!);
        activeRetryTimers.delete(tunnelName);
      }

      const initialNextRetryIn = Math.ceil(retryInterval / 1000);
      let currentNextRetryIn = initialNextRetryIn;

      broadcastTunnelStatus(tunnelName, {
        connected: false,
        status: CONNECTION_STATES.WAITING,
        retryCount: retryCount,
        maxRetries: maxRetries,
        nextRetryIn: currentNextRetryIn,
      });

      const countdownInterval = setInterval(() => {
        currentNextRetryIn--;
        if (currentNextRetryIn > 0) {
          broadcastTunnelStatus(tunnelName, {
            connected: false,
            status: CONNECTION_STATES.WAITING,
            retryCount: retryCount,
            maxRetries: maxRetries,
            nextRetryIn: currentNextRetryIn,
          });
        }
      }, 1000);

      countdownIntervals.set(tunnelName, countdownInterval);

      const timer = setTimeout(() => {
        clearInterval(countdownInterval);
        countdownIntervals.delete(tunnelName);
        activeRetryTimers.delete(tunnelName);

        if (!manualDisconnects.has(tunnelName)) {
          activeTunnels.delete(tunnelName);
          connectSSHTunnel(tunnelConfig, retryCount).catch((error) => {
            tunnelLogger.error(
              `Failed to connect tunnel ${tunnelConfig.name}: ${getErrorMessage(error)}`,
            );
          });
        }
      }, retryInterval);

      activeRetryTimers.set(tunnelName, timer);
    }
  } else {
    broadcastTunnelStatus(tunnelName, {
      connected: false,
      status: CONNECTION_STATES.FAILED,
    });

    activeTunnels.delete(tunnelName);
  }
}

export function setupPingInterval(tunnelName: string): void {
  const pingKey = `${tunnelName}_ping`;
  if (verificationTimers.has(pingKey)) {
    clearInterval(verificationTimers.get(pingKey)!);
    verificationTimers.delete(pingKey);
  }

  const pingInterval = setInterval(() => {
    const currentStatus = connectionStatus.get(tunnelName);
    if (currentStatus?.status === CONNECTION_STATES.CONNECTED) {
      if (!activeTunnels.has(tunnelName)) {
        broadcastTunnelStatus(tunnelName, {
          connected: false,
          status: CONNECTION_STATES.DISCONNECTED,
          reason: "Tunnel connection lost",
        });
        clearInterval(pingInterval);
        verificationTimers.delete(pingKey);
      }
    } else {
      clearInterval(pingInterval);
      verificationTimers.delete(pingKey);
    }
  }, 120000);

  verificationTimers.set(pingKey, pingInterval);
}

export async function connectEndpointThroughSource(
  sourceClient: Client,
  tunnelConfig: TunnelConfig,
  endpointCredentials: {
    password?: string;
    sshKey?: string;
    keyPassword?: string;
    keyType?: string;
    authMethod?: string;
  },
): Promise<Client> {
  const endpointSock = await forwardOut(
    sourceClient,
    tunnelConfig.endpointIP,
    tunnelConfig.endpointSSHPort,
    tunnelConfig.name,
  );
  const endpointOptions: Record<string, unknown> = {
    sock: endpointSock,
    username: tunnelConfig.endpointUsername,
    tryKeyboard: true,
    keepaliveInterval: tunnelConfig.keepaliveInterval ?? 30000,
    keepaliveCountMax: tunnelConfig.keepaliveCountMax ?? 3,
    readyTimeout: 60000,
    tcpKeepAlive: true,
    tcpKeepAliveInitialDelay: 30000,
    algorithms: getManagedTunnelAlgorithms(),
  };

  applyAuthOptions(endpointOptions, endpointCredentials);
  return connectClient(endpointOptions, tunnelConfig.name, "endpoint");
}

export function resolveS2SLocalTargetHost(tunnelConfig: TunnelConfig): string {
  const targetHost = tunnelConfig.targetHost?.trim();

  if (
    !targetHost ||
    targetHost === tunnelConfig.endpointHost ||
    targetHost === tunnelConfig.hostName
  ) {
    return "127.0.0.1";
  }

  return targetHost;
}

export function isSingleHostTunnel(tunnelConfig: TunnelConfig): boolean {
  if (!tunnelConfig.endpointHost && !tunnelConfig.endpointIP) return true;
  if (
    tunnelConfig.endpointHost === "127.0.0.1" ||
    tunnelConfig.endpointHost === "localhost"
  ) {
    return true;
  }
  if (
    tunnelConfig.endpointIP &&
    tunnelConfig.endpointIP === tunnelConfig.sourceIP &&
    tunnelConfig.endpointSSHPort === tunnelConfig.sourceSSHPort
  ) {
    return true;
  }
  return false;
}

export function shouldEstablishDirectTunnel(
  tunnelConfig: TunnelConfig,
): boolean {
  if (isSingleHostTunnel(tunnelConfig)) return true;
  const mode = getTunnelMode(tunnelConfig);
  return mode !== "remote" && !tunnelConfig.endpointUsername;
}

export async function establishDirectTunnel(
  sourceClient: Client,
  tunnelConfig: TunnelConfig,
): Promise<void> {
  const tunnelName = tunnelConfig.name;
  const mode = getTunnelMode(tunnelConfig);
  const bindHost = getTunnelBindHost(tunnelConfig);
  const sourcePort = tunnelConfig.sourcePort;
  const targetHost =
    tunnelConfig.targetHost || tunnelConfig.endpointHost || "127.0.0.1";
  const targetPort = tunnelConfig.endpointPort;

  if (mode === "remote") {
    const remoteBindPort = await bindForwardIn(
      sourceClient,
      targetHost,
      sourcePort,
    );
    const sockets = new Set<TcpSocket>();
    sourceClient.on("tcp connection", (info, accept, reject) => {
      if (info.destPort !== remoteBindPort) {
        reject();
        return;
      }
      const inbound = accept();
      const local = new TcpSocket();
      sockets.add(local);
      local.connect(targetPort, bindHost, () => {
        pipeTunnelStreams(inbound, Promise.resolve(local), tunnelName);
      });
      local.on("error", () => {
        inbound.destroy();
        sockets.delete(local);
      });
      local.on("close", () => sockets.delete(local));
    });

    const close = () => {
      unbindForwardIn(sourceClient, targetHost, remoteBindPort);
      for (const s of sockets) s.destroy();
      sockets.clear();
      try {
        sourceClient.end();
      } catch {
        // expected
      }
    };

    activeTunnelRuntimes.set(tunnelName, {
      sourceClient,
      bindHost: targetHost,
      bindPort: remoteBindPort,
      close,
    });
    activeTunnels.set(tunnelName, sourceClient);
    return;
  }

