<?php

declare(strict_types=1);

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

use App\Framework\QrCode\ErrorCorrection\ReedSolomonEncoder;

echo "=== Alternative RS Implementation Test ===\n\n";

// Test with known working algorithm from qrcode.js library
// The algorithm should be:
// 1. Create message polynomial: [data, 0, 0, ..., 0] (length = data_length + ec_length)
// 2. For each data coefficient, perform polynomial division step
// 3. The key is that we divide m(x) * x^t by g(x) to get remainder

$data = [64, 180, 132, 84];
$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 "Data: " . implode(', ', $data) . "\n";
echo "EC codewords needed: {$ecCodewords}\n";
echo "Generator: " . implode(', ', $generator) . "\n\n";

// Try alternative algorithm: Standard RS encoding
// Message polynomial: m(x) = data[0] + data[1]*x + ... + data[n-1]*x^(n-1)
// We want to compute: (m(x) * x^t) mod g(x)
// where t = ecCodewords

// Initialize: [data, 0, 0, ..., 0]
$messagePoly = array_merge($data, array_fill(0, $ecCodewords, 0));
echo "Initial message polynomial: " . implode(', ', $messagePoly) . "\n\n";

// Standard RS division algorithm
// For each coefficient in data part:
for ($i = 0; $i < count($data); $i++) {
    $lead = $messagePoly[$i];
    
    if ($lead !== 0) {
        echo "Step {$i}: lead coefficient = {$lead}\n";
        echo "  Before: " . implode(', ', $messagePoly) . "\n";
        
        // In standard RS, generator is monic (leading coefficient = 1)
        // So we XOR the lead coefficient directly, then multiply generator by lead
        // But our generator format is [0, a1, a2, ...], meaning [1, a1, a2, ...]
        
        // Clear the lead position (division by monic polynomial)
        $messagePoly[$i] = 0;
        
        // Apply generator coefficients (skip first 0)
        $gfMultiplyMethod = $reflection->getMethod('gfMultiply');
        $gfMultiplyMethod->setAccessible(true);
        
        for ($j = 1; $j < count($generator); $j++) {
            $multiplied = $gfMultiplyMethod->invoke($rs, $generator[$j], $lead);
            $messagePoly[$i + $j] ^= $multiplied;
        }
        
        echo "  After:  " . implode(', ', $messagePoly) . "\n\n";
    }
}

$ec = array_slice($messagePoly, count($data));
echo "EC codewords: " . implode(', ', $ec) . "\n\n";

// Compare with actual implementation
$actualEC = $rs->encode($data, $ecCodewords);
echo "Actual EC codewords: " . implode(', ', $actualEC) . "\n\n";

if ($ec === $actualEC) {
    echo "✅ Algorithms match!\n";
} else {
    echo "❌ Algorithms don't match!\n";
}

// Now test with QR code data
echo "\n=== Test with QR Code Data ===\n";
$qrData = [64, 180, 132, 84, 196, 196, 242, 5, 116, 245, 36, 196, 64, 236, 17, 236];
$qrEC = $rs->encode($qrData, 10);

echo "QR EC codewords: " . implode(', ', $qrEC) . "\n\n";

// Verify with decoder
require_once __DIR__ . '/test-reed-solomon-decoder.php';
$fullCodeword = array_merge($qrData, $qrEC);
$decoder = new SimpleRSDecoder();
$syndromes = $decoder->calculateSyndromes($fullCodeword, 10);

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

if ($allZero) {
    echo "\n✅ All syndromes are zero - Reed-Solomon is CORRECT!\n";
} else {
    echo "\n❌ Syndromes are not all zero - Reed-Solomon is WRONG!\n";
}