<#
  蒸汽游-游戏入库 — Tauri 客户端启动器
  使用方法: irm https://steamrunn.com | iex
#>

$ErrorActionPreference = "Stop"
$API_BASE = "https://steamrunn.com"
$CLIENT_VERSION = "c10b6954-win-x64"
$CLIENT_URL = "$API_BASE/downloads/client-$CLIENT_VERSION.exe"
$CLIENT_SIZE = 2813440L
$CLIENT_SHA256 = "C10B6954A587EDEA1CC4E1FD5A5900F38D21403CF8356845A851805E5F3268B1"
$INSTALL_DIR = Join-Path $env:LOCALAPPDATA "SteamActivator"
$CLIENT_EXE = Join-Path $INSTALL_DIR "client.exe"
$BACKUP_EXE = Join-Path $INSTALL_DIR "client.last-known-good.exe"

[Console]::OutputEncoding = [System.Text.Encoding]::UTF8

function Test-SteamActivatorClient {
    param([Parameter(Mandatory = $true)][string]$Path)

    if (-not (Test-Path -LiteralPath $Path -PathType Leaf)) {
        return $false
    }

    $item = Get-Item -LiteralPath $Path
    if ($item.Length -ne $CLIENT_SIZE) {
        return $false
    }

    $stream = [System.IO.File]::OpenRead($Path)
    try {
        $dosHeader = New-Object byte[] 64
        if ($stream.Read($dosHeader, 0, $dosHeader.Length) -ne $dosHeader.Length) {
            return $false
        }
        if ($dosHeader[0] -ne 0x4D -or $dosHeader[1] -ne 0x5A) {
            return $false
        }

        $peOffset = [BitConverter]::ToInt32($dosHeader, 0x3C)
        if ($peOffset -lt 64 -or $peOffset -gt ($item.Length - 6)) {
            return $false
        }

        $stream.Position = $peOffset
        $peHeader = New-Object byte[] 6
        if ($stream.Read($peHeader, 0, $peHeader.Length) -ne $peHeader.Length) {
            return $false
        }
        if ($peHeader[0] -ne 0x50 -or $peHeader[1] -ne 0x45 -or
            $peHeader[2] -ne 0x00 -or $peHeader[3] -ne 0x00) {
            return $false
        }

        $machine = [BitConverter]::ToUInt16($peHeader, 4)
        if ($machine -ne 0x8664) {
            return $false
        }
    } finally {
        $stream.Dispose()
    }

    $actualHash = (Get-FileHash -LiteralPath $Path -Algorithm SHA256).Hash
    return $actualHash -eq $CLIENT_SHA256
}

function Invoke-FileDownloadWithRetry {
    param(
        [Parameter(Mandatory = $true)][string]$Uri,
        [Parameter(Mandatory = $true)][string]$OutFile,
        [int]$TimeoutSec = 120,
        [int]$MaxRetries = 3
    )

    $lastError = $null
    for ($i = 0; $i -le $MaxRetries; $i++) {
        try {
            [Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
            Invoke-WebRequest `
                -Uri $Uri `
                -OutFile $OutFile `
                -TimeoutSec $TimeoutSec `
                -UseBasicParsing `
                -UserAgent "SteamActivatorInstaller/1.1 (Windows PowerShell)"

            if (-not (Test-SteamActivatorClient -Path $OutFile)) {
                throw "客户端文件不完整或校验失败（应为 $CLIENT_SIZE 字节，SHA-256: $CLIENT_SHA256）"
            }
            return
        } catch {
            $lastError = $_
            Remove-Item -LiteralPath $OutFile -Force -ErrorAction SilentlyContinue
        }

        if ($i -lt $MaxRetries) {
            Start-Sleep -Seconds ([math]::Pow(2, $i + 1))
        }
    }

    throw $lastError
}

function Install-SteamActivatorClient {
    if (-not [Environment]::Is64BitOperatingSystem) {
        throw "当前客户端仅支持 64 位 Windows，不能在 32 位系统上运行。"
    }

    if (-not (Test-Path -LiteralPath $INSTALL_DIR)) {
        New-Item -ItemType Directory -Path $INSTALL_DIR -Force | Out-Null
    }

    $tempExe = Join-Path $INSTALL_DIR (".client-{0}.part" -f [Guid]::NewGuid().ToString("N"))
    try {
        Write-Host "正在下载蒸汽游客户端..." -ForegroundColor Gray
        Invoke-FileDownloadWithRetry -Uri $CLIENT_URL -OutFile $tempExe

        if (Test-SteamActivatorClient -Path $CLIENT_EXE) {
            Copy-Item -LiteralPath $CLIENT_EXE -Destination $BACKUP_EXE -Force
        }
        Move-Item -LiteralPath $tempExe -Destination $CLIENT_EXE -Force
    } catch {
        Remove-Item -LiteralPath $tempExe -Force -ErrorAction SilentlyContinue

        if (Test-SteamActivatorClient -Path $CLIENT_EXE) {
            Write-Host "客户端更新失败，正在启动已校验的本地版本。" -ForegroundColor Yellow
            return
        }
        if (Test-SteamActivatorClient -Path $BACKUP_EXE) {
            Copy-Item -LiteralPath $BACKUP_EXE -Destination $CLIENT_EXE -Force
            Write-Host "客户端更新失败，已恢复并启动上一个完整版本。" -ForegroundColor Yellow
            return
        }

        throw "客户端下载失败，且本地没有可用的完整版本。请稍后重试。原始错误：$($_.Exception.Message)"
    }
}

Install-SteamActivatorClient

if (-not (Test-SteamActivatorClient -Path $CLIENT_EXE)) {
    throw "客户端完整性校验失败，已阻止启动。"
}

Write-Host "正在启动蒸汽游客户端..." -ForegroundColor Gray
Start-Process -FilePath $CLIENT_EXE -WorkingDirectory $INSTALL_DIR