  // Local and dynamic modes: listen locally, forward through SSH
  const sockets = new Set<TcpSocket>();
  const tcpServer = createTcpServer((socket) => {
    sockets.add(socket);
    socket.on("close", () => sockets.delete(socket));
    socket.on("error", () => {
      sockets.delete(socket);
      socket.destroy();
    });

    if (mode === "dynamic") {
      handleSocks5Connect(
        socket,
        (host, port) => forwardOut(sourceClient, host, port),
        tunnelName,
      );
      return;
    }

    forwardOut(sourceClient, targetHost, targetPort, tunnelName)
      .then((outbound) =>
        pipeTunnelStreams(socket, Promise.resolve(outbound), tunnelName),
      )
      .catch(() => socket.destroy());
  });

  await new Promise<void>((resolve, reject) => {
    tcpServer.once("error", reject);
    tcpServer.listen({ host: bindHost, port: sourcePort }, () => {
      tcpServer.removeListener("error", reject);
      resolve();
    });
  });

  tunnelLogger.info("Direct tunnel listener started", {
    operation: "direct_tunnel_listen",
    tunnelName,
    mode,
    bindHost,
    sourcePort,
    targetHost,
    targetPort,
  });

  const close = () => {
    for (const s of sockets) s.destroy();
    sockets.clear();
    tcpServer.close();
    try {
      sourceClient.end();
    } catch {
      // expected
    }
  };

  sourceClient.on("close", () => {
    close();
  });

  activeTunnelRuntimes.set(tunnelName, {
    sourceClient,
    tcpServer,
    bindHost,
    bindPort: sourcePort,
    close,
  });
  activeTunnels.set(tunnelName, sourceClient);
}

export async function establishManagedS2STunnel(
  sourceClient: Client,
  tunnelConfig: TunnelConfig,
  endpointCredentials: {
    password?: string;
    sshKey?: string;
    keyPassword?: string;
    keyType?: string;
    authMethod?: string;
  },
): Promise<void> {
  const tunnelName = tunnelConfig.name;
  const mode = getTunnelMode(tunnelConfig);
  const bindHost = getTunnelBindHost(tunnelConfig);
  const endpointClient = await connectEndpointThroughSource(
    sourceClient,
    tunnelConfig,
    endpointCredentials,
  );

  const bindClient = mode === "remote" ? endpointClient : sourceClient;
  const outboundClient = mode === "remote" ? sourceClient : endpointClient;
  const bindPort =
    mode === "remote" ? tunnelConfig.endpointPort : tunnelConfig.sourcePort;
  const staticTargetHost =
    mode === "remote"
      ? tunnelConfig.targetHost || "127.0.0.1"
      : resolveS2SLocalTargetHost(tunnelConfig);
  const staticTargetPort =
    mode === "remote" ? tunnelConfig.sourcePort : tunnelConfig.endpointPort;

  tunnelLogger.info("Managed S2S tunnel route resolved", {
    operation: "managed_tunnel_route_resolved",
    tunnelName,
    mode,
    bindHost,
    bindPort,
    targetHost: staticTargetHost,
    targetPort: staticTargetPort,
    endpointHost: tunnelConfig.endpointHost,
    endpointIP: tunnelConfig.endpointIP,
  });

  const actualPort = await bindForwardIn(bindClient, bindHost, bindPort);

  const tcpHandler = (
    info: {
      destIP: string;
      destPort: number;
      srcIP: string;
      srcPort: number;
    },
    accept: () => ClientChannel,
    reject: () => void,
  ) => {
    if (info.destPort !== actualPort) {
      reject();
      return;
    }

    const inbound = accept();
    if (mode === "dynamic") {
      handleSocks5Connect(
        inbound,
        (host, port) => forwardOut(outboundClient, host, port),
        tunnelName,
      );
      return;
    }

    pipeTunnelStreams(
      inbound,
      forwardOut(
        outboundClient,
        staticTargetHost,
        staticTargetPort,
        tunnelName,
      ),
      tunnelName,
    );
  };

  bindClient.on("tcp connection", tcpHandler);

  const close = () => {
    bindClient.off("tcp connection", tcpHandler);
    unbindForwardIn(bindClient, bindHost, actualPort);
    try {
      endpointClient.end();
    } catch {
      // expected during shutdown
    }
    try {
      sourceClient.end();
    } catch {
      // expected during shutdown
    }
  };

  activeTunnelRuntimes.set(tunnelName, {
    sourceClient,
    endpointClient,
    bindClient,
    bindHost,
    bindPort: actualPort,
    close,
  });

  activeTunnels.set(tunnelName, sourceClient);
}

export async function connectSSHTunnel(
  tunnelConfig: TunnelConfig,
  retryAttempt = 0,
): Promise<void> {
  const tunnelName = tunnelConfig.name;
  tunnelLogger.info("Tunnel creation request received", {
    operation: "tunnel_create_request",
    userId: tunnelConfig.sourceUserId,
    hostId: tunnelConfig.sourceHostId,
    tunnelName,
    tunnelType: tunnelConfig.tunnelType || "remote",
    sourcePort: tunnelConfig.sourcePort,
    endpointHost: tunnelConfig.endpointHost,
    endpointPort: tunnelConfig.endpointPort,
  });

