Merge *.cs files into the one file

CS-merger.ps1

param(
    [Parameter(Mandatory=$true)]
    $source,
    [Parameter(Mandatory=$true)]
    $output,
    $header = "/// © Pavel Timofeev",
    $excludes = @("AssemblyInfo.cs", "*.Designer.cs", "TemporaryGeneratedFile_*" ),
    $copyAsIs = @(),        # list of filemasks that should be copy as is without merge
    $addFileNames = $false, # add names of src files 
    $leftComments = $false, # remove line commented with //
    $compactify = $true     # remove empty lines
)

$usings = @()
$classes = @()

Get-ChildItem $source -Filter "*.cs" -Recurse -Exclude $excludes | % { 

    $name = $_.Name
    "Processing $name`r`n"

    if($addFileNames) { $classes += ("`r`n// {0}" -f $name) }
    
    if(($copyAsIs | ? { $name -match $_ }).Count -eq 0)
    {
        gc -Path $_.FullName | % {

            $str = $_.ToString().Trim()

            if($str -match "using " -and $str -notmatch "using \(") {
            
                $usings += $str
            }
            else {
               if($leftComments -or !$str.StartsWith("//") )
               { 
                    if( !$compactify -or $str -ne "")
                    {
                        $classes += $_ 
                    }
               }
            }
        }
    }
    else
    {
        copy-item $_.FullName -Destination (Split-Path $output -Parent)
    }
}

sc $output '///' # cleanup output file
ac $output $header
ac $output "/// Changed at $((Get-Date).GetDateTimeFormats('s'))`r`n"
ac $output ($usings | Sort | Get-Unique)
ac $output $classes