# Last Updated: 2022/04/07
# NOTES:
# - This script checks the last successful backup date using the Windows Server Backup PowerShell module
#   https://docs.microsoft.com/en-us/powershell/module/windowsserverbackup/?view=windowsserver2022-ps
# - It also counts the number of warning and error events in the "Microsoft/Windows/Backup" Event Logs 
#   that are within the period specified in the $rpoHours variable
#
# - Your check matching condition should be:
#   Subject - Is Exactly - Windows Server Backup Summary: COMPUTERNAME
#
# - The activity that gets created in CheckCentral will contain a summary line similar to this: "Recent: True, Errors: 0, Warnings: 0"
# - Your check success condition should be:
#   Body Text - Contains - Recent: True, Errors: 0, Warnings: 0
# - Your check warning conditions should be:
#   Body Text - Contains - Recent: True, Errors: 0
#   Body Text - Does Not Contain - Warnings: 0


###################
# Script Settings #
###################

# CheckCentral API key ("createActivities Only" token type is recommended)
$apiToken = ""

# Set the recovery point objective time to check here (in hours)
# If your job runs daily, set this to 24 hours to make sure
#  the last successful backup is less than 24 hours old.
# If your job runs more frequently, e.g. hourly, then set this to
#  1 so that the script confirms the latest backup is less than 1 hour old
$rpoHours = 24

####################################################
# Script Processing (Don't modify below this line) #
####################################################

$ErrorActionPreference = 'Stop'

function New-CCActivity
{
    Param([string]$apiToken,[string]$subject,[string]$body)

    Write-Output "`n[INFO] Creating the activity in CheckCentral...`n"

    # Create the object to store the activity data
    $ccActivity = [PSCustomObject]@{
        sendNotifications = $true
        sendTicketingSystems = $true
        activities = @(
            [PSCustomObject]@{
                subject = $subject
                body = $body
            }
        )
    }

    # Create the activity via the createActivities endpoint
    $ccCreateActivitiesRequest = Invoke-WebRequest -Uri "https://api.checkcentral.cc/createActivities/?apiToken=$apiToken" -Method "POST" -ContentType "text/json" -Body $(($ccActivity | ConvertTo-Json)) -UseBasicParsing

    # Get the number of activities sent and successfully saved
    $ccActivitiesSent = ($ccCreateActivitiesRequest.Content | ConvertFrom-Json).activities_received
    $ccActivitiesSaved = ($ccCreateActivitiesRequest.Content | ConvertFrom-Json).activities_saved

    # Verify that the number of activities saved matches the number of activities sent
    if ($ccActivitiesSaved -lt $ccActivitiesSent)
    {
        Write-Output "[FAIL] Failed to create $($ccActivitiesSent - $ccActivitiesSaved) activities in CheckCentral"
    }
    elseif ($ccActivitiesSaved -eq $ccActivitiesSent)
    {
        Write-Output "[INFO] Successfully created $($ccActivitiesSaved) activities"
    }
}

# Bail out if $apiToken has an empty value
if ($apiToken -eq "")
{
    Write-Output "[FAIL] API token is not set in the script settings"
    exit
}

# Build the activity title
$title = "Windows Server Backup Summary: " + $env:COMPUTERNAME

# Get the summary from Windows Server Backup
try 
{
    Write-Output "[INFO] Getting the Windows Server Backup summary..."
    $wbSummary = Get-WBSummary
}
catch
{
    # Write the error to the console
    $errorMessage = "[FAIL] Get-WBSummary failed to run with the following error: $($Error[0])"
    Write-Output $errorMessage

    # Create the activity in CheckCentral
    New-CCActivity -apiToken $apiToken -subject $title -body $errorMessage
    
    # Exit the script
    Write-Output "[INFO] Exiting the script..."
    exit
}

# Check whether the last successful backup is within the RPO window
$lastBackupRecent = ($wbSummary.LastSuccessfulBackupTime -gt (Get-Date).AddHours(-$rpoHours))

# Get the number of errors in the $rpoHours time window
try
{
    $wbErrors = (Get-WinEvent Microsoft-Windows-Backup | Where-Object {($_.TimeCreated -gt (Get-Date).AddHours(-$rpoHours)) -and ($_.LevelDisplayName -eq "Error")}).Count
}
catch
{
    if ($Error[0].ToString() -eq "No events were found that match the specified selection criteria.")
    {
        $wbErrors = 0
    }
    else
    {
        $errorMessage = "[FAIL] Get-WinEvent failed to run with the following error: $($Error[0])"
        Write-Output $errorMessage

        # Create the activity in CheckCentral
        New-CCActivity -apiToken $apiToken -subject $title -body $errorMessage
    
        # Exit the script
        Write-Output "[INFO] Exiting the script..."
        exit
    }
}

# Get the number of warnings in the $rpoHours time window
try
{
    $wbWarnings = (Get-WinEvent Microsoft-Windows-Backup | Where-Object {($_.TimeCreated -gt (Get-Date).AddHours(-$rpoHours)) -and ($_.LevelDisplayName -eq "Warning")}).Count
}
catch
{
    if ($Error[0].ToString() -eq "No events were found that match the specified selection criteria.")
    {
        $wbWarnings = 0
    }
    else
    {
        $errorMessage = "[FAIL] Get-WinEvent failed to run with the following error: $($Error[0])"
        Write-Output $errorMessage

        # Create the activity in CheckCentral
        New-CCActivity -apiToken $apiToken -subject $title -body $errorMessage
    
        # Exit the script
        Write-Output "[INFO] Exiting the script..."
        exit
    }
}

# Build the results
$wbResults = @"
Last successful backup newer than specified RPO time: $(($lastBackupRecent | Out-String).Trim()) ($rpoHours hours set in script)

Number of errors in the RPO time window: $wbErrors (Checked the last $rpoHours hours as set in script)

Number of warnings in the RPO time window: $wbWarnings (Checked the last $rpoHours hours as set in script)

Summary: Recent: $(($lastBackupRecent | Out-String).Trim()), Errors: $wbErrors, Warnings: $wbWarnings

$(($WBSummary | Out-String).Trim())

Sent from $($MyInvocation.MyCommand) on $env:COMPUTERNAME
"@

# Create the activity in CheckCentral
New-CCActivity -apiToken $apiToken -subject $title -body $wbResults