# prtg-openweathermap
#
#  http://openweathermap.org/appid
# https://openweathermap.org/?q=hövelhof,de
#
[cmdletbinding()]
param (
	$apiurl="http://api.openweathermap.org/data/2.5/weather?",
	$cityid="6553131",   # einfach auf http://openweathermap.org/city/ den eigenen Ort suchen und dann die ID aus der URL auslesen
						# oder aus der Liste von http://bulk.openweathermap.org/sample/city.list.json.gz aussuchen
	$apikey="11111111111111111111111111111111",
	$cachefilename = ".\prtg-openweathermap.xml",
	$historyfilename = ".\prtg-openweathermap.csv"
)

if ($PSScriptRoot.EndsWith("EXEXML")) {
    write-verbose "Check-ADFS: Assume PRTG EXEXML-Mode"
}
else {
    Set-PSDEBUG -strict  # enable strict variable checking. Not usable with PRTG
	$VerbosePreference = "continue"
}

write-verbose "PRTG-OpenWeatherMap: Start"
write-verbose " Parameter: apiurl      : $($apiurl)"
write-verbose " Parameter: cityid      : $($cityid)"
write-verbose " Parameter: apikey      : $($apikey)"
write-verbose " Parameter: Cachfilename: $($cachefilename)"

write-verbose "Reading Filedate of cachefile $($cachefilename)"
$error.clear()
$cachefile = get-item -path $cachefilename -erroraction silentlycontinue
if ($error) {
	write-verbose "- No LastWrite. set to now -11 Minutes"
	$lastwritetime = (get-date).addminutes(-11)
	$error.clear()
}
else {
	write-verbose "- Cachfile found"
	$lastwritetime = ($cachefile).lastwritetime
}
write-verbose "- LastWriteTime: $($lastwritetime)"

if (((get-date) - $lastwritetime).totalminutes -lt 10) {
	write-verbose "- Reading data from cache due 10 Min Interval"
	$result = import-clixml $cachefilename
}
else {
	write-verbose "- Loading data from OpenWeatherMap"
	write-verbose "- Building APIURL"
	# http://api.openweathermap.org/data/2.5/forecast?id=524901&APPID=1111111111 
	# http://samples.openweathermap.org/data/2.5/forecast?id=524901&appid=b1b15e88fa797225412429c1c50c122a1
	$url = $apiurl+"id=$($cityid)&APPID=$($apikey)"
	write-verbose "    URL = $($url)"

	try {
		write-verbose "- Starting Rest-Query"
		$result = invoke-restmethod -uri $url
		write-verbose "   Write Data to CacheFile $($cachefilename)"
		$result | export-clixml $cachefilename
	}
	catch {
		write-verbose "   Error fetching data from openweathermap"
		$result = $null
	}
}

if ($result) {
	write-verbose "- Processing Results"
	write-verbose " Timestamp $($result.dt_txt)"

	if ($historyfilename) {
		Write-Verbose " Append History CSV"
		$csventry= ""| select timestamp,temp,pressure,humiditiy,cloudiness 
		$csventry.timestamp=$result.dt_txt
		$csventry.temp=([decimal]($result.main.temp) - 273.15)
		$csventry.pressure=$result.main.pressure
		$csventry.humiditiy=$result.main.humiditiy
		$csventry.cloudiness=$result.clouds.all
		$csventry | export-csv -Path $historyfilename -Append -NoTypeInformation
	}
#$result

	$prtgresult = '<?xml version="1.0" encoding="UTF-8" ?>
	<prtg>
	   <result>
		  <channel>temp C</channel>
		  <value>'+([decimal]($result.main.temp) - 273.15)+'</value>
		  <unit>Grad C</unit>
		  <float>1</float>
	   </result>
	   <result>
		  <channel>pressure mBar</channel>
		  <value>'+$result.main.pressure+'</value>
		  <unit>mBar</unit>
		  </result>   
	   <result>
		  <channel>humiditiy (%)</channel>
		  <value>'+$result.main.humidity+'</value>
		  <unit>%</unit>		  
	   </result>   
	   <result>
		  <channel>Cloudiness (%)</channel>
		  <value>'+$result.clouds.all+'</value>
		  <unit>%</unit>
	   </result>
	   <status>LastUpdate'+$result.dt_txt+'</status>
	</prtg>'
	write-verbose "Send PRTG-Result to STD-Out"
	$prtgresult
	
}
else {
	write-verbose "- no Results to process"

	Write-Output "<prtg>"
	Write-Output "<error>1</error>"
	Write-Output "<text>Error receiving data from URL or Cchefile</text>"
	Write-Output "</prtg>"
	Exit
}

write-verbose "PRTG-OpenWeatherMap: End"