<#
.SYNOPSIS
    Windows RDP Session Prometheus Metrics Exporter
.DESCRIPTION
    Prometheus exporter for per-session RDP protocol metrics - active, disconnected,
    and console sessions, per-session info, protocol performance (input/output frames,
    bytes, round-trip time, bandwidth), graphics quality, encoding time, skipped
    frames, and per-session resource usage. Works on any Windows machine with RDP
    enabled (does not require the full RDS role). Exports metrics as Prometheus-
    compatible text format.
.PARAMETER Mode
    Output mode: 'stdout' (default), 'textfile', or 'http'
.PARAMETER Port
    HTTP port for http mode (default: 9398)
.PARAMETER TextfileDir
    Directory for textfile collector output (default: C:\ProgramData\node_exporter)
.PARAMETER InstallScheduledTask
    Switch to create a scheduled task for auto-start on system boot
.PARAMETER TaskIntervalMinutes
    Interval in minutes for the scheduled task (default: 2)
.NOTES
    Author:  Phil Connor
    Contact: contact@mylinux.work
    Website: https://mylinux.work
    License: MIT
    Version: 1.0

    Metrics Exported:
      Core Status:
        - rdp_session_up
        - rdp_session_exporter_info{version}

      Sessions:
        - rdp_sessions_active_total
        - rdp_sessions_disconnected_total
        - rdp_sessions_console_total
        - rdp_session_info{user,session_id,state,client_name,client_ip}

      Protocol Performance:
        - rdp_session_input_frames{session_name}
        - rdp_session_output_frames{session_name}
        - rdp_session_input_bytes_total{session_name}
        - rdp_session_output_bytes_total{session_name}
        - rdp_session_round_trip_time_ms{session_name}
        - rdp_session_bandwidth_kbps{session_name}

      Graphics:
        - rdp_session_frame_quality{session_name}
        - rdp_session_graphics_source_frames{session_name}
        - rdp_session_graphics_skipped_frames{session_name}
        - rdp_session_graphics_encoding_time_ms{session_name}

      Resources:
        - rdp_session_working_set_bytes{session_name}
        - rdp_session_handles{session_name}
        - rdp_session_threads{session_name}

      Exporter:
        - rdp_session_exporter_duration_seconds
        - rdp_session_exporter_last_run_timestamp
#>

param(
    [ValidateSet('stdout', 'textfile', 'http')]
    [string]$Mode = 'stdout',

    [int]$Port = 9398,

    [string]$TextfileDir = 'C:\ProgramData\node_exporter',

    [switch]$InstallScheduledTask,

    [int]$TaskIntervalMinutes = 2
)

# Create a scheduled task to run this script every $TaskIntervalMinutes minutes
if ($InstallScheduledTask) {
    $taskName = "RdpSessionMetricsExporter"
    $existingTask = Get-ScheduledTask -TaskName $taskName -ErrorAction SilentlyContinue

    if (-not $existingTask) {
        $taskAction = New-ScheduledTaskAction -Execute "powershell.exe" -Argument "-NoProfile -ExecutionPolicy Bypass -File `"$($MyInvocation.MyCommand.Path)`" -Mode textfile"

        if (-not $TaskIntervalMinutes -or $TaskIntervalMinutes -le 0) {
            throw "TaskIntervalMinutes must be a positive integer"
        }

        $taskTrigger = New-ScheduledTaskTrigger -Once -At (Get-Date).AddMinutes(1) -RepetitionInterval (New-TimeSpan -Minutes $TaskIntervalMinutes) -RepetitionDuration (New-TimeSpan -Days 365)
        $taskPrincipal = New-ScheduledTaskPrincipal -UserId "SYSTEM" -LogonType ServiceAccount -RunLevel Highest

        try {
            Write-Host "Creating scheduled task: $taskName"
            Register-ScheduledTask -TaskName $taskName -Action $taskAction -Trigger $taskTrigger -Principal $taskPrincipal -Description "Exports RDP session metrics for Prometheus every $TaskIntervalMinutes minutes"

            $createdTask = Get-ScheduledTask -TaskName $taskName -ErrorAction SilentlyContinue
            if (-not $createdTask) {
                throw "Failed to verify scheduled task creation"
            }
            Write-Host "Successfully created scheduled task: $taskName" -ForegroundColor Green
        } catch {
            Write-Error "Failed to create scheduled task: $($_.Exception.Message)"
            throw
        }
    } else {
        Write-Host "Scheduled task '$taskName' already exists, skipping creation"
    }
}

