<?php

/**
 * @file
 * Qforms module.
 *
 * Main qforms logic. Defines textfield, textarea, radio group, checkbox group
 * and select box qforms elements.
 */

/*************/
/*** Hooks ***/
/*************/

/**
* Implementation of hook_menu().
*/
function qforms_menu() {
  $items['node/%node/qforms-results'] = array(
    'title' => 'Submission results',
    'page callback' => 'qforms_results_submissions',
    'page arguments' => array(1),
    'access callback' => 'qforms_check_node_access',
    'access arguments' => array('update', 1),
    'file' => 'qforms.pages.inc',
    'weight' => 2,
    'type' => MENU_LOCAL_TASK,
  );

  $items['node/%node/qforms-results/export'] = array(
    'title' => 'Submission results export',
    'page callback' => 'qforms_results_submissions_export',
    'page arguments' => array(1),
    'access callback' => 'qforms_check_node_access',
    'access arguments' => array('update', 1),
    'file' => 'qforms.pages_export.inc',
    'type' => MENU_CALLBACK,
  );

  $items['node/%node/qforms-result/%'] = array(
    'title' => 'View submission result',
    'page callback' => 'qforms_submission_page',
    'page arguments' => array(1, 3),
    'access callback' => 'qforms_check_node_access',
    'access arguments' => array('update', 1),
    'file' => 'qforms.pages.inc',
    'type' => MENU_CALLBACK,
  );

  $items['node/%node/qforms-result/%/delete'] = array(
    'title' => 'Delete submission result',
    'page callback' => 'qforms_submission_confirm_delete_page',
    'page arguments' => array(1, 3),
    'access callback' => 'qforms_check_node_access',
    'access arguments' => array('delete', 1),
    'file' => 'qforms.pages.inc',
    'type' => MENU_CALLBACK,
  );

  return $items;
}

/**
 * Implementation of hook_qforms().
 *
 * This hook should return qform configuration array. Array consist of two
 * elements:
 *   - js - defines js files that needs to be loaded for qform.
 *   - elements - defines all qforms elements and apropriate function calls.
 */
function qforms_qforms() {
  $module_path = drupal_get_path('module', 'qforms');

  return array(
    'js' => array($module_path . '/js/qforms.js'),
    'css' => array($module_path . '/qforms.css'),
    'elements' => array(
      'textfield' => array(
        'file' => $module_path . '/inc/qforms.textfield.inc',
        'name' => t('Single line text field'),
        'fapi' => 'qforms_fapi_textfield',
        'element' => 'qforms_element_textfield',
        'group' => 'core',
      ),
      'textarea' => array(
        'file' => $module_path . '/inc/qforms.textarea.inc',
        'name' => t('Multi line text area'),
        'fapi' => 'qforms_fapi_textarea',
        'element' => 'qforms_element_textarea',
        'group' => 'core',
      ),
      'checkboxes' => array(
        'file' => $module_path . '/inc/qforms.checkboxes.inc',
        'name' => t('Checkbox group'),
        'fapi' => 'qforms_fapi_checkboxes',
        'element' => 'qforms_element_checkboxes',
        'prepare_for_saving' => 'qforms_element_options_prepare_for_saving',
        'prepare_for_csv_export' => 'qforms_element_checkboxes_prepare_for_csv_export',
        'group' => 'core',
      ),
      'select' => array(
        'file' => $module_path . '/inc/qforms.select.inc',
        'name' => t('Single/Multi select list'),
        'fapi' => 'qforms_fapi_select',
        'element' => 'qforms_element_select',
        'element_validate' => 'qforms_element_select_validate',
        'prepare_for_saving' => 'qforms_element_options_prepare_for_saving',
        'prepare_for_csv_export' => 'qforms_element_select_prepare_for_csv_export',
        'group' => 'core',
      ),
      'radios' => array(
        'file' => $module_path . '/inc/qforms.radios.inc',
        'name' => t('Radio group'),
        'fapi' => 'qforms_fapi_radios',
        'element' => 'qforms_element_radios',
        'element_validate' => 'qforms_element_radios_validate',
        'prepare_for_saving' => 'qforms_element_options_prepare_for_saving',
        'prepare_for_csv_export' => 'qforms_element_radios_prepare_for_csv_export',
        'group' => 'core',
      ),
    ),
  );
}

