Automatically maintain shortcuts to files in subdirectories

maintain-links.ps1

param(
    [parameter(Mandatory=$true, Position=0)]
    [String[]] $Path,

    [Switch]   $Watch
)

function main
{
    Remove-InvalidShortcuts
    Create-Shortcuts $Path

    if ($Watch.IsPresent) {
        Register-FileWatcher
    }
}

function Create-Shortcuts($path)
{
    $slnFiles = Get-Item $path
    foreach ($link in $slnFiles | Select-LinkToTargetMapping) {
        Create-Shortcut $link.LinkFile $link.TargetFile
    }
}

function Remove-InvalidShortcuts
{
    param( [string]$Path = '.' )

    $shortcuts = Get-ChildItem (Join-Path $Path *) -Include *.lnk |
                 foreach { Get-Shortcut $_ }
    $nonexistent = $shortcuts | where { -not (Test-Path $_.TargetPath) }
    foreach ($shortcut in $nonexistent)
    {
        Remove-Item $shortcut.FullName
    }
}

function Register-FileWatcher
{
    $scriptPath = $script:MyInvocation.MyCommand.Path

    # http://gallery.technet.microsoft.com/scriptcenter/Powershell-FileSystemWatche-dfd7084b
    $watcher = New-Object IO.FileSystemWatcher '.'
    $changed = Register-ObjectEvent $watcher Changed -MessageData @{ ScriptPath = $scriptPath; Args = @( $Path ) } -Action {
        try {
            & $event.MessageData.ScriptPath $event.MessageData.Args
        } catch [Exception] {
            Write-Host $_.Exception.Message
        }
    }
    $watcher.EnableRaisingEvents = $true
}

filter Select-LinkToTargetMapping
{
    $path = $_.Directory | Resolve-Path -Relative
    $name = $path -replace '^.\\','' -replace '\\','-'
    $lnkFile = Join-Path $Pwd ($name + '.lnk')
    return @{ LinkFile = $lnkFile; TargetFile = $_ }
}

function Get-Shortcut
{
    param ( [string]$Path )

    $file = Get-Item $Path

    $wsh = New-Object -ComObject WScript.Shell
    $shortcut = $wsh.CreateShortcut($Path)

    return @{
        FullName = $file.FullName;
        TargetPath = $shortcut.TargetPath;
        Description = $shortcut.Description;
        WorkingDirectory = $shortcut.WorkingDirectory;
    }
}

function Create-Shortcut
{
    # Adapted from a post by CB (http://stackoverflow.com/a/9701907/27581)
    param ( [string]$Path, [string]$Target )

    $wsh = New-Object -ComObject WScript.Shell
    $shortcut = $wsh.CreateShortcut($Path)

    $targetItem = Get-Item $Target
    $shortcut.TargetPath = $targetItem.FullName

    if ($targetItem.Directory)
    {
        $shortcut.WorkingDirectory = $targetItem.Directory.FullName
    }

    $shortcut.Save()
}

main