$ErrorActionPreference = "Stop"
$appId = "airport-guide-dashboard"
$appRoot = Join-Path $PSScriptRoot "app"
$nodePath = Join-Path $PSScriptRoot "runtime\node.exe"
$serverPath = Join-Path $appRoot "server.js"
$dataRoot = Join-Path $env:LOCALAPPDATA "AirportGuideDashboard"
$configPath = Join-Path $dataRoot "config.json"
$portPath = Join-Path $dataRoot "port.txt"
$outputLogPath = Join-Path $dataRoot "launcher.log"
$errorLogPath = Join-Path $dataRoot "launcher-error.log"

function Show-LauncherError([string]$message) {
  try {
    Add-Type -AssemblyName PresentationFramework
    [System.Windows.MessageBox]::Show(
      $message,
      "Airport Guide",
      [System.Windows.MessageBoxButton]::OK,
      [System.Windows.MessageBoxImage]::Error
    ) | Out-Null
  } catch {
    Write-Host $message
  }
}

function Get-DashboardHealth([int]$port) {
  try {
    return Invoke-RestMethod `
      -Uri "http://127.0.0.1:$port/api/health" `
      -Method Get `
      -TimeoutSec 1
  } catch {
    return $null
  }
}

function Test-PortAvailable([int]$port) {
  $listener = $null
  try {
    $listener = [System.Net.Sockets.TcpListener]::new(
      [System.Net.IPAddress]::Loopback,
      $port
    )
    $listener.Start()
    return $true
  } catch {
    return $false
  } finally {
    if ($null -ne $listener) {
      try { $listener.Stop() } catch {}
    }
  }
}

function Open-Dashboard([int]$port) {
  if ($env:AIRPORT_GUIDE_SKIP_BROWSER -eq "1") {
    return
  }
  $browserStart = [System.Diagnostics.ProcessStartInfo]::new()
  $browserStart.FileName = "http://127.0.0.1:$port"
  $browserStart.UseShellExecute = $true
  [System.Diagnostics.Process]::Start($browserStart) | Out-Null
}

try {
  if (-not (Test-Path -LiteralPath $nodePath -PathType Leaf)) {
    throw "Missing runtime\node.exe. Extract the complete package and try again."
  }
  if (-not (Test-Path -LiteralPath $serverPath -PathType Leaf)) {
    throw "Missing app\server.js. Extract the complete package and try again."
  }

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

  # Reuse the last known instance when possible.
  if (Test-Path -LiteralPath $portPath) {
    $savedPort = 0
    if ([int]::TryParse(
      (Get-Content -LiteralPath $portPath -Raw).Trim(),
      [ref]$savedPort
    ) -and $savedPort -ge 8890 -and $savedPort -le 8999) {
      $health = Get-DashboardHealth $savedPort
      if ($null -ne $health -and $health.app -eq $appId) {
        Open-Dashboard $savedPort
        exit 0
      }
    }
  }

  $selectedPort = 0
  foreach ($port in 8890..8999) {
    if (Test-PortAvailable $port) {
      $selectedPort = $port
      break
    }
    # Only query ports that are actually occupied. This avoids long startup
    # delays on Windows PowerShell when unused ports take time to fail.
    $health = Get-DashboardHealth $port
    if ($null -ne $health -and $health.app -eq $appId) {
      Set-Content -LiteralPath $portPath -Value $port -Encoding ASCII
      Open-Dashboard $port
      exit 0
    }
  }
  if ($selectedPort -eq 0) {
    throw "Ports 8890 through 8999 are unavailable. Close other programs and try again."
  }

  if (-not (Test-Path -LiteralPath $configPath)) {
    Copy-Item -LiteralPath (Join-Path $appRoot "config.json") -Destination $configPath
  }

  $env:GUIDE_WEB_HOST = "127.0.0.1"
  $env:GUIDE_WEB_PORT = [string]$selectedPort
  $env:GUIDE_WEB_CONFIG_PATH = $configPath
  if ([string]::IsNullOrWhiteSpace($env:GUIDE_WEB_AUTO_EXIT_MS)) {
    $env:GUIDE_WEB_AUTO_EXIT_MS = "30000"
  }

  # PowerShell Start-Process can fail when Windows contains both Path and PATH
  # environment variables. ProcessStartInfo avoids that PowerShell bug.
  $nodeStart = [System.Diagnostics.ProcessStartInfo]::new()
  $nodeStart.FileName = $env:ComSpec
  $nodeStart.Arguments = '/d /s /c ""{0}" server.js 1>>"{1}" 2>>"{2}""' -f `
    $nodePath, $outputLogPath, $errorLogPath
  $nodeStart.WorkingDirectory = $appRoot
  $nodeStart.UseShellExecute = $false
  $nodeStart.CreateNoWindow = $true
  $nodeStart.WindowStyle = [System.Diagnostics.ProcessWindowStyle]::Hidden
  $nodeProcess = [System.Diagnostics.Process]::Start($nodeStart)

  $ready = $false
  for ($attempt = 0; $attempt -lt 40; $attempt += 1) {
    Start-Sleep -Milliseconds 250
    if ($nodeProcess.HasExited) {
      break
    }
    $health = Get-DashboardHealth $selectedPort
    if ($null -ne $health -and $health.app -eq $appId) {
      $ready = $true
      break
    }
  }

  if (-not $ready) {
    if (-not $nodeProcess.HasExited) {
      Stop-Process -Id $nodeProcess.Id -Force
    }
    throw "The service did not start. Error log: $errorLogPath"
  }

  Set-Content -LiteralPath $portPath -Value $selectedPort -Encoding ASCII
  Open-Dashboard $selectedPort
} catch {
  try {
    Add-Content `
      -LiteralPath (Join-Path $dataRoot "launcher-startup-error.log") `
      -Value ("{0:u} {1}" -f (Get-Date), $_.Exception.Message) `
      -Encoding UTF8
  } catch {}
  Show-LauncherError $_.Exception.Message
  exit 1
}