/**
 * Implements hook_node_info().
 */
function qforms_node_info() {
  return array(
    'qform' => array(
      'name' => t('Qform'),
      'base' => 'qforms',
      'description' => t('A <em>qforms</em> is a survey content type. It allows site users to create custom forms (like surveys) for which other site users can submit data.'),
      'title_label' => t('Title'),
      'locked' => TRUE,
    )
  );
}

/**
 * Implements hook_form().
 */
function qforms_form($node, &$form_state) {
  _qforms_init_css_js();

  $form = node_content_form($node, $form_state);

  $form['qforms'] = array(
    '#type' => 'fieldset',
    '#title' => t('Form builder'),
    '#weight' => 1,
    '#collapsible' => FALSE,
    '#collapsed' => FALSE,
  );

  $form['qforms']['qforms_form_actions'] = array(
    '#markup' => theme('qforms_form_actions'),
  );

  $elements_def = qforms_get_elements_definition();
  $elements_options = array('' => t('Add new form element...'));
  foreach ($elements_def['elements'] as $key => $element) {
    $elements_options[$element['group']][$key] = $element['name'];
  }

  // Control for adding new form elements with ajax.
  $form['qforms']['qforms_add_element'] = array(
    '#type' => 'select',
    '#options' => $elements_options,
    '#ajax' => array(
      'callback' => 'qforms_add_form_element',
      'wrapper' => 'qforms-elements',
      'effect' => 'fade',
      'method' => 'append',
    ),
  );

  $form['qforms']['elements'] = array(
    '#prefix' => '<div id="qforms-elements">',
    '#suffix' => '</div>',
  );

  // If we are on first form load.
  if (!isset($form_state['qforms_elements'])) {
    $form_state['qforms_elements'] = array(); // This persistent array is storing all added form elements (new (from ajax) and old (from db) one).
    $form_state['qforms_last_element_id'] = 0;

    // Do we have stored form elements from database?
    if (!empty($node->qforms_form_definition)) {

      if (isset($node->qforms_form_definition['qforms_last_element_id'])) {
        $form_state['qforms_last_element_id'] = $node->qforms_form_definition['qforms_last_element_id'];
      }
      foreach ($node->qforms_form_definition as $weight => $element) {
        if (is_array($element)) {
          $form_state['qforms_elements'] += qforms_create_element($element, $form_state);
        }
      }
    }
  }

  $telement = NULL;
  if (isset($form_state['triggering_element'])) {
    $telement = & $form_state['triggering_element'];
  }

  // If we are in ajax event for deleting a form element we need to delete this
  //  element from $form_state['qforms_elements'].
  if (isset($telement) && isset($telement['#ajax']) && $telement['#ajax']['callback'] == 'qforms_delete_form_element_callback') {
    $element_key = $telement['#ajax']['wrapper'];
    unset($form_state['qforms_elements'][$element_key]);

    // We also need to remove element data from node - it will be there if user
    // previewed node before.
    foreach ($node as $key => $value) {
      if (strpos($key, $element_key) === 0) {
        unset($node->$key);
      }
    }
  }

  // Restore elements from $form_state['qforms_elements'].
  if (!empty($form_state['qforms_elements'])) {

    // If we are in ajax submission check do we need to update some form element.
    if (isset($telement) && isset($telement['#ajax'])) {
      $key = isset($telement['#ajax']['qforms_parent']) ? $telement['#ajax']['qforms_parent'] : NULL;
      if (isset($key) && array_key_exists($key, $form_state['qforms_elements'])) {
        // Update element.
        $element = & $form_state['qforms_elements'][$key];

        // Load ajax qforms_include file if needed.
        if (isset($telement['#ajax']['qforms_include'])) {
          include_once $telement['#ajax']['qforms_include'];
        }

        call_user_func_array($telement['#ajax']['qforms_callback'], array($key, & $element, & $form_state));
      }
    }

    $form['qforms']['elements'] += $form_state['qforms_elements'];
  }

  // If we are in ajax event for adding a new element.
  if (!empty($form_state['values']['qforms_add_element']) && $form_state['values']['qforms_add_element']) {
    ++$form_state['qforms_last_element_id'];

