param (
    $Path,
    $ItemCount = 100
)

function MakeRss {
# Creates an RSS feed
# Parameter input is for "site": Path, Title, Url, Description
# Pipeline input is for feed items: hashtable with Title, Link, Author, Description, and pubDate keys
    param (
        $Path = "$( throw 'Path is a mandatory parameter.' )",
        $Title = "Site Title",
        $homePageUrl = "http://$( $env:computername )",
        $Description = "Description of site"
    )
    Begin {
        # feed metadata
        $encoding = [System.Text.Encoding]::UTF8
        $writer = New-Object System.Xml.XmlTextWriter( $Path, $encoding )
        $writer.WriteStartDocument()
        $writer.WriteStartElement( "rss" )
        $writer.WriteAttributeString( "version", "2.0" )
        $writer.WriteStartElement( "channel" )
        $writer.WriteElementString( "title", $Title )
        $writer.WriteElementString( "link", $Url )
        $writer.WriteElementString( "description", $Description )
    }
    Process {
        # Construct feed items
        $writer.WriteStartElement( "item" )
        $writer.WriteElementString( "title", $_.title )
        $writer.WriteElementString( "link", $_.link )
        $writer.WriteElementString( "author", $_.author )
        $writer.WriteStartElement( "description" )
        $writer.WriteRaw( "<![CDATA[" ) # desc can contain HTML, so its escaped using SGML escape code
        $writer.WriteRaw( $_.description )
        $writer.WriteRaw( "]]>" )
        $writer.WriteEndElement()
        $writer.WriteElementString( "pubDate", $_.pubDate.toString( 'r' ) )
        $writer.WriteElementString( "guid", $homePageUrl + "/" + [guid]::NewGuid() )
        $writer.WriteEndElement()
    }
    End {
        $writer.WriteEndElement()
        $writer.WriteEndElement()
        $writer.WriteEndDocument()
        $writer.Close()
    }
}

# Connect-VIServer -Server "localhost"
$Title = "VirtualCenter events for $( $env:computername )"
$Url = "https://$( $env:computername )"
$Description = "Error log for VirtualCenter service"
if ( !$Path ) {
    $appData = [system.Environment]::GetFolderPath('CommonApplicationData')
    $docRoot = $appData + "\VMware\VMware VirtualCenter\docRoot"
    $Path = $docRoot + "\events.rss"
}

# Retrieve error events
$event = Get-VIEvent -MaxSamples $ItemCount -Types 'Error'
$feedItems = @()
$event | ForEach-Object {
    $item = @{}
    $item.Title = $_.key
    $item.Link = "https://$( $env:computername )"
    $item.Author = $_.username
    $item.Description = $_.fullFormattedMessage
    $item.pubDate = $_.createdTime
    $feedItems += $item
}
$feedItems | makeRss -title $Title -url $Url -description $Description -path $Path