<?php

$width  = 120;
$height = 60;
$PASSWORD = "Ky/6lG3kbA>/TM?C(V@S";

// --- Helpers ---
function setPixel(int $x, int $y, int $width, &$bitmap) {
    if ($x < 0 || $y < 0) return;
    $index = $y * $width + $x;
    $byteIdx = intdiv($index, 8);
    $bitPos  = $index % 8;
    $bitmap[$byteIdx] |= (1 << $bitPos);
}

function createImageBitmap(array $pixelsOn, int $width, int $height): array {
    $totalBits = $width * $height;
    $bitmapSize = intdiv($totalBits + 7, 8);
    $bitmap = array_fill(0, $bitmapSize, 0);
    foreach ($pixelsOn as [$x, $y]) {
        setPixel($x, $y, $width, $bitmap);
    }
    return $bitmap;
}

function packBitmap(array $bitmap): string {
    return implode('', array_map(fn($b) => pack('C', $b), $bitmap));
}

function createImageObject(int $width, int $height, array $bitmap, int $xOffset = 0, int $yOffset = 0): string {
    $payload  = pack('C', $width);
    $payload .= pack('C', $height);
    $payload .= packBitmap($bitmap);
    $header = pack('C*', 0x01, $xOffset, $yOffset); // Type = 1
    return $header . $payload;
}

function createScrollObject(int $xOffset, int $yOffset, int $width, int $height, int $contentWidth, array $bitmap, int $speed = 0, bool $directionRight = false, bool $wrap = true): string {
    $CW = pack('v', $contentWidth);
    $UF = (($wrap ? 1 : 0) << 7) | (($directionRight ? 1 : 0) << 6) | ($speed & 0x3F);
    $payload  = pack('C', $width);
    $payload .= pack('C', $height);
    $payload .= $CW;
    $payload .= pack('C', $UF);
    $payload .= packBitmap($bitmap);
    $header = pack('C*', 0x03, $xOffset, $yOffset);
    return $header . $payload;
}

function createBlob(array $objects, string $fileName) {
    $blob = '';
    $blob .= pack('C*', 0x42, 0x4E, 0x17, 0xEE);
    $blob .= pack('C', count($objects));
    foreach ($objects as $obj) {
        $blob .= $obj;
    }
    file_put_contents($fileName, $blob);
    echo "Blob written to {$fileName} (" . strlen($blob) . " bytes)\n";
}

// --- Validation ---
if (!isset($_POST['password'])) die("password missing.");
if (htmlspecialchars($_POST['password']) !== htmlspecialchars($PASSWORD)) die("wrong password.");

// --- Determine mode ---
$mode = $_POST['mode'] ?? 'image';
$objects = [];
$fileName = 'out/' . $_POST['fileName'] . '.bin' ?? 'out/' .'output.bin';

mkdir('out/');
// --- Handle Image Mode ---
if ($mode === 'image') {
    $pixelsOn = json_decode($_POST['array_output'] ?? '[]', true);
    if (!is_array($pixelsOn)) die("invalid or missing array_output for image mode.");
    $bitmap = createImageBitmap($pixelsOn, $width, $height);
    $objects[] = createImageObject($width, $height, $bitmap, 0, 0);
}

// --- Handle Text Mode (scrolling text) ---
elseif ($mode === 'text') {
    $scrolls = json_decode($_POST['scrolls'] ?? '[]', true);
    if (!is_array($scrolls) || empty($scrolls)) die("invalid or missing scrolls for text mode.");

    foreach ($scrolls as $scroll) {
        $pixelsOn = $scroll['pixelsOn'] ?? [];
        $bitmap = createImageBitmap($pixelsOn, $scroll['contentWidth'], $scroll['height']);
        $objects[] = createScrollObject(
            $scroll['x'] ?? 0,
            $scroll['y'] ?? 0,
            $scroll['width'] ?? $width,
            $scroll['height'] ?? 8,
            $scroll['contentWidth'] ?? 60,
            $bitmap,
            $scroll['speed'] ?? 0,
            $scroll['directionRight'] ?? false,
            $scroll['wrap'] ?? true
        );
    }
}

else {
    die("unknown mode: {$mode}");
}

createBlob($objects, $fileName);