    $new_element = qforms_create_element_form_state($form, $form_state);
    $form['qforms']['elements'] += $new_element;
    $form_state['qforms_elements'] += $new_element;
  }

  $form['qforms_last_element_id'] = array(
    '#type' => 'value',
    '#value' => $form_state['qforms_last_element_id'],
    );

  // Settings section for qforms form.
  $form['qforms_settings'] = array(
    '#type' => 'fieldset',
    '#title' => t('Form settings'),
    '#group' => 'additional_settings',
    '#collapsible' => TRUE,
    '#collapsed' => TRUE,
  );

  $form['qforms_settings']['qforms_submit_action'] = array(
    '#type' => 'select',
    '#title' => t('Action to take on form submission'),
    '#options' => array(
      'no_action' => t('No action'),
      'custom_message' => t('Show custom message'),
      'redirect' => t('Redirect'),
    ),
    '#default_value' => isset($node->qforms_submit_action)? $node->qforms_submit_action : '',
  );
  $form['qforms_settings']['qforms_submit_action_custom_message'] = array(
    '#type' => 'textfield',
    '#title' => t('Custom message text'),
    '#states' => array(
      'visible' => array(':input[name="qforms_submit_action"]' => array('value' => 'custom_message')),
    ),
    '#default_value' => isset($node->qforms_submit_action_custom_message)? $node->qforms_submit_action_custom_message : '',
  );

  $default_value_redirect = '';
  if (isset($node->qforms_submit_action_redirect)) {
    $default_value_redirect = ($node->qforms_submit_action_redirect != '<front>')? check_url($node->qforms_submit_action_redirect) : '<front>';
  }
  $form['qforms_settings']['qforms_submit_action_redirect'] = array(
    '#type' => 'textfield',
    '#title' => t('Redirect URL'),
    '#description' => t('Input absolute URL or page path, for example http://example.com or node/123.'),
    '#states' => array(
      'visible' => array(':input[name="qforms_submit_action"]' => array('value' => 'redirect')),
    ),
    '#default_value' => $default_value_redirect,
  );

  $form['qforms_settings']['qforms_submit_email'] = array(
    '#type' => 'checkbox',
    '#title' => t('Send an email on form submission'),
    '#default_value' => isset($node->qforms_submit_email) ? $node->qforms_submit_email : FALSE,
  );
  $form['qforms_settings']['qforms_submit_email_values'] = array(
    '#type' => 'textarea',
    '#title' => t('Email addresses'),
    '#description' => t('You can enter multiple emails, add one email address per line.'),
    '#states' => array(
      'visible' => array(':input[name="qforms_submit_email"]' => array('checked' => TRUE)),
    ),
    '#default_value' => isset($node->qforms_submit_email_values)? $node->qforms_submit_email_values : '',
  );
  $form['qforms_settings']['qforms_submit_disable'] = array(
    '#type' => 'checkbox',
    '#title' => t('Disable form'),
    '#description' => t('Do not show form when viewing this node.'),
    '#default_value' => isset($node->qforms_submit_disable) ? $node->qforms_submit_disable : FALSE,
  );

  return $form;
}

/**
* Implements hook_validate().
*/
function qforms_validate($node, $form, &$form_state) {
  // When form submition is invalid form will not be rebuilded so we need to
  // include css and js files just to be sure they will be present.
  _qforms_init_css_js();

  // Validate qform elements.
  foreach ($form['qforms']['elements']  as $id => $element) {

    // Validate common element data.
    if (is_array($element) && isset($element['#qforms_type'])) {
      $data = & $element[$id . '_data'];

      // If size exist it can be empty or number.
      $value_key = $id . '_size';
      if (isset($data[$value_key]) && (!empty($data[$value_key]['#value']) && !is_numeric($data[$value_key]['#value']))) {
        form_set_error($value_key, t('Please enter a valid round number for element size.'));
      }

      // Weight always exists and can be number.
      $value_key = $id . '_weight';
      if (!is_numeric($data[$value_key]['#value'])) {
        form_set_error($value_key, t('Please enter a valid number for element weight.'));
      }

