# microManager installer for Windows (x64). In PowerShell:
#
#   irm https://micromanager.win/install.ps1 | iex
#
# What it does, in order:
#   1. reads the release manifest (latest.yml) and downloads the installer it names,
#   2. checks the installer's SHA-512 against the manifest and stops if they differ,
#   3. runs it for your user only (no administrator rights), which installs microManager under
#      %LOCALAPPDATA%\Programs and adds it to the Start menu,
#   4. removes the downloaded installer.
# The app updates itself from then on.
#
# Settings (environment variables, for example: $env:MICROMANAGER_SILENT = '1'; irm ... | iex):
#   MICROMANAGER_SILENT=1               install without showing the installer's progress window
#   MICROMANAGER_NO_RUN=1               only download and check the installer, into the current folder
#                                       (works on any system with PowerShell)
#   MICROMANAGER_BASE_URL=https://...   release server (default https://micromanager.win)
#
# Everything runs inside Install-MicroManager, called on the last line, so a partly downloaded copy
# of this script does nothing.

function Install-MicroManager {
  $ErrorActionPreference = 'Stop'
  Set-StrictMode -Version 3.0
  # Invoke-WebRequest's progress bar slows downloads in Windows PowerShell 5.1 by orders of magnitude.
  $ProgressPreference = 'SilentlyContinue'

  function Say([string] $message) {
    Write-Host "microManager: $message"
  }

  # The reason goes out as one plain line (PowerShell wraps and decorates error records), then the throw stops the
  # script without closing the window `irm | iex` runs in.
  function Fail([string] $message) {
    Write-Host "microManager: error: $message"
    throw 'microManager: stopped; see the error above.'
  }

  function Get-Setting([string] $name) {
    $value = [Environment]::GetEnvironmentVariable($name)
    if ($null -eq $value) { return '' }
    return $value
  }

  function Save-Url([string] $url, [string] $path) {
    try {
      Invoke-WebRequest -Uri $url -OutFile $path -UseBasicParsing
    } catch {
      Fail "could not download ${url}: $($_.Exception.Message)"
    }
  }

  # electron-builder writes each file's SHA-512 in base64.
  function Get-Sha512Base64([string] $path) {
    $stream = [System.IO.File]::OpenRead($path)
    $sha = [System.Security.Cryptography.SHA512]::Create()
    try {
      return [Convert]::ToBase64String($sha.ComputeHash($stream))
    } finally {
      $sha.Dispose()
      $stream.Dispose()
    }
  }

  # The version and the installer's file name and SHA-512 from latest.yml.
  function Read-Manifest([string] $text) {
    $version = ''
    $files = New-Object System.Collections.Generic.List[object]
    $url = ''
    foreach ($rawLine in ($text -split "`n")) {
      $line = $rawLine.TrimEnd("`r", ' ', "`t")
      if ($line -match '^version:\s*(.+)$') {
        $version = $Matches[1].Trim().Trim('"', "'")
      } elseif ($line -match '^\s*-\s*url:\s*(.+)$') {
        $url = $Matches[1].Trim().Trim('"', "'")
      } elseif ($url -and $line -match '^\s*sha512:\s*(.+)$') {
        $files.Add([pscustomobject] @{ Url = $url; Sha512 = $Matches[1].Trim().Trim('"', "'") })
        $url = ''
      }
    }
    $installer = $files | Where-Object { $_.Url -like '*.exe' } | Select-Object -First 1
    return [pscustomobject] @{ Version = $version; Installer = $installer }
  }

  $noRun = (Get-Setting 'MICROMANAGER_NO_RUN') -eq '1'
  # Windows PowerShell (5.1) only runs on Windows; PowerShell 6 and later say where they run.
  $isCore = $PSVersionTable.PSVersion.Major -ge 6
  $runningOnWindows = (-not $isCore) -or $IsWindows
  if (-not $noRun) {
    if (-not $runningOnWindows) {
      Fail 'this installer is for Windows; on macOS and Linux run: curl -fsSL https://micromanager.win/install.sh | sh'
    }
    $arch = $env:PROCESSOR_ARCHITEW6432
    if (-not $arch) { $arch = $env:PROCESSOR_ARCHITECTURE }
    if ($arch -ne 'AMD64') {
      Fail "there is no microManager build for $arch Windows yet (x64 only). See https://micromanager.win/install#windows"
    }
  }

  $baseUrl = Get-Setting 'MICROMANAGER_BASE_URL'
  if (-not $baseUrl) { $baseUrl = 'https://micromanager.win' }
  $baseUrl = $baseUrl.TrimEnd('/')
  if ($baseUrl -notmatch '^https://' -and $baseUrl -notmatch '^http://(127\.0\.0\.1|localhost):\d+$') {
    Fail 'MICROMANAGER_BASE_URL must be an https:// URL.'
  }
  if (-not $isCore) {
    # Windows PowerShell 5.1 may still default to TLS 1.0.
    [Net.ServicePointManager]::SecurityProtocol = [Net.ServicePointManager]::SecurityProtocol -bor [Net.SecurityProtocolType]::Tls12
  }
  $releasesUrl = "$baseUrl/releases/win"

  $workDir = Join-Path ([System.IO.Path]::GetTempPath()) ("micromanager-install-" + [Guid]::NewGuid().ToString('N'))
  New-Item -ItemType Directory -Path $workDir | Out-Null
  try {
    Say 'checking the newest release for Windows'
    $manifestPath = Join-Path $workDir 'latest.yml'
    Save-Url "$releasesUrl/latest.yml" $manifestPath
    $manifest = Read-Manifest ([System.IO.File]::ReadAllText($manifestPath))
    if (-not $manifest.Version) { Fail 'the release manifest has no version.' }
    if (-not $manifest.Installer) {
      Fail "version $($manifest.Version) has no Windows installer yet. See https://micromanager.win/install#windows"
    }
    $fileName = $manifest.Installer.Url
    if ($fileName -notmatch '^[A-Za-z0-9][A-Za-z0-9._-]*\.exe$') {
      Fail "unexpected file name in the release manifest: $fileName"
    }

    Say "downloading microManager $($manifest.Version)"
    $installer = Join-Path $workDir $fileName
    Save-Url "$releasesUrl/$fileName" $installer
    if ((Get-Sha512Base64 $installer) -ne $manifest.Installer.Sha512) {
      Fail "the download's SHA-512 does not match the release manifest; nothing was installed."
    }
    Say 'checksum verified'

    if ($noRun) {
      $kept = Join-Path (Get-Location).ProviderPath $fileName
      Move-Item -LiteralPath $installer -Destination $kept -Force
      Say "saved the checked installer as $kept; run it when you are ready."
      return
    }

    Say "installing microManager $($manifest.Version) for $env:USERNAME"
    if ((Get-Setting 'MICROMANAGER_SILENT') -eq '1') {
      $process = Start-Process -FilePath $installer -ArgumentList '/S' -Wait -PassThru
    } else {
      $process = Start-Process -FilePath $installer -Wait -PassThru
    }
    if ($process.ExitCode -ne 0) {
      Fail "the installer stopped with exit code $($process.ExitCode)."
    }
    Say "installed microManager $($manifest.Version). Open it from the Start menu."
  } finally {
    Remove-Item -LiteralPath $workDir -Recurse -Force -ErrorAction SilentlyContinue
  }
}

Install-MicroManager