<?php
/**
 * @file
 * global_filter.storage.inc
 *
 * Implements via Session Cache API several ways to store the user's current
 * global filter settings. For example:
 * o in a cookie, i.e. on the user's computer
 * o on the database, i.e. on the server (disk)
 * o on the HTTP session, i.e. in server memory (RAM) aka $_SESSION
 */

define('GLOBAL_FILTER_DB_VAR', 'global_filters');
define('GLOBAL_FILTER_BLOCK_ID_PREFIX',   'global_filter_'); // Legacy, can't change
define('GLOBAL_FILTER_FILTER_KEY_PREFIX', 'global_filter_');

/**
 * Return value of a module configuration parameter, as set via the admin UI.
 *
 * Note that there is no global_filter_set_module_parameter() function. All
 * module parameters are set via the UI on admin/config/content/global_filter.
 *
 * @param string $name, name of the parameter on the admin config page.
 * @param default, value to return if the parameter hasn't been set yet
 * @return value, maybe a number, string or array.
 */
function global_filter_get_module_parameter($name, $default = NULL) {
  return variable_get('global_filter_' . $name, $default);
}

/**
 * Returns parameter value of the specified filter or all parameters if omitted.
 *
 * @param int $filter_key, positive integer or NULL to retrieve all
 * @param string $name, name of the filter parameter to retrieve, omit for all
 * @return a single value, array or two-dimensional array
 */
function global_filter_get_parameter($filter_key, $name = NULL) {
  // Take advantage of the cache inside global_filter_set_parameter() to
  // fetch all parameters. Then return the one requested or all if $name==null
  $parameters = global_filter_set_parameter(NULL, NULL, NULL);
  if (empty($filter_key) && empty($name)) {
    return $parameters;
  }
  if (empty($name)) {
    return isset($parameters[$filter_key]) ? $parameters[$filter_key] : NULL;
  }
  return isset($parameters[$filter_key][$name]) ? $parameters[$filter_key][$name] : NULL;
}

/**
 * Set a name/value pair on the filter by the key $key.
 *
 * Special cases:
 * o global_filter_set_parameter(NULL, NULL, NULL) simply returns
 *   all filter parameters keyed by filter key first and parameter name second.
 * o global_filter_set_parameter($filter_key, NULL, NULL) deletes the filter
 *
 * @param int $filter_key, a positive integer
 * @param string $name, name of parameter to set, use NULL to delete the filter
 * @param $value
 * @return parameter array
 */
function global_filter_set_parameter($key, $name, $value, $reset = FALSE) {
  // For multiple get's during the same request cache the values. The cache
  // lives in this function as it needs to be updated with every set operation.
  $parameters = &drupal_static(__FUNCTION__, NULL, $reset);

  if (!isset($parameters)) {
    $parameters = variable_get(GLOBAL_FILTER_DB_VAR, array());
    $legacy_parameters_set = variable_get('global_filter_legacy_parameters_set', FALSE);
    for ($j = 1; $j <= 9; $j++) {

      if (empty($parameters[$j]['name'])) {
        if (!$legacy_parameters_set) {
          if (_global_filter_load_legacy_parameters($j, $parameters[$j])) {
            drupal_set_message(t('Global Filter settings from 7.x-1.8 version or older were successfully loaded and saved in the new format. Filters in the old format were kept also. If you want to revert to the older version of this module AND keep the old settings do NOT uninstall this module. Just copy the old version over the top of this new one.'), 'warning', FALSE);
            // Now that the parameters have been set, we'll never get here again...
          }
          variable_set('global_filter_legacy_parameters_set', TRUE);
        }
        else {
          unset($parameters[$j]);
          continue;
        }
      }
      if (empty($parameters[$j]['block'])) {
        $parameters[$j]['block'] = GLOBAL_FILTER_BLOCK_ID_PREFIX . $j;
      }
      // Set remaining parameters to empty string to avoid NULLs (defensive programming)
      foreach (_global_filter_get_all_parameter_names() as $parameter_name) {
        if (!isset($parameters[$j][$parameter_name])) {
          $parameters[$j][$parameter_name] = '';
        }
      }
    }
  }
  if (isset($key)) {
    // Update cache and its db backup.
    if (isset($name)) {
      $parameters[$key][$name] = $value;
    }
    else {
      // Delete this filter
      unset($parameters[$key]);
    }
  }
  if (isset($key) || (isset($legacy_parameters_set) && $legacy_parameters_set === FALSE)) {
    variable_set(GLOBAL_FILTER_DB_VAR, $parameters);
  }
  return $parameters;
}