    }

    // Custom element validation.
    if (isset($element['#qforms_type']) && $qcall = qforms_get_callback('element_validate', $element['#qforms_type'])) {
      call_user_func_array($qcall, array($id, &$form_state));
    }
  }

  if ($node->qforms_submit_action == 'custom_message' && empty($node->qforms_submit_action_custom_message)) {
    form_set_error('qforms_submit_action_custom_message', t('Please enter custom message text.'));
  }

  if ($node->qforms_submit_action == 'redirect') {
    if (empty($node->qforms_submit_action_redirect)) {
      form_set_error('qforms_submit_action_redirect', t('Please enter redirect URL.'));
    }
    elseif (!drupal_valid_path($node->qforms_submit_action_redirect)) {
      form_set_error('qforms_submit_action_redirect', t('Please enter a valid URL.'));
    }
  }

  if ($node->qforms_submit_email) {
    if (empty($node->qforms_submit_email_values)) {
      form_set_error('qforms_submit_email_values', t('Please enter email addresses.'));
    }
    else {

      $emails = preg_split("/\n/", $node->qforms_submit_email_values);
      foreach ($emails as $email) {
        $email = trim($email);
        if (!valid_email_address($email)) {
          form_set_error('qforms_submit_email_values', t('Entered email @email is not valid.', array('@email' => $email)));
        }
      }
    }
  }
}

/**
 * Implements hook_node_submit().
 */
function qforms_node_submit($node, $form, $form_state) {
  if ($node->type != 'qform') {
    return;
  }

  // Transform all submited elemements data into nice structured array.
  // Format of a $key is qforms_element_(weight)_(type)_(data)
  $elements = array();
  foreach ($node as $key => $value) {
    if (strpos($key, 'qforms_element_') === 0) {
      // Remove "qforms_element_" part.
      $part = substr($key, 15, strlen($key));

      // Get 'id' right position and id.
      $id_pos = strpos($part, '_');
      $id = (int) substr($part, 0, $id_pos);

      // Get 'type' right position.
      $tpos = strpos($part, '_', $id_pos + 1);
      $type = substr($part, $id_pos + 1, $tpos - $id_pos - 1);

      // Get fapi element key.
      $element_id = _qforms_get_element_id($id, $type);

      // Get 'data'.
      $data = substr($part, $tpos + 1);

      // Remove certan data that we do not need.
      if ($data == 'delete') { // For now this is only delete - from delete form element button.
        continue;
      }

      if (!isset($elements[$element_id])) {
        $elements[$element_id] = array();
        $elements[$element_id]['type'] = $type;
      }

      $elements[$element_id][$data] = $value;
    }
  }

  // Check if form elements needs to change data before saving.
  foreach ($elements as $id => & $element) {
    if ($qcall = qforms_get_callback('prepare_for_saving', $element['type'])) {
      call_user_func_array($qcall, array(&$element));
    }
  }

  $elements['qforms_last_element_id'] = $node->qforms_last_element_id;
  $node->qforms_form_definition = $elements;
}

/**
 * Implements hook_insert().
 */
function qforms_insert($node) {
  qforms_node_save($node);
}

/**
 * Implements hook_update().
 */
function qforms_update($node) {
  qforms_node_save($node);
}

/**
 * Implements hook_delete().
 */
function qforms_delete($node) {
  qforms_db_delete_form($node->nid);
  qforms_db_delete_all_submissions($node->nid);
}

/**
 * Implements hook_load().
 */
function qforms_load($nodes) {
  foreach ($nodes as $node) {
    // Load qforms.
    if ($form = _qforms_db_load_form($node->nid)) {
      // Form definition.
      $node->qforms_form_definition = unserialize($form['form_definition']);

      $form_options = unserialize($form['form_options']);

