# Ridgun installer for Windows (www-ridgun FR-DL-003), written by https://ridgun.com/install.ps1 for Ridgun 1.0.9.
#
#   irm https://ridgun.com/install.ps1 | iex
#
# The same steps as install.sh, in PowerShell 5.1 or later. Into a temporary folder it downloads what omni needs: the
# release for this system, the newest libs and the index. It checks the release against its SHA256SUMS before running
# anything from it, then hands over to `omni setup`, which checks every signature with the release key built into omni
# (ADR-0004) and installs ridgunc, stable and omni in %USERPROFILE%\.local\bin and the standard libraries in
# %USERPROFILE%\.local\lib\ridgun (it keeps its own copy in %USERPROFILE%\.omni). Nothing is installed if a check
# fails. Nothing else on the system is touched: not even PATH, which it only tells you how to change.
& {
  $ErrorActionPreference = 'Stop'
  $ProgressPreference = 'SilentlyContinue'

  $version = '1.0.9'
  $base = 'https://ridgun.com'
  $files = 'x86_64-linux ridgun-1.0.9-x86_64-linux.tar.gz
arm64-linux ridgun-1.0.9-arm64-linux.tar.gz
x86_64-macos ridgun-1.0.9-x86_64-macos.tar.gz
arm64-macos ridgun-1.0.9-arm64-macos.tar.gz
x86_64-windows ridgun-1.0.9-x86_64-windows.tar.gz
arm64-windows ridgun-1.0.9-arm64-windows.tar.gz'

  function Say([string] $m) { Write-Host "ridgun: $m" }
  function Fail([string] $m) { throw "ridgun: $m" }

  if (-not $version) { Fail "no Ridgun release is published yet: see $base/download" }

  # A 32-bit PowerShell on 64-bit Windows names the machine in PROCESSOR_ARCHITEW6432.
  $machine = $env:PROCESSOR_ARCHITEW6432
  if (-not $machine) { $machine = $env:PROCESSOR_ARCHITECTURE }
  switch ($machine) {
    'AMD64' { $arch = 'x86_64' }
    'ARM64' { $arch = 'arm64' }
    default { $arch = "$machine".ToLower() }
  }
  $target = "$arch-windows"
  $file = $null
  foreach ($line in ($files -split "`n")) {
    $parts = $line.Trim() -split ' '
    if ($parts.Count -eq 2 -and $parts[0] -eq $target) { $file = $parts[1]; break }
  }
  if (-not $file) { Fail "Ridgun $version has no download for $target yet: see $base/download" }
  if (-not (Get-Command tar.exe -ErrorAction SilentlyContinue)) { Fail "needs tar.exe, which comes with Windows 10 (1803) and later" }

  # Windows PowerShell 5.1 may not offer TLS 1.2 by itself.
  [Net.ServicePointManager]::SecurityProtocol = [Net.ServicePointManager]::SecurityProtocol -bor [Net.SecurityProtocolType]::Tls12

  function Get-To([string] $url, [string] $path) {
    try { Invoke-WebRequest -UseBasicParsing -Uri $url -OutFile $path } catch { return $false }
    return $true
  }

  # The temporary folder is laid out like $base/downloads, so omni reads it as its mirror.
  $tmp = Join-Path ([IO.Path]::GetTempPath()) ('ridgun-' + [guid]::NewGuid().ToString('N'))
  New-Item -ItemType Directory -Path $tmp | Out-Null
  $hadMirror = Test-Path Env:OMNI_DOWNLOADS_MIRROR
  $oldMirror = $env:OMNI_DOWNLOADS_MIRROR
  try {
    # A release folder: one file with its SHA256SUMS and their signature.
    function Get-Release([string] $folder, [string] $name) {
      $dir = Join-Path $tmp $folder
      New-Item -ItemType Directory -Force -Path $dir | Out-Null
      if (-not (Get-To "$base/downloads/$folder/$name" (Join-Path $dir $name))) { Fail "could not download $name" }
      if (-not (Get-To "$base/downloads/$folder/SHA256SUMS" (Join-Path $dir 'SHA256SUMS'))) { Fail "could not download the SHA256SUMS of $name" }
      if (-not (Get-To "$base/downloads/$folder/SHA256SUMS.minisig" (Join-Path $dir 'SHA256SUMS.minisig'))) { Fail "could not download the signature of $name" }
    }

    Say "downloading Ridgun $version for $target"
    $index = Join-Path $tmp 'index.tsv'
    if (-not (Get-To "$base/downloads/index.tsv" $index)) { Fail 'could not download the index of releases' }
    Get-Release $version $file
    $archive = Join-Path (Join-Path $tmp $version) $file
    $want = $null
    foreach ($line in (Get-Content (Join-Path (Join-Path $tmp $version) 'SHA256SUMS'))) {
      if ($line -match '^([0-9a-f]{64})  (.+)$' -and $Matches[2] -eq $file) { $want = $Matches[1] }
    }
    $got = (Get-FileHash -Algorithm SHA256 -Path $archive).Hash.ToLower()
    if (-not $want -or $want -ne $got) { Fail "the checksum of $file does not match: nothing installed" }

    # The newest libs in the index (columns: product, version, target, path).
    $libs = $null; $best = -1
    foreach ($line in (Get-Content $index)) {
      $c = $line -split "`t"
      if ($c.Count -ge 4 -and $c[0] -eq 'libs' -and $c[1] -match '^(\d+)\.(\d+)\.(\d+)') {
        $k = [long]$Matches[1] * 1000000 + [long]$Matches[2] * 1000 + [long]$Matches[3]
        if ($k -ge $best) { $best = $k; $libs = $c[3] }
      }
    }
    if (-not $libs) { Fail 'the index has no standard libraries (libs)' }
    $libsName = $libs.Substring($libs.LastIndexOf('/') + 1)
    Say "downloading the standard libraries ($($libsName -replace '\.tar\.gz$', ''))"
    Get-Release $libs.Substring(0, $libs.LastIndexOf('/')) $libsName

    & tar.exe -xzf $archive -C $tmp
    if ($LASTEXITCODE -ne 0) { Fail "could not unpack $file" }
    $omni = Join-Path $tmp "ridgun-$version\bin\omni.exe"
    if (-not (Test-Path $omni)) { Fail "this release has no omni: see $base/download" }
    $env:OMNI_DOWNLOADS_MIRROR = $tmp
    & $omni setup $target
    if ($LASTEXITCODE -ne 0) { Fail 'omni setup failed: nothing more was installed' }
  } finally {
    if ($hadMirror) { $env:OMNI_DOWNLOADS_MIRROR = $oldMirror } else { Remove-Item Env:OMNI_DOWNLOADS_MIRROR -ErrorAction SilentlyContinue }
    Remove-Item -Recurse -Force -Path $tmp -ErrorAction SilentlyContinue
  }

  $dest = Join-Path $env:USERPROFILE '.local\bin'
  if (($env:Path -split ';') -contains $dest) {
    & (Join-Path $dest 'ridgunc.exe') --version
  } else {
    Say "add $dest to your PATH, then open a new terminal:"
    Write-Host "  [Environment]::SetEnvironmentVariable('Path', '$dest;' + [Environment]::GetEnvironmentVariable('Path', 'User'), 'User')"
  }
  Say "add a library to a project with: omni install <library>; install a package's programs with: omni install -g <package> (see $base/packages)"
}