michaelschiemer/tests/debug/test-full-decode-correct.php

<?php

declare(strict_types=1);

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

use App\Framework\QrCode\QrCodeGenerator;
use App\Framework\QrCode\ValueObjects\ErrorCorrectionLevel;
use App\Framework\QrCode\ValueObjects\QrCodeConfig;
use App\Framework\QrCode\ValueObjects\QrCodeVersion;
use App\Framework\QrCode\ValueObjects\EncodingMode;

echo "=== Full Decode Test (Correct Interpretation) ===\n\n";

$testData = 'HELLO WORLD';
$config = new QrCodeConfig(
    version: QrCodeVersion::fromNumber(1),
    errorCorrectionLevel: ErrorCorrectionLevel::M,
    encodingMode: EncodingMode::BYTE
);

echo "Test data: '{$testData}'\n\n";

$matrix = QrCodeGenerator::generate($testData, $config);
$size = $matrix->getSize();

// Extract format info
$formatCols = [0, 1, 2, 3, 4, 5, 7, 8, $size - 1, $size - 2, $size - 3, $size - 4, $size - 5, $size - 6, $size - 7];
$formatH = '';
foreach ($formatCols as $col) {
    $formatH .= $matrix->getModuleAt(8, $col)->isDark() ? '1' : '0';
}

$xorMask = "101010000010010";
$unmasked = '';
for ($i = 0; $i < 15; $i++) {
    $unmasked .= (int)$formatH[$i] ^ (int)$xorMask[$i];
}

$maskBits = substr($unmasked, 2, 3);
$maskPattern = bindec($maskBits);

use App\Framework\QrCode\Masking\MaskPattern as MaskPatternEnum;

$mask = match($maskPattern) {
    0 => MaskPatternEnum::PATTERN_0,
    1 => MaskPatternEnum::PATTERN_1,
    2 => MaskPatternEnum::PATTERN_2,
    3 => MaskPatternEnum::PATTERN_3,
    4 => MaskPatternEnum::PATTERN_4,
    5 => MaskPatternEnum::PATTERN_5,
    6 => MaskPatternEnum::PATTERN_6,
    7 => MaskPatternEnum::PATTERN_7,
};

// Read ALL data bits
$dataBits = [];
$bitCount = 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;
            
            // Skip function patterns
            if (($row <= 8 && $currentCol <= 8) ||
                ($row <= 7 && $currentCol >= $size - 8) ||
                ($row >= $size - 8 && $currentCol <= 7) ||
                $row === 6 || $currentCol === 6 ||
                ($row === 8 && (($currentCol >= 0 && $currentCol <= 5) || $currentCol === 7 || $currentCol === 8 || $currentCol >= $size - 8)) ||
                ($currentCol === 8 && (($row >= 0 && $row <= 5) || $row === 7 || $row === 8 || $row >= $size - 7)) ||
                ($row === 13 && $currentCol === 8)) {
                continue;
            }
            
            $maskedBit = $matrix->getModuleAt($row, $currentCol)->isDark() ? 1 : 0;
            $unmaskedBit = $mask->shouldInvert($row, $currentCol) ? (1 - $maskedBit) : $maskedBit;
            $dataBits[] = $unmaskedBit;
            $bitCount++;
        }
    }
}

$bitString = implode('', $dataBits);
echo "Read {$bitCount} data bits\n\n";

// Decode correctly:
// 1. Mode indicator (4 bits)
$modeBits = substr($bitString, 0, 4);
$mode = bindec($modeBits);
echo "Mode (bits 0-3): {$modeBits} = {$mode} (expected: 4)\n";

if ($mode !== 4) {
    echo "❌ Mode is wrong!\n";
    exit(1);
}

// 2. Character count (8 bits for version 1-9 byte mode)
$countBits = substr($bitString, 4, 8);
$count = bindec($countBits);
echo "Count (bits 4-11): {$countBits} = {$count} (expected: " . strlen($testData) . ")\n";

if ($count !== strlen($testData)) {
    echo "❌ Count is wrong!\n";
    exit(1);
}

// 3. Data bytes (8 bits each)
$dataStart = 12; // After mode (4) + count (8)
$decodedData = '';
for ($i = 0; $i < $count; $i++) {
    $byteStart = $dataStart + ($i * 8);
    if ($byteStart + 8 <= strlen($bitString)) {
        $byteBits = substr($bitString, $byteStart, 8);
        $byte = bindec($byteBits);
        $decodedData .= chr($byte);
    }
}

echo "\nDecoded data: '{$decodedData}'\n";
echo "Expected data: '{$testData}'\n";

if ($decodedData === $testData) {
    echo "✅ DECODING IS CORRECT!\n";
    echo "\nThis means the QR code structure is correct.\n";
    echo "If it still doesn't scan, the issue might be:\n";
    echo "1. Reed-Solomon error correction (EC codewords)\n";
    echo "2. SVG rendering (Quiet Zone, module size)\n";
    echo "3. Some scanner apps require specific implementations\n";
} else {
    echo "❌ Decoded data doesn't match!\n";
    echo "First difference at position: ";
    for ($i = 0; $i < min(strlen($decodedData), strlen($testData)); $i++) {
        if ($decodedData[$i] !== $testData[$i]) {
            echo "{$i} (got '{$decodedData[$i]}' (ord: " . ord($decodedData[$i]) . "), expected '{$testData[$i]}' (ord: " . ord($testData[$i]) . "))\n";
            break;
        }
    }
}