<#
.SYNOPSIS
    JetScale installer / updater for Windows.

.DESCRIPTION
    Usage:
        irm https://jetscale.sh/install.ps1 | iex

    What it does:
        1. Detects your CPU architecture.
        2. Asks the server for the latest version + commit (latest.json).
        3. Compares it against the version you already have installed (if any).
        4. Downloads and installs only when the versions differ.

    Release artifacts are flat files named:
        jetscale.<os>.<arch>.<version>.<commit>
    served from the download base alongside latest.json, e.g.
        https://jetscale.sh/jetscale.windows.amd64.2026-06-28-abc1234.abc1234

    The script is split into small functions to keep it easy to maintain.
    Execution starts at the bottom in Install-Main.
#>

$ErrorActionPreference = "Stop"

###############################################################################
# Configuration
###############################################################################

# Binary name and where releases are hosted.
$AppName = "jetscale"
$DownloadBase = "https://jetscale.sh"

# Endpoint that returns JSON describing the latest release, e.g.
#   { "version": "2026-06-28-abc1234", "commit": "abc1234" }
$LatestJson = "$DownloadBase/latest.json"

# Where the binary is installed and the matching executable path.
$InstallDir = "$env:LOCALAPPDATA\Programs\$AppName"
$BinaryPath = Join-Path $InstallDir "$AppName.exe"

###############################################################################
# Output helpers
###############################################################################

# Write-Status prints a "==>" status line.
function Write-Status([string]$Message) {
    Write-Host "==> $Message"
}

###############################################################################
# Platform detection
###############################################################################

# Get-Arch maps the OS architecture onto the token used in release file names.
function Get-Arch {
    $arch = [System.Runtime.InteropServices.RuntimeInformation]::OSArchitecture
    switch ($arch) {
        "X64" { return "amd64" }
        "Arm64" { return "arm64" }
        default { throw "Unsupported architecture: $arch" }
    }
}

###############################################################################
# Version discovery
###############################################################################

# Normalize-Version strips a leading "v" and whitespace so that "v1.2.3" and
# "1.2.3" compare as equal.
function Normalize-Version([string]$Version) {
    if (-not $Version) { return "" }
    return ($Version.Trim() -replace '^v', '')
}

# Get-LatestRelease fetches latest.json and returns its parsed object with
# .version and .commit fields.
function Get-LatestRelease {
    $latest = Invoke-RestMethod $LatestJson
    if (-not $latest.version) {
        throw "Unable to determine the latest version from $LatestJson."
    }
    if (-not $latest.commit) {
        throw "Unable to determine the latest commit from $LatestJson."
    }
    return $latest
}

# Get-InstalledVersion returns the version of the installed binary, or $null
# if it is not present. The CLI prints its raw version string; we take the
# last token of the first line so it also works if the output is prefixed.
function Get-InstalledVersion {
    if (-not (Test-Path $BinaryPath)) { return $null }

    try {
        $raw = & $BinaryPath --version 2>$null
        if (-not $raw) { $raw = & $BinaryPath version 2>$null }
    }
    catch {
        return $null
    }

    if (-not $raw) { return $null }

    $line = ([string[]]$raw)[0]
    return ($line -split '\s+' | Where-Object { $_ })[-1]
}

###############################################################################
# Download + install
###############################################################################

# Install-Binary downloads the raw release binary for the given version and
# commit and installs it. Artifacts are single executables named
# jetscale.<os>.<arch>.<version>.<commit> (no archive), so there is nothing
# to extract.
function Install-Binary([string]$Version, [string]$Commit, [string]$Arch) {
    $file = "${AppName}.windows.${Arch}.${Version}.${Commit}"
    $url = "$DownloadBase/$file"

    # Use a fresh temp directory for the download.
    $temp = Join-Path $env:TEMP "$AppName-install"
    Remove-Item $temp -Recurse -Force -ErrorAction Ignore
    New-Item -ItemType Directory -Path $temp | Out-Null

    $downloaded = Join-Path $temp "$AppName.exe"

    Write-Status "Downloading $file..."
    Invoke-WebRequest $url -OutFile $downloaded

    Write-Status "Installing to $InstallDir"
    New-Item -ItemType Directory -Force -Path $InstallDir | Out-Null
    Copy-Item $downloaded $BinaryPath -Force

    Remove-Item $temp -Recurse -Force -ErrorAction Ignore
}

# Add-ToPath appends the install directory to the user's PATH if missing.
function Add-ToPath {
    $userPath = [Environment]::GetEnvironmentVariable("Path", "User")

    if ($userPath -notlike "*$InstallDir*") {
        [Environment]::SetEnvironmentVariable(
            "Path",
            "$userPath;$InstallDir",
            "User"
        )

        Write-Host ""
        Write-Host "Added $InstallDir to PATH."
        Write-Host "Restart your terminal."
    }
}

###############################################################################
# Entry point
###############################################################################

function Install-Main {
    Write-Status "Detecting platform..."
    $arch = Get-Arch

    Write-Status "Fetching latest release..."
    $latest = Get-LatestRelease
    Write-Status "Latest version:    $($latest.version)"

    # Skip the download entirely if the installed version already matches.
    $current = Get-InstalledVersion
    if ($current) {
        Write-Status "Installed version: $current"
        if ((Normalize-Version $current) -eq (Normalize-Version $latest.version)) {
            Write-Status "$AppName is already up to date."
            return
        }
        Write-Status "Updating $current -> $($latest.version)"
    }

    Install-Binary $latest.version $latest.commit $arch
    Add-ToPath

    Write-Host ""
    Write-Host "Installation complete!"
    Write-Host ""
    Write-Host "$AppName --version"
}

Install-Main