<?php
declare(strict_types=1);

require_once __DIR__ . '/../../backend/php/NiroRawSnappy.php';

function checkSnappy(bool $condition, string $message): void
{
    if (!$condition) {
        throw new RuntimeException($message);
    }
}

/** Independent literal-only reader for synthetic encoder tests. */
function readLiteralSnappy(string $encoded): string
{
    $position = 0;
    $length = 0;
    $shift = 0;
    do {
        checkSnappy($position < strlen($encoded) && $shift <= 28, 'invalid varint');
        $byte = ord($encoded[$position++]);
        $length |= ($byte & 0x7f) << $shift;
        $shift += 7;
    } while (($byte & 0x80) !== 0);

    $output = '';
    while ($position < strlen($encoded)) {
        $tag = ord($encoded[$position++]);
        checkSnappy(($tag & 3) === 0, 'non-literal tag');
        $size = $tag >> 2;
        if ($size >= 60) {
            $count = $size - 59;
            checkSnappy($position + $count <= strlen($encoded), 'truncated size');
            $size = 0;
            for ($i = 0; $i < $count; ++$i) {
                $size |= ord($encoded[$position++]) << ($i * 8);
            }
        }
        ++$size;
        checkSnappy($position + $size <= strlen($encoded), 'truncated literal');
        $output .= substr($encoded, $position, $size);
        $position += $size;
    }
    checkSnappy(strlen($output) === $length, 'uncompressed length mismatch');
    return $output;
}

$cases = ['', 'a', "synthetic\0payload"];
foreach ([60, 61, 255, 256, 65535, 65536, 65537, 131073] as $length) {
    $cases[] = str_repeat('x', $length);
}
foreach ($cases as $plain) {
    $encoded = NiroRawSnappy::encodeLiteral($plain);
    checkSnappy(readLiteralSnappy($encoded) === $plain, 'round trip failed');
    checkSnappy($encoded === NiroRawSnappy::encodeLiteral($plain), 'not deterministic');
}
$rejected = false;
try {
    NiroRawSnappy::encodeLiteral(str_repeat('x', 8 * 1024 * 1024 + 1));
} catch (InvalidArgumentException $expected) {
    $rejected = true;
}
checkSnappy($rejected, 'oversized input was accepted');
echo 'NiroRawSnappyTest passed cases=' . count($cases) . PHP_EOL;