[CmdletBinding()]
param(
    [int]$CUSTOMER_ID,
    [int]$SOFTWARE_ID=101,
    [string]$AGENT_FILENAME='EmberkomAgentSetup.exe'
)

## Get temporary path
$TEMP = [System.IO.Path]::GetTempPath()

## Setup log file and function to write to it
$LOGFILE = "{0}EmberkomAgentSetup_{1}.log" -f $TEMP, $(Get-Date -Format "yyyyMMddHHmmss")
If (! (Test-Path $LOGFILE) ) { New-Item -Path $LOGFILE -ItemType File }
Function Write-Log([string]$message)
{
    $entry = "{0} : {1}" -f $(Get-Date -Format "yyyyMMddHHmmss"), $Message
    Add-Content -Path $LOGFILE -Value $entry
}
Write-Log "Agent installation script has started"

## Immediately delete this script from disk
$THIS_SCRIPT = $MyInvocation.InvocationName
Write-Log "Deleting this script: ${THIS_SCRIPT}"
Try { Remove-Item $MyInvocation.InvocationName -Force }
Catch { Write-Log "This script tried to delete itself but failed!" }

Write-Log "CUSTOMER_ID: ${CUSTOMER_ID}"
Write-Log "SOFTWARE_ID: ${SOFTWARE_ID}"

## Build the path for $AGENT_INSTALLER
$AGENT_INSTALLER = "${TEMP}\${AGENT_FILENAME}"
Write-Log "Agent installer will be saved to: ${AGENT_INSTALLER}"

## Make sure the CUSTOMER_ID is specified
If ( $CUSTOMER_ID )
{
    ## Make sure we need to install the agent
    If ( !(Test-Path 'HKLM:SOFTWARE\N-able Technologies\NcentralAsset') -and !(Test-Path 'SOFTWARE\Wow6432Node\N-able Technologies\NcentralAsset'))
    {
        ## Build the AGENT_URL
        $AGENT_URL = "{0}{1}{2}{3}" -f 'https://manage.emberkom.com/dms/FileDownload?customerID=',$CUSTOMER_ID.ToString(),'&softwareID=',$SOFTWARE_ID.ToString()

        ## Delete $AGENT_INSTALLER if it already exists
        If ( Test-Path $AGENT_INSTALLER )
        {
            Write-Log "Deleting previous agent installer: ${AGENT_INSTALLER}"
            Try { Remove-Item $AGENT_INSTALLER -Force }
            Catch { Write-Log $_.Exception.Message }
        }

        ### Setup security and certificate parameters to download from untrusted sources
        #[System.Net.ServicePointManager]::ServerCertificateValidationCallback = {$true}
        #[Net.ServicePointManager]::SecurityProtocol = 
        #    [Net.SecurityProtocolType]::Tls12 -bor `
        #    [Net.SecurityProtocolType]::Tls11 -bor `
        #    [Net.SecurityProtocolType]::Tls

        ## Download the agent installer
        Write-Log "Downloading agent installer from: ${AGENT_URL}"
        Try { (New-Object System.Net.WebClient).DownloadFile($AGENT_URL, $AGENT_INSTALLER) }
        Catch { Write-Log $_.Exception.Message ; Exit }

        ## Install the agent
        Write-Log "Begin installing agent"
        Try { Start-Process $AGENT_INSTALLER -ArgumentList '/quiet /passive' -Wait }
        Catch { Write-Log $_.Exception.Message }

        ## Remove the agent installer
        If ( Test-Path $AGENT_INSTALLER )
        {
            Write-Log "Deleting agent installer: ${AGENT_INSTALLER}"
            Try { Remove-Item -Path $AGENT_INSTALLER -Force }
            Catch { Write-Log $_.Exception.Message }
        }

        Write-Log "Agent installation script has finished"
    } Else { Write-Log "The agent is already installed on this endpoint." }
} Else { Write-Log "No CUSTOMER_ID was specified!" }