      // Form options.
      $node->qforms_submit_action = $form_options['qforms_submit_action'];
      $node->qforms_submit_action_custom_message = $form_options['qforms_submit_action_custom_message'];
      $node->qforms_submit_action_redirect = $form_options['qforms_submit_action_redirect'];
      $node->qforms_submit_email = $form_options['qforms_submit_email'];
      $node->qforms_submit_email_values = $form_options['qforms_submit_email_values'];
      $node->qforms_submit_disable = $form_options['qforms_submit_disable'];
    }
  }

  return $node;
}

/**
 * Implement hook_view().
 */
function qforms_view($node, $view_mode) {
  // Show qform form.
  if (($view_mode == 'full') && user_access('view and submit qform') && (!$node->qforms_submit_disable)) {
    $preview = isset($node->in_preview)? $node->in_preview : FALSE;
    $node->content['qform'] = array(
      'form' => drupal_get_form('qforms_submit_form', $node->nid, $node->qforms_form_definition, $preview),
      '#weight' => 10,
    );
  }

  return $node;
}

/**
 * Implements hook_mail().
 */
function qforms_mail($key, &$message, $params) {
  switch ($key) {
    case 'submission':
      $langcode = $message['language']->language;
      $site = variable_get('site_name', '');

      $message['subject'] = t('Notification from !site - qform submission', array('!site' => $site), array('langcode' => $langcode));
      $message['body'][] = t('Qform submission for !node_url.\nYou can see submited data on !data_url',
        array(
          '!node_url' => url('node/' . $params['nid'], array('absolute' => TRUE)),
          '!data_url' => url('node/' . $params['nid'] . '/qforms-result/' . $params['sid'], array('absolute' => TRUE)),
        ),
        array('langcode' => $langcode)
      );
      break;
  }
}

/**
 * Implementation of hook_theme().
 */
function qforms_theme() {
  return array(
    'qforms_submission_author' => array(
      'variables' => array('submission', 'account'),
      'file' => 'qforms.theme.inc',
    ),
    'qforms_select' => array(
      'render element' => 'element',
      'file' => 'qforms.theme.inc',
    ),
    'qforms_form_actions' => array(
      'file' => 'qforms.theme.inc',
    ),
  );
}

/**
 * Implementation of hook_permission()
 */
function qforms_permission() {
  return array(
    'view and submit qform' => array(
      'title' => t('View and submit qform'),
      'description' => t('Give users a permission to view and submit qform.'),
    ),
  );
}

/**********************/
/*** Menu callbacks ***/
/**********************/

/**
 * Ajax callback for adding a new form element.
 */
function qforms_add_form_element(&$form, &$form_state) {
  $id = _qforms_get_element_id($form_state['qforms_last_element_id'], $form_state['values']['qforms_add_element']);
  return $form['qforms']['elements'][$id];
}

/**
 * Ajax callback for removing a form element.
 */
function qforms_delete_form_element_callback(&$form, &$form_state) {
  return '';
}

/************************/
/*** Helper functions ***/
/************************/

/**
 * Returns TRUE if a node is of a type qform and user has access to op on that
 * node.
 *
 * @param $op
 *  Node operation, like update, delete...
 * @param $node
 *  Drupal node object.
 */
function qforms_check_node_access($op, $node) {
  if ($node->type == 'qform' && node_access($op, $node)) {
    return TRUE;
  }
  return FALSE;
}

/**
 * Returns qforms element call function if it exist or FALSE.
 *
 * @param $element_function
 *  Base of a element call function.
 * @param $element_type
 *  Qform element type.
 * @return
 *  String of a call function if it exist or FALSE.
 */
function qforms_get_callback($element_function, $element_type) {
  $elements_def = qforms_get_elements_definition();

  // Check if we have definition of element type and element function that we need.
  if (!isset($elements_def['elements'][$element_type]) || !isset($elements_def['elements'][$element_type][$element_function])) {
    return FALSE;
  }

  // Load qforms.inc with commons functions that is needed by all elements.
  module_load_include('inc', 'qforms');

  // Include inc file if it is defined.
  if (isset($elements_def['elements'][$element_type]['file'])) {
    include_once $elements_def['elements'][$element_type]['file'];
  }

  return $elements_def['elements'][$element_type][$element_function];
}

/**
 * Create form element array from form_state array.
 */
function qforms_create_element_form_state(&$form, &$form_state) {
  $type = $form_state['values']['qforms_add_element'];
  if ($qcall = qforms_get_callback('element', $type)) {
    $element_data = array(
      'id' => _qforms_get_element_id($form_state['qforms_last_element_id'], $type),
      'type' => $type,
      'weight' => $form_state['qforms_last_element_id']
    );

    return array(
      $element_data['id'] => call_user_func_array($qcall, array($element_data))
    );
  }
}

