Param(
    [string]$WebApplication,
    [string]$source,
    [string]$file1,
    [string]$file2
)
$SnapIn = "Microsoft.SharePoint.PowerShell"
if ( (Get-PSSnapin -Name $SnapIn -ErrorAction SilentlyContinue) -eq $null )
{
    Add-PsSnapin $SnapIn
}
$testsource = test-path $source
if ($testsource)
{
    Write-Host "Path already exists!"
}
else
{
    New-Item -Path $source -ItemType directory
}
$SourceFile1 = $source + "\\" + $file1
$SourceFile2 = $source + "\\" + $file2
$TestSourceFile1 = test-path $SourceFile1
$TestSourceFile2 = test-path $SourceFile2
if($TestSourceFile2)
{
    if($TestSourceFile1)
    {
         $date1 = [datetime](Get-ItemProperty -Path $SourceFile1 -Name LastWriteTime).lastwritetime
         $date2 = [datetime](Get-ItemProperty -Path $SourceFile2 -Name LastWriteTime).lastwritetime
         if($date1 -gt $date2)
         {
            backup-spsite -Identity $WebApplication -path $SourceFile2 -force
         }
         else
         {
            backup-spsite -Identity $WebApplication -path $SourceFile1 -force
         }
    }
    else
    {
        backup-spsite -Identity $WebApplication -path $SourceFile1 -force
    }
}
elseif($TestSourceFile1)
{
    backup-spsite -Identity $WebApplication -path $SourceFile1 -force
}
else
{ 
    backup-spsite -Identity $WebApplication -path $SourceFile2 -force
}