$ErrorActionPreference = 'SilentlyContinue'

# ============================================================================
# HELPER FUNCTIONS
# ============================================================================

function Get-UnixTimestamp {
    [int][double]::Parse((Get-Date -UFormat '%s'))
}

function Format-MetricValue {
    param([double]$Value, [int]$Decimals = 2)
    [math]::Round($Value, $Decimals)
}

function Sanitize-Label {
    param([string]$Value)
    if (-not $Value) { return '' }
    $Value -replace '[\\"]', '' -replace '\s+$', ''
}

function Get-QwinstaOutput {
    try {
        $raw = & qwinsta /server:localhost 2>$null
        if (-not $raw -or $raw.Count -lt 2) { return @() }

        $sessions = @()
        foreach ($line in $raw[1..($raw.Count - 1)]) {
            if ($line.Length -lt 20) { continue }

            $sessionName = $line.Substring(1, 18).Trim()
            $userName    = $line.Substring(19, 22).Trim()
            $sessionId   = $line.Substring(41, 7).Trim()
            $state       = $line.Substring(48, 8).Trim()

            if (-not $sessionId -or $sessionId -notmatch '^\d+$') { continue }

            $sessions += [PSCustomObject]@{
                SessionName = $sessionName
                UserName    = $userName
                SessionId   = [int]$sessionId
                State       = $state
            }
        }
        return $sessions
    } catch {
        return @()
    }
}

# ============================================================================
# SESSION COUNT METRICS
# ============================================================================

function Get-SessionCountMetrics {
    param($Sessions)

    $sb = [System.Text.StringBuilder]::new()

    # --- Active Sessions ---
    [void]$sb.AppendLine('# HELP rdp_sessions_active_total Total active RDP sessions')
    [void]$sb.AppendLine('# TYPE rdp_sessions_active_total gauge')
    try {
        $active = @($Sessions | Where-Object { $_.State -eq 'Active' -and $_.SessionName -ne 'console' -and $_.SessionName -match '^rdp-' }).Count
        [void]$sb.AppendLine("rdp_sessions_active_total $active")
    } catch {
        [void]$sb.AppendLine("rdp_sessions_active_total 0")
    }
    [void]$sb.AppendLine('')

    # --- Disconnected Sessions ---
    [void]$sb.AppendLine('# HELP rdp_sessions_disconnected_total Total disconnected RDP sessions')
    [void]$sb.AppendLine('# TYPE rdp_sessions_disconnected_total gauge')
    try {
        $disc = @($Sessions | Where-Object { $_.State -eq 'Disc' }).Count
        [void]$sb.AppendLine("rdp_sessions_disconnected_total $disc")
    } catch {
        [void]$sb.AppendLine("rdp_sessions_disconnected_total 0")
    }
    [void]$sb.AppendLine('')

    # --- Console Sessions ---
    [void]$sb.AppendLine('# HELP rdp_sessions_console_total Total console sessions')
    [void]$sb.AppendLine('# TYPE rdp_sessions_console_total gauge')
    try {
        $console = @($Sessions | Where-Object { $_.SessionName -eq 'console' -and $_.State -eq 'Active' }).Count
        [void]$sb.AppendLine("rdp_sessions_console_total $console")
    } catch {
        [void]$sb.AppendLine("rdp_sessions_console_total 0")
    }
    [void]$sb.AppendLine('')

    $sb.ToString()
}

# ============================================================================
# PER-SESSION INFO METRICS
# ============================================================================

function Get-SessionInfoMetrics {
    param($Sessions)

    $sb = [System.Text.StringBuilder]::new()

    [void]$sb.AppendLine('# HELP rdp_session_info Per-session information')
    [void]$sb.AppendLine('# TYPE rdp_session_info gauge')
    try {
        $tsSessions = Get-CimInstance -Namespace 'root\cimv2\TerminalServices' -ClassName 'Win32_TS_Session' -ErrorAction SilentlyContinue
        $tsLookup = @{}
        if ($tsSessions) {
            foreach ($ts in $tsSessions) {
                $tsLookup[$ts.SessionId] = $ts
            }
        }

        foreach ($s in $Sessions) {
            if (-not $s.UserName) { continue }

            $user       = Sanitize-Label $s.UserName
            $sessionId  = $s.SessionId
            $state      = Sanitize-Label $s.State
            $clientName = ''
            $clientIp   = ''

            if ($tsLookup.ContainsKey($sessionId)) {
                $clientName = Sanitize-Label $tsLookup[$sessionId].ClientName
                $clientIp   = Sanitize-Label $tsLookup[$sessionId].ClientIPAddress
            }

