<?php

/**
 * @file
 * APCu instrumentation for Munin.
 *
 * @copyright (c) 2011-2019 Ouest Systèmes Informatiques
 *
 * Licensed under the General Public License version 2 or later.
 */

/**
 * Implements hook_munin_api_info().
 *
 * Returns an array of Munin graph informations, indexed by graph name, each
 * containing an array of field information.
 */
function munin_apc_munin_api_info() {
  $int = [
    '#graph_printf' => '%d',
  ];

  $ret = [
    '#title' => t('APCu'),
    '#description' => t('Graphs about PHP APCu memory use'),

    'munin_apc' => [
      '#title' => t('APCu Caching'),
      '#info' => t('Collect memory-level information for the Alternative PHP Cache for user data). This graph uses IEC binary sizes.'),
      '#graph_args' => '--base 1024 --lower-limit 0',

      'total_size' => $int + [
        '#label' => t('Bytes allocated'),
        '#type' => MUNIN_API_GAUGE,
        '#info' => t('Number of bytes allocated to APCu.'),
      ],
      'used_size' => $int + [
        '#label' => t('Bytes in use'),
        '#type' => MUNIN_API_GAUGE,
        '#info' => t('Number of bytes actually used by APCu, either cached or deleted'),
      ],
    ],

    'munin_apc_entries' => [
      '#title' => t('APCu Entries'),
      '#info' => t('Collect entries-level information for APCu.'),
      '#graph_args' => '--base 1000 --lower-limit 0',

      'num_hits' => $int + [
        '#label' => t('Hits since last restart'),
        '#type' => MUNIN_API_COUNTER,
      ],
      'num_misses' => $int + [
        '#label' => t('Misses since last restart'),
        '#type' => MUNIN_API_COUNTER,
      ],
      'num_inserts' => $int + [
        '#label' => t('Insertions since last restart'),
        '#type' => MUNIN_API_COUNTER,
      ],
      /*
      'hit_rate' => $int + [
        '#label' => t('Hit/miss ratio since last restart'),
        '#type' => MUNIN_API_GAUGE,
      ],
       */
      'cache_entries' => $int + [
        '#label' => t('Number of cache entries'),
        '#type' => MUNIN_API_GAUGE,
      ],
      'deleted_entries' => $int + [
        '#label' => t('Number of deleted entries'),
        '#type' => MUNIN_API_GAUGE,
        '#info' => t('Deleted entries lingering until the garbage collection TTL elapses'),
      ],
    ],

    'munin_apc_uptime' => [
      '#title' => t('APC Uptime'),
      '#info' => t('Uptime information for APCu.'),
      '#graph_vlabel' => t('Uptime in days'),
      '#graph_scale' => 'no',

      'uptime' => $int + [
        '#label' => t('Up-time of APCu instance'),
        '#type' => MUNIN_API_GAUGE,
        '#info' => t('Days since last APCu restart.'),
        '#draw' => MUNIN_API_DRAW_AREA,
      ],
    ],
  ];

  return $ret;
}

/**
 * Implements hook_munin_api_fetch().
 *
 * The static cache is useless at this point, but will likely become useful
 * if module builds Munin multigraphs.
 */
function munin_apc_munin_api_fetch($graph_name) {

  static $cache = [];

  if (empty($cache)) {
    $info = apcu_sma_info();

    // SMA Info.
    $total = $info['num_seg'] * $info['seg_size'];
    $cache['munin_apc']['total_size'] = (int) $total;
    $cache['munin_apc']['used_size'] = (int) ($total - $info['avail_mem']);

    // Cache info.
    $info = apcu_cache_info();
    $cache['munin_apc_uptime']['uptime'] = (REQUEST_TIME - $info['start_time']) / 86400;
    foreach (['num_hits', 'num_misses', 'num_inserts'] as $field) {
      $cache['munin_apc_entries'][$field] = $info[$field];
    }

    $cache['munin_apc_entries']['cache_entries']   = $info['num_entries'] ?? count($info['cache_list']);
    $cache['munin_apc_entries']['deleted_entries'] = count($info['deleted_list']);
  }

  $ret = $cache[$graph_name];
  return $ret;
}