# SWAT+ Toolbox installer / updater for Windows (per user, no administrator rights).
#
#   irm https://install.swat.tamu.edu/spt.ps1 | iex
#
# Downloads the SWAT+ Toolbox setup for this computer (x64, or ARM64 for Windows
# on Arm) from the download mirror, checks its SHA-256 and runs it silently. The
# Toolbox goes to %USERPROFILE%\SWATPlus\SWATPlusToolbox, where SWAT+ Editor looks
# for it, and keeps itself up to date from then on. Re-running this updates the
# Toolbox when the mirror has a newer version and leaves it alone otherwise;
# -Force installs the mirror's version even when it is the one installed.
#
# With options:
#
#   & ([scriptblock]::Create((irm https://install.swat.tamu.edu/spt.ps1))) -Check
#
#   -Check       only check the requirements; install nothing. Throws when one is
#                not met, returns normally when all are.
#   -Force       install even when the installed version matches the mirror's,
#                to replace a build with a rebuild of the same version
#   -Uninstall   remove the Toolbox
#
# Windows PowerShell 5.1 or PowerShell 7. Errors are thrown, never `exit`, which
# would close the window the command was pasted into.
param([switch]$Check, [switch]$Force, [switch]$Uninstall)

& {
$ErrorActionPreference = 'Stop'
$ProgressPreference = 'SilentlyContinue'   # Invoke-WebRequest is many times slower with it
[Net.ServicePointManager]::SecurityProtocol = [Net.ServicePointManager]::SecurityProtocol -bor [Net.SecurityProtocolType]::Tls12

# Download mirrors, tried in order.
$Bases = @(
    'https://install.swat.tamu.edu/downloads'
    'https://install.swatplus.link/downloads'
)
$Feed = 'sptoolbox/windows'
$UninstallRoot = 'HKCU:\Software\Microsoft\Windows\CurrentVersion\Uninstall'
# the uninstall entry Velopack writes for the Toolbox
$OwnKey = "$UninstallRoot\celray.SWATPlusToolbox"

function Say([string]$m)  { Write-Host '==> ' -ForegroundColor Cyan -NoNewline; Write-Host $m }
function Warn([string]$m) { Write-Host '!!  ' -ForegroundColor Yellow -NoNewline; Write-Host $m }

# A mirror can answer a missing file with a 200 and an HTML page, so every
# download is checked for what it should be before it is used.
function Test-Download([string]$kind, [string]$file) {
    $head = [byte[]]::new(16)
    $fs = [IO.File]::OpenRead($file)
    try { $n = $fs.Read($head, 0, 16) } finally { $fs.Close() }
    switch ($kind) {
        'exe'     { return $n -ge 2 -and $head[0] -eq 0x4D -and $head[1] -eq 0x5A }
        'sha256'  { return (Get-Content -Raw $file) -match '^[0-9a-fA-F]{64}' }
        'version' { return (Get-Content -Raw $file) -match '^v?\d+\.\d+' }
    }
    return $false
}

function Get-FromMirror([string]$rel, [string]$out, [string]$kind) {
    foreach ($base in $Bases) {
        try { Invoke-WebRequest -UseBasicParsing -Uri "$base/$rel" -OutFile $out -TimeoutSec 900 } catch { continue }
        if (Test-Download $kind $out) { return $true }
    }
    return $false
}

# The Toolbox installed by Velopack, with the version of its current\ folder.
# The Toolbox updates itself, and current\sq.version follows those updates; the
# registry entry is the fallback.
function Get-InstalledToolbox {
    $e = Get-ItemProperty $OwnKey -ErrorAction SilentlyContinue
    if (-not $e) { return }
    $version = $e.DisplayVersion
    $channel = ''
    $sq = Join-Path "$($e.InstallLocation)" 'current\sq.version'
    if ($e.InstallLocation -and (Test-Path $sq)) {
        try {
            $meta = ([xml](Get-Content -Raw $sq)).package.metadata
            if ($meta.version) { $version = $meta.version }
            $channel = "$($meta.channel)"
        } catch { }
    }
    [pscustomobject]@{ Version = $version; Channel = $channel; Location = $e.InstallLocation; Entry = $e }
}

# Toolbox uninstall entries from other installers (an Inno Setup "SWAT+ Toolbox
# 4.0.1"). When one points at the same folder, its uninstaller deletes files the
# Velopack install uses, swatplusToolboX.exe among them.
function Get-OtherInstall {
    if (-not (Test-Path $UninstallRoot)) { return }
    Get-ChildItem $UninstallRoot | Where-Object { $_.PSChildName -ne 'celray.SWATPlusToolbox' } |
        ForEach-Object { Get-ItemProperty $_.PSPath } |
        Where-Object { "$($_.DisplayName)" -like 'SWAT+ Toolbox*' }
}

if ($Uninstall) {
    $t = Get-InstalledToolbox
    if (-not $t) { Warn 'The SWAT+ Toolbox is not installed.'; return }
    if (Get-Process -Name 'swatplusToolboX' -ErrorAction SilentlyContinue) { throw 'The SWAT+ Toolbox is running. Close it, then run this again.' }
    $update = Join-Path $t.Location 'Update.exe'
    if (-not (Test-Path $update)) { throw "The Toolbox's uninstaller is missing: $update" }
    Say "Removing the SWAT+ Toolbox $($t.Version)"
    $p = Start-Process -FilePath $update -ArgumentList '--uninstall', '--silent' -Wait -PassThru
    if ($p.ExitCode -ne 0) { throw "The Toolbox's uninstaller failed (exit code $($p.ExitCode))." }
    if (Test-Path $OwnKey) { throw 'The uninstaller finished, but Windows still lists the SWAT+ Toolbox as installed.' }
    Say 'Done.'
    return
}

