<#
.SYNOPSIS
Starts the SSH tunnel required by the local DeerFlow backend's remote MySQL connection.

.DESCRIPTION
The local backend is configured to reach MySQL at 127.0.0.1:13307. This script forwards
that port over SSH to the MySQL listener on the remote server. It deliberately does not
store the SSH password; OpenSSH prompts for it when the tunnel starts.
#>
[CmdletBinding()]
param(
    [string]$RemoteHost = "119.254.86.251",
    [int]$SshPort = 22322,
    [string]$SshUser = "root",
    [int]$LocalPort = 13307,
    [int]$RemoteMySqlPort = 3307
)

$existing = Get-NetTCPConnection -State Listen -LocalPort $LocalPort -ErrorAction SilentlyContinue
if ($existing) {
    Write-Host "本地端口 $LocalPort 已在监听；SSH 隧道应已启动。" -ForegroundColor Yellow
    exit 0
}

Write-Host "正在建立 MySQL SSH 隧道：127.0.0.1:$LocalPort -> $RemoteHost`:$RemoteMySqlPort"
Write-Host "请保持此窗口运行；按 Ctrl+C 可关闭隧道。"

ssh -N `
    -o ExitOnForwardFailure=yes `
    -o ServerAliveInterval=30 `
    -o ServerAliveCountMax=3 `
    -L "${LocalPort}:127.0.0.1:${RemoteMySqlPort}" `
    -p $SshPort `
    "${SshUser}@${RemoteHost}"