<#
.SYNOPSIS
    Creates a new engine project from _Template/.

.DESCRIPTION
    Copies _Template/ to <Destination>/OpenNest.Engine.<Name>/ and replaces the __NAME__
    placeholder in file names and contents. The new engine builds against OpenNest via
    Directory.Build.props, which must sit in <Destination> or a parent folder.

    With -IncludeBuildFiles, Directory.Build.props/.targets are copied into <Destination>
    too, so the engine can live outside this repo, e.g. in an Engines/ folder inside an
    OpenNest checkout (the props detect that layout on their own).

.EXAMPLE
    ./New-Engine.ps1 -Name Nova
    ./New-Engine.ps1 -Name Nova -Destination C:/bench/run1/OpenNest/Engines -IncludeBuildFiles
#>
param(
    [Parameter(Mandatory)]
    [ValidatePattern('^[A-Z][A-Za-z0-9]*$')]
    [string]$Name,
    [string]$Destination = $PSScriptRoot,
    [switch]$IncludeBuildFiles
)

$ErrorActionPreference = 'Stop'
$template = Join-Path $PSScriptRoot '_Template'
$target = Join-Path $Destination "OpenNest.Engine.$Name"
if (Test-Path $target) { throw "'$target' already exists." }

New-Item -ItemType Directory -Force $Destination | Out-Null
Copy-Item $template $target -Recurse

Get-ChildItem $target -Recurse -File | ForEach-Object {
    $text = [IO.File]::ReadAllText($_.FullName)
    [IO.File]::WriteAllText($_.FullName, $text.Replace('__NAME__', $Name))
}
# Deepest paths first so renaming a folder never invalidates a pending child path.
Get-ChildItem $target -Recurse | Where-Object Name -like '*__NAME__*' |
    Sort-Object { $_.FullName.Length } -Descending |
    ForEach-Object { Rename-Item $_.FullName $_.Name.Replace('__NAME__', $Name) }

if ($IncludeBuildFiles) {
    foreach ($file in 'Directory.Build.props', 'Directory.Build.targets') {
        Copy-Item (Join-Path $PSScriptRoot $file) $Destination -Force
    }
}

Write-Host "Created $target"