param(
  [string]$JavaPath = "$env:USERPROFILE\jenkins-local\jdk-21\jdk-21.0.11+10\bin\java.exe",
  [string]$JenkinsWar = "$env:USERPROFILE\jenkins-local\jenkins.war",
  [string]$JenkinsHome = "$env:USERPROFILE\.jenkins",
  [int]$HttpPort = 8080,
  [int]$AgentPort = 50000,
  [int]$RestartDelaySeconds = 10
)

$ErrorActionPreference = "Stop"

function Write-Log {
  param([string]$Message)
  $timestamp = Get-Date -Format "yyyy-MM-dd HH:mm:ss"
  Write-Output "[$timestamp] $Message"
}

function Get-ListeningProcessId {
  param([int]$Port)
  $line = netstat -ano | Select-String -Pattern "LISTENING\s+(\d+)$" | Where-Object {
    $_.Line -match "[:.]$Port\s+"
  } | Select-Object -First 1

  if (-not $line) {
    return $null
  }

  if ($line.Line -match "LISTENING\s+(\d+)$") {
    return [int]$Matches[1]
  }

  return $null
}

function Test-JenkinsProcess {
  param([int]$ProcessId)
  if (-not $ProcessId) {
    return $false
  }

  $process = Get-CimInstance Win32_Process -Filter "ProcessId = $ProcessId" -ErrorAction SilentlyContinue
  if (-not $process) {
    return $false
  }

  return ($process.CommandLine -like "*jenkins.war*")
}

if (-not (Test-Path -LiteralPath $JavaPath)) {
  throw "Java path not found: $JavaPath"
}

if (-not (Test-Path -LiteralPath $JenkinsWar)) {
  throw "Jenkins war not found: $JenkinsWar"
}

New-Item -ItemType Directory -Force -Path $JenkinsHome | Out-Null

while ($true) {
  $listeningPid = Get-ListeningProcessId -Port $HttpPort

  if ($listeningPid -and (Test-JenkinsProcess -ProcessId $listeningPid)) {
    Write-Log "Jenkins is already listening on port $HttpPort with pid $listeningPid; monitoring it."
    try {
      Wait-Process -Id $listeningPid
    } catch {
      Write-Log "Existing Jenkins process wait failed: $($_.Exception.Message)"
    }
  } elseif ($listeningPid) {
    Write-Log "Port $HttpPort is occupied by pid $listeningPid, but it is not Jenkins. Retrying in ${RestartDelaySeconds}s."
    Start-Sleep -Seconds $RestartDelaySeconds
    continue
  } else {
    $arguments = @(
      "-Djenkins.install.runSetupWizard=false",
      "-jar", $JenkinsWar,
      "--httpPort=$HttpPort",
      "--agentPort=$AgentPort"
    )

    Write-Log "Starting local Jenkins controller on port $HttpPort."
    $previousJenkinsHome = $env:JENKINS_HOME
    $env:JENKINS_HOME = $JenkinsHome
    $process = Start-Process -FilePath $JavaPath -ArgumentList $arguments -WorkingDirectory (Split-Path -Parent $JenkinsWar) -NoNewWindow -PassThru
    $env:JENKINS_HOME = $previousJenkinsHome
    try {
      Wait-Process -Id $process.Id
    } catch {
      Write-Log "Started Jenkins process wait failed: $($_.Exception.Message)"
    }
  }

  Write-Log "Jenkins controller stopped; retrying in ${RestartDelaySeconds}s."
  Start-Sleep -Seconds $RestartDelaySeconds
}