Add a template suggestion for each context in effect (Drupal 7)

template.php

<?php
/**
 * Implements hook_preprocess()
 *
 * For each context currently activated, add a theme suggestion for each
 * existing suggestion. If you have a context called "everywhere", we don't
 * generate a suggestion for that context.
 * 
 * FIXME: This doesn't indicate which context is positioning each
 * individual item. Usually this isn't a problem, but it should be fixed.
 */
function THEME_preprocess(&$vars, $hook) {
  $context = context_get();
  if(!empty($context['context'])) {
    foreach(array_keys($context['context']) as $context_name) {
      // Skip the "everywhere" context.
      // TODO: generalize this to a condition check.
      if ($context_name == 'everywhere') {
        continue;
      }

      // Template suggestions must not contain dashes (so functions can
      // implement them) but contexts can contain dashes. This will produce
      // collisions if there are two contexts "some_thing" and "some-thing",
      // for example, but if that happens, your site is pretty far off the
      // rails already.
      $lc_context_name = str_replace('-', '_', strtolower($context_name));
      $new_suggestions = array();

      $new_suggestions[] = $hook . '__context_' . $lc_context_name;
      foreach ($vars['theme_hook_suggestions'] as $suggestion) {
        $new_suggestions[] = $suggestion;
        $new_suggestions[] = $suggestion . '__context_' . $lc_context_name;
      }
      $vars['theme_hook_suggestions'] = $new_suggestions;
    }
  }
}