Function Test-IsSourceFileVersionHigherThanTarget {
<#
.SYNOPSIS
    Given two file paths, and a common filename, determine which is the latter version

.EXAMPLE
$ProviderTargets = @('BankService','CoreService', 'NotificationService','SecurityManagementService','Radium','Nag','NagConfigurationService')

foreach($target in $ProviderTargets) {
    $probePath = (Join-Path (Join-Path "C:\Orb\" $target) "bin")
    if (!(Test-Path $probePath)) {
        $probePath = Split-Path $probePath
    }
    
    $filesInProbe = @((Get-ChildItem -Path $probePath -Filter *.dll).Name)
    foreach ($file in $filesInProbe) {
        if (Test-IsSourceFileVersionHigherThanTarget $file $probePath "C:\Orb\Shared" $file) {
            Write-Host "found $file in $probePath higher than shared"
        }
    }
}
#>
    [CmdletBinding()]
    param(
        [Parameter(Mandatory = $true,Position=0)]
		[ValidateNotNullOrEmpty()]
        [string]$filename,
 
        [Parameter(Mandatory = $true,Position=1)]
		[ValidateScript( {Test-Path (Resolve-Path $_)})]
		[ValidateNotNullOrEmpty()]
        [string]$sourceFolderPath,
		
        [Parameter(Mandatory = $true,Position=2)]
		[ValidateScript( {Test-Path (Resolve-Path $_)})]
		[ValidateNotNullOrEmpty()]
        [string]$targetFolderPath,
		
        [Parameter(Mandatory = $true,Position=3)]
		[ValidateNotNullOrEmpty()]
        [string]$packageName
    )
    process {
		$loglead = "File tester"

		$sourceFile = (Join-Path $sourceFolderPath $filename);
		$targetFile = (Join-Path $targetFolderPath $filename);
		if ((Test-Path $sourceFile) -and (Test-Path $targetFile)) {
			$stringVersionFromSourceFileVersion = (Get-Item $sourceFile).VersionInfo.FileVersion
			$stringVersionFromTargetFileVersion = (Get-Item $targetFile).VersionInfo.FileVersion
			
            ## Both strings have values, so we can read something from that
			if (![System.String]::IsNullOrWhiteSpace($stringVersionFromSourceFileVersion) -and ![System.String]::IsNullOrWhiteSpace($stringVersionFromTargetFileVersion)) {
                ## The version info FileVersion has a space and other content in it, so take what comes before the space.
				$versionFromSourceFile = ([System.Version](((Get-Item $sourceFile).VersionInfo.FileVersion -split ' ')[0]))
				$versionFromTargetFile = ([System.Version](((Get-Item $targetFile).VersionInfo.FileVersion -split ' ')[0]))
				Write-Verbose "$loglead : $versionFromSourceFile : $sourceFile";
				Write-Verbose "$loglead : $versionFromTargetFile : $targetFile";

                ## [System.Version] has .CompareTo so we can let it do the native comparison.
                ## -1 = source version is lower than target
                ##  0 = source version equals target
                ##  1 = source version is higher than the target
				$result = $versionFromSourceFile.CompareTo($versionFromTargetFile) -gt 0;
                
                ## If we decided we are supposed to copy the file _and_ we match this condition of the target file matching a file that already exists
                ## We want to emit an error that the files are different and that we shouldn't be copying the files so we can investigate.
				if (!$result -and ($targetFile -match $packageName) -and $versionFromSourceFile.CompareTo($versionFromTargetFile) -eq 0) {
					if ((Get-FileHash $sourceFile).Hash -ne (Get-FileHash $targetFile).Hash) {
						$message = "The files $sourceFile and $targetFile have the same version [$versionFromSourceFile] but the hashes don't match!";
						Write-Error $message;
						return $false
					}
				}
				Write-Verbose "$loglead : Result was $result";
				return $result;
			} else {
				Write-Warning "$loglead : Can not compare these two files because the version info is missing: $sourceFile [$stringVersionFromSourceFileVersion] - $targetFile [$stringVersionFromTargetFileVersion]"
			}
		} else {
			if (($targetFile -match $packageName) -and (Test-Path $sourceFile) -and (Test-Path $targetFile)){
				if ((Get-FileHash $sourceFile).Hash -ne (Get-FileHash $targetFile).Hash) {
					$versionFromSourceFile = ([System.Version](((Get-Item $sourceFile).VersionInfo.FileVersion -split ' ')[0]))
					$message = "The files $sourceFile and $targetFile have the same version [$versionFromSourceFile] but the hashes don't match!";
					Write-Error $message;
				}
			}

			$result = ((Test-Path $sourceFile) -and !(Test-Path $targetFile));
			Write-Verbose "$loglead : Did the source exist and not the target? $result."
            ## Honestly, we don't care about files that only exist in the final folder and not shared
			return $false;
		}
	}
}