$tmp = Join-Path ([IO.Path]::GetTempPath()) ('swatplus-' + [guid]::NewGuid().ToString('N'))
New-Item -ItemType Directory -Path $tmp | Out-Null
try {
    # The machine's architecture from the system environment: a PowerShell running
    # under emulation reports the emulated one in its environment.
    $native = (Get-ItemProperty 'HKLM:\SYSTEM\CurrentControlSet\Control\Session Manager\Environment').PROCESSOR_ARCHITECTURE
    $rid = switch ($native) { 'AMD64' { 'win-x64' } 'ARM64' { 'win-arm64' } default { '' } }
    Say "SWAT+ Toolbox installer (Windows, $native)"

    # --- requirements: Windows 10 or newer on x64 or ARM64, and a setup on a mirror
    if ([Environment]::OSVersion.Version.Major -lt 10) { throw 'The SWAT+ Toolbox needs Windows 10 or newer.' }
    if (-not $rid) { throw "The SWAT+ Toolbox is built for x64 and ARM64 Windows; this computer is $native." }
    $SetupName = "SWATPlusToolbox-$rid-Setup.exe"
    $shaFile = Join-Path $tmp 'setup.sha256'
    if (-not (Get-FromMirror "$Feed/$SetupName.sha256" $shaFile 'sha256')) { throw "Could not find $SetupName on any mirror." }
    $installed = Get-InstalledToolbox
    foreach ($o in @(Get-OtherInstall)) {
        $same = $installed -and $o.InstallLocation -and ($o.InstallLocation.TrimEnd('\') -eq "$($installed.Location)".TrimEnd('\'))
        $where = if ($same) { 'the same folder' } else { $o.InstallLocation }
        Warn "$($o.DisplayName) from another installer is registered in $where. Its uninstaller deletes files the Toolbox installed here uses; remove '$($o.DisplayName)' in Settings > Apps before installing to avoid this."
    }
    if ($Check) {
        Say 'SWAT+ Toolbox requirements met.'
        return
    }

    # --- install or update
    $verFile = Join-Path $tmp 'version.txt'
    if (-not (Get-FromMirror "$Feed/version.txt" $verFile 'version')) { throw 'Could not read the Toolbox version from any mirror.' }
    $version = (Get-Content -Raw $verFile).Trim()

    if ($installed -and $installed.Version -eq $version -and -not $Force) {
        $ch = if ($installed.Channel) { ", channel $($installed.Channel)" } else { '' }
        Say "The SWAT+ Toolbox $version is up to date$ch. Run with -Force to reinstall it."
        return
    }
    if (Get-Process -Name 'swatplusToolboX' -ErrorAction SilentlyContinue) {
        throw 'The SWAT+ Toolbox is running. Close it, then run this again.'
    }
    $want = ((Get-Content -Raw $shaFile) -split '\s+')[0].ToLower()
    $from = if ($installed -and $installed.Version -ne $version) { "$($installed.Version) -> " } else { '' }
    $again = if ($installed -and $installed.Version -eq $version) { ' to reinstall it' } else { '' }
    Say "Downloading the SWAT+ Toolbox $from$version ($rid)$again"
    $setup = Join-Path $tmp $SetupName
    if (-not (Get-FromMirror "$Feed/$SetupName" $setup 'exe')) { throw 'Could not download the Toolbox setup from any mirror.' }
    if ((Get-FileHash $setup -Algorithm SHA256).Hash.ToLower() -ne $want) { throw "Checksum mismatch for $SetupName." }
    Say 'Checksum OK; installing (this unpacks a self-contained .NET app and may take a minute)'
    $p = Start-Process -FilePath $setup -ArgumentList '/S' -Wait -PassThru
    if ($p.ExitCode -ne 0) { throw "The Toolbox setup failed (exit code $($p.ExitCode)). Its log is %TEMP%\spt-velopack-setup.log." }
    $now = Get-InstalledToolbox
    if (-not $now -or $now.Version -ne $version) { throw "The Toolbox setup finished, but Windows does not list the SWAT+ Toolbox $version as installed." }
    if (-not (Test-Path (Join-Path $now.Location 'swatplusToolboX.exe'))) { throw "The Toolbox setup finished, but $($now.Location)\swatplusToolboX.exe is missing." }
    Say "Installed the SWAT+ Toolbox $version -> $($now.Location)"
} finally {
    Remove-Item -Recurse -Force $tmp -ErrorAction SilentlyContinue
}
}