<?php

declare(strict_types=1);

use App\Core\Auth;
use App\Core\Database;

require_once dirname(__DIR__, 2) . '/app/bootstrap.php';

Auth::requireAdmin();

$sqlPath = base_path('database/import_old_site_generated.sql');
$summaryPath = base_path('storage/import_old_site_summary.json');
$progressPath = base_path('storage/import_old_site_progress.json');
$summary = is_file($summaryPath)
    ? json_decode((string) file_get_contents($summaryPath), true)
    : [];
$message = null;
$error = null;
$progress = is_file($progressPath)
    ? json_decode((string) file_get_contents($progressPath), true)
    : [];
$importSignature = is_file($sqlPath)
    ? ((string) filesize($sqlPath) . ':' . (string) filemtime($sqlPath))
    : 'missing';

if (($progress['import_signature'] ?? null) !== $importSignature) {
    $progress = [];
}

function old_site_import_default_progress(string $importSignature): array
{
    return [
        'import_signature' => $importSignature,
        'offset' => 0,
        'statement' => '',
        'in_quote' => false,
        'escaped' => false,
        'executed' => 0,
        'done' => false,
        'started_at' => date('Y-m-d H:i:s'),
        'updated_at' => date('Y-m-d H:i:s'),
    ];
}

function save_old_site_import_progress(string $path, array $progress): void
{
    $progress['updated_at'] = date('Y-m-d H:i:s');
    file_put_contents($path, json_encode($progress, JSON_UNESCAPED_UNICODE | JSON_PRETTY_PRINT));
}

function execute_old_site_import_batch(string $sqlPath, string $progressPath, array $progress): array
{
    if (!is_file($sqlPath)) {
        throw new RuntimeException('Файл импорта не найден.');
    }

    @set_time_limit(20);

    $pdo = Database::pdo();
    $handle = fopen($sqlPath, 'rb');

    if ($handle === false) {
        throw new RuntimeException('Не удалось открыть файл импорта.');
    }

    $fileSize = max(1, filesize($sqlPath) ?: 1);
    $offset = max(0, (int) ($progress['offset'] ?? 0));
    $statement = (string) ($progress['statement'] ?? '');
    $executedTotal = (int) ($progress['executed'] ?? 0);
    $executedBatch = 0;
    $inQuote = (bool) ($progress['in_quote'] ?? false);
    $escaped = (bool) ($progress['escaped'] ?? false);
    $started = microtime(true);
    $maxSeconds = 7.0;
    $maxStatements = 500;

    $pdo->exec('SET FOREIGN_KEY_CHECKS = 0');
    fseek($handle, $offset);

    while (($chunk = fread($handle, 256 * 1024)) !== false && $chunk !== '') {
        $length = strlen($chunk);
        $chunkStartOffset = $offset;

        for ($i = 0; $i < $length; $i++) {
            $char = $chunk[$i];
            $statement .= $char;
            $offset = $chunkStartOffset + $i + 1;

            if ($inQuote) {
                if ($escaped) {
                    $escaped = false;
                } elseif ($char === '\\') {
                    $escaped = true;
                } elseif ($char === "'") {
                    $inQuote = false;
                }
                continue;
            }

            if ($char === "'") {
                $inQuote = true;
                continue;
            }

            if ($char !== ';') {
                continue;
            }

            $sql = trim($statement);
            $statement = '';

            if ($sql === '') {
                continue;
            }

            $pdo->exec($sql);
            $executedBatch++;
            $executedTotal++;

            if ($executedBatch >= $maxStatements || (microtime(true) - $started) >= $maxSeconds) {
                $progress = [
                    'offset' => $offset,
                    'statement' => '',
                    'in_quote' => false,
                    'escaped' => false,
                    'executed' => $executedTotal,
                    'done' => false,
                    'import_signature' => $progress['import_signature'] ?? '',
                    'started_at' => $progress['started_at'] ?? date('Y-m-d H:i:s'),
                ];
                save_old_site_import_progress($progressPath, $progress);
                $pdo->exec('SET FOREIGN_KEY_CHECKS = 1');
                fclose($handle);

                return $progress + [
                    'batch_executed' => $executedBatch,
                    'percent' => min(99.9, round(($offset / $fileSize) * 100, 1)),
                ];
            }
        }
    }

    fclose($handle);

    $tail = trim($statement);
    if ($tail !== '') {
        $pdo->exec($tail);
        $executedBatch++;
        $executedTotal++;
    }

    $pdo->exec('SET FOREIGN_KEY_CHECKS = 1');

    $progress = [
        'offset' => $fileSize,
        'statement' => '',
        'in_quote' => false,
        'escaped' => false,
        'executed' => $executedTotal,
        'done' => true,
        'import_signature' => $progress['import_signature'] ?? '',
        'started_at' => $progress['started_at'] ?? date('Y-m-d H:i:s'),
    ];
    save_old_site_import_progress($progressPath, $progress);

    return $progress + [
        'batch_executed' => $executedBatch,
        'percent' => 100,
    ];
}

function normalize_old_site_product_categories(PDO $pdo): void
{
    $pdo->exec(
        "UPDATE products p
         SET p.category_id = (
             SELECT pcl.category_id
             FROM product_category_links pcl
             INNER JOIN categories c ON c.id = pcl.category_id
             WHERE pcl.product_id = p.id
               AND c.is_active = 1
             ORDER BY c.parent_id IS NULL, pcl.sort_order, pcl.category_id
             LIMIT 1
         )
         WHERE p.legacy_path LIKE '/katalog/product/view/1/%'
           AND EXISTS (
               SELECT 1
               FROM product_category_links pcl_exists
               WHERE pcl_exists.product_id = p.id
           )"
    );
}

