<?php

/**
 * @file
 * Contains bibcite_footnotes.module.
 */

use Drupal\Core\Field\EntityReferenceFieldItemListInterface;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Routing\RouteMatchInterface;
use Drupal\Core\Url;
use Drupal\Core\Link;
use Drupal\bibcite_footnotes\CitationTools;
use Drupal\bibcite_footnotes\Plugin\Filter\ReferenceFootnotesFilter;
use Drupal\field\Entity\FieldConfig;

/**
 * Implements hook_theme().
 */
function bibcite_footnotes_theme() {
  return [
    'bibcite_footnote_link' => [
      'render element' => 'fn',
      'template' => 'bibcite-footnote-link',
    ],
    'bibcite_footnote_list' => [
      'render element' => 'footnotes',
      'path' => drupal_get_path('module', 'bibcite_footnotes') . '/templates',
      'template' => 'bibcite-footnote-list',
      'variables' => [
        'notes' => [],
        'note_type' => [],
        'config' => [],
      ],
    ],
  ];
}

/**
 * Implements hook_help().
 */
function bibcite_footnotes_help($route_name, RouteMatchInterface $route_match) {
  switch ($route_name) {
    // Main module help for the bibcite_footnotes module.
    case 'help.page.bibcite_footnotes':
      $output = '';
      $output .= '<h3>' . t('About') . '</h3>';
      $output .= '<p>' . t('Inline footnote links for BibCite References') . '</p>';
      return $output;

    default:
  }
}

/**
 * Implementation of hook_preprocess_bibcite_footnote_list().
 *
 * Gatehrs all notes and prints out Notes and References as separate lists.
 *
 * @param $variables Theme variables.
 *
 * @throws \Drupal\Component\Plugin\Exception\InvalidPluginDefinitionException
 * @throws \Drupal\Component\Plugin\Exception\PluginNotFoundException
 */
function bibcite_footnotes_preprocess_bibcite_footnote_list(&$variables) {
  $config = $variables['config'];
  $footnotes = $variables['notes'];

  $notes = [
    '#theme' => 'item_list',
    '#list_type' => 'ul',
    '#title' => $variables['note_type'] == ReferenceFootnotesFilter::ENDNOTE ? $config['notes_section_label'] : $config['references_section_label'],
    '#attributes' => ['class' => 'footnotes'],
    '#wrapper_attributes' => ['class' => 'container'],
  ];

  $notes['#attached']['library'][] = 'bibcite_footnotes/reference_footnote';
  $dont_show_backlink_text = $config['reference_dont_show_backlink_text'];
  $sort_references_by = $config['reference_sort_by'];
  $citation_tools = new CitationTools();
  if (empty($footnotes)) {
    return;
  }
  foreach ($footnotes as $fn) {
    $item = [
      '#id' => $fn['fn_id'],
      '#wrapper_attributes' => [
        'class' => ['footnote'],
      ],
    ];
    $build = [];
    $reference_entity_id = $fn['reference'];

    $footnote_link_text = ($dont_show_backlink_text && $reference_entity_id) ? '^' : $fn['value'];
    if (!is_array($fn['ref_id'])) {
      $url = Url::fromUserInput('#' . $fn['ref_id'], ['attributes' => ['id' => $fn['fn_id'], 'class' => 'footnote-link']]);
      $link = Link::fromTextAndUrl(($footnote_link_text), $url)->toRenderable();
      $build['footnote-link'] = $link;
      $override_page_in_citation = $fn['page'] ? $fn['page'] : FALSE;
    }
    else {
      // Output footnote that has more than one reference to it in the body.
      // The only difference is to insert backlinks to all references.
      // Helper: we need to enumerate a, b, c...
      $abc = str_split("abcdefghijklmnopqrstuvwxyz");
      $i = 0;

      $url = Url::fromUserInput('#' . $fn['ref_id'][0], ['attributes' => ['id' => $fn['fn_id'], 'class' => 'footnote-link']]);
      $build['footnote-link'] = Link::fromTextAndUrl($footnote_link_text, $url)->toRenderable();

      foreach ($fn['ref_id'] as $ref) {
        $url = Url::fromUserInput( '#' . $ref, ['attributes' => ['id' => $fn['fn_id'], 'class' => 'footnote-multi']]);
        $build[] = Link::fromTextAndUrl($abc[$i], $url)->toRenderable();

        $i++;
      }
      $override_page_in_citation = FALSE;
    }

    if (isset($fn['ibid']) && $fn['ibid']) {
      $build['footnote-text'] = [
        '#type' => 'markup',
        '#markup' => ' <span class="endnote-text"><span class="ibid">'
          . t('Ibid') . '.</span>'
          . (!empty($fn['page']) ? ', ' . $fn['page'] : '')
          . '</span>',
      ];
    }
    else if (!empty($fn['text']) && $variables['note_type'] == ReferenceFootnotesFilter::ENDNOTE) {
      $build['footnote-link'] = Link::fromTextAndUrl($fn['value'], $url)->toRenderable();
      $build['footnote-text'] = [
        '#type' => 'markup',
        '#markup' => ' <span class="endnote-text">' . $fn['text'] . '</span>',
      ];

    }

    if (!empty($reference_entity_id)) {
      if (empty($fn['ibid'])) {
        $citation_build = $citation_tools->getRenderableReference($reference_entity_id);
        if ($override_page_in_citation) {
          $citation_build['#data']['page'] = $override_page_in_citation;
        }

        $build[] = $citation_build;
      }

      $render = render($build);
      $item['sort'] = trim(strip_tags(render($citation_build)));
    }

//    $item['#markup'] = $render;
    $notes['#items'][] = $build;
    $reference_entity_id = FALSE;
    $render = FALSE;
  }

  if ($sort_references_by == 'alphabetical' && $variables['note_type'] == ReferenceFootnotesFilter::REFERENCE) {
    usort($notes['#items'], '_bibcite_footnotes_reference_array_cmp');
  }
  $variables['notes'] = $notes;
}

/**
 * Comparator function for sorting lists of references.
 *
 * @param $a First item to compare
 * @param $b Second item to compare
 * @return int Result of the comparison.
 */
function _bibcite_footnotes_reference_array_cmp($a, $b) {
  $a1 = (!empty($a['sort']) ? strtolower($a['sort']) : '');
  $b1 = (!empty($b['sort']) ? strtolower($b['sort']) : '');
  return strcmp($a1, $b1);
}

/**
 * Implementation of hook_preprocess_bibcite_footnote_link().
 *
 * Construct a link inside a block of text so that it points to the reference list.
 *
 * @param $variables
 */
function bibcite_footnotes_preprocess_bibcite_footnote_link(&$variables) {
//  $variables['fn']['fn']['#type'] = 'markeup';
//  $variables['fn']['fn']['#markup'] = '<h2>Hello!</h2>';
  $fn = $variables['fn']['fn'];
  // TODO: Make a more formal way to denote inline citations.

  $class = 'see-footnote';
  // Generate the hover text
  $citation_tools = new CitationTools();
  $citation_entity_id = $fn['reference'];
  $citation_data = $citation_tools->getRenderableReference($citation_entity_id);

  // Citation contains a page reference, so construct parenthetical footnote.
  if (!empty($fn['page'])) {
    $fn['value'] = "({$fn['value']}, {$fn['page']})";
    $citation_data['#data']['page'] = $fn['page'];
    $class .= '-inline';
  }

  $title = trim(strip_tags(render($citation_data)));
  $url = Url::fromUserInput('#' . $fn['fn_id'], ['attributes' => ['id' => $fn['ref_id'], 'class' => $class, 'title' => $title]]);

// We need to delete the