  if (manualDisconnects.has(tunnelName)) {
    return;
  }

  tunnelConnecting.add(tunnelName);

  await cleanupTunnelResources(tunnelName, true);

  if (retryAttempt === 0) {
    retryExhaustedTunnels.delete(tunnelName);
    retryCounters.delete(tunnelName);
  }

  const currentStatus = connectionStatus.get(tunnelName);
  if (!currentStatus || currentStatus.status !== CONNECTION_STATES.WAITING) {
    broadcastTunnelStatus(tunnelName, {
      connected: false,
      status: CONNECTION_STATES.CONNECTING,
      retryCount: retryAttempt > 0 ? retryAttempt : undefined,
    });
  }

  if (
    !tunnelConfig ||
    !tunnelConfig.sourceIP ||
    !tunnelConfig.sourceUsername ||
    !tunnelConfig.sourceSSHPort
  ) {
    const missingFields = [];
    if (!tunnelConfig) missingFields.push("tunnelConfig");
    if (!tunnelConfig?.sourceIP) missingFields.push("sourceIP");
    if (!tunnelConfig?.sourceUsername) missingFields.push("sourceUsername");
    if (!tunnelConfig?.sourceSSHPort) missingFields.push("sourceSSHPort");

    tunnelLogger.error("Invalid tunnel connection details", undefined, {
      operation: "tunnel_connect_validation_failed",
      tunnelName,
      missingFields: missingFields.join(", "),
      hasSourceIP: !!tunnelConfig?.sourceIP,
      hasSourceUsername: !!tunnelConfig?.sourceUsername,
      hasSourceSSHPort: !!tunnelConfig?.sourceSSHPort,
    });
    broadcastTunnelStatus(tunnelName, {
      connected: false,
      status: CONNECTION_STATES.FAILED,
      reason: "Missing required connection details",
    });
    tunnelConnecting.delete(tunnelName);
    return;
  }

  let resolvedSourceCredentials = {
    password: tunnelConfig.sourcePassword,
    sshKey: tunnelConfig.sourceSSHKey,
    keyPassword: tunnelConfig.sourceKeyPassword,
    keyType: tunnelConfig.sourceKeyType,
    authMethod: tunnelConfig.sourceAuthMethod,
  };

  const effectiveUserId =
    tunnelConfig.requestingUserId || tunnelConfig.sourceUserId;

  // Resolve source credentials server-side when not provided by frontend
  if (
    tunnelConfig.sourceHostId &&
    effectiveUserId &&
    !tunnelConfig.sourcePassword &&
    !tunnelConfig.sourceSSHKey
  ) {
    try {
      const { resolveHostById } = await import("../host-resolver.js");
      const resolvedHost = await resolveHostById(
        tunnelConfig.sourceHostId,
        effectiveUserId,
      );
      if (resolvedHost) {
        resolvedSourceCredentials = {
          password: resolvedHost.password,
          sshKey: resolvedHost.key,
          keyPassword: resolvedHost.keyPassword,
          keyType: resolvedHost.keyType,
          authMethod: resolvedHost.authType,
        };
        if (tunnelConfig.keepaliveInterval === undefined) {
          tunnelConfig.keepaliveInterval =
            typeof resolvedHost.terminalConfig?.keepaliveInterval === "number"
              ? resolvedHost.terminalConfig.keepaliveInterval * 1000
              : 60000;
        }
        if (tunnelConfig.keepaliveCountMax === undefined) {
          tunnelConfig.keepaliveCountMax =
            typeof resolvedHost.terminalConfig?.keepaliveCountMax === "number"
              ? resolvedHost.terminalConfig.keepaliveCountMax
              : 5;
        }
      }
    } catch (error) {
      tunnelLogger.warn("Failed to resolve source host credentials", {
        operation: "tunnel_connect",
        tunnelName,
        sourceHostId: tunnelConfig.sourceHostId,
        error: getErrorMessage(error),
      });
    }
  } else if (tunnelConfig.sourceCredentialId && effectiveUserId) {
    // Legacy: credential resolution from credentialId
    try {
      if (tunnelConfig.sourceHostId) {
        const { resolveHostById } = await import("../host-resolver.js");
        const resolvedHost = await resolveHostById(
          tunnelConfig.sourceHostId,
          effectiveUserId,
        );
        if (resolvedHost) {
          resolvedSourceCredentials = {
            password: resolvedHost.password,
            sshKey: resolvedHost.key,
            keyPassword: resolvedHost.keyPassword,
            keyType: resolvedHost.keyType,
            authMethod: resolvedHost.authType,
          };
        }
      }
    } catch (error) {
      tunnelLogger.warn("Failed to resolve source credentials", {
        operation: "tunnel_connect",
        tunnelName,
        credentialId: tunnelConfig.sourceCredentialId,
        error: getErrorMessage(error),
      });
    }
  }

  let resolvedEndpointCredentials = {
    password: tunnelConfig.endpointPassword,
    sshKey: tunnelConfig.endpointSSHKey,
    keyPassword: tunnelConfig.endpointKeyPassword,
    keyType: tunnelConfig.endpointKeyType,
    authMethod: tunnelConfig.endpointAuthMethod,
  };

  if (tunnelConfig.endpointCredentialId && tunnelConfig.endpointUserId) {
    try {
      if (DataCrypto.getUserDataKey(tunnelConfig.endpointUserId) !== null) {
        const credential =
          await createCurrentHostResolutionRepository().findCredentialByIdForUser(
            tunnelConfig.endpointCredentialId,
            tunnelConfig.endpointUserId,
          );

