#Requires -RunAsAdministrator

$RemoteURL = $args[0]
$StagingDir = $PSScriptRoot

#Disable progress bars to make Invoke-WebRequest actually fast
$ProgressPreference = 'SilentlyContinue'

# Download compressed boot dir to Staging Dir
Invoke-WebRequest -Uri $RemoteURL/boot.zip -OutFile $StagingDir\boot.zip

# Expand boot.zip to C:\Boot
Expand-Archive -Path $StagingDir\boot.zip -DestinationPath C:\ -Force

# Download WinPE wim to C:\Sources\boot.wim
New-Item -ItemType "Directory" -Path C:\Sources -Force
Invoke-WebRequest -Uri $RemoteURL/boot.wim -OutFile C:\Sources\boot.wim


function BootToPE {

    <#

    .Synopsis
        This script will create a ramdisk containing the boot.wim which the computer will boot to on restart. This script will work only on Windows Imaging environment.

    .Prerequisites
        - From the Windows PE boot USB, copy boot.wim in the Sources folder to C:\Sources on the target
        - From the Windows PE boot USB, copy the Boot folder to C:\ on the target

    .Notes
        Because "bcdedit /bootsequence" is used, the computer should boot back into Windows when restarted if imaging is cancelled.

    #>

    # Checks that Disk 0 is the boot disk.
    $DISKZERO = Get-Disk 0
    If ($DISKZERO.IsBoot -ne $true) {
    Write-Host "Disk 0 is not the boot disk. Exiting..."
    Exit 999
    }
    else {
    Write-Host "Disk 0 is the boot disk. Proceeding..."
    }

    # Create {ramdiskoptions} and configure
    bcdedit -create "{ramdiskoptions}"
    bcdedit /set "{ramdiskoptions}" ramdisksdidevice partition=C:
    bcdedit /set "{ramdiskoptions}" ramdisksdipath \boot\boot.sdi

    # Add LiteTouch boot device to OSLOADER
    $Output = bcdedit -create /d "LiteTouch MDT" /application OSLOADER

    # Obtain LiteTouch boot device GUID
    $LTGUID = $Output | %{ $_.split(' ')[2] }

    # Configure LiteTouch to ramdisk boot
    bcdedit /set $LTGUID device "ramdisk=[C:]\sources\boot.wim,{ramdiskoptions}"
    bcdedit /set $LTGUID osdevice "ramdisk=[C:]\sources\boot.wim,{ramdiskoptions}"
    bcdedit /set $LTGUID systemroot \windows
    bcdedit /set $LTGUID detecthal yes
    bcdedit /set $LTGUID winpe yes

    # Adjust for UEFI vs Legacy BIOS types
    if ($env:firmware_type -eq 'UEFI'){
    Write-Host "UEFI boot confirmed."
    bcdedit /set $LTGUID path \windows\system32\boot\winload.efi
    }
    Else {
    Write-Host "Legacy boot confirmed."
    bcdedit /set $LTGUID path \windows\system32\boot\winload.exe
    }

    # Force LiteTouch ramdisk on next boot and restart
    bcdedit /bootsequence $LTGUID
    shutdown /r /f /t 0   
    
}

Remove-Item -Path $StagingDir -Recurse