/**
 * Create form element array from element data, element data are unserialized
 * from database.
 */
function qforms_create_element($element, &$form_state) {
  $type = $element['type'];
  if ($qcall = qforms_get_callback('element', $type)) {
    return array(
      $element['id'] => call_user_func_array($qcall, array($element))
    );
  }
}

/**
 * Helper function for saving qform definition on node insert or update.
 *
 * @param $node
 */
function qforms_node_save($node) {
  // Delete previous form if it is available.
  qforms_db_delete_form($node->nid);

  $ser_form = serialize($node->qforms_form_definition);

  // Prepare form settings options.
  $form_options['qforms_submit_action'] = $node->qforms_submit_action;
  $form_options['qforms_submit_action_custom_message'] = $node->qforms_submit_action_custom_message;
  $form_options['qforms_submit_action_redirect'] = $node->qforms_submit_action_redirect;
  $form_options['qforms_submit_email'] = $node->qforms_submit_email;
  $form_options['qforms_submit_email_values'] = $node->qforms_submit_email_values;
  $form_options['qforms_submit_disable'] = $node->qforms_submit_disable;
  $form_options = serialize($form_options);

  qforms_db_save_form($node->nid, $ser_form, $form_options);
}

/**
 * Builds submit form using Drupal FAPI.
 *
 * @param $entity_id
 *   Entity id of entity we are building form. For example node id.
 * @param $form_def
 *   Qform form definition.
 * @param $preview
 *   TRUE if we are previewing this qform.
 * @return
 *   Builded Drupal form array.
 */
function qforms_submit_form($form, &$form_state, $entity_id, $form_def, $preview = FALSE) {
  return _qforms_build_drupal_form($entity_id, $form_def, NULL, $preview);
}

function qforms_submit_form_submit($form, &$form_state) {
  $nid = $form_state['values']['entity_id'];

  // Prepare submitted data for saving.
  foreach ($form_state['values'] as $key => $value) {
    if (strpos($key, 'qforms_') === 0) {
      $data[$key] = $value;
    }
  }
  $data = serialize($data);
  if (empty($data)) {
    return;
  }

  // Save submitted data.
  $sid = qforms_db_save_submission($nid, $data);
  watchdog('qforms', 'Submitted qform for node !nid. Submission sid is !sid', array('!nid' => $nid, '!sid' => $sid));

  // Now let's execute any custom submit action.

  // Load qform data.
  $qform = qforms_db_load_form($form_state['values']['entity_id']);
  $options = & $qform['form_options'];

  // Mail sending.
  if ($options['qforms_submit_email']) {
    // Get email address for sending.
    $to = array();
    $emails = preg_split("/\n/", $options['qforms_submit_email_values']);
    foreach ($emails as $email) {
      $to[] = trim($email);
    }
    $to = join(', ', $to);

    $params = array('nid' => $nid, 'sid' => $sid);

    drupal_mail('qforms', 'submission', $to, language_default(), $params);
  }

  // Other custom actions.
  switch ($options['qforms_submit_action']) {
    case 'no_action':
      drupal_set_message(t('Thank you for your submission.'));
      break;
    case 'custom_message':
      drupal_set_message(check_plain($options['qforms_submit_action_custom_message']));
      break;
    case 'redirect':
      drupal_goto($options['qforms_submit_action_redirect']);
      break;
  }
}

/**
 * Builds page for submited results view.
 *
 * @param <type> $form
 * @param <type> $form_state
 * @param <type> $entity_id
 * @param <type> $sid
 * @return string
 */
function qforms_submit_view_form($form, &$form_state, $entity_id, $sid) {
  $form = _qforms_build_drupal_form($entity_id, NULL, $sid);

  $form['sid'] = array(
    '#type' => 'value',
    '#value' => $sid,
  );

  $form['entity_id'] = array(
    '#type' => 'value',
    '#value' => $entity_id,
  );

  // Load submission results.
  $submission = qforms_db_load_submission($sid);

