<?php

declare(strict_types=1);

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

use App\Framework\QrCode\ErrorCorrection\ReedSolomonEncoder;

echo "=== Reed-Solomon Verification ===\n\n";

// Test with known data codewords for "HELLO WORLD"
// These are the correct data codewords that we generate
$dataCodewords = [64, 180, 132, 84, 196, 196, 242, 5, 116, 245, 36, 196, 64, 236, 17, 236];

echo "Data codewords (16):\n";
echo implode(', ', $dataCodewords) . "\n\n";

// Generate EC codewords
$reedSolomon = new ReedSolomonEncoder();
$ecCodewords = $reedSolomon->encode($dataCodewords, 10);

echo "EC codewords (10):\n";
echo implode(', ', $ecCodewords) . "\n\n";

// Verify Reed-Solomon encoding
// For Reed-Solomon, if we encode data and then decode, we should get the original data back
// But we can also verify by checking if the polynomial division was correct

echo "=== Reed-Solomon Verification ===\n";
echo "For RS(n, k), where n = total codewords and k = data codewords:\n";
echo "  n = 26 (total codewords)\n";
echo "  k = 16 (data codewords)\n";
echo "  t = 10 (EC codewords)\n";
echo "  Can correct up to t/2 = 5 errors\n\n";

// Test: Create a message polynomial and verify encoding
echo "Message polynomial (data + zeros for EC):\n";
$messagePoly = array_merge($dataCodewords, array_fill(0, 10, 0));
echo "  " . implode(', ', $messagePoly) . "\n\n";

// Get generator polynomial
$reflection = new ReflectionClass($reedSolomon);
$getGeneratorMethod = $reflection->getMethod('getGeneratorPolynomial');
$getGeneratorMethod->setAccessible(true);
$generator = $getGeneratorMethod->invoke($reedSolomon, 10);

echo "Generator polynomial (degree 10):\n";
echo "  " . implode(', ', $generator) . "\n\n";

// Verify: The generator polynomial should have 11 coefficients (degree 10 + 1)
if (count($generator) === 11) {
    echo "✅ Generator polynomial has correct degree (10)\n";
} else {
    echo "❌ Generator polynomial has wrong degree: " . (count($generator) - 1) . " (expected: 10)\n";
}

// Test GF field operations
echo "\n=== GF(256) Field Operations Test ===\n";
$gfMultiplyMethod = $reflection->getMethod('gfMultiply');
$gfMultiplyMethod->setAccessible(true);

// Test some multiplications
$testCases = [
    [0, 5, 0],      // 0 * anything = 0
    [1, 5, 5],      // 1 * x = x
    [2, 3, 6],      // 2 * 3 = 6
    [87, 1, 87],    // Generator coefficient
    [251, 1, 251],  // Generator coefficient
];

$allCorrect = true;
foreach ($testCases as [$a, $b, $expected]) {
    $result = $gfMultiplyMethod->invoke($reedSolomon, $a, $b);
    $match = $result === $expected ? '✅' : '❌';
    if ($result !== $expected) {
        $allCorrect = false;
    }
    echo "  {$a} * {$b} = {$result} (expected: {$expected}) {$match}\n";
}

if ($allCorrect) {
    echo "\n✅ GF multiplication is correct\n";
} else {
    echo "\n❌ GF multiplication has errors\n";
}

// Test generator polynomial coefficients
echo "\n=== Generator Polynomial Coefficients ===\n";
echo "Expected for 10 EC codewords (from QR spec):\n";
echo "  [0, 251, 67, 46, 61, 118, 70, 64, 94, 32, 45]\n";
echo "Actual:\n";
echo "  [" . implode(', ', $generator) . "]\n";

if ($generator === [0, 251, 67, 46, 61, 118, 70, 64, 94, 32, 45]) {
    echo "\n✅ Generator polynomial matches specification!\n";
} else {
    echo "\n❌ Generator polynomial doesn't match specification!\n";
    echo "Differences:\n";
    $expected = [0, 251, 67, 46, 61, 118, 70, 64, 94, 32, 45];
    for ($i = 0; $i < min(count($generator), count($expected)); $i++) {
        if ($generator[$i] !== $expected[$i]) {
            echo "  Coefficient {$i}: got {$generator[$i]}, expected {$expected[$i]}\n";
        }
    }
}

// Final check: Can we decode the encoded data?
echo "\n=== Decode Test ===\n";
echo "Note: Full decode test requires error correction decoder.\n";
echo "For now, we verify that EC codewords are generated correctly.\n";
echo "If EC codewords are wrong, QR scanners will fail the error correction check.\n";