# Install or update CST-Agent on Windows from a Gitea release.
#
#   irm https://git.whcself.xyz/WHC/CST-agent/raw/branch/main/scripts/install_windows.ps1 | iex
#   powershell -ExecutionPolicy Bypass -File install_windows.ps1 [-Version 0.6.0] [-Prefix DIR] [-Zip FILE] [-NoPath]
#
# Installs into %LOCALAPPDATA%\Programs\cst-agent (no admin rights needed),
# adds it to the user PATH and leaves cst-agent-update.cmd beside the exe,
# which reruns this script for that folder. Environment overrides:
# CST_VERSION, CST_PREFIX, CST_GITEA (server URL), CST_REPO (owner/name).
# Needs Windows 10 1903+ / Server 2022+ (UTF-8 process code page).
# Keep this file ASCII: Windows PowerShell 5.1 reads BOM-less scripts in the
# ANSI code page.
param(
  [string]$Version = $env:CST_VERSION,
  [string]$Prefix = $env:CST_PREFIX,
  [string]$Zip = "",
  [switch]$NoPath
)
$ErrorActionPreference = "Stop"
$ProgressPreference = "SilentlyContinue"
[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12

$Server = if ($env:CST_GITEA) { $env:CST_GITEA.TrimEnd("/") } else { "https://git.whcself.xyz" }
$Repo = if ($env:CST_REPO) { $env:CST_REPO } else { "WHC/CST-agent" }
if (-not $Prefix) { $Prefix = Join-Path $env:LOCALAPPDATA "Programs\cst-agent" }
$Prefix = [IO.Path]::GetFullPath($Prefix)

$build = [Environment]::OSVersion.Version.Build
if ($build -lt 18362) {
  throw "CST-Agent needs Windows 10 1903 (build 18362) or newer; this is build $build."
}

$work = Join-Path ([IO.Path]::GetTempPath()) ("cst-agent-install-" + [Guid]::NewGuid().ToString("N"))
New-Item -ItemType Directory -Force $work | Out-Null
try {
  if (-not $Zip) {
    $api = "$Server/api/v1/repos/$Repo/releases"
    $url = if (-not $Version -or $Version -eq "latest") { "$api/latest" } else { "$api/tags/v$($Version.TrimStart('v'))" }
    Write-Host "==> $url"
    try {
      $rel = Invoke-RestMethod -Uri $url -UseBasicParsing
    } catch {
      throw "no release found at $url ($($_.Exception.Message))"
    }
    $asset = $rel.assets | Where-Object { $_.name -like "*-windows-x86_64.zip" } | Select-Object -First 1
    if (-not $asset) { throw "release $($rel.tag_name) has no *-windows-x86_64.zip" }
    $Zip = Join-Path $work $asset.name
    Write-Host "==> download $($asset.name) ($($rel.tag_name))"
    Invoke-WebRequest -Uri $asset.browser_download_url -OutFile $Zip -UseBasicParsing
    $sum = $rel.assets | Where-Object { $_.name -eq "$($asset.name).sha256" } | Select-Object -First 1
    if ($sum) {
      $sumFile = Join-Path $work $sum.name
      Invoke-WebRequest -Uri $sum.browser_download_url -OutFile $sumFile -UseBasicParsing
      $want = ((Get-Content $sumFile -Raw).Trim() -split "\s+")[0].ToLower()
      $got = (Get-FileHash -Algorithm SHA256 $Zip).Hash.ToLower()
      if ($want -ne $got) { throw "sha256 mismatch for $($asset.name): expected $want, got $got" }
      Write-Host "==> sha256 ok"
    }
  }

  Expand-Archive -Path $Zip -DestinationPath $work -Force
  $src = Join-Path $work "windows-x86_64"
  if (-not (Test-Path (Join-Path $src "cst-agent.exe"))) { throw "$Zip has no windows-x86_64\cst-agent.exe" }

  New-Item -ItemType Directory -Force $Prefix | Out-Null
  # A running exe cannot be overwritten but can be renamed out of the way.
  foreach ($name in @("cst-agent.exe", "busybox.exe")) {
    $dst = Join-Path $Prefix $name
    $old = "$dst.old"
    if (Test-Path $old) { Remove-Item -Force $old -ErrorAction SilentlyContinue }
    if (Test-Path $dst) {
      try { Remove-Item -Force $dst } catch { Rename-Item -Force $dst "$name.old" }
    }
  }
  Copy-Item -Force -Recurse (Join-Path $src "*") $Prefix

  $update = Join-Path $Prefix "cst-agent-update.cmd"
  if (-not (Test-Path $update)) {
    Set-Content -Encoding Ascii -Path $update -Value @(
      "@echo off",
      "rem Update CST-Agent in this folder from the latest release.",
      "powershell -NoProfile -ExecutionPolicy Bypass -File `"%~dp0install_windows.ps1`" -Prefix `"%~dp0.`" %*"
    )
  }
  if (-not (Test-Path (Join-Path $Prefix "install_windows.ps1")) -and $PSCommandPath) {
    Copy-Item -Force $PSCommandPath (Join-Path $Prefix "install_windows.ps1")
  }

  if (-not $NoPath) {
    $userPath = [Environment]::GetEnvironmentVariable("Path", "User")
    $parts = @($userPath -split ";" | Where-Object { $_ })
    if (-not ($parts | Where-Object { $_.TrimEnd("\") -ieq $Prefix.TrimEnd("\") })) {
      [Environment]::SetEnvironmentVariable("Path", (($parts + $Prefix) -join ";"), "User")
      Write-Host "==> added $Prefix to the user PATH (open a new terminal to use it)"
    }
    if (-not (($env:Path -split ";") | Where-Object { $_.TrimEnd("\") -ieq $Prefix.TrimEnd("\") })) {
      $env:Path = "$env:Path;$Prefix"
    }
  }

  $ver = (& (Join-Path $Prefix "cst-agent.exe") --version) 2>&1 | Select-Object -First 1
  Write-Host "==> installed $ver in $Prefix"
  Write-Host "Run 'cst-agent' inside a project folder; update later with 'cst-agent-update'."
} finally {
  Remove-Item -Recurse -Force $work -ErrorAction SilentlyContinue
}