            [void]$sb.AppendLine("rdp_session_info{user=`"$user`",session_id=`"$sessionId`",state=`"$state`",client_name=`"$clientName`",client_ip=`"$clientIp`"} 1")
        }
    } catch { }
    [void]$sb.AppendLine('')

    $sb.ToString()
}

# ============================================================================
# PROTOCOL PERFORMANCE METRICS
# ============================================================================

function Get-ProtocolMetrics {
    param($Sessions)

    $sb = [System.Text.StringBuilder]::new()

    # --- Input Frames ---
    [void]$sb.AppendLine('# HELP rdp_session_input_frames Input frames per second')
    [void]$sb.AppendLine('# TYPE rdp_session_input_frames gauge')
    try {
        $counters = Get-Counter '\Terminal Services Session(*)\Input Frames/Second' -ErrorAction Stop
        foreach ($sample in $counters.CounterSamples) {
            $instance = Sanitize-Label $sample.InstanceName
            if ($instance -eq '_total') { continue }
            $val = Format-MetricValue $sample.CookedValue
            [void]$sb.AppendLine("rdp_session_input_frames{session_name=`"$instance`"} $val")
        }
    } catch { }
    [void]$sb.AppendLine('')

    # --- Output Frames ---
    [void]$sb.AppendLine('# HELP rdp_session_output_frames Output frames per second')
    [void]$sb.AppendLine('# TYPE rdp_session_output_frames gauge')
    try {
        $counters = Get-Counter '\Terminal Services Session(*)\Output Frames/Second' -ErrorAction Stop
        foreach ($sample in $counters.CounterSamples) {
            $instance = Sanitize-Label $sample.InstanceName
            if ($instance -eq '_total') { continue }
            $val = Format-MetricValue $sample.CookedValue
            [void]$sb.AppendLine("rdp_session_output_frames{session_name=`"$instance`"} $val")
        }
    } catch { }
    [void]$sb.AppendLine('')

    # --- Input Bytes Total ---
    [void]$sb.AppendLine('# HELP rdp_session_input_bytes_total Total input bytes')
    [void]$sb.AppendLine('# TYPE rdp_session_input_bytes_total counter')
    try {
        $counters = Get-Counter '\Terminal Services Session(*)\Total Bytes Received' -ErrorAction Stop
        foreach ($sample in $counters.CounterSamples) {
            $instance = Sanitize-Label $sample.InstanceName
            if ($instance -eq '_total') { continue }
            $val = [math]::Round($sample.CookedValue)
            [void]$sb.AppendLine("rdp_session_input_bytes_total{session_name=`"$instance`"} $val")
        }
    } catch { }
    [void]$sb.AppendLine('')

    # --- Output Bytes Total ---
    [void]$sb.AppendLine('# HELP rdp_session_output_bytes_total Total output bytes')
    [void]$sb.AppendLine('# TYPE rdp_session_output_bytes_total counter')
    try {
        $counters = Get-Counter '\Terminal Services Session(*)\Total Bytes Sent' -ErrorAction Stop
        foreach ($sample in $counters.CounterSamples) {
            $instance = Sanitize-Label $sample.InstanceName
            if ($instance -eq '_total') { continue }
            $val = [math]::Round($sample.CookedValue)
            [void]$sb.AppendLine("rdp_session_output_bytes_total{session_name=`"$instance`"} $val")
        }
    } catch { }
    [void]$sb.AppendLine('')

    # --- Round Trip Time ---
    [void]$sb.AppendLine('# HELP rdp_session_round_trip_time_ms Current round-trip time in milliseconds')
    [void]$sb.AppendLine('# TYPE rdp_session_round_trip_time_ms gauge')
    try {
        $wmiSessions = Get-CimInstance -ClassName 'Win32_PerfFormattedData_TermService_TerminalServicesSession' -ErrorAction Stop
        foreach ($w in $wmiSessions) {
            $instance = Sanitize-Label $w.Name
            if ($instance -eq '_total' -or -not $instance) { continue }
            $val = $w.CurrentRoundTripTime
            [void]$sb.AppendLine("rdp_session_round_trip_time_ms{session_name=`"$instance`"} $val")
        }
    } catch { }
    [void]$sb.AppendLine('')