  // We will also check if entity_id that we are getting from url is different from stored submission result nid.
  if (!$submission || $submission->nid != $entity_id) {
    return drupal_not_found();
  }

  // Load author info.
  $author = user_load($submission->uid);
  $form['author'] = array(
    '#type' => 'fieldset',
    '#title' => t('Submission Information'),
    '#weight' => -1,
    '#collapsible' => TRUE,
    '#collapsed' => FALSE,
  );
  $form['author']['info'] = array(
    '#markup' => theme('qforms_submission_author', array('submission' => $submission, 'account' => $author)),
  );

  unset($form['actions']['submit']);
  $form['actions']['ok'] = array(
    '#type' => 'submit',
    '#value' => t('OK'),
    '#submit' => array('qforms_submit_view_form_submit_ok'),
    '#limit_validation_errors' => array(),
  );
  $form['actions']['delete'] = array(
    '#type' => 'submit',
    '#value' => t('Delete'),
    '#submit' => array('qforms_submit_view_form_submit_delete'),
    '#limit_validation_errors' => array(),
  );

  return $form;
}

function qforms_submit_view_form_submit_ok($form, &$form_state) {
  $form_state['redirect'] = 'node/' . $form['entity_id']['#value'] . '/qforms-results';
}

function qforms_submit_view_form_submit_delete($form, &$form_state) {
  $form_state['redirect'] = 'node/' . $form['entity_id']['#value'] . '/qforms-result/' . $form['sid']['#value'] . '/delete';
}

/**
 * Helper function for form building.
 */
function _qforms_build_drupal_form($entity_id, $form_def = NULL, $sid = NULL, $preview = FALSE) {
  // Load form definition.
  if (isset($entity_id) && !isset($form_def)) {
    $qform = qforms_db_load_form($entity_id);
    $form_def = $qform['form_definition'];
    if (empty($form_def)) {
      return;
    }
  }

  $submission_results = NULL;
  if ($sid) {
    // Load submission results.
    $submission_results = qforms_db_load_submission($sid);

    // If entity_id is different from stored submission result nid stop execution.
    if (!$submission_results || $entity_id != $submission_results->nid) {
      return;
    }
  }

  $form = array();

  // Lets collect all qforms elements definitions.
  $elements_def = qforms_get_elements_definition();

  // Add form elements.
  foreach ($form_def as $key => $element) {
    if (is_array($element)) {
      $element['key'] = $key;
      $params = array($element);

      // If we have submission results then we need to get submited values for defaults.
      if ($submission_results) {

        if (isset($elements_def['elements'][$element['type']]['submission_results'])) {
          // @TODO (grid) - this code will be tested in future when we add grid element.
          call_user_func_array($elements_def['elements'][$element['type']]['submission_results'], array(&$params, $submission_results));
        }
        else {
          // Usually data[$key] do not exist when form definition is changed after submited data.
          if (isset($submission_results->data[$key])) {
            $params[1]['default_value'] = $submission_results->data[$key]; // default value
            $params[1]['readonly'] = TRUE; // read-only
            if (isset($submission_results->data[$key . '_other'])) {
              $params[1]['default_value_other'] = $submission_results->data[$key . '_other'];
            }
          }
        }
      }

      // Call apropriate fapi function for form element generation.
      if ($qcall = qforms_get_callback('fapi', $element['type'])) {
        $form[$key] = call_user_func_array($qcall, $params);
      }

      $form[$key]['#weight'] = $params[0]['weight'];

      // Is element visible?
      if ((isset($element['visible'])) && ($element['visible'] != 1)) {
        $form[$key]['#access'] = FALSE;
      }
      if (isset($element['required'])) {
        $form[$key]['#required'] = ($element['required']) ? TRUE : FALSE;
      }
    }
  }

  $form['actions'] = array('#type' => 'actions');
  $form['actions']['submit'] = array(
    '#type' => 'submit',
    '#value' => t('Submit'),
    '#disabled' => $preview,
  );

  $form['entity_id'] = array(
    '#type' => 'value',
    '#value' => $entity_id
  );

  return $form;
}

/**
 * Returns qform elements definition in all modules.
 */
function qforms_get_elements_definition() {
  static $defs = NULL;

  if (isset($defs)) {
    return $defs;
  }

  $defs = module_invoke_all('qforms');

  return $defs;
}

/**
 * Returns unique qform element id for form array key.
 */
function _qforms_get_element_id($element_id, $type) {
  return 'qforms_element_' . $element_id . '_' . $type;
}

