<?php
declare(strict_types=1);

namespace App\Domain\Notification;

use PDO;
use InvalidArgumentException;

/** Persists validated notifications as per-user rows with database-backed deduplication. */
final class NotificationQueue
{
    public function __construct(private readonly ?NotificationRecord $records = null)
    {
    }

    /** @return list<int> inserted notification ids */
    public function enqueue(PDO $pdo, array $record): array
    {
        $validation = ($this->records ?? new NotificationRecord())->validate($record);
        if (!$validation['valid']) throw new InvalidArgumentException('Invalid notification: ' . implode(' ', $validation['errors']));
        $title = is_scalar($record['title'] ?? null) ? trim((string)$record['title']) : '';
        if ($title === '' || mb_strlen($title) > 190) throw new InvalidArgumentException('Notification title is required and must be 190 characters or fewer.');
        $lookup = $pdo->prepare('SELECT id FROM users WHERE email = :email AND is_active = 1 LIMIT 1');
        $insert = $pdo->prepare('INSERT INTO notifications (user_id, type, title, body, deduplication_key, read_at) VALUES (:user, :type, :title, :body, :dedup, :read_at) ON DUPLICATE KEY UPDATE id = LAST_INSERT_ID(id)');
        $ids = [];
        $startedTransaction = false;
        try {
            if (!$pdo->inTransaction()) {
                $pdo->beginTransaction();
                $startedTransaction = true;
            }
            foreach ($validation['recipients'] as $email) {
                $dto = ($this->records ?? new NotificationRecord())->toQueueDto($record, $email);
                $lookup->execute(['email' => $email]);
                $userId = $lookup->fetchColumn();
                if ($userId === false) continue;
                $insert->execute(['user' => $userId, 'type' => $dto['type'], 'title' => $dto['title'], 'body' => $dto['body'], 'dedup' => $dto['deduplication_key'], 'read_at' => $dto['is_read'] ? date('Y-m-d H:i:s') : null]);
                $id = (int)$pdo->lastInsertId();
                if ($id > 0 && !in_array($id, $ids, true)) $ids[] = $id;
            }
            if ($startedTransaction) $pdo->commit();
        } catch (\Throwable $exception) {
            if ($startedTransaction && $pdo->inTransaction()) $pdo->rollBack();
            throw $exception;
        }
        return $ids;
    }

    /** Map a multi-recipient notification into one queue DTO for one user. */
    public function mapForUser(array $record, string $recipient): array
    {
        return ($this->records ?? new NotificationRecord())->toQueueDto($record, $recipient);
    }

    /** Mark a notification read only for the authenticated user's row. */
    public function markRead(PDO $pdo, int|string $userId, array $command): bool
    {
        $user = filter_var($userId, FILTER_VALIDATE_INT, ['options' => ['min_range' => 1]]);
        $validation = ($this->records ?? new NotificationRecord())->validateMarkRead($command);
        if ($user === false || !$validation['valid']) throw new InvalidArgumentException('Invalid mark-read command.');
        $stmt = $pdo->prepare('UPDATE notifications SET read_at = COALESCE(read_at, CURRENT_TIMESTAMP) WHERE id = :id AND user_id = :user');
        $stmt->execute(['id' => $validation['notification_id'], 'user' => $user]);
        return $stmt->rowCount() > 0;
    }

    /** Mark a notification unread only for the authenticated user's row. */
    public function markUnread(PDO $pdo, int|string $userId, array $command): bool
    {
        $user = filter_var($userId, FILTER_VALIDATE_INT, ['options' => ['min_range' => 1]]);
        $validation = ($this->records ?? new NotificationRecord())->validateMarkUnread($command);
        if ($user === false || !$validation['valid']) throw new InvalidArgumentException('Invalid mark-unread command.');
        $stmt = $pdo->prepare('UPDATE notifications SET read_at = NULL WHERE id = :id AND user_id = :user');
        $stmt->execute(['id' => $validation['notification_id'], 'user' => $user]);
        return $stmt->rowCount() > 0;
    }
}