[CmdletBinding()]
param(
    [ValidateSet("start", "stop", "restart")]
    [string]$Action,
    [string]$ServiceName = "ScreenJobBackend"
)

Set-StrictMode -Version Latest
$ErrorActionPreference = "Stop"

function Wait-ForStatus {
    param(
        [Parameter(Mandatory = $true)]$Service,
        [Parameter(Mandatory = $true)][System.ServiceProcess.ServiceControllerStatus]$TargetStatus,
        [int]$TimeoutSeconds = 20
    )

    $deadline = (Get-Date).AddSeconds($TimeoutSeconds)
    while ((Get-Date) -lt $deadline) {
        $Service.Refresh()
        if ($Service.Status -eq $TargetStatus) {
            return
        }
        Start-Sleep -Milliseconds 350
    }

    throw "Timed out waiting for service '$($Service.ServiceName)' to reach status '$TargetStatus'."
}

$service = Get-Service -Name $ServiceName -ErrorAction Stop

switch ($Action) {
    "start" {
        if ($service.Status -ne [System.ServiceProcess.ServiceControllerStatus]::Running) {
            Start-Service -Name $ServiceName -ErrorAction Stop
            Wait-ForStatus -Service $service -TargetStatus ([System.ServiceProcess.ServiceControllerStatus]::Running)
        }
    }
    "stop" {
        if ($service.Status -ne [System.ServiceProcess.ServiceControllerStatus]::Stopped) {
            Stop-Service -Name $ServiceName -Force -ErrorAction Stop
            Wait-ForStatus -Service $service -TargetStatus ([System.ServiceProcess.ServiceControllerStatus]::Stopped)
        }
    }
    "restart" {
        if ($service.Status -eq [System.ServiceProcess.ServiceControllerStatus]::Running) {
            Restart-Service -Name $ServiceName -Force -ErrorAction Stop
        } else {
            Start-Service -Name $ServiceName -ErrorAction Stop
        }
        Wait-ForStatus -Service $service -TargetStatus ([System.ServiceProcess.ServiceControllerStatus]::Running)
    }
}