    # --- Bandwidth ---
    [void]$sb.AppendLine('# HELP rdp_session_bandwidth_kbps Session bandwidth in kbps')
    [void]$sb.AppendLine('# TYPE rdp_session_bandwidth_kbps gauge')
    try {
        $wmiSessions = Get-CimInstance -ClassName 'Win32_PerfFormattedData_TermService_TerminalServicesSession' -ErrorAction Stop
        foreach ($w in $wmiSessions) {
            $instance = Sanitize-Label $w.Name
            if ($instance -eq '_total' -or -not $instance) { continue }
            $val = Format-MetricValue $w.CurrentBandwidth
            [void]$sb.AppendLine("rdp_session_bandwidth_kbps{session_name=`"$instance`"} $val")
        }
    } catch { }
    [void]$sb.AppendLine('')

    $sb.ToString()
}

# ============================================================================
# GRAPHICS METRICS
# ============================================================================

function Get-GraphicsMetrics {
    $sb = [System.Text.StringBuilder]::new()

    # --- Frame Quality ---
    [void]$sb.AppendLine('# HELP rdp_session_frame_quality Frame quality percentage')
    [void]$sb.AppendLine('# TYPE rdp_session_frame_quality gauge')
    try {
        $counters = Get-Counter '\RemoteFX Graphics(*)\Frame Quality' -ErrorAction Stop
        foreach ($sample in $counters.CounterSamples) {
            $instance = Sanitize-Label $sample.InstanceName
            if ($instance -eq '_total') { continue }
            $val = Format-MetricValue $sample.CookedValue
            [void]$sb.AppendLine("rdp_session_frame_quality{session_name=`"$instance`"} $val")
        }
    } catch { }
    [void]$sb.AppendLine('')

    # --- Source Frames Per Second ---
    [void]$sb.AppendLine('# HELP rdp_session_graphics_source_frames Source frames per second')
    [void]$sb.AppendLine('# TYPE rdp_session_graphics_source_frames gauge')
    try {
        $counters = Get-Counter '\RemoteFX Graphics(*)\Source Frames/Second' -ErrorAction Stop
        foreach ($sample in $counters.CounterSamples) {
            $instance = Sanitize-Label $sample.InstanceName
            if ($instance -eq '_total') { continue }
            $val = Format-MetricValue $sample.CookedValue
            [void]$sb.AppendLine("rdp_session_graphics_source_frames{session_name=`"$instance`"} $val")
        }
    } catch { }
    [void]$sb.AppendLine('')

    # --- Skipped Frames ---
    [void]$sb.AppendLine('# HELP rdp_session_graphics_skipped_frames Skipped frames per second')
    [void]$sb.AppendLine('# TYPE rdp_session_graphics_skipped_frames gauge')
    try {
        $counters = Get-Counter '\RemoteFX Graphics(*)\Skipped Frames/Second' -ErrorAction Stop
        foreach ($sample in $counters.CounterSamples) {
            $instance = Sanitize-Label $sample.InstanceName
            if ($instance -eq '_total') { continue }
            $val = Format-MetricValue $sample.CookedValue
            [void]$sb.AppendLine("rdp_session_graphics_skipped_frames{session_name=`"$instance`"} $val")
        }
    } catch { }
    [void]$sb.AppendLine('')

    # --- Average Encoding Time ---
    [void]$sb.AppendLine('# HELP rdp_session_graphics_encoding_time_ms Average encoding time in milliseconds')
    [void]$sb.AppendLine('# TYPE rdp_session_graphics_encoding_time_ms gauge')
    try {
        $counters = Get-Counter '\RemoteFX Graphics(*)\Average Encoding Time' -ErrorAction Stop
        foreach ($sample in $counters.CounterSamples) {
            $instance = Sanitize-Label $sample.InstanceName
            if ($instance -eq '_total') { continue }
            $val = Format-MetricValue $sample.CookedValue
            [void]$sb.AppendLine("rdp_session_graphics_encoding_time_ms{session_name=`"$instance`"} $val")
        }
    } catch { }
    [void]$sb.AppendLine('')

    $sb.ToString()
}

# ============================================================================
# RESOURCE METRICS
# ============================================================================

function Get-ResourceMetrics {
    $sb = [System.Text.StringBuilder]::new()

