<#
.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 and the shared Engine.Testing
    source kit are copied into <Destination>, 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
# A built template contains binary/obj files. Copy only source files, never rewrite binaries.
$template = (Resolve-Path $template).Path
Get-ChildItem $template -Recurse -File |
    Where-Object { $_.FullName.Substring($template.Length) -notmatch '[\\/](bin|obj)[\\/]' } |
    ForEach-Object {
        $relative = $_.FullName.Substring($template.Length + 1).Replace('__NAME__', $Name)
        $output = Join-Path $target $relative
        New-Item -ItemType Directory -Force (Split-Path $output -Parent) | Out-Null
        $text = [IO.File]::ReadAllText($_.FullName)
        [IO.File]::WriteAllText($output, $text.Replace('__NAME__', $Name))
    }

if ($IncludeBuildFiles) {
    foreach ($file in 'Directory.Build.props', 'Directory.Build.targets') {
        Copy-Item (Join-Path $PSScriptRoot $file) $Destination -Force
    }
    # The acceptance tests reference the shared, read-only kit beside the engine.
    $kitTarget = Join-Path $Destination 'Engine.Testing'
    New-Item -ItemType Directory -Force $kitTarget | Out-Null
    Get-ChildItem (Join-Path $PSScriptRoot 'Engine.Testing') -File |
        Where-Object { $_.Extension -in '.cs', '.csproj' } |
        Copy-Item -Destination $kitTarget -Force
}

Write-Host "Created $target"