<?php
if (!defined('_GNUBOARD_'))
  exit;

class GML_Hook extends Hook
{
  protected $filters = ['count' => 0];
  protected $callback_filters = [];
  protected static $current_filter = false;

  protected function runAction($action, $args)
  {
    $function = $action['function'];
    $argsNumber = $action['arguments'];

    $args = $this->getArguments($argsNumber, $args);

    if (is_callable($function)) {
      return call_user_func_array($function, $args);
    } elseif (is_array($function) && isset($function[0], $function[1])) {
      $class = $function[0];
      $method = $function[1];

      if ($obj = call_user_func([$class, $this->singleton])) {
        return $obj !== false ? call_user_func_array([$obj, $method], $args) : false;
      } elseif (class_exists($class)) {
        $instance = new $class();
        return call_user_func_array([$instance, $method], $args);
      }
    }

    return false;
  }

  protected function getFilters($tag, $remove)
  {
    $filters = isset($this->callback_filters[$tag]) ? $this->callback_filters[$tag] : [];
    if ($remove) {
      unset($this->callback_filters[$tag]);
    }
    return $filters;
  }

  public static function get_properties($type, $is_callback = false)
  {
    $that = self::getInstance(self::$id);
    if ($type === 'event') {
      return $is_callback ? $that->callbacks : $that->actions;
    }
    return $is_callback ? $that->callback_filters : $that->filters;
  }

  public static function addFilter($tag, $func, $priority = 8, $args = 0)
  {
    $that = self::getInstance(self::$id);
    $that->callback_filters[$tag][$priority][] = [
      'function' => $func,
      'arguments' => $args,
    ];
    return true;
  }

  public static function apply_filters($tag, $args = [], $remove = true)
  {
    $that = self::getInstance(self::$id);
    self::$current_filter = $tag;
    $that->filters['count']++;

    if (!isset($that->filters[$tag])) {
      $that->filters[$tag] = 0;
    }
    $that->filters[$tag]++;

    $filters = $that->getFilters($tag, $remove);
    ksort($filters);

    $value = isset($args[0]) ? $args[0] : null;

    foreach ($filters as $priority) {
      foreach ($priority as $filter) {
        if (isset($args[0])) {
          $args[0] = $value;
        }
        $replace = $that->runAction($filter, $args);
        if ($replace !== false) {
          $value = $replace;
        }
      }
    }

    self::$current_filter = false;
    return $value;
  }

  protected function getArguments($argsNumber, $arguments)
  {
    if ($argsNumber === 1 && is_string($arguments)) {
      return [$arguments];
    }

    if (is_array($arguments) && $argsNumber === count($arguments)) {
      return $arguments;
    }

    return array_slice((array) $arguments, 0, $argsNumber);
  }

  public static function remove_filter($tag, $func, $priority)
  {
    $that = self::getInstance(self::$id);
    return self::remove_callback($that->callback_filters, $tag, $func, $priority);
  }

  public static function remove_action($tag, $func, $priority)
  {
    $that = self::getInstance(self::$id);
    return self::remove_callback($that->callbacks, $tag, $func, $priority);
  }

  private static function remove_callback(&$array, $tag, $func, $priority)
  {
    if (!isset($array[$tag][$priority])) {
      return false;
    }

    foreach ($array[$tag][$priority] as $key => $value) {
      if (isset($value['function']) && $value['function'] === $func) {
        unset($array[$tag][$priority][$key]);
        return true;
      }
    }

    return false;
  }
}