param(
  [string]$InstallDir = (Join-Path $env:LOCALAPPDATA 'SangLive'),
  [switch]$ReplaceEnv,
  [switch]$NoShortcut
)

$ErrorActionPreference = 'Stop'
[Console]::OutputEncoding = [System.Text.UTF8Encoding]::new()

$packageUrl = 'https://slive.misalab.com/sanglive.zip?v=20260511-author2'
$tempRoot = Join-Path $env:TEMP ('sanglive-install-' + [guid]::NewGuid().ToString('N'))
$zipPath = Join-Path $tempRoot 'sanglive.zip'
$extractPath = Join-Path $tempRoot 'extract'
$envBackupPath = Join-Path $tempRoot '.env.backup'

function Assert-Node {
  $node = Get-Command node -ErrorAction SilentlyContinue
  if (-not $node) {
    throw 'Node.js is required. Install Node.js 20 LTS first: https://nodejs.org/'
  }
}

function Resolve-SourceDir {
  param([string]$ExtractPath)

  if (Test-Path (Join-Path $ExtractPath 'install.ps1')) { return $ExtractPath }
  $candidate = Get-ChildItem -Path $ExtractPath -Directory | Where-Object {
    Test-Path (Join-Path $_.FullName 'install.ps1')
  } | Select-Object -First 1
  if ($candidate) { return $candidate.FullName }
  throw 'install.ps1 not found in downloaded package.'
}

New-Item -ItemType Directory -Force -Path $tempRoot | Out-Null
New-Item -ItemType Directory -Force -Path $InstallDir | Out-Null

try {
  Assert-Node
  Write-Host "Downloading S-Live from $packageUrl"
  Invoke-WebRequest -Uri $packageUrl -OutFile $zipPath -UseBasicParsing

  Write-Host 'Extracting package...'
  Expand-Archive -Path $zipPath -DestinationPath $extractPath -Force
  $sourceDir = Resolve-SourceDir -ExtractPath $extractPath

  Write-Host "Installing to $InstallDir"
  $installedEnv = Join-Path $InstallDir '.env'
  $hasExistingEnv = Test-Path $installedEnv
  if ($hasExistingEnv -and -not $ReplaceEnv) {
    Copy-Item -LiteralPath $installedEnv -Destination $envBackupPath -Force
  }

  Copy-Item -Path (Join-Path $sourceDir '*') -Destination $InstallDir -Recurse -Force

  if ($hasExistingEnv -and -not $ReplaceEnv) {
    Copy-Item -LiteralPath $envBackupPath -Destination $installedEnv -Force
  }

  $installer = Join-Path $InstallDir 'install.ps1'
  if (-not (Test-Path $installer)) { throw 'install.ps1 not found after extraction.' }

  $installArgs = @('-NoProfile', '-ExecutionPolicy', 'Bypass', '-File', $installer)
  if ($NoShortcut) { $installArgs += '-NoShortcut' }
  & powershell @installArgs
  if ($LASTEXITCODE -ne 0) { throw 'S-Live installer failed.' }

  Write-Host ''
  Write-Host 'Install complete.'
  Write-Host 'Run the same command again later to update S-Live.'
  Write-Host 'Use the Desktop shortcut named "S-Live" to start the app.'
} finally {
  Remove-Item $tempRoot -Recurse -Force -ErrorAction SilentlyContinue
}