# DragonMoonlight Pre-Installation Check Script
# Runs elevated before files are copied during installation

param()

$ErrorActionPreference = "Stop"

function Write-Info { Write-Host $args -ForegroundColor Cyan }
function Write-Success { Write-Host $args -ForegroundColor Green }
function Write-Warning { Write-Host $args -ForegroundColor Yellow }
function Write-Error { Write-Host $args -ForegroundColor Red }

try {
    Write-Info "=== DragonMoonlight Pre-Installation Checks ==="
    
    # Check if running elevated
    $isElevated = ([Security.Principal.WindowsPrincipal] [Security.Principal.WindowsIdentity]::GetCurrent()).IsInRole([Security.Principal.WindowsBuiltInRole] "Administrator")
    if (-not $isElevated) {
        Write-Error "This script must run elevated (as Administrator). Installation cannot proceed."
        [Windows.Forms.MessageBox]::Show(
            "DragonMoonlight installation failed.`r`nThis installer requires Administrator privileges.",
            "Installation Error",
            [Windows.Forms.MessageBoxButtons]::OK,
            [Windows.Forms.MessageBoxIcon]::Error
        )
        exit 1
    }
    Write-Success "✓ Running with elevated privileges"
    
    # Check Windows version
    $osVersion = [Environment]::OSVersion.Version
    $buildNumber = [int](Get-ItemProperty 'HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion' 'CurrentBuildNumber').CurrentBuildNumber
    
    Write-Info "Windows version: $($osVersion.Major).$($osVersion.Minor) Build $buildNumber"
    
    # Wintun requires Windows 10 2004 (Build 19041) or later
    if ($buildNumber -lt 19041) {
        Write-Error "This system does not meet the minimum requirements."
        Write-Error "DragonMoonlight requires Windows 10 (Build 19041/2004) or later."
        Write-Error "Current build: $buildNumber"
        
        [Windows.Forms.MessageBox]::Show(
            "DragonMoonlight requires Windows 10 (Build 2004) or later.`r`n`r`nYour system is running Build $buildNumber, which does not support the required Windows Filtering Platform features for Wintun.`r`n`r`nPlease update Windows and try again.",
            "Unsupported Windows Version",
            [Windows.Forms.MessageBoxButtons]::OK,
            [Windows.Forms.MessageBoxIcon]::Error
        )
        exit 1
    }
    
    Write-Success "✓ Windows version check passed (Build $buildNumber >= 19041)"
    
    # Warn about driver signature enforcement
    Write-Info "Checking driver signature enforcement status..."
    
    try {
        $signingLevel = (Get-ItemProperty 'HKLM:\SYSTEM\CurrentControlSet\Control\SecureBoot\State' 'UEFISecureBootEnabled' -ErrorAction SilentlyContinue).UEFISecureBootEnabled
        if ($signingLevel -eq 1) {
            Write-Warning "⚠ Secure Boot is enabled. Ensure that Wintun driver signing certificate is trusted."
        } else {
            Write-Success "✓ Secure Boot is disabled or not detected"
        }
    } catch {
        Write-Info "Could not determine Secure Boot status (this is normal on non-UEFI systems)"
    }
    
    # Log pre-install success to event log
    Write-Info "Logging pre-installation check to event log..."
    try {
        if (-not ([System.Diagnostics.EventLog]::SourceExists("DragonMoonlight"))) {
            New-EventLog -LogName Application -Source "DragonMoonlight" -ErrorAction SilentlyContinue
        }
        Write-EventLog -LogName Application -Source "DragonMoonlight" -EventId 1000 `
            -Message "DragonMoonlight pre-install check passed. Build: $buildNumber" -EntryType Information
        Write-Success "✓ Event log entry created"
    } catch {
        Write-Warning "Could not write to event log (non-critical): $_"
    }
    
    Write-Success "=== Pre-installation checks completed successfully ==="
    exit 0
}
catch {
    Write-Error "Pre-installation check failed: $_"
    [Windows.Forms.MessageBox]::Show(
        "Pre-installation check failed:`r`n`r`n$_",
        "Installation Error",
        [Windows.Forms.MessageBoxButtons]::OK,
        [Windows.Forms.MessageBoxIcon]::Error
    )
    exit 1
}