$ErrorActionPreference = 'Stop'
$ProgressPreference = 'SilentlyContinue'

$env:PUB_HOSTED_URL = 'https://pub.flutter-io.cn'
$env:FLUTTER_STORAGE_BASE_URL = 'https://storage.flutter-io.cn'

function Get-FreeGb([string]$letter) {
  $d = Get-PSDrive -Name $letter -ErrorAction SilentlyContinue
  if (-not $d) { return 0 }
  return [math]::Round($d.Free / 1GB, 1)
}

$sdkRoot = if ((Get-FreeGb 'D') -gt 8) { 'D:\' } else { 'C:\' }
$flutterDir = Join-Path $sdkRoot 'flutter'
$work = Join-Path $sdkRoot 'oa-build-cache'
New-Item -ItemType Directory -Force -Path $work | Out-Null

function Test-Flutter {
  $bat = Join-Path $flutterDir 'bin\flutter.bat'
  return (Test-Path $bat)
}

function Ensure-Flutter {
  if (Test-Flutter) {
    Write-Host "Flutter already at $flutterDir"
    return
  }
  $zip = Join-Path $work 'flutter_windows_3.27.4-stable.zip'
  if (-not (Test-Path $zip) -or ((Get-Item $zip).Length -lt 100MB)) {
    $urls = @(
      'https://storage.flutter-io.cn/flutter_infra_release/releases/stable/windows/flutter_windows_3.27.4-stable.zip',
      'https://fast-mirror.isrc.ac.cn/flutter/flutter_infra/releases/stable/windows/flutter_windows_3.27.4-stable.zip'
    )
    $ok = $false
    foreach ($u in $urls) {
      Write-Host "Downloading Flutter from $u"
      try {
        Invoke-WebRequest -Uri $u -OutFile $zip -UseBasicParsing
        $ok = $true
        break
      } catch {
        Write-Host "download failed: $_"
      }
    }
    if (-not $ok) { throw 'Flutter SDK 下载失败' }
  }
  Write-Host "Extracting Flutter to $flutterDir"
  if (Test-Path $flutterDir) { Remove-Item $flutterDir -Recurse -Force }
  Expand-Archive -Path $zip -DestinationPath $sdkRoot -Force
  if (-not (Test-Flutter)) { throw "unzip 后仍没有 $flutterDir\bin\flutter.bat" }
}

function Ensure-VsBuildTools {
  $vswhere = "${env:ProgramFiles(x86)}\Microsoft Visual Studio\Installer\vswhere.exe"
  $ok = $false
  if (Test-Path $vswhere) {
    $path = & $vswhere -latest -products * -requires Microsoft.VisualStudio.Component.VC.Tools.x86.x64 -property installationPath
    if ($path) { $ok = $true }
  }
  if ($ok) {
    Write-Host "VS C++ tools already installed"
    return
  }
  $boot = Join-Path $work 'vs_BuildTools.exe'
  if (-not (Test-Path $boot)) {
    Write-Host 'Downloading VS 2022 Build Tools bootstrapper'
    $urls = @(
      'https://aka.ms/vs/17/release/vs_BuildTools.exe'
    )
    $got = $false
    foreach ($u in $urls) {
      try {
        Invoke-WebRequest -Uri $u -OutFile $boot -UseBasicParsing
        $got = $true
        break
      } catch {
        Write-Host "bootstrapper download failed: $_"
      }
    }
    if (-not $got) { throw 'VS Build Tools 引导程序下载失败' }
  }
  $installPath = Join-Path $sdkRoot 'BuildTools'
  Write-Host "Installing VS Build Tools to $installPath (this takes a while)"
  $p = Start-Process -FilePath $boot -ArgumentList @(
    '--quiet', '--wait', '--norestart', '--nocache',
    '--installPath', $installPath,
    '--add', 'Microsoft.VisualStudio.Workload.VCTools',
    '--includeRecommended',
    '--add', 'Microsoft.VisualStudio.Component.Windows11SDK.22621'
  ) -Wait -PassThru
  if ($p.ExitCode -ne 0 -and $p.ExitCode -ne 3010) {
    throw "VS Build Tools install failed: $($p.ExitCode)"
  }
}

function Ensure-Inno {
  $iscc = @(
    "${env:ProgramFiles}\Inno Setup 7\ISCC.exe",
    "${env:ProgramFiles(x86)}\Inno Setup 7\ISCC.exe",
    "${env:ProgramFiles(x86)}\Inno Setup 6\ISCC.exe",
    "${env:ProgramFiles}\Inno Setup 6\ISCC.exe"
  ) | Where-Object { Test-Path $_ } | Select-Object -First 1
  if ($iscc) {
    Write-Host "Inno Setup already at $iscc"
    return
  }
  $setup = Join-Path $work 'innosetup.exe'
  Write-Host 'Downloading Inno Setup'
  Invoke-WebRequest -Uri 'https://jrsoftware.org/download.php/is.exe' -OutFile $setup -UseBasicParsing
  $p = Start-Process -FilePath $setup -ArgumentList '/VERYSILENT','/SUPPRESSMSGBOXES','/NORESTART' -Wait -PassThru
  if ($p.ExitCode -ne 0) { throw "Inno Setup install failed: $($p.ExitCode)" }
}

Ensure-Flutter
Ensure-VsBuildTools
Ensure-Inno
Write-Host 'toolchain ready'
Write-Host "flutter=$flutterDir\bin\flutter.bat"