<?php
class OperationLockManager
{
    private PDO $pdo;
    private int $companyId;
    private int $userId;

    public function __construct(PDO $pdo, int $company_id, int $user_id)
    {
        $this->pdo       = $pdo;
        $this->companyId = $company_id;
        $this->userId    = $user_id;
    }

    public function acquire(string $operation_type, int $ttl_minutes = 120): array
    {
        $operation_type = trim($operation_type);
        $ttl_minutes    = max(1, min(480, $ttl_minutes));

        if ($operation_type === '') {
            throw new Exception('operation_type is required.');
        }

        $now     = date('Y-m-d H:i:s');
        $expires = date('Y-m-d H:i:s', strtotime("+{$ttl_minutes} minutes"));

        $this->pdo->beginTransaction();

        try {
            $sth = $this->pdo->prepare(
                "SELECT * FROM md_lock_operation
                 WHERE company_id = :cid AND operation_type = :op_type
                 FOR UPDATE"
            );
            $sth->execute([':cid' => $this->companyId, ':op_type' => $operation_type]);
            $lock = $sth->fetch(PDO::FETCH_ASSOC);

            if ($lock) {
                $this->pdo->rollBack();
                return [
                    'success'    => 0,
                    'message'    => 'Operation "' . $operation_type . '" is already running. Please wait.',
                    'expires_at' => $lock['expires_at'],
                    'locked_at'  => $lock['locked_at'],
                ];
            }

            $this->pdo->prepare(
                "INSERT INTO md_lock_operation (company_id, operation_type, user_id, locked_at, expires_at)
                 VALUES (:cid, :op_type, :uid, :locked_at, :expires_at)"
            )->execute([
                ':cid'        => $this->companyId,
                ':op_type'    => $operation_type,
                ':uid'        => $this->userId,
                ':locked_at'  => $now,
                ':expires_at' => $expires,
            ]);

            $this->pdo->commit();
            return ['success' => 1, 'message' => 'Lock acquired.'];

        } catch (Throwable $e) {
            if ($this->pdo->inTransaction()) $this->pdo->rollBack();
            throw $e;
        }
    }

    public function release(string $operation_type): void
    {
        $operation_type = trim($operation_type);
        if ($operation_type === '') {
            throw new Exception('operation_type is required.');
        }

        $this->pdo->prepare(
            "DELETE FROM md_lock_operation
             WHERE company_id = :cid AND operation_type = :op_type"
        )->execute([':cid' => $this->companyId, ':op_type' => $operation_type]);
    }
}
?>