# end2end-restransmit
#
# Reading the TCP Retransmits
#
# https://www.msxfaq.de/code/powershell/psperfcounter.htm
#
# 20190702 Initial Version
# Pending
#   International Language
#   
#

param (
	[string]$csvfilename  = "$PWD\end2end-retrantmit_$($env:COMPUTERNAME).csv",	# Path to CSV File. Clear to disable CSV
	[byte]$samplecount=60,     
	[long]$sampleinterval = 1, 
	[switch]$sendtopipeline = $false
)

set-psdebug -strict

Write-Host "end2end-retransmit: Start"
Write-Host "  Param CSVFile       : $($csvfilename)"
Write-Host "  Param samplecount   : $($samplecount)"
Write-Host "  Param sampleinterval: $($sampleinterval)"
$host.ui.RawUI.WindowTitle = "end2end-retransmit on $($env:COMPUTERNAME)"

if ($csvfilename -ne "") {
	Write-Host "Initialize CSV-File"$csvfilename
	if (!(test-path $csvfilename -pathtype leaf)){
		Write-Host "Adding CSV-Header"
		"Timestamp,Min,Avg,Max,Total" | out-file $csvfilename -append
	}
}

Write-Host "Description: 0= Noretransmits, 2= 1-2 retransmits, 5 = 3-5 retransmits 9= 6-9 retransmit X=11+ Restransmit"

while ($true) {
	$result = [pscustomobject][ordered]@{
			timestamp = ((get-date).ToUniversalTime().tostring("u"))
			min = [long]9999999
			avg = [long]0
			max = [long]0
			total = [long]0
	}	
	[long]$Avgsum = 0

	Get-Counter `
		-Counter "\TCPv4\erneut übertragene Segmente/s" `
		-SampleInterval $sampleinterval `
		-MaxSamples $samplecount `
	| ForEach-Object {
		$result.total++
		$value = [math]::Round($_.countersamples[0].cookedvalue)
		#write-host "Value: $($value)"
		switch ($value) {
			{$_ -le 1} 		{Write-Host "0" -nonewline -backgroundcolor blue;break;}
			{$_ -le 2} 		{Write-Host "2" -nonewline -backgroundcolor green -foregroundcolor black;break;}
			{$_ -le 5} 		{Write-Host "5" -nonewline -backgroundcolor yellow -foregroundcolor black;break;}
			{$_ -le 10} 	{Write-Host "9" -nonewline -backgroundcolor magenta;break;}
			default 		{Write-Host "X" -nonewline -backgroundcolor red}
		}
		if ($value -le $result.min) {$result.min = $value} 
		if ($value -ge $result.max) {$result.max = $value}
		$avgsum+=$value
	}

	$Result.avg = [math]::Round($avgsum/$result.total)
	Write-Host " $($result.timestamp) Min/Avg/Max/Total: $($Result.min)/$($Result.avg)/$($Result.max)/$($Result.total)"
	
	if ($csvfilename -ne "") {
		"$($result.timestamp),$($result.min),$($result.avg),$($result.max),$($result.total)" | out-file $csvfilename -append
	}
	if ($sendtopipeline) {
		Write-Host "Sending result to Pipeline"
		$result
	}

	# Wait for next second
	$waittime = 1000 - (get-date).millisecond
	if ($waittime -ge 0) {
		start-sleep -milliseconds $waittime 
	}
}	  

Write-Host "end2end-retransmit: End"