<?php
/**
 * @file
 * Code for the Farm Log feature.
 */

// Include Features code.
include_once 'farm_log.features.inc';

/**
 * Implements hook_form_alter().
 */
function farm_log_form_alter(&$form, &$form_state, $form_id) {

  // If this is a log form, attempt to prepopulate name and reference fields.
  if ($form_id == 'log_form') {
    farm_log_prepopulate_log_form_name($form);
    farm_log_prepopulate_log_form_references($form);
  }
}

/**
 * Implements hook_entity_presave().
 */
function farm_log_entity_presave($entity, $type) {

  // When a log entity is being saved, populate the geometry field from areas.
  if ($type == 'log') {
    farm_log_populate_geometry($entity);
  }
}

/**
 * Helper function for creating log categories. Terms will only be added if
 * they don't already exist.
 *
 * @param array $categories
 *   An array of strings that will be added as terms to the Farm Log Categories
 *   vocabulary.
 */
function farm_log_categories_create($categories) {

  // If the categories is not an array, bail.
  if (!is_array($categories)) {
    return;
  }

  // Define the vocabulary machine name.
  $vocabulary_machine_name = 'farm_log_categories';

  // Load the vocabulary.
  $vocabulary = taxonomy_vocabulary_machine_name_load($vocabulary_machine_name);

  // If the vocabulary doesn't exist, bail.
  if (empty($vocabulary->vid)) {
    return;
  }

  // Iterate through the categories.
  foreach ($categories as $category) {

    // First, check to see if the term already exists. If it does, skip it.
    $terms = taxonomy_get_term_by_name($category, $vocabulary_machine_name);
    if (!empty($terms)) {
      continue;
    }

    // Translate the category name.
    $term_name = t($category);

    // Create the new term.
    $term = new stdClass();
    $term->name = $term_name;
    $term->vid = $vocabulary->vid;
    taxonomy_term_save($term);
  }

  // Always reset the categories to alphabetical order.
  /**
   * @see taxonomy_vocabulary_confirm_reset_alphabetical_submit()
   */
  db_update('taxonomy_term_data')
    ->fields(array('weight' => 0))
    ->condition('vid', $vocabulary->vid)
    ->execute();
}

/**
 * Create log categories on behalf of all modules that provide them.
 */
function farm_log_categories_create_all() {
  $categories = module_invoke_all('farm_log_categories');
  if (!empty($categories)) {
    farm_log_categories_create($categories);
  }
}

/**
 * Helper function for populating a log's geometry from an area reference field.
 *
 * @param Entity $entity
 *   The entity to act upon.
 *
 * @see farm_log_entity_movement_presave().
 */
function farm_log_populate_geometry($entity) {

  // Define the area field name.
  $area_field = 'field_farm_area';

  // If the log doesn't have an area reference field, bail.
  if (!isset($entity->{$area_field})) {
    return;
  }

  // If a geometry is already defined, bail.
  if (!empty($entity->field_farm_geofield[LANGUAGE_NONE][0]['geom'])) {
    return;
  }

  // Load the area(s) referenced by the area reference field.
  $area_ids = array();
  if (!empty($entity->{$area_field}[LANGUAGE_NONE])) {
    foreach ($entity->{$area_field}[LANGUAGE_NONE] as $area_reference) {
      if (!empty($area_reference['tid'])) {
        $area_ids[] = $area_reference['tid'];
      }
    }
  }

  // Extract geometries from the areas.
  $geoms = farm_area_extract_geoms($area_ids);

  // Populate the geofield.
  farm_map_geofield_populate($entity, $geoms);
}

/**
 * Helper function for populating the name field in log forms.
 *
 * @param array $form
 *   The form array to modify, passed by reference.
 */
function farm_log_prepopulate_log_form_name(&$form) {

  // If the GET parameter isn't set, bail.
  $params = drupal_get_query_parameters();
  if (empty($params['name'])) {
    return;
  }

  // If the log form name field already has a default value, bail.
  if (!empty($form['name']['#default_value'])) {
    return;
  }

  // Set the name in the form.
  $form['name']['#default_value'] = $params['name'];
}

/**
 * Helper function for populating entity reference fields in log forms.
 *
 * @param array $form
 *   The form array to modify, passed by reference.
 */
function farm_log_prepopulate_log_form_references(&$form) {

  // Define the fields we will be populating.
  $fields = array(
    'field_farm_asset' => array(
      'entity_type' => 'farm_asset',
      'url_param' => 'farm_asset',
    ),
    'field_farm_area' => array(
      'entity_type' => 'taxonomy_term',
      'url_param' => 'farm_area',
    ),
    'field_farm_log_category' => array(
      'entity_type' => 'taxonomy_term',
      'lookup' => TRUE,
      'vocabulary' => 'farm_log_categories',
      'url_param' => 'category',
    ),
    'field_farm_log_owner' => array(
      'entity_type' => 'user',
    ),
  );

  // Populate the fields.
  foreach ($fields as $field => $info) {

    // Start with an empty array of IDs.
    $ids = array();

    // If the field does not exist on the log, skip it.
    if (!isset($form[$field])) {
      continue;
    }

    // If a URL param is available, get a list of entity IDs from it.
    if (!empty($info['url_param'])) {

      // Get query parameters.
      $params = drupal_get_query_parameters();

      // If the URL param is set, pull the IDs out.
      if (!empty($params[$info['url_param']])) {
        $ids = $params[$info['url_param']];
      }
    }

    // Or, if the entity type is 'user', load the ID from the current user.
    elseif ($info['entity_type'] == 'user') {
      global $user;
      if (!empty($user->uid)) {
        $ids[] = $user->uid;
      }
    }

    // Ensure that the IDs are an array.
    if (!is_array($ids)) {
      $ids = array($ids);
    }

    // If there are no IDs, skip.
    if (empty($ids)) {
      continue;
    }

    // Look up taxonomy term IDs, if necessary.
    if ($info['entity_type'] == 'taxonomy_term' && !empty($info['lookup']) && !empty($info['vocabulary'])) {
      $term_names = $ids;
      $ids = array();
      foreach ($term_names as $name) {
        $terms = taxonomy_get_term_by_name($name, $info['vocabulary']);
        $term = reset($terms);
        if (!empty($term->tid)) {
          $ids[] = $term->tid;
        }
      }
    }

    // Prepopulate with the farm_fields helper function.
    farm_fields_prepopulate_entityreference($form, $info['entity_type'], $field, $ids);
  }
}