<?php

declare(strict_types=1);

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

use App\Framework\QrCode\ErrorCorrection\ReedSolomonEncoder;

echo "=== Polynomial Division Fix Test ===\n\n";

// Test with simple data
$data = [1, 2, 3];
$ecCodewords = 3;

$rs = new ReedSolomonEncoder();
$reflection = new ReflectionClass($rs);

// Get generator polynomial
$getGeneratorMethod = $reflection->getMethod('getGeneratorPolynomial');
$getGeneratorMethod->setAccessible(true);
$generator = $getGeneratorMethod->invoke($rs, $ecCodewords);

echo "Generator polynomial: " . implode(', ', $generator) . "\n";
echo "Note: First coefficient is 0, which is unusual.\n\n";

// The issue might be that we're using the generator polynomial incorrectly
// In standard Reed-Solomon, the generator polynomial is monic (leading coefficient = 1)
// But our stored polynomials start with 0

// Let's check if we should skip the first coefficient
if ($generator[0] === 0) {
    echo "Generator polynomial starts with 0 - this might be the issue.\n";
    echo "In standard RS, generator should be monic (leading coefficient = 1).\n\n";
    
    // Try without the first coefficient
    $generatorWithoutZero = array_slice($generator, 1);
    echo "Generator without leading 0: " . implode(', ', $generatorWithoutZero) . "\n";
    echo "This would be a monic polynomial of degree " . (count($generatorWithoutZero) - 1) . "\n\n";
}

// Test the actual encoding
$ec = $rs->encode($data, $ecCodewords);
echo "EC codewords: " . implode(', ', $ec) . "\n\n";

// Now let's verify with our decoder
require_once __DIR__ . '/test-reed-solomon-decoder.php';

$fullCodeword = array_merge($data, $ec);
$decoder = new SimpleRSDecoder();
$syndromes = $decoder->calculateSyndromes($fullCodeword, $ecCodewords);

echo "Syndromes: " . implode(', ', $syndromes) . "\n";
$allZero = true;
foreach ($syndromes as $s) {
    if ($s !== 0) {
        $allZero = false;
        break;
    }
}

if ($allZero) {
    echo "✅ All syndromes are zero - codeword is valid!\n";
} else {
    echo "❌ Syndromes are not all zero - codeword is invalid!\n";
    echo "\nThe problem is in the polynomial division algorithm.\n";
}