<?php
// $Id: riddler.module,v 1.4 2009-07-03 12:19:39 awolfey Exp $

/**
 * @file
 * Adds a question and answer type to the Captcha module.
 *
 * When enabled this module will add a required field to forms of your choice
 * asking a simple question to avoid automatic content creation by
 * spambots. The question and answers are custimizable.
 * Thanks to: nkoponen. Ported to D6 by awolfey.
 */

/**
 * Implementation of hook_help().
 */

function riddler_help($path, $arg) {
  switch ($path) {
      case 'admin/modules#description':
            return t('Requires anonymous users to answer a simple question to be answered forms are processed. A primitive but effective way to counter spam.');
      break;
  }
}

/**
 * Implementation of hook_perm().
 */

function riddler_perm() {
  return array(
    'administer riddler',
  );
}

/**
 * Implementation of hook_menu().
 */

function riddler_menu() {
  $items = array();
    $items['admin/user/captcha/riddler'] = array(
      'title' => 'Riddler',
      'description' => 'Allows you to force a question to a number of forms to counter f.e. spammers.',
      'page callback' => 'drupal_get_form',
      'page arguments' => array('riddler_settings'),
      'access arguments' => array('administer riddler'),
      'type' => MENU_LOCAL_TASK
    );
  return $items;
}

// Riddler settings form, called by drupal_get_form in menu.
function riddler_settings() {
  $form = array();
  $form['riddler_weight'] = array(
    '#type' => 'select',
    '#title' => t('Weight'),
    '#default_value' => variable_get('riddler_weight', 0),
    '#options' => drupal_map_assoc(range(-10, 10)),
    '#description' => t('Weight of the Riddler form element'),
    '#required' => TRUE,
  );
  $form['riddler_groups'] = array(
    '#type' => 'fieldset',
    '#title' => t('Riddles'),
    '#description' => t('If you need more riddles, just submit the form, 3 empty riddles will appear.'),
  );
  $form['riddler_groups']['riddler_group_0'] = array(
    '#type' => 'fieldset',
    '#title' => variable_get('riddler_question_0', '') ? 'Default riddle: '. variable_get('riddler_question_0', '') : t('Riddle !i', array('!i' => 1)),
    '#description' => t('Empty question and answer to erase this group.'),
    '#collapsible' => TRUE,
      '#collapsed' => TRUE,
  );
  $form['riddler_groups']['riddler_group_0']['riddler_question_0'] = array(
    '#type' => 'textfield',
    '#title' => t('Question'),
    '#description' => t('A question that you require anonymous users to answer'),
    '#default_value' => variable_get('riddler_question_0', 'Do you hate spam? (yes or no)'),
    '#required' => FALSE,
  );
  $form['riddler_groups']['riddler_group_0']['riddler_answer_0'] = array(
    '#type' => 'textfield',
    '#title' => t('Answer'),
    '#default_value' => variable_get('riddler_answer_0', 'yes'),
    '#description' => t('Answer to the above question. You may allow more than one correct answer by entering a comma or space-separated list. Answers are not case sensitive. Answers must be only one word.'),
    '#required' => FALSE,
  );
  $number = variable_get('riddler_number', 1);
  for ( $i=1; $i<$number + 3; $i++) {
    $form['riddler_groups']['riddler_group_'. $i] = array(
      '#type' => 'fieldset',
      '#title' => variable_get('riddler_question_'. $i, '') ? 'Riddle '.  $i . ': '. variable_get('riddler_question_'. $i, '') : t('Riddle !i', array('!i' => $i)),
      '#description' => t('Empty question and answer to erase this group.'),
      '#collapsible' => TRUE,
      '#collapsed' => $i < $number,
    );
    $form['riddler_groups']['riddler_group_'. $i]['riddler_question_'. $i] = array(
      '#type' => 'textfield',
      '#title' => t('Question'),
      '#description' => t('A question that you require anonymous users to answer'),
      '#default_value' => variable_get('riddler_question_'. $i, ''),
      '#required' => FALSE,
    );
    $form['riddler_groups']['riddler_group_'. $i]['riddler_answer_'. $i] = array(
      '#type' => 'textfield',
      '#title' => t('Answer'),
      '#default_value' => variable_get('riddler_answer_'. $i, ''),
    '#description' => t('Answer to the above question. You may allow more than one correct answer by entering a comma or space-separated list. Answers are not case sensitive.  Answers must be only one word.'),
      '#required' => FALSE,
    );
  }
  $form['#validate'][] = 'riddler_settings_validate';
  $form['#submit'][] = 'riddler_settings_submit';

  return system_settings_form($form);
}

// Validating the settings form.
function riddler_settings_validate($form, &$form_state) {
  $i = 0;
  while (array_key_exists('riddler_question_'. $i, $form_state['values'])) {
    if ($form_state['values']['riddler_question_'. $i] != '' && $form_state['values']['riddler_answer_'. $i] == '') {
      form_set_error('riddler_answer_'. $i, t('Group !i is incomplete (answer is missing).', array('!i' => $i+1)));
    }
    if ($form_state['values']['riddler_question_'. $i] == '' && $form_state['values']['riddler_answer_'. $i] != '') {
      form_set_error('riddler_question_'. $i, t('Group !i is incomplete (question is missing).', array('!i' => $i+1)));
    }
    $i++;
  }
}

// Processing the settings form.
function riddler_settings_submit($form, &$form_state) {
  variable_set('riddler_weight', $form_state['values']['riddler_weight']);
  $i = 0;
  $number = 0;
  while (array_key_exists('riddler_question_'. $i, $form_state['values'])) {
    if ($form_state['values']['riddler_question_'. $i] != '') {
      variable_set('riddler_question_'. $number, $form_state['values']['riddler_question_'. $i]);
      variable_set('riddler_answer_'. $number, $form_state['values']['riddler_answer_'. $i]);
      $number++;
    }
    $i++;
  }
  variable_set('riddler_number', $number);
}

/**
 * Implementation of hook_captcha().
 */
function riddler_captcha($op, $captcha_type='') {
  switch ($op) {
    case 'list' :
      return array('Riddler');
      break;
    case 'generate' :
      $result = array();
      if ($captcha_type == 'Riddler') {
        $i = rand(1, variable_get('riddler_number', 1)) - 1;
        $result['form']['captcha_response'] = array(
          '#type' => 'textfield',
          '#title' => variable_get('riddler_question_'. $i, 'Do you hate spam? (yes or no)'),
          '#description' => t('Fill in the blank'),
          '#size' => 50,
          '#maxlength' => 50,
          '#required' => TRUE,
          '#weight' => variable_get('riddler_weight', 0),
        );
        $result['solution'] = (string)(drupal_strtolower(variable_get('riddler_answer_'. $i, 'yes')));
        $result['captcha_validate'] = 'riddler_captcha_validate';
        return $result;
      }
    break;
  }
}

// Custom captcha validation.
function riddler_captcha_validate($solution, $response) {
  $solution = str_ireplace(',', '', $solution);
  $solution = explode(' ', $solution);
  return in_array(drupal_strtolower($response), $solution);
}