param(
  [string]$Repository = 'https://github.com/DD4SN/DD4SN.github.io.git'
)

$ErrorActionPreference = 'Stop'

$projectRoot = Split-Path -Parent $PSScriptRoot
$siteSource = Join-Path $projectRoot 'pages-dist'
$workflowSource = Join-Path $projectRoot 'pages/deploy.yml'
$temporaryRoot = Join-Path ([System.IO.Path]::GetTempPath()) ("holodori-pages-{0}" -f [guid]::NewGuid().ToString('N'))
$checkout = Join-Path $temporaryRoot 'repository'

try {
  & npm --prefix $projectRoot run build:pages
  if ($LASTEXITCODE -ne 0) { throw 'Pages build failed.' }

  New-Item -ItemType Directory -Path $temporaryRoot | Out-Null
  & git clone $Repository $checkout
  if ($LASTEXITCODE -ne 0) { throw 'Pages repository clone failed.' }

  $resolvedCheckout = (Resolve-Path -LiteralPath $checkout).Path
  $resolvedTemporaryRoot = (Resolve-Path -LiteralPath $temporaryRoot).Path
  if (-not $resolvedCheckout.StartsWith($resolvedTemporaryRoot, [System.StringComparison]::OrdinalIgnoreCase)) {
    throw 'Refusing to update a checkout outside the temporary deployment directory.'
  }

  $oldSiteTarget = Join-Path $resolvedCheckout 'site'
  if (Test-Path -LiteralPath $oldSiteTarget) {
    Remove-Item -LiteralPath $oldSiteTarget -Recurse -Force
  }
  foreach ($generatedPath in @('assets', 'icons', 'index.html', 'README.txt', 'VERSION.txt', '.nojekyll')) {
    $target = Join-Path $resolvedCheckout $generatedPath
    if (Test-Path -LiteralPath $target) {
      Remove-Item -LiteralPath $target -Recurse -Force
    }
  }
  Copy-Item -Path (Join-Path $siteSource '*') -Destination $resolvedCheckout -Recurse -Force
  New-Item -ItemType File -Path (Join-Path $resolvedCheckout '.nojekyll') -Force | Out-Null

  $workflowTarget = Join-Path $resolvedCheckout '.github/workflows'
  New-Item -ItemType Directory -Path $workflowTarget -Force | Out-Null
  Copy-Item -LiteralPath $workflowSource -Destination (Join-Path $workflowTarget 'deploy.yml') -Force

  Push-Location $resolvedCheckout
  try {
    & git add --all -- .
    if ($LASTEXITCODE -ne 0) { throw 'Failed to stage Pages files.' }
    & git diff --cached --quiet
    if ($LASTEXITCODE -eq 0) {
      Write-Output 'GitHub Pages output is already up to date.'
      return
    }

    $package = Get-Content -LiteralPath (Join-Path $projectRoot 'package.json') -Raw | ConvertFrom-Json
    & git commit -m ("deploy: HolodoriCalc v{0}" -f $package.version)
    if ($LASTEXITCODE -ne 0) { throw 'Pages commit failed.' }
    & git push origin HEAD:main
    if ($LASTEXITCODE -ne 0) { throw 'Pages push failed.' }
  } finally {
    Pop-Location
  }
} finally {
  if (Test-Path -LiteralPath $temporaryRoot) {
    $resolvedTemporaryRoot = (Resolve-Path -LiteralPath $temporaryRoot).Path
    $systemTemporaryRoot = [System.IO.Path]::GetFullPath([System.IO.Path]::GetTempPath()).TrimEnd('\')
    if ($resolvedTemporaryRoot.StartsWith($systemTemporaryRoot, [System.StringComparison]::OrdinalIgnoreCase) -and
        (Split-Path -Leaf $resolvedTemporaryRoot).StartsWith('holodori-pages-')) {
      Remove-Item -LiteralPath $resolvedTemporaryRoot -Recurse -Force
    }
  }
}