Reliable way to get list of enabled payment methods

Did you look at what the payment method checkout pane does (see commerce_payment_pane_checkout_form())?

This snippet is responsible for collecting payment methods via Rules that are then stored in that array on the order object:

  // Invoke the payment methods event that will populate the order with
  // an array of method IDs for available payment methods.
  $order->payment_methods = array();
  rules_invoke_all('commerce_payment_methods', $order);

Code below that formats it into an options list for the radio buttons element.

Hi Kirill!
Try this way:

foreach (commerce_payment_methods() as $id => $method) {
  $payment = commerce_payment_method_instance_load("$id|commerce_payment_$id");
  dpm($payment);
}

Here is what you want:

  $active_payment_rules = db_select('rules_config', 'rc')
  ->fields('rc', array('id', 'name'))
  ->condition('rc.module', 'commerce_payment')
  ->condition('rc.active', 1)
  ->execute()
  ->fetchAllKeyed(0,1);

  foreach ($active_payment_rules as $rule_name) {
    // Cut "commerce_payment_" to get the id
    $id = substr($rule_name, 17);
    $payment = commerce_payment_method_instance_load("$id|commerce_payment_$id");
    dpm($payment);
  }

UPD: Actually, my solution is pretty similar to yours, so I can confirm there's no more "reliable" way to get the payment instances.

Hi,
Why not try and join the rules config and rules trigger table to get what you want ?
rules trigger table has mapping of rule ids and events.

function get_active_payments_method_rules() {
  $query = db_select('rules_config', 'rc');
  $query->join('rules_trigger', 'rt', 'rc.id = rt.id');
  $query->fields('rc', array('id', 'name'))
      ->condition('rt.event', 'commerce_payment_methods')
      ->condition('rc.active', 1);
  $active_payment_rules = $query->execute()->fetchAllKeyed(0, 1);
  foreach ($active_payment_rules as $rule_name) {
    $rule = rules_config_load($rule_name);
    dpm($rule);
foreach ($rule->actions() as $action) {
      $action_machine_name = $action->getElementName();
      dpm($action_machine_name);
    }
  }
}

Very old question, but I realized that, since enabled payment methods depend on rules, to get effective enabled payment methods, per user and per order, rules must be evalued.

And evaluation results may depend on many factors and contexts.

The following function returns enabled payment methods on checkout form, but results may depend on contexts (for axample: user country, if a rule has a condition on this)

function mymodule_get_avail_checkout_payment_methods($order){
    if(isset($order->payment_methods)){
        //already set
    }else{
        $order->payment_methods = array();
        rules_invoke_all('commerce_payment_methods', $order);

    }
    $ret = array();
    foreach ($order->payment_methods as $instance_id => $method_info) {
        // Ensure we've received a valid payment method that can be used on the
        // checkout form.
        if ($payment_method = commerce_payment_method_load($method_info['method_id'])) {
            if (!empty($payment_method['checkout'])) {
                $ret[$instance_id] = $payment_method;
            }
        }
    }
    return $ret;
}

(fwiw, just marking fixed b/c there are multiple solutions in here now and this is almost certainly outdated. : )