<?php
/**
 * Define our admin URL here, then use it everywhere.
 */
define('VARIABLECHECK_REPORT_PATH', 'admin/reports/variablecheck');

/**
 * Implementation of hook_permission()
 */
function variablecheck_permission() {
  return array(
    'check variables' => array(
      'title' => t('Check System Variables'),
      'description' => t('Check the validity of settings in the variable table.'),
      'restrict access' => TRUE,
    ),
  );
}

/**
 * Implementation of hook_menu().
 */
function variablecheck_menu() {
  $items['admin/reports/variablecheck'] = array(
    'title' => 'Check System Variables',
    'description' => 'Check the validity of settings in the variable table.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('variablecheck_check_variables_form'),
    'access arguments' => array('check variables'),
  );
  return $items;
}

/**
 * Implementation of hook_requirements()
 */
function variablecheck_requirements($phase) {
  $problem = count(variablecheck_check_variables());

  $requirements = array();
  $requirements['variablecheck'] = array(
    'title' => 'Variables',
    'value' => !empty($problem) ? format_plural($problem, 'One invalid variable', '@count invalid variables') : t('No problem'),
    'description' => !empty($problem) ? t('The variable table contains an invalid entry. Please check the <a href="!url">variable report</a> for more information.', array('!url' => url(VARIABLECHECK_REPORT_PATH))) : '',
    'severity' => !empty($problem) ? REQUIREMENT_WARNING : REQUIREMENT_OK,
  );

  // If the user has no access to the variables admin UI, override the status
  // description and do not include a link!
  if (!empty($problem) && !user_access('check variables')) {
    $requirements['variablecheck']['description'] = t('The variable table contains an invalid entry, but you need %permission permission to access the report.', array('%permission' => 'Check System Variables'));
  }

  return $requirements;
}

/**
 * Helper that returs a list of invalid variables and their values.
 */
function variablecheck_check_variables() {
  $rows = null;

  $select = db_select('variable', 'v')
              ->fields('v', array('name', 'value'))
              ->orderBy('name', 'ASC')
              ->comment('Load all variables')
              ->execute();
  $entries = $select->fetchAll();

  $rows = array();
  // Test each entry for validity.
  foreach ($entries as $entry) {
    // Suppress the notice.
    $value = @unserialize($entry->value);

    // If the unserialize call returned FALSE and the stored value is NOT a
    // boolean false, list it in the report.
    if ($value === FALSE && $entry->value != serialize(FALSE)) {
      $row = array('name' => $entry->name, 'value' => $entry->value);
      $rows[$entry->name] = $row;
    }
  }
  return $rows;
}

/**
 * Helper that displays a form which allows users to delete
 * variables that fail to unserialize, causing ugly Notices
 * on production sites.
 */
function variablecheck_check_variables_form($form, $form_state) {

  if (isset($form_state['values']['submit']) && $form_state['values']['submit'] == 'Delete') {
    return variablecheck_delete_confirm($form, $form_state, array_filter($form_state['values']['variables']));
  }

  $options = variablecheck_check_variables();

  $header = array(
    'name' => t('Name'),
    'value' => t('Value'),
  );

  drupal_set_title(t('Invalid Variables'));

  if ($count = count($options)) {
    drupal_set_message(format_plural($count, 'Found one invalid variable', 'Found @count invalid variables'), 'error');
    $info = format_plural($count,
        'You will want to either delete this variable or let the module developer know there is a problem with their module.',
        'You will want to either delete these variables or let the module developer know there is a problem with their module.');
  }
  else {
    $info = t('');
  }

  $form = array();
  $form['info'] = array(
    '#markup' => $info,
  );
  $form['variables'] = array(
    '#type' => 'tableselect',
    '#header' => $header,
    '#options' => $options,
    '#empty' => t('No invalid variables found'),
  );
  $form['submit'] = array(
    '#type' => 'submit',
    '#value' => t('Delete'),
    '#access' => !empty($options) ? TRUE : FALSE,
  );
  return $form;
}

/**
 * Ensure the form handler doesn't receive weird data that it shouldn't.
 */
function variablecheck_check_variables_form_validate($form, &$form_state) {
  $variables = variablecheck_check_variables();
  $submitted = array_filter($form_state['values']['variables']);

  $missing = array_keys(array_diff_key($submitted, $variables));

  foreach ($missing as $name) {
    form_set_error('', t('The variable %name does not exist in the Drupal database.', array('%name' => $name)));
  }
}

function variablecheck_check_variables_form_submit($form, &$form_state) {
  $form_state['rebuild'] = TRUE;
}

/**
 * Confirm to delete specified variables.
 */
function variablecheck_delete_confirm($form, &$form_state, $variables) {
  $form['variables'] = array('#prefix' => '<ul>', '#suffix' => '</ul>', '#tree' => TRUE);
  foreach($variables as $variable) {
    $form['variables'][$variable] = array(
      '#type' => 'hidden',
      '#value' => $variable,
      '#prefix' => '<li>',
      '#suffix' => check_plain($variable) . "</li>\n",
    );
  }
  $form['#submit'][] = 'variablecheck_delete_confirm_submit';
  $confirm_question = format_plural(count($variables),
                                  'Are you sure you want to delete this variable?',
                                  'Are you sure you want to delete these variables?');
  return confirm_form($form,
                    $confirm_question,
                    VARIABLECHECK_REPORT_PATH, t('This action cannot be undone.'),
                    t('Delete'), t('Cancel'));
}

/**
 * Delete specified variables.
 */
function variablecheck_delete_confirm_submit($form, &$form_state) {
  if ($form_state['values']['confirm']) {
    db_delete('variable')
      ->condition('name', $form_state['values']['variables'], 'IN')
      ->execute();
    $count = count($form_state['values']['variables']);
    watchdog('content', 'Deleted @count variables.', array('@count' => $count));
    drupal_set_message(format_plural($count, 'Deleted 1 variable.', 'Deleted @count variables.'));
  }
  $form_state['redirect'] = VARIABLECHECK_REPORT_PATH;
}