/**
 * Load all CSS and JS files we need.
 */
function _qforms_init_css_js() {
  static $done = FALSE;

  if ($done === TRUE) {
    return;
  }

  $done = TRUE;
  $path = drupal_get_path('module', 'qforms');

  drupal_add_library('system', 'ui.sortable');

  // If we have scrollTo jquery plugin lets add it.
  if (file_exists($path . '/js/jquery.scrollTo-min.js')) {
    drupal_add_js($path . '/js/jquery.scrollTo-min.js');
  }

  // Load js files.
  $elements_def = qforms_get_elements_definition();
  foreach ($elements_def['js'] as $js_path) {
    drupal_add_js($js_path);
  }

  // Load css files.
  foreach ($elements_def['css'] as $css_path) {
    drupal_add_css($css_path);
  }
}

/**************/
/*** DB API ***/
/**************/

/**
 * Saves qform definition to database.
 *
 * @param $entity_id
 * @param $form_data
 * @param $form_options
 */
function qforms_db_save_form($entity_id, $form_data, $form_options) {
  db_insert('qforms_definition')
    ->fields(array(
      'nid' => $entity_id,
      'form_definition' => $form_data,
      'form_options' => $form_options, ))
    ->execute();
}

/**
 * Loads qform definition from database.
 *
 * @return
 *   Array with form definition and form options.
 */
function qforms_db_load_form($entity_id) {
  $form = _qforms_db_load_form($entity_id);
  $form['form_definition'] = unserialize($form['form_definition']);
  $form['form_options'] = unserialize($form['form_options']);
  return $form;
}

/**
 * Helper function for loading form definition from database.
 */
function _qforms_db_load_form($entity_id) {
  static $forms = array();

  if (!isset($forms[$entity_id])) {
    $forms[$entity_id] = db_query(
      'SELECT form_definition, form_options FROM {qforms_definition} WHERE nid = :nid',
      array(':nid' => $entity_id))
      ->fetchAssoc();
  }

  return $forms[$entity_id];
}

/**
 * Delete qform definition from database.
 *
 * @param $entity_id
 *   Node id.
 */
function qforms_db_delete_form($entity_id) {
  db_delete('qforms_definition')
    ->condition('nid', $entity_id)
    ->execute();
}

/**
 * Saves submission data for given entity_id.
 *
 * @param $entity_id
 * @param $data
 * @return
 *   Submission id 'sid' of saved submission data.
 */
function qforms_db_save_submission($entity_id, $data) {
  global $user;

  return db_insert('qforms_submission')
    ->fields(array(
      'nid' => $entity_id,
      'uid' => $user->uid,
      'time' => REQUEST_TIME,
      'ip' => ip_address(),
      'data' => $data,
    ))
    ->execute();
}

/**
 * Loads submission result for the given sid.
 *
 * @param $sid
 *   Submission id.
 * @return
 *   Submission result object on success, or FALSE.
 */
function qforms_db_load_submission($sid) {
  static $submissions = array();

  if (!isset($submissions[$sid])) {
    $select = db_select('qforms_submission', 's');
    $select->join('users', 'u', 's.uid = u.uid');
    $select->fields('s');
    $select->addField('u', 'name', 'username');
    $select->condition('s.sid', $sid);
    $submissions[$sid] = $select->execute()->fetchObject();
    if ($submissions[$sid]) {
      $submissions[$sid]->data = unserialize($submissions[$sid]->data);
    }
  }

  return $submissions[$sid];
}

/**
 * Delete submission result for the given sid.
 *
 * @param $sid
 *   Submission id.
 */
function qforms_db_delete_submission($sid) {
  db_delete('qforms_submission')->condition('sid', $sid)->execute();
}

/**
 * Delete all submission result for the given entity id.
 *
 * @param $entity_id
 *   Entity id.
 */
function qforms_db_delete_all_submissions($entity_id) {
  db_delete('qforms_submission')->condition('nid', $entity_id)->execute();
}