    # --- Working Set (Memory) ---
    [void]$sb.AppendLine('# HELP rdp_session_working_set_bytes Session working set memory in bytes')
    [void]$sb.AppendLine('# TYPE rdp_session_working_set_bytes gauge')
    try {
        $counters = Get-Counter '\Terminal Services Session(*)\Working Set' -ErrorAction Stop
        foreach ($sample in $counters.CounterSamples) {
            $instance = Sanitize-Label $sample.InstanceName
            if ($instance -eq '_total') { continue }
            $val = [math]::Round($sample.CookedValue)
            [void]$sb.AppendLine("rdp_session_working_set_bytes{session_name=`"$instance`"} $val")
        }
    } catch { }
    [void]$sb.AppendLine('')

    # --- Handle Count ---
    [void]$sb.AppendLine('# HELP rdp_session_handles Session handle count')
    [void]$sb.AppendLine('# TYPE rdp_session_handles gauge')
    try {
        $counters = Get-Counter '\Terminal Services Session(*)\Handle Count' -ErrorAction Stop
        foreach ($sample in $counters.CounterSamples) {
            $instance = Sanitize-Label $sample.InstanceName
            if ($instance -eq '_total') { continue }
            $val = [math]::Round($sample.CookedValue)
            [void]$sb.AppendLine("rdp_session_handles{session_name=`"$instance`"} $val")
        }
    } catch { }
    [void]$sb.AppendLine('')

    # --- Thread Count ---
    [void]$sb.AppendLine('# HELP rdp_session_threads Session thread count')
    [void]$sb.AppendLine('# TYPE rdp_session_threads gauge')
    try {
        $counters = Get-Counter '\Terminal Services Session(*)\Thread Count' -ErrorAction Stop
        foreach ($sample in $counters.CounterSamples) {
            $instance = Sanitize-Label $sample.InstanceName
            if ($instance -eq '_total') { continue }
            $val = [math]::Round($sample.CookedValue)
            [void]$sb.AppendLine("rdp_session_threads{session_name=`"$instance`"} $val")
        }
    } catch { }
    [void]$sb.AppendLine('')

    $sb.ToString()
}

# ============================================================================
# COLLECT ALL METRICS
# ============================================================================

function Get-AllMetrics {
    $scriptStart = Get-Date
    $sb = [System.Text.StringBuilder]::new()

    # Exporter up - test RDP service availability
    [void]$sb.AppendLine('# HELP rdp_session_up RDP session exporter status (1=up, 0=down)')
    [void]$sb.AppendLine('# TYPE rdp_session_up gauge')
    try {
        $termService = Get-Service -Name 'TermService' -ErrorAction Stop
        $upVal = if ($termService.Status -eq 'Running') { 1 } else { 0 }
        [void]$sb.AppendLine("rdp_session_up $upVal")
    } catch {
        [void]$sb.AppendLine("rdp_session_up 0")
        $scriptEnd = Get-Date
        $duration = Format-MetricValue ($scriptEnd - $scriptStart).TotalSeconds
        [void]$sb.AppendLine('')
        [void]$sb.AppendLine('# HELP rdp_session_exporter_duration_seconds Time to generate all metrics')
        [void]$sb.AppendLine('# TYPE rdp_session_exporter_duration_seconds gauge')
        [void]$sb.AppendLine("rdp_session_exporter_duration_seconds $duration")
        [void]$sb.AppendLine('')
        [void]$sb.AppendLine('# HELP rdp_session_exporter_last_run_timestamp Unix timestamp of last run')
        [void]$sb.AppendLine('# TYPE rdp_session_exporter_last_run_timestamp gauge')
        [void]$sb.AppendLine("rdp_session_exporter_last_run_timestamp $(Get-UnixTimestamp)")
        return $sb.ToString()
    }
    [void]$sb.AppendLine('')

    # Exporter info
    [void]$sb.AppendLine('# HELP rdp_session_exporter_info Exporter version information')
    [void]$sb.AppendLine('# TYPE rdp_session_exporter_info gauge')
    [void]$sb.AppendLine('rdp_session_exporter_info{version="1.0"} 1')
    [void]$sb.AppendLine('')

    # Gather session list from qwinsta
    $sessions = Get-QwinstaOutput

    # Collect session count metrics
    [void]$sb.Append((Get-SessionCountMetrics -Sessions $sessions))

    # Collect per-session info
    [void]$sb.Append((Get-SessionInfoMetrics -Sessions $sessions))

    # Collect protocol performance metrics
    [void]$sb.Append((Get-ProtocolMetrics -Sessions $sessions))

    # Collect graphics metrics
    [void]$sb.Append((Get-GraphicsMetrics))

    # Collect resource metrics
    [void]$sb.Append((Get-ResourceMetrics))

    # Exporter runtime
    $scriptEnd = Get-Date
    $duration = Format-MetricValue ($scriptEnd - $scriptStart).TotalSeconds
    $timestamp = Get-UnixTimestamp