        if (credential) {
          resolvedEndpointCredentials = {
            password: credential.password as string | undefined,
            sshKey: (credential.key || credential.privateKey) as
              string | undefined,
            keyPassword: credential.keyPassword as string | undefined,
            keyType: credential.keyType as string | undefined,
            authMethod: credential.authType as string,
          };
        } else {
          tunnelLogger.warn("No endpoint credentials found in database", {
            operation: "tunnel_connect",
            tunnelName,
            credentialId: tunnelConfig.endpointCredentialId,
          });
        }
      }
    } catch (error) {
      tunnelLogger.warn(
        `Failed to resolve endpoint credentials for tunnel ${tunnelName}: ${getErrorMessage(error)}`,
      );
    }
  } else if (tunnelConfig.endpointCredentialId) {
    tunnelLogger.warn("Missing userId for endpoint credential resolution", {
      operation: "tunnel_connect",
      tunnelName,
      credentialId: tunnelConfig.endpointCredentialId,
      hasUserId: !!tunnelConfig.endpointUserId,
    });
  }

  if (
    !shouldEstablishDirectTunnel(tunnelConfig) &&
    resolvedEndpointCredentials.authMethod === "password" &&
    !resolvedEndpointCredentials.password
  ) {
    const errorMessage = `Cannot connect tunnel '${tunnelName}': endpoint host requires password authentication but no plaintext password available. Enable autostart for endpoint host or configure credentials in tunnel connection.`;
    tunnelLogger.error(errorMessage, undefined, {
      operation: "tunnel_endpoint_password_unavailable",
      tunnelName,
      endpointHost: `${tunnelConfig.endpointUsername}@${tunnelConfig.endpointIP}:${tunnelConfig.endpointPort}`,
      endpointAuthMethod: resolvedEndpointCredentials.authMethod,
    });
    broadcastTunnelStatus(tunnelName, {
      connected: false,
      status: CONNECTION_STATES.FAILED,
      reason: errorMessage,
    });
    tunnelConnecting.delete(tunnelName);
    return;
  }

  if (
    !shouldEstablishDirectTunnel(tunnelConfig) &&
    resolvedEndpointCredentials.authMethod === "key" &&
    !resolvedEndpointCredentials.sshKey
  ) {
    const errorMessage = `Cannot connect tunnel '${tunnelName}': endpoint host requires key authentication but no plaintext key available. Enable autostart for endpoint host or configure credentials in tunnel connection.`;
    tunnelLogger.error(errorMessage, undefined, {
      operation: "tunnel_endpoint_key_unavailable",
      tunnelName,
      endpointHost: `${tunnelConfig.endpointUsername}@${tunnelConfig.endpointIP}:${tunnelConfig.endpointPort}`,
      endpointAuthMethod: resolvedEndpointCredentials.authMethod,
    });
    broadcastTunnelStatus(tunnelName, {
      connected: false,
      status: CONNECTION_STATES.FAILED,
      reason: errorMessage,
    });
    tunnelConnecting.delete(tunnelName);
    return;
  }

  const conn = new Client();

  const connectionTimeout = setTimeout(() => {
    if (conn) {
      if (activeRetryTimers.has(tunnelName)) {
        return;
      }

      tunnelLogger.error(
        `Tunnel connection timeout after 60 seconds for '${tunnelName}'`,
        undefined,
        {
          operation: "tunnel_connection_timeout",
          tunnelName,
          sourceHost: `${tunnelConfig.sourceUsername}@${tunnelConfig.sourceIP}:${tunnelConfig.sourceSSHPort}`,
          endpointHost: `${tunnelConfig.endpointUsername}@${tunnelConfig.endpointIP}:${tunnelConfig.endpointPort}`,
          retryAttempt,
          usingSocks5: tunnelConfig.useSocks5 || false,
        },
      );

      try {
        conn.end();
      } catch {
        // expected
      }

      activeTunnels.delete(tunnelName);

      if (!activeRetryTimers.has(tunnelName)) {
        handleDisconnect(
          tunnelName,
          tunnelConfig,
          !manualDisconnects.has(tunnelName),
        );
      }
    }
  }, 60000);

  conn.on("error", (err) => {
    clearTimeout(connectionTimeout);

    const errorType = classifyTunnelError(err.message);

    tunnelLogger.error(`Tunnel connection failed for '${tunnelName}'`, err, {
      operation: "tunnel_connect_error",
      tunnelName,
      errorType,
      errorMessage: err.message,
      sourceHost: `${tunnelConfig.sourceUsername}@${tunnelConfig.sourceIP}:${tunnelConfig.sourceSSHPort}`,
      endpointHost: `${tunnelConfig.endpointUsername}@${tunnelConfig.endpointIP}:${tunnelConfig.endpointPort}`,
      tunnelType: tunnelConfig.tunnelType || "remote",
      sourcePort: tunnelConfig.sourcePort,
      retryAttempt,
      usingSocks5: tunnelConfig.useSocks5 || false,
      authMethod: tunnelConfig.sourceAuthMethod,
    });

    tunnelConnecting.delete(tunnelName);

    if (activeRetryTimers.has(tunnelName)) {
      return;
    }

    if (!manualDisconnects.has(tunnelName)) {
      broadcastTunnelStatus(tunnelName, {
        connected: false,
        status: CONNECTION_STATES.FAILED,
        errorType: errorType,
        reason: err.message,
      });
    }

    activeTunnels.delete(tunnelName);

    const shouldNotRetry =
      errorType === "AUTHENTICATION_FAILED" ||
      errorType === "CONNECTION_FAILED" ||
      manualDisconnects.has(tunnelName);

    handleDisconnect(tunnelName, tunnelConfig, !shouldNotRetry);
  });

  conn.on("close", () => {
    clearTimeout(connectionTimeout);

    tunnelConnecting.delete(tunnelName);

    if (activeRetryTimers.has(tunnelName)) {
      return;
    }

    if (!manualDisconnects.has(tunnelName)) {
      const currentStatus = connectionStatus.get(tunnelName);
      if (!currentStatus || currentStatus.status !== CONNECTION_STATES.FAILED) {
        broadcastTunnelStatus(tunnelName, {
          connected: false,
          status: CONNECTION_STATES.DISCONNECTED,
        });
      }

      if (!activeRetryTimers.has(tunnelName)) {
        handleDisconnect(
          tunnelName,
          tunnelConfig,
          !manualDisconnects.has(tunnelName),
        );
      }
    }
  });

