$bootFile = "boot.bin"
$gameFile = "game.bin"
$adfFile = "giochino.adf"

# Read Bootblock
$bootBytes = [System.IO.File]::ReadAllBytes($bootFile)
if ($bootBytes.Length -lt 1024) {
    $padding = New-Object byte[] (1024 - $bootBytes.Length)
    $bootBytes = $bootBytes + $padding
}
$bootBytes = [byte[]]$bootBytes

# Calculate Checksum
# Checksum is at offset 4 (4 bytes)
# Clear it first
$bootBytes[4] = 0
$bootBytes[5] = 0
$bootBytes[6] = 0
$bootBytes[7] = 0

$chk = [uint32]0
for ($i = 0; $i -lt 1024; $i += 4) {
    # Big Endian ULONG
    [uint32]$val = ([uint32]$bootBytes[$i] -shl 24) -bor ([uint32]$bootBytes[$i + 1] -shl 16) -bor ([uint32]$bootBytes[$i + 2] -shl 8) -bor [uint32]$bootBytes[$i + 3]
    
    # Add with carry handling
    [uint64]$temp = [uint64]$chk + [uint64]$val
    if ($temp -gt 4294967295) {
        $chk = [uint32](($temp -band 4294967295) + 1)
    }
    else {
        $chk = [uint32]$temp
    }
}

# NOT operation
$chk = $chk -bxor 4294967295

Write-Host "Checksum: $("0x{0:X}" -f $chk)"

# Write Checksum back (Big Endian)
$bootBytes[4] = ($chk -shr 24) -band 0xFF
$bootBytes[5] = ($chk -shr 16) -band 0xFF
$bootBytes[6] = ($chk -shr 8) -band 0xFF
$bootBytes[7] = $chk -band 0xFF

# Read Game
$gameBytes = [System.IO.File]::ReadAllBytes($gameFile)
Write-Host "Game Size: $($gameBytes.Length) bytes"

# Create ADF (880KB)
$adfSize = 880 * 1024
$adfBytes = New-Object byte[] $adfSize

# Copy Bootblock
[System.Array]::Copy($bootBytes, 0, $adfBytes, 0, 1024)

# Copy Game (Offset 1024)
[System.Array]::Copy($gameBytes, 0, $adfBytes, 1024, $gameBytes.Length)

# Save ADF
[System.IO.File]::WriteAllBytes($adfFile, $adfBytes)
Write-Host "Created $adfFile"