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    try {
        $action = (string) ($_POST['action'] ?? 'start');

        if ($action === 'start') {
            $progress = old_site_import_default_progress($importSignature);
            save_old_site_import_progress($progressPath, $progress);
        }

        if (($progress['import_signature'] ?? null) !== $importSignature) {
            throw new RuntimeException('Файл импорта обновился. Нажмите «Запустить импорт заново».');
        }

        $progress = execute_old_site_import_batch($sqlPath, $progressPath, $progress);

        if (!empty($progress['done'])) {
            normalize_old_site_product_categories(Database::pdo());
            $message = 'Импорт выполнен. SQL-команд выполнено: ' . (int) $progress['executed'] . '.';
        } else {
            $message = 'Импорт продолжается: ' . (float) $progress['percent'] . '%, команд за этот шаг: ' . (int) $progress['batch_executed'] . '.';
        }
    } catch (Throwable $exception) {
        $error = $exception->getMessage();
    }
}

$fileSize = is_file($sqlPath) ? max(1, filesize($sqlPath) ?: 1) : 1;
$progressPercent = !empty($progress['done'])
    ? 100
    : min(99.9, round((((int) ($progress['offset'] ?? 0)) / $fileSize) * 100, 1));
?>
<!doctype html>
<html lang="ru">
<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <title>Импорт старого сайта - Рыбсток</title>
    <link rel="stylesheet" href="/assets/css/app.css">
</head>
<body>
    <main class="page">
        <section class="panel">
            <p class="eyebrow">Админка</p>
            <h1>Импорт старого сайта</h1>
            <p class="muted">Страница переносит подготовленные данные Joomla/JoomShopping в новую структуру Рыбсток.</p>
            <p class="muted">Импорт выполняется маленькими шагами, чтобы сервер не обрывал процесс по 504 Gateway Timeout.</p>

            <?php if ($message !== null): ?>
                <div class="status-box"><?= e($message) ?></div>
            <?php endif; ?>

            <?php if ($error !== null): ?>
                <div class="status-box danger"><?= e($error) ?></div>
            <?php endif; ?>

            <?php if ($summary !== []): ?>
                <dl class="settings-list">
                    <div><dt>Категорий</dt><dd><?= e((string) ($summary['categories'] ?? 0)) ?></dd></div>
                    <div><dt>Товаров</dt><dd><?= e((string) ($summary['products'] ?? 0)) ?></dd></div>
                    <div><dt>Фасовок</dt><dd><?= e((string) ($summary['product_variants'] ?? 0)) ?></dd></div>
                    <div><dt>Связей товар-категория</dt><dd><?= e((string) ($summary['product_category_links'] ?? 0)) ?></dd></div>
                    <div><dt>Картинок товаров</dt><dd><?= e((string) ($summary['copied_product_images'] ?? 0)) ?></dd></div>
                    <div><dt>Картинок категорий</dt><dd><?= e((string) ($summary['copied_category_images'] ?? 0)) ?></dd></div>
                    <div><dt>Картинок из описаний</dt><dd><?= e((string) ($summary['copied_content_images'] ?? 0)) ?></dd></div>
                    <div><dt>Редиректов категорий из sitemap</dt><dd><?= e((string) ($summary['sitemap_category_redirects'] ?? 0)) ?></dd></div>
                    <div><dt>SQL-файл</dt><dd><?= e((string) ($summary['sql_file'] ?? '')) ?></dd></div>
                </dl>
            <?php endif; ?>

            <?php if ($progress !== []): ?>
                <div class="status-box">
                    <strong><?= e((string) $progressPercent) ?>%</strong>
                    <span>Выполнено SQL-команд: <?= e((string) ((int) ($progress['executed'] ?? 0))) ?></span>
                </div>
            <?php endif; ?>

            <?php if ($error === null && $progress !== [] && empty($progress['done'])): ?>
                <form id="continue-import-form" method="post">
                    <input type="hidden" name="action" value="continue">
                    <button class="primary-button" type="submit">Продолжить импорт</button>
                </form>
                <script>
                    window.setTimeout(function () {
                        document.getElementById('continue-import-form').submit();
                    }, 700);
                </script>
            <?php else: ?>
                <form method="post" onsubmit="return confirm('Запустить импорт заново? Текущие товары и категории будут заменены данными старого сайта.');">
                    <input type="hidden" name="action" value="start">
                    <button class="primary-button" type="submit">Запустить импорт заново</button>
                </form>
            <?php endif; ?>

            <p>
                <a class="secondary-button" href="/admin/">Вернуться в админку</a>
            </p>
        </section>
    </main>
</body>
</html>