paramscript.ps1

#requires -Version 5.1

<#
This is a script with a more defined set of parameters.
Consider this a controller script that calls functions and cmdlets
to meet a desired outcome.
#>

Param(
    [Parameter(Position = 0)]
    [ValidateNotNullOrEmpty()]
    [string]$Computername = $env:COMPUTERNAME,

    [Parameter(Mandatory, HelpMessage = 'Enter the name of the log to query')]
    [ValidateNotNullOrEmpty()]
    [string]$LogName,

    [Parameter(HelpMessage = 'Enter the number of events to retrieve between 1 and 1000')]
    [ValidateRange(1, 1000)]
    [int]$Count = 20,

    [Parameter(HelpMessage = 'Enter the path to save the report. Do not include a filename.')]
    [ValidateScript({ Test-Path $_ })]
    [string]$Path = '.'
)

#a script version used in the HTML report
$scriptVersion = '1.0.1'

#build a filename using a date pattern
$fileName = "$($ComputerName.toUpper())-$(Get-Date -Format yyyy_MM-dd-hh-mm).html"
#don't concatenate strings to make a path. Use Join-Path.
$reportPath = Join-Path -Path $Path -ChildPath $fileName

# !Alert! This script has no error handling for the sake of simplicity
$splatParams = @{
    FilterHashtable = @{LogName = $LogName; Level = 2, 3 }
    MaxEvents       = $Count
    ComputerName    = $Computername
}
$data = Get-WinEvent @splatParams

$group = $data | Group-Object -Property ProviderName
#create a collection of HTML fragments
$fragments = @()
$fragments += "<H1>$($data[0].MachineName)</H1>"

foreach ($item in $group) {
    $fragments += "<H2>$($item.Name)</H2>"
    $fragments += $group[0].group | Select-Object -Property TimeCreated, ID, LevelDisplayName, Message |
    ConvertTo-Html -As Table -Fragment
}

#define a here string for the html header
$head = @'
<style>
body { background-color:#FAFAFA;
font-family:Arial;
font-size:12pt; }
td, th { border:1px solid black;
    border-collapse:collapse; }
th { color:white;
background-color:black; }
table, tr, td, th { padding: 2px; margin: 0px }
tr:nth-child(odd) {background-color: LightGray}
table { margin-left:50px; }
img
{
float:left;
margin: 0px 25px;
}
</style>
<br>
'@

#HTML to display at the end of the report
$footer = @"
<br>
<i>
Date&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;: $(Get-Date)<br>
Author&nbsp;&nbsp;: $env:USERDOMAIN\$env:username<br>
Script&nbsp;&nbsp;&nbsp;: $(Convert-Path $MyInvocation.InvocationName)<br>
Version: $scriptVersion<br>
Source&nbsp;: $($Env:COMPUTERNAME)<br>
</i>
"@

#create the HTML document
ConvertTo-Html -Head $head -Body $fragments -PostContent $footer |
Out-File -FilePath $reportPath

#display the report path
Get-Item -Path $reportPath