function _global_filter_load_legacy_parameters($j, &$parametersj) {
  // Check for legacy data
  $name = variable_get(GLOBAL_FILTER_BLOCK_ID_PREFIX . $j);
  if (empty($name)) {
    return FALSE;
  }
  $parametersj['name'] = $name;
  foreach (_global_filter_get_all_parameter_names() as $parameter_name) {
    if (!isset($parametersj[$parameter_name])) {
      $parametersj[$parameter_name] = variable_get(GLOBAL_FILTER_BLOCK_ID_PREFIX . $j . '_' . $parameter_name);
    }
  }
  if (!isset($parametersj['uses_view'])) {
    $parametersj['uses_view'] = (strpos($name, 'view_') === 0);
    if ($parametersj['uses_view']) {
      $parametersj['view'] = $name;
    }
    else {
      $parametersj['field'] = $name;
    }
  }
  return TRUE;
}

function global_filter_get_session_value($name = NULL) {

  $filters = session_cache_get('global_filter');
  if (empty($filters) || !is_array($filters)) {
    return NULL; // this is different from '', which means "all"
  }
  return empty($name) ? $filters : (isset($filters[$name]) ? $filters[$name] : '');
}

/**
 * Sets the filter of the supplied name to the supplied value.
 *
 * @param $name, eg 'field_country', must not be empty
 * @param $value to be set to filter of $name
 */
function global_filter_set_on_session($name, $value) {

  if (empty($name)) {
    drupal_set_message(t('Global Filter: filter name empty. Cannot set value.'), 'warning');
    return;
  }
  if (is_array($value)) {
    $value = global_filter_array_flatten($value); // e.g. hierarchical select
    if (empty($value)) {
      $value = '';
    }
  }
  $prev_value = global_filter_get_session_value($name); // gets and caches all filters
  if ($prev_value == $value) {
    gf_dbg(t('Global Filter %name: no change in value. No need to set.', array('%name' => $name)));
    return;
  }

  $filters = global_filter_get_session_value(); // may return '' or NULL
  if (empty($filters)) {
    $filters = array();
  }
  // Update the selected filter with the new value.
  $filters[$name] = $value;

  $prev_value = !isset($prev_value) || $prev_value == '' ? t('all') : (is_array($prev_value) ? implode('+', $prev_value) : $prev_value);
  $value      = !isset($value)      || $value == ''      ? t('all') : (is_array($value)      ? implode('+', $value)      : $value);
  gf_dbg(t('Global Filter %name: changing from %prev_value to %value', array(
    '%name' => $name,
    '%prev_value' => $prev_value,
    '%value' => $value
  )));

  if ($name != 'view_autocycle' && global_filter_get_module_parameter('mutex_mode', FALSE)) {
    gf_dbg(t('Global Filter mutex mode is on, so setting other filters back to their global defaults...'));

    foreach (global_filter_get_parameter(NULL) as $filter) {
      $nm = $filter['name'];
      if ($nm && $nm != $name && $nm != 'view_autocycle') {
        $filters[$nm] = global_filter_get_global_default($nm);
        gf_dbg(t('Global Filter %name: mutex reset to global default: "%value"', array(
          '%name' => $nm,
          '%value' => is_array($filters[$nm]) ? implode('+', $filters[$nm]) : $filters[$nm]
        )));
      }
    }
  }
  // Set all updated filters
  session_cache_set('global_filter', $filters);
}

/**
 * Return an array of filter parameter names.
 *
 * @return array of strings
 */
function _global_filter_get_all_parameter_names() {
  return array(
    'uses_view', 'view', 'field', 'widget', 'label', 'option_all_text',
    'convert_to_range', 'confirm_question', 'set_on_select',
    'global_php_default', 'global_field_or_view_default'
  );
}