RouterOS/RouterOSAssistant/Core/Networking/SSHTransport.swift

import Foundation
import Citadel

/// SSH+CLI transport fallback for RouterOS devices/firmware without the REST API (pre-7.1).
///
/// Known limitation (tracked for M7 hardening): host key validation currently accepts any key.
/// This is acceptable for now because REST already provides certificate TOFU on the primary
/// path and this fallback is used for local-network devices only, but it should get the same
/// trust-on-first-use treatment before wider distribution.
final class SSHTransport: RouterOSTransport {
    let kind: RouterOSTransportKind = .ssh

    private let credentials: RouterOSCredentials
    private var client: SSHClient?

    init(credentials: RouterOSCredentials) {
        self.credentials = credentials
    }

    func connect() async throws {
        do {
            client = try await SSHClient.connect(
                host: credentials.host,
                port: credentials.sshPort,
                authenticationMethod: .passwordBased(username: credentials.username, password: credentials.password),
                hostKeyValidator: .acceptAnything(),
                reconnect: .never
            )
        } catch {
            // NIOSSHError's `.localizedDescription` is a useless generic NSError-bridged string
            // ("The operation couldn't be completed."); its real diagnostics only surface via
            // CustomStringConvertible, which `String(describing:)` picks up.
            throw RouterOSError.transportUnavailable("SSH-Verbindung fehlgeschlagen: \(String(describing: error))")
        }
    }

    func fetchDeviceInfo() async throws -> RouterDeviceInfo {
        let output = try await run("/system resource print without-paging")
        return RouterOSCliParser.parseDeviceInfo(output)
    }

    func fetchInterfaces() async throws -> [NetworkInterface] {
        let output = try await run("/interface print without-paging terse")
        return RouterOSCliParser.parseInterfaces(output)
    }

    func disconnect() async {
        try? await client?.close()
        client = nil
    }

    /// Full human-readable config export (`/export terse`), used for local backups.
    func exportConfiguration() async throws -> String {
        try await run("/export terse")
    }

    func apply(_ command: RouterOSCommand) async throws {
        _ = try await run(command.cliLine)
    }

    private func run(_ command: String) async throws -> String {
        guard let client else { throw RouterOSError.notConnected }
        let buffer = try await client.executeCommand(command)
        return String(buffer: buffer)
    }
}