    [void]$sb.AppendLine('# HELP rdp_session_exporter_duration_seconds Time to generate all metrics')
    [void]$sb.AppendLine('# TYPE rdp_session_exporter_duration_seconds gauge')
    [void]$sb.AppendLine("rdp_session_exporter_duration_seconds $duration")
    [void]$sb.AppendLine('')
    [void]$sb.AppendLine('# HELP rdp_session_exporter_last_run_timestamp Unix timestamp of last successful run')
    [void]$sb.AppendLine('# TYPE rdp_session_exporter_last_run_timestamp gauge')
    [void]$sb.AppendLine("rdp_session_exporter_last_run_timestamp $timestamp")
    [void]$sb.AppendLine('')

    $sb.ToString()
}

# ============================================================================
# HTTP SERVER MODE
# ============================================================================

function Start-HttpServer {
    param([int]$ListenPort)

    $prefix = "http://+:$ListenPort/"
    $listener = [System.Net.HttpListener]::new()
    $listener.Prefixes.Add($prefix)

    try {
        $listener.Start()
        Write-Host "Starting RDP session metrics exporter on port $ListenPort..." -ForegroundColor Green
        Write-Host "Metrics available at http://localhost:$ListenPort/metrics"

        while ($listener.IsListening) {
            $context  = $listener.GetContext()
            $request  = $context.Request
            $response = $context.Response

            if ($request.Url.AbsolutePath -eq '/metrics') {
                $metrics = Get-AllMetrics
                $buffer  = [System.Text.Encoding]::UTF8.GetBytes($metrics)
                $response.ContentType = 'text/plain; version=0.0.4; charset=utf-8'
            }
            else {
                $html = @"
<!DOCTYPE html>
<html>
<head><title>RDP Session Metrics Exporter v1.0</title></head>
<body>
<h1>RDP Session Metrics Exporter v1.0</h1>
<p><a href="/metrics">Metrics</a></p>
<h2>Metrics</h2>
<ul>
<li>Active, disconnected, and console session counts</li>
<li>Per-session info (user, client name, client IP, state)</li>
<li>Protocol performance (frames, bytes, RTT, bandwidth)</li>
<li>Graphics quality, source/skipped frames, encoding time</li>
<li>Per-session resource usage (memory, handles, threads)</li>
</ul>
</body>
</html>
"@
                $buffer = [System.Text.Encoding]::UTF8.GetBytes($html)
                $response.ContentType = 'text/html; charset=utf-8'
            }

            $response.ContentLength64 = $buffer.Length
            $response.OutputStream.Write($buffer, 0, $buffer.Length)
            $response.OutputStream.Close()
        }
    }
    catch {
        Write-Error "HTTP server error: $_"
        Write-Error "If access denied, run: netsh http add urlacl url=http://+:$ListenPort/ user=Everyone"
    }
    finally {
        if ($listener.IsListening) {
            $listener.Stop()
        }
    }
}

# ============================================================================
# MAIN EXECUTION
# ============================================================================

switch ($Mode) {
    'http' {
        Start-HttpServer -ListenPort $Port
    }
    'textfile' {
        $OutputFile = Join-Path $TextfileDir 'rdp_session_metrics.prom'

        $outputDir = Split-Path $OutputFile -Parent
        if (-not (Test-Path $outputDir)) {
            New-Item -Path $outputDir -ItemType Directory -Force | Out-Null
        }

        $tempFile = Join-Path $outputDir ".rdp_session_metrics.$PID.tmp"

        try {
            $metrics = Get-AllMetrics
            $metrics | Out-File -FilePath $tempFile -Encoding utf8 -NoNewline

            $lineCount = ($metrics -split "`n").Count
            if ($lineCount -lt 10) {
                Remove-Item -Path $tempFile -Force -ErrorAction SilentlyContinue
                Write-Error "Metrics file too small ($lineCount lines), keeping previous"
                exit 1
            }

            Move-Item -Path $tempFile -Destination $OutputFile -Force
            Write-Host "Metrics written to $OutputFile ($lineCount lines)" -ForegroundColor Green
        }
        catch {
            Remove-Item -Path $tempFile -Force -ErrorAction SilentlyContinue
            Write-Error "Failed to generate metrics: $_"
            exit 1
        }
    }
    default {
        Get-AllMetrics | Write-Output
    }
}