michaelschiemer/tests/debug/test-qr-before-after-mask.php

<?php

declare(strict_types=1);

require_once __DIR__ . '/../../vendor/autoload.php';

use App\Framework\QrCode\ValueObjects\QrCodeMatrix;
use App\Framework\QrCode\ValueObjects\QrCodeVersion;
use App\Framework\QrCode\ValueObjects\Module;
use App\Framework\QrCode\ValueObjects\ModulePosition;
use App\Framework\QrCode\Structure\FinderPattern;
use App\Framework\QrCode\Structure\TimingPattern;
use App\Framework\QrCode\Structure\AlignmentPattern;
use App\Framework\QrCode\Structure\FormatInformation;
use App\Framework\QrCode\ErrorCorrection\ReedSolomonEncoder;
use App\Framework\QrCode\Masking\MaskEvaluator;
use App\Framework\QrCode\ValueObjects\ErrorCorrectionLevel;

echo "=== Before/After Masking Comparison ===\n\n";

$data = "HELLO";
$version = QrCodeVersion::fromNumber(1);
$errorLevel = ErrorCorrectionLevel::M;

// Build matrix up to data placement (before masking)
$matrix = QrCodeMatrix::create($version);
$matrix = FinderPattern::apply($matrix);
$matrix = FinderPattern::applySeparators($matrix);
$matrix = AlignmentPattern::apply($matrix);
$matrix = TimingPattern::apply($matrix);

// Add dark module
$darkModuleRow = 4 * 1 + 9;
$matrix = $matrix->setModuleAt($darkModuleRow, 8, Module::dark());

// Encode data
$bits = '0100'; // Mode
$bits .= str_pad(decbin(strlen($data)), 8, '0', STR_PAD_LEFT); // Count

for ($i = 0; $i < strlen($data); $i++) {
    $bits .= str_pad(decbin(ord($data[$i])), 8, '0', STR_PAD_LEFT);
}

// Add padding
$ecInfo = ReedSolomonEncoder::getECInfo(1, 'M');
$requiredBits = $ecInfo['dataCodewords'] * 8;
$terminatorLength = min(4, max(0, $requiredBits - strlen($bits)));
$bits .= str_repeat('0', $terminatorLength);

$remainder = strlen($bits) % 8;
if ($remainder !== 0) {
    $bits .= str_repeat('0', 8 - $remainder);
}

$padBytes = ['11101100', '00010001'];
$padIndex = 0;
while (strlen($bits) < $requiredBits) {
    $bits .= $padBytes[$padIndex % 2];
    $padIndex++;
}

// Convert to codewords
$dataCodewords = [];
for ($i = 0; $i < strlen($bits); $i += 8) {
    $byte = substr($bits, $i, 8);
    $dataCodewords[] = bindec($byte);
}

// Generate EC
$reedSolomon = new ReedSolomonEncoder();
$ecCodewords = $reedSolomon->encode($dataCodewords, $ecInfo['ecCodewords']);
$allCodewords = array_merge($dataCodewords, $ecCodewords);

// Place data
$size = 21;
$allBits = '';
foreach ($allCodewords as $codeword) {
    $allBits .= str_pad(decbin($codeword), 8, '0', STR_PAD_LEFT);
}

$bitIndex = 0;
for ($col = $size - 1; $col >= 1; $col -= 2) {
    if ($col === 6) {
        $col--;
    }

    $upward = ((int) (($size - 1 - $col) / 2) % 2) === 0;

    for ($i = 0; $i < $size; $i++) {
        $row = $upward ? ($size - 1 - $i) : $i;

        for ($c = 0; $c < 2; $c++) {
            $currentCol = $col - $c;
            $position = ModulePosition::at($row, $currentCol);

            // Skip function patterns and format info
            if ($row <= 8 && $currentCol <= 8) continue;
            if ($row <= 8 && $currentCol >= $size - 8) continue;
            if ($row >= $size - 8 && $currentCol <= 8) continue;
            if ($row === 6 || $currentCol === 6) continue;
            if ($row === 8 || $currentCol === 8) continue;

            if ($bitIndex < strlen($allBits)) {
                $bit = $allBits[$bitIndex];
                $module = ($bit === '1') ? Module::dark() : Module::light();
                $matrix = $matrix->setModule($position, $module);
                $bitIndex++;
            }
        }
    }
}

echo "=== BEFORE Masking ===\n";
echo "First 64 data bits: " . substr($allBits, 0, 64) . "\n";
echo "Decoded bytes:\n";
for ($i = 0; $i < 8; $i++) {
    $byte = substr($allBits, $i * 8, 8);
    $decimal = bindec($byte);
    $char = $decimal >= 32 && $decimal < 127 ? chr($decimal) : '.';
    echo "  Byte " . ($i + 1) . ": {$byte} = {$decimal} ('{$char}')\n";
}

echo "\n=== Expected Encoding ===\n";
echo "Mode (Byte):  0100\n";
echo "Count (5):    00000101\n";
echo "H (72):       01001000\n";
echo "E (69):       01000101\n";
echo "L (76):       01001100\n";
echo "L (76):       01001100\n";
echo "O (79):       01001111\n";

$expectedStart = '0100' . '00000101' . '01001000' . '01000101' . '01001100' . '01001100' . '01001111';
$actualStart = substr($allBits, 0, strlen($expectedStart));

echo "\nComparison:\n";
echo "Expected: {$expectedStart}\n";
echo "Actual:   {$actualStart}\n";
echo ($expectedStart === $actualStart) ? "✅ MATCH!\n" : "❌ MISMATCH!\n";

// Now apply mask
echo "\n=== Applying Mask ===\n";
$maskEvaluator = new MaskEvaluator();
$bestMask = $maskEvaluator->selectBestMask($matrix);
echo "Selected mask pattern: {$bestMask->value}\n";

$maskedMatrix = $maskEvaluator->applyMask($matrix, $bestMask);

// Add format info
$maskedMatrix = FormatInformation::apply($maskedMatrix, $errorLevel, $bestMask->value);

echo "\n=== AFTER Masking ===\n";
// Extract masked bits
$maskedBits = '';
$bitIdx = 0;

for ($col = $size - 1; $col >= 1; $col -= 2) {
    if ($col === 6) {
        $col--;
    }

    $upward = ((int) (($size - 1 - $col) / 2) % 2) === 0;

    for ($i = 0; $i < $size; $i++) {
        $row = $upward ? ($size - 1 - $i) : $i;

        for ($c = 0; $c < 2; $c++) {
            $currentCol = $col - $c;

            if ($row <= 8 && $currentCol <= 8) continue;
            if ($row <= 8 && $currentCol >= $size - 8) continue;
            if ($row >= $size - 8 && $currentCol <= 8) continue;
            if ($row === 6 || $currentCol === 6) continue;
            if ($row === 8 || $currentCol === 8) continue;

            if ($bitIdx < 64) {
                $maskedBits .= $maskedMatrix->getModuleAt($row, $currentCol)->isDark() ? '1' : '0';
                $bitIdx++;
            }
        }
    }
}

echo "First 64 masked bits: {$maskedBits}\n";
echo "Decoded bytes:\n";
for ($i = 0; $i < 8; $i++) {
    $byte = substr($maskedBits, $i * 8, 8);
    $decimal = bindec($byte);
    $char = $decimal >= 32 && $decimal < 127 ? chr($decimal) : '.';
    echo "  Byte " . ($i + 1) . ": {$byte} = {$decimal} ('{$char}')\n";
}