  conn.on("ready", async () => {
    clearTimeout(connectionTimeout);
    tunnelLogger.info("Creating managed SSH tunnel", {
      operation: "managed_tunnel_connection_create",
      userId: tunnelConfig.sourceUserId,
      hostId: tunnelConfig.sourceHostId,
      tunnelName,
      scope: getTunnelScope(tunnelConfig),
      mode: getTunnelMode(tunnelConfig),
    });

    const isAlreadyVerifying = tunnelVerifications.has(tunnelName);
    if (isAlreadyVerifying) {
      return;
    }

    try {
      if (getTunnelScope(tunnelConfig) !== "s2s") {
        throw new Error(
          "C2S tunnels must be started from the desktop client local configuration",
        );
      }

      if (shouldEstablishDirectTunnel(tunnelConfig)) {
        await establishDirectTunnel(conn, tunnelConfig);
      } else {
        await establishManagedS2STunnel(
          conn,
          tunnelConfig,
          resolvedEndpointCredentials,
        );
      }

      tunnelConnecting.delete(tunnelName);
      tunnelLogger.success("Managed tunnel creation complete", {
        operation: "managed_tunnel_create_complete",
        userId: tunnelConfig.sourceUserId,
        hostId: tunnelConfig.sourceHostId,
        tunnelName,
        mode: getTunnelMode(tunnelConfig),
        sourcePort: tunnelConfig.sourcePort,
        endpointPort: tunnelConfig.endpointPort,
      });

      logAudit({
        userId: tunnelConfig.sourceUserId,
        username: tunnelConfig.sourceUserId,
        action: "tunnel_connect",
        resourceType: "tunnel",
        resourceId: String(tunnelConfig.sourceHostId),
        resourceName: tunnelName,
        details: JSON.stringify({
          mode: getTunnelMode(tunnelConfig),
          sourcePort: tunnelConfig.sourcePort,
        }),
        success: true,
      });

      broadcastTunnelStatus(tunnelName, {
        connected: true,
        status: CONNECTION_STATES.CONNECTED,
      });
      setupPingInterval(tunnelName);
    } catch (error) {
      const message = getErrorMessage(error, "Failed to create tunnel");
      const errorType = classifyTunnelError(message);
      tunnelLogger.error("Failed to create managed tunnel", error, {
        operation: "managed_tunnel_create_failed",
        tunnelName,
        errorType,
        retryAttempt,
      });
      tunnelConnecting.delete(tunnelName);
      activeTunnels.delete(tunnelName);
      activeTunnelRuntimes.delete(tunnelName);
      try {
        conn.end();
      } catch {
        // expected
      }
      broadcastTunnelStatus(tunnelName, {
        connected: false,
        status: CONNECTION_STATES.FAILED,
        errorType,
        reason: message,
      });
      const shouldNotRetry =
        errorType === "AUTHENTICATION_FAILED" ||
        errorType === "CONNECTION_FAILED";
      handleDisconnect(tunnelName, tunnelConfig, !shouldNotRetry);
    }
  });

  const connOptions: Record<string, unknown> = {
    host:
      tunnelConfig.sourceIP?.replace(/^\[|\]$/g, "") || tunnelConfig.sourceIP,
    port: tunnelConfig.sourceSSHPort,
    username: tunnelConfig.sourceUsername,
    tryKeyboard: true,
    keepaliveInterval: tunnelConfig.keepaliveInterval ?? 30000,
    keepaliveCountMax: tunnelConfig.keepaliveCountMax ?? 3,
    readyTimeout: 60000,
    tcpKeepAlive: true,
    tcpKeepAliveInitialDelay: 30000,
    env: {
      TERM: "xterm-256color",
      LANG: "en_US.UTF-8",
      LC_ALL: "en_US.UTF-8",
      LC_CTYPE: "en_US.UTF-8",
      LC_MESSAGES: "en_US.UTF-8",
      LC_MONETARY: "en_US.UTF-8",
      LC_NUMERIC: "en_US.UTF-8",
      LC_TIME: "en_US.UTF-8",
      LC_COLLATE: "en_US.UTF-8",
      COLORTERM: "truecolor",
    },
    algorithms: {
      kex: [
        "curve25519-sha256",
        "curve25519-sha256@libssh.org",
        "ecdh-sha2-nistp521",
        "ecdh-sha2-nistp384",
        "ecdh-sha2-nistp256",
        "diffie-hellman-group-exchange-sha256",
        "diffie-hellman-group14-sha256",
        "diffie-hellman-group14-sha1",
        "diffie-hellman-group-exchange-sha1",
        "diffie-hellman-group1-sha1",
      ],
      serverHostKey: [
        "ssh-ed25519",
        "ecdsa-sha2-nistp521",
        "ecdsa-sha2-nistp384",
        "ecdsa-sha2-nistp256",
        "rsa-sha2-512",
        "rsa-sha2-256",
        "ssh-rsa",
        "ssh-dss",
      ],
      cipher: SSH_ALGORITHMS.cipher,
      hmac: [
        "hmac-sha2-512-etm@openssh.com",
        "hmac-sha2-256-etm@openssh.com",
        "hmac-sha2-512",
        "hmac-sha2-256",
        "hmac-sha1",
        "hmac-md5",
      ],
      compress: ["none", "zlib@openssh.com", "zlib"],
    },
  };

  if (
    resolvedSourceCredentials.authMethod === "key" &&
    resolvedSourceCredentials.sshKey
  ) {
    try {
      connOptions.privateKey = preparePrivateKeyForSSH2(
        resolvedSourceCredentials.sshKey,
        resolvedSourceCredentials.keyPassword,
      );
    } catch (error) {
      const message = getErrorMessage(error, "Invalid SSH key format");
      tunnelLogger.error(
        `Invalid SSH key format for tunnel '${tunnelName}': ${message}`,
        undefined,
        {
          operation: "tunnel_invalid_ssh_key_format",
          tunnelName,
          sourceHost: `${tunnelConfig.sourceUsername}@${tunnelConfig.sourceIP}:${tunnelConfig.sourceSSHPort}`,
          keyType: resolvedSourceCredentials.keyType,
        },
      );
      broadcastTunnelStatus(tunnelName, {
        connected: false,
        status: CONNECTION_STATES.FAILED,
        reason: message,
      });
      tunnelConnecting.delete(tunnelName);
      return;
    }

    if (resolvedSourceCredentials.keyPassword) {
      connOptions.passphrase = resolvedSourceCredentials.keyPassword;
    }
    if (
      resolvedSourceCredentials.keyType &&
      resolvedSourceCredentials.keyType !== "auto"
    ) {
      connOptions.privateKeyType = resolvedSourceCredentials.keyType;
    }
  } else if (resolvedSourceCredentials.authMethod === "key") {
    tunnelLogger.error(
      `SSH key authentication requested but no key provided for tunnel '${tunnelName}'`,
      undefined,
      {
        operation: "tunnel_ssh_key_missing",
        tunnelName,
        sourceHost: `${tunnelConfig.sourceUsername}@${tunnelConfig.sourceIP}:${tunnelConfig.sourceSSHPort}`,
        authMethod: resolvedSourceCredentials.authMethod,
      },
    );
    broadcastTunnelStatus(tunnelName, {
      connected: false,
      status: CONNECTION_STATES.FAILED,
      reason: "SSH key authentication requested but no key provided",
    });
    tunnelConnecting.delete(tunnelName);
    return;
  } else {
    connOptions.password = resolvedSourceCredentials.password;
  }

  const finalStatus = connectionStatus.get(tunnelName);
  if (!finalStatus || finalStatus.status !== CONNECTION_STATES.WAITING) {
    broadcastTunnelStatus(tunnelName, {
      connected: false,
      status: CONNECTION_STATES.CONNECTING,
      retryCount: retryAttempt > 0 ? retryAttempt : undefined,
    });
  }

  if (
    tunnelConfig.useSocks5 &&
    (tunnelConfig.socks5Host ||
      (tunnelConfig.socks5ProxyChain &&
        tunnelConfig.socks5ProxyChain.length > 0))
  ) {
    try {
      const socks5Socket = await createSocks5Connection(
        tunnelConfig.sourceIP,
        tunnelConfig.sourceSSHPort,
        {
          useSocks5: tunnelConfig.useSocks5,
          socks5Host: tunnelConfig.socks5Host,
          socks5Port: tunnelConfig.socks5Port,
          socks5Username: tunnelConfig.socks5Username,
          socks5Password: tunnelConfig.socks5Password,
          socks5ProxyChain: tunnelConfig.socks5ProxyChain,
        },
      );

      if (socks5Socket) {
        connOptions.sock = socks5Socket;
        conn.connect(connOptions);
        return;
      }
    } catch (socks5Error) {
      tunnelLogger.error("SOCKS5 connection failed for tunnel", socks5Error, {
        operation: "tunnel_socks5_connection_failed",
        tunnelName,
        sourceHost: `${tunnelConfig.sourceIP}:${tunnelConfig.sourceSSHPort}`,
        proxyHost: tunnelConfig.socks5Host,
        proxyPort: tunnelConfig.socks5Port || 1080,
        hasProxyAuth: !!(
          tunnelConfig.socks5Username && tunnelConfig.socks5Password
        ),
        errorMessage: getErrorMessage(socks5Error),
      });
      broadcastTunnelStatus(tunnelName, {
        connected: false,
        status: CONNECTION_STATES.FAILED,
        reason:
          "SOCKS5 proxy connection failed: " + getErrorMessage(socks5Error),
      });
      tunnelConnecting.delete(tunnelName);
      return;
    }
  }

  try {
    await resolveSshConnectConfigHost(connOptions);
  } catch (error) {
    tunnelLogger.error("Tunnel source hostname resolution failed", error, {
      operation: "tunnel_dns_resolve",
      tunnelName,
      sourceHost: `${tunnelConfig.sourceIP}:${tunnelConfig.sourceSSHPort}`,
      retryAttempt,
    });
    broadcastTunnelStatus(tunnelName, {
      connected: false,
      status: CONNECTION_STATES.FAILED,
      reason: getErrorMessage(
        error,
        "Failed to resolve tunnel source hostname",
      ),
    });
    tunnelConnecting.delete(tunnelName);
    return;
  }

  conn.connect(connOptions);
}

export async function killRemoteTunnelByMarker(
  tunnelConfig: TunnelConfig,
  tunnelName: string,
  callback: (err?: Error) => void,
) {
  const tunnelMarker = getTunnelMarker(tunnelName);
  tunnelLogger.info("Killing remote tunnel process", {
    operation: "tunnel_remote_kill",
    userId: tunnelConfig.sourceUserId,
    hostId: tunnelConfig.sourceHostId,
    tunnelName,
    marker: tunnelMarker,
  });

  let resolvedSourceCredentials = {
    password: tunnelConfig.sourcePassword,
    sshKey: tunnelConfig.sourceSSHKey,
    keyPassword: tunnelConfig.sourceKeyPassword,
    keyType: tunnelConfig.sourceKeyType,
    authMethod: tunnelConfig.sourceAuthMethod,
  };

  if (
    tunnelConfig.sourceHostId &&
    tunnelConfig.sourceUserId &&
    !tunnelConfig.sourcePassword &&
    !tunnelConfig.sourceSSHKey
  ) {
    try {
      const { resolveHostById } = await import("../host-resolver.js");
      const resolvedHost = await resolveHostById(
        tunnelConfig.sourceHostId,
        tunnelConfig.sourceUserId,
      );
      if (resolvedHost) {
        resolvedSourceCredentials = {
          password: resolvedHost.password,
          sshKey: resolvedHost.key,
          keyPassword: resolvedHost.keyPassword,
          keyType: resolvedHost.keyType,
          authMethod: resolvedHost.authType,
        };
      }
    } catch (error) {
      tunnelLogger.warn("Failed to resolve source credentials for cleanup", {
        tunnelName,
        sourceHostId: tunnelConfig.sourceHostId,
        error: getErrorMessage(error),
      });
    }
  }

  if (
    resolvedSourceCredentials.authMethod === "key" &&
    resolvedSourceCredentials.sshKey
  ) {
    try {
      preparePrivateKeyForSSH2(
        resolvedSourceCredentials.sshKey,
        resolvedSourceCredentials.keyPassword,
      );
    } catch (error) {
      callback(
        error instanceof Error ? error : new Error("Invalid SSH key format"),
      );
      return;
    }
  }

  const poolKey = `tunnel:${tunnelConfig.sourceUserId}:${tunnelConfig.sourceIP}:${tunnelConfig.sourceSSHPort}:${tunnelConfig.sourceUsername}`;

  const factory = async (): Promise<Client> => {
    const connOptions: Record<string, unknown> = {
      host:
        tunnelConfig.sourceIP?.replace(/^\[|\]$/g, "") || tunnelConfig.sourceIP,
      port: tunnelConfig.sourceSSHPort,
      username: tunnelConfig.sourceUsername,
      keepaliveInterval: tunnelConfig.keepaliveInterval ?? 60000,
      keepaliveCountMax: tunnelConfig.keepaliveCountMax ?? 5,
      readyTimeout: 60000,
      tcpKeepAlive: true,
      tcpKeepAliveInitialDelay: 30000,
      algorithms: {
        kex: [
          "diffie-hellman-group14-sha256",
          "diffie-hellman-group14-sha1",
          "diffie-hellman-group1-sha1",
          "diffie-hellman-group-exchange-sha256",
          "diffie-hellman-group-exchange-sha1",
          "ecdh-sha2-nistp256",
          "ecdh-sha2-nistp384",
          "ecdh-sha2-nistp521",
        ],
        cipher: [
          "aes128-ctr",
          "aes192-ctr",
          "aes256-ctr",
          "aes128-gcm@openssh.com",
          "aes256-gcm@openssh.com",
          "aes128-cbc",
          "aes192-cbc",
          "aes256-cbc",
          "3des-cbc",
        ],
        hmac: [
          "hmac-sha2-256-etm@openssh.com",
          "hmac-sha2-512-etm@openssh.com",
          "hmac-sha2-256",
          "hmac-sha2-512",
          "hmac-sha1",
          "hmac-md5",
        ],
        compress: ["none", "zlib@openssh.com", "zlib"],
      },
    };

    if (
      resolvedSourceCredentials.authMethod === "key" &&
      resolvedSourceCredentials.sshKey
    ) {
      connOptions.privateKey = preparePrivateKeyForSSH2(
        resolvedSourceCredentials.sshKey,
        resolvedSourceCredentials.keyPassword,
      );
      if (resolvedSourceCredentials.keyPassword) {
        connOptions.passphrase = resolvedSourceCredentials.keyPassword;
      }
      if (
        resolvedSourceCredentials.keyType &&
        resolvedSourceCredentials.keyType !== "auto"
      ) {
        connOptions.privateKeyType = resolvedSourceCredentials.keyType;
      }
    } else {
      connOptions.password = resolvedSourceCredentials.password;
    }

    if (
      tunnelConfig.useSocks5 &&
      (tunnelConfig.socks5Host ||
        (tunnelConfig.socks5ProxyChain &&
          tunnelConfig.socks5ProxyChain.length > 0))
    ) {
      try {
        const socks5Socket = await createSocks5Connection(
          tunnelConfig.sourceIP,
          tunnelConfig.sourceSSHPort,
          {
            useSocks5: tunnelConfig.useSocks5,
            socks5Host: tunnelConfig.socks5Host,
            socks5Port: tunnelConfig.socks5Port,
            socks5Username: tunnelConfig.socks5Username,
            socks5Password: tunnelConfig.socks5Password,
            socks5ProxyChain: tunnelConfig.socks5ProxyChain,
          },
        );

        if (socks5Socket) {
          connOptions.sock = socks5Socket;
        } else {
          throw new Error("Failed to create SOCKS5 connection");
        }
      } catch (socks5Error) {
        tunnelLogger.error(
          "SOCKS5 connection failed for killing tunnel",
          socks5Error,
          {
            operation: "socks5_connect_kill",
            tunnelName,
            proxyHost: tunnelConfig.socks5Host,
            proxyPort: tunnelConfig.socks5Port || 1080,
          },
        );
        throw new Error(
          "SOCKS5 proxy connection failed: " + getErrorMessage(socks5Error),
          { cause: socks5Error },
        );
      }
    }

    if (!connOptions.sock) {
      await resolveSshConnectConfigHost(connOptions);
    }

    return new Promise<Client>((resolve, reject) => {
      const conn = new Client();
      conn.on("ready", () => resolve(conn));
      conn.on("error", (err) => reject(err));
      conn.connect(connOptions);
    });
  };

  const execCommand = (client: Client, cmd: string): Promise<string> =>
    new Promise((resolve, reject) => {
      client.exec(cmd, (err, stream) => {
        if (err) {
          reject(err);
          return;
        }
        let output = "";
        stream.on("data", (data: Buffer) => {
          output += data.toString();
        });
        stream.stderr.on("data", (data: Buffer) => {
          const stderr = data.toString().trim();
          if (stderr && !stderr.includes("debug1")) {
            tunnelLogger.warn(
              `Kill command stderr for '${tunnelName}': ${stderr}`,
            );
          }
        });
        stream.on("close", () => resolve(output.trim()));
      });
    });

  try {
    await withConnection(poolKey, factory, async (client) => {
      const checkCmd = `ps aux | grep -F '${tunnelMarker}' | grep -v grep`;

      const checkOutput = await execCommand(client, checkCmd);
      if (!checkOutput) {
        tunnelLogger.warn("Remote tunnel process not found", {
          operation: "tunnel_remote_not_found",
          userId: tunnelConfig.sourceUserId,
          hostId: tunnelConfig.sourceHostId,
          tunnelName,
          marker: tunnelMarker,
        });
        return;
      }

      tunnelLogger.info("Remote tunnel process found, proceeding to kill", {
        operation: "tunnel_remote_found",
        userId: tunnelConfig.sourceUserId,
        hostId: tunnelConfig.sourceHostId,
        tunnelName,
        marker: tunnelMarker,
      });

      const killCmds = [
        `pkill -TERM -f '${tunnelMarker}'`,
        `sleep 2 && pkill -9 -f '${tunnelMarker}'`,
      ];

      for (const killCmd of killCmds) {
        try {
          await execCommand(client, killCmd);
        } catch (err) {
          tunnelLogger.warn(
            `Kill command failed for '${tunnelName}': ${(err as Error).message}`,
          );
        }
      }

      const verifyOutput = await execCommand(client, checkCmd);
      if (verifyOutput) {
        tunnelLogger.warn(
          `Some tunnel processes may still be running for '${tunnelName}'`,
        );
      } else {
        tunnelLogger.success("Remote tunnel process killed", {
          operation: "tunnel_remote_killed",
          userId: tunnelConfig.sourceUserId,
          hostId: tunnelConfig.sourceHostId,
          tunnelName,
        });
      }
    });
    callback();
  } catch (err) {
    tunnelLogger.error(
      `Failed to connect to source host for killing tunnel '${tunnelName}': ${(err as Error).message}`,
    );
    callback(err as Error);
  }
}

/**
 * @openapi
 * /ssh/tunnel/status:
 *   get:
 *     summary: Get all tunnel statuses
 *     description: Retrieves the status of all SSH tunnels.
 *     tags:
 *       - SSH Tunnels
 *     responses:
 *       200:
 *         description: A list of all tunnel statuses.
 */

export async function initializeAutoStartTunnels(): Promise<void> {
  try {
    const systemCrypto = SystemCrypto.getInstance();
    const internalAuthToken = await systemCrypto.getInternalAuthToken();

    const autostartHosts = await fetchInternalHosts(
      "internal",
      internalAuthToken,
    );
    const allHosts = await fetchInternalHosts(
      "internal/all",
      internalAuthToken,
    );
    const autoStartTunnels: TunnelConfig[] = [];
    tunnelLogger.info(
      `Found ${autostartHosts.length} autostart hosts and ${allHosts.length} total hosts for endpointHost resolution`,
    );

    for (const host of autostartHosts) {
      if (host.enableTunnel && host.tunnelConnections) {
        for (const tunnelConnection of host.tunnelConnections) {
          if (tunnelConnection.autoStart) {
            const endpointHost = findHostByTunnelEndpoint(
              allHosts,
              tunnelConnection.endpointHost,
            );
            const mode =
              tunnelConnection.mode || tunnelConnection.tunnelType || "remote";
            const allowDirectTarget = mode !== "remote";

            if (endpointHost || allowDirectTarget) {
              const tunnelIndex =
                host.tunnelConnections.indexOf(tunnelConnection);
              const tunnelConfig: TunnelConfig = {
                name: normalizeTunnelName(
                  host.id,
                  tunnelIndex,
                  host.name || `${host.username}@${host.ip}`,
                  tunnelConnection.sourcePort,
                  tunnelConnection.endpointHost,
                  tunnelConnection.endpointPort,
                ),
                scope: tunnelConnection.scope || "s2s",
                mode,
                bindHost: tunnelConnection.bindHost,
                targetHost: tunnelConnection.targetHost,
                tunnelType: tunnelConnection.tunnelType || "remote",
                sourceHostId: host.id,
                tunnelIndex: tunnelIndex,
                hostName: host.name || `${host.username}@${host.ip}`,
                sourceIP: host.ip,
                sourceSSHPort: host.port,
                sourceUsername: host.username,
                sourceAuthMethod: host.authType,
                sourceKeyType: host.keyType,
                sourceCredentialId: host.credentialId,
                sourceUserId: host.userId,
                endpointIP: endpointHost?.ip || tunnelConnection.endpointHost,
                endpointSSHPort: endpointHost?.port || 22,
                endpointUsername: endpointHost?.username || "",
                endpointHost: tunnelConnection.endpointHost,
                endpointAuthMethod:
                  tunnelConnection.endpointAuthType ||
                  endpointHost?.authType ||
                  "none",
                endpointKeyType:
                  tunnelConnection.endpointKeyType || endpointHost?.keyType,
                endpointCredentialId: endpointHost?.credentialId,
                endpointUserId: endpointHost?.userId,
                sourcePort: tunnelConnection.sourcePort,
                endpointPort: tunnelConnection.endpointPort,
                maxRetries: tunnelConnection.maxRetries,
                retryInterval: tunnelConnection.retryInterval * 1000,
                autoStart: tunnelConnection.autoStart,
                isPinned: host.pin,
                useSocks5: host.useSocks5,
                socks5Host: host.socks5Host,
                socks5Port: host.socks5Port,
                socks5Username: host.socks5Username,
                socks5Password: host.socks5Password,
              };

              autoStartTunnels.push(tunnelConfig);
            } else {
              tunnelLogger.error(
                `Failed to find endpointHost '${tunnelConnection.endpointHost}' for tunnel from ${host.name || `${host.username}@${host.ip}`}. Available hosts: ${allHosts.map((h) => h.name || `${h.username}@${h.ip}`).join(", ")}`,
              );
            }
          }
        }
      }
    }

    for (const tunnelConfig of autoStartTunnels) {
      tunnelConfigs.set(tunnelConfig.name, tunnelConfig);

      setTimeout(() => {
        connectSSHTunnel(tunnelConfig, 0).catch((error) => {
          tunnelLogger.error(
            `Failed to connect tunnel ${tunnelConfig.name}: ${getErrorMessage(error)}`,
          );
        });
      }, 1000);
    }
  } catch (error) {
    tunnelLogger.error(
      "Failed to initialize auto-start tunnels:",
      getErrorMessage(error),
    );
  }
}
