param(
  [Parameter(Mandatory = $true)]
  [string]$AppDir,

  [Parameter(Mandatory = $true)]
  [string]$OutputExe,

  [Parameter(Mandatory = $true)]
  [string]$Version,

  [string]$BuildNumber = "dev",

  [long]$MinInstallerBytes = 10485760
)

$ErrorActionPreference = "Stop"

function Find-Makensis() {
  $command = Get-Command makensis -ErrorAction SilentlyContinue
  if ($command) {
    return $command.Source
  }

  $searchRoots = @(
    "${env:ProgramFiles(x86)}\NSIS\makensis.exe",
    "${env:ProgramFiles}\NSIS\makensis.exe"
  )

  foreach ($candidate in $searchRoots) {
    if (Test-Path $candidate) {
      return $candidate
    }
  }

  throw "Could not find makensis. Install NSIS 3.x on the Windows build agent."
}

function Get-DirectoryBytes {
  param([string]$Path)

  $total = 0
  foreach ($item in Get-ChildItem -LiteralPath $Path -Recurse -File -Force) {
    $total += $item.Length
  }
  return $total
}

$rootDir = Split-Path -Parent $PSScriptRoot
$nsiPath = Join-Path $rootDir "packaging/windows/farmcontrol.nsi"
$installerInclude = Join-Path $rootDir "packaging/windows/installer.nsh"
$fileListGenerator = Join-Path $rootDir "scripts/generate-nsis-file-list.ps1"
$workDir = Join-Path $env:TEMP "farmcontrol-nsis"
$localInstallerName = "farmcontrol-installer.exe"

if (Test-Path $workDir) {
  Remove-Item $workDir -Recurse -Force
}
New-Item -ItemType Directory -Path $workDir | Out-Null

$appDirPath = (Resolve-Path -LiteralPath $AppDir).Path
$stagingAppDir = Join-Path $workDir "app"

Write-Host "Staging application files for NSIS from $appDirPath"
Copy-Item -LiteralPath $appDirPath -Destination $stagingAppDir -Recurse -Force

$stagedAppBytes = Get-DirectoryBytes $stagingAppDir
Write-Host "Staged application size: $([math]::Round($stagedAppBytes / 1MB, 2)) MB"

if ($stagedAppBytes -lt 5242880) {
  throw "Staged application is only $([math]::Round($stagedAppBytes / 1KB, 1)) KiB. Expected a full Electrobun app bundle before building the installer."
}

$requiredExe = Join-Path $stagingAppDir "bin\FarmControl.exe"
$requiredDeeplinkScript = Join-Path $stagingAppDir "bin\deeplink.js"
if (-not (Test-Path $requiredExe)) {
  throw "Staged application is missing bin\FarmControl.exe"
}
if (-not (Test-Path $requiredDeeplinkScript)) {
  throw "Staged application is missing bin\deeplink.js"
}

Copy-Item -LiteralPath $nsiPath -Destination (Join-Path $workDir "farmcontrol.nsi")
Copy-Item -LiteralPath $installerInclude -Destination (Join-Path $workDir "installer.nsh")
Copy-Item -LiteralPath $fileListGenerator -Destination (Join-Path $workDir "generate-nsis-file-list.ps1")

$iconPath = Join-Path $rootDir "assets\installer.ico"
if (Test-Path $iconPath) {
  Copy-Item -LiteralPath $iconPath -Destination (Join-Path $workDir "icon.ico") -Force
  Write-Host "Using installer icon from $iconPath"
}

$uninstallerIconPath = Join-Path $rootDir "assets\uninstaller.ico"
if (Test-Path $uninstallerIconPath) {
  Copy-Item -LiteralPath $uninstallerIconPath -Destination (Join-Path $workDir "uninstaller.ico") -Force
  Write-Host "Using uninstaller icon from $uninstallerIconPath"
}

$makensis = Find-Makensis
$outputExePath = $ExecutionContext.SessionState.Path.GetUnresolvedProviderPathFromPSPath($OutputExe)
$outputDir = Split-Path $outputExePath -Parent
if (-not (Test-Path $outputDir)) {
  New-Item -ItemType Directory -Path $outputDir | Out-Null
}

$makensisArgs = @(
  "/V3"
  "/NOCD"
  "/DOUTFILE=$localInstallerName"
  "/DVERSION=$Version"
  "/DBUILD_NUMBER=$BuildNumber"
  "/DAPP_SOURCE_DIR=app"
  "/DAPP_FILE_LIST_GENERATOR=generate-nsis-file-list.ps1"
)

if (Test-Path (Join-Path $workDir "icon.ico")) {
  $makensisArgs += "/DINSTALLER_ICON=icon.ico"
}

if (Test-Path (Join-Path $workDir "uninstaller.ico")) {
  $makensisArgs += "/DUNINSTALLER_ICON=uninstaller.ico"
}

$makensisArgs += (Join-Path $workDir "farmcontrol.nsi")

Push-Location $workDir
try {
  & $makensis @makensisArgs
  if ($LASTEXITCODE -ne 0) {
    throw "makensis failed with exit code $LASTEXITCODE"
  }
} finally {
  Pop-Location
}

$localInstallerPath = Join-Path $workDir $localInstallerName
if (-not (Test-Path $localInstallerPath)) {
  throw "NSIS installer was not created at $localInstallerPath"
}

$installerBytes = (Get-Item -LiteralPath $localInstallerPath).Length
Write-Host "NSIS installer size: $([math]::Round($installerBytes / 1MB, 2)) MB"

if ($installerBytes -lt $MinInstallerBytes) {
  throw "NSIS installer is only $([math]::Round($installerBytes / 1KB, 1)) KiB at $localInstallerPath. The application files were not packaged. Check NSIS logs above."
}

Move-Item -LiteralPath $localInstallerPath -Destination $outputExePath -Force

Write-Host "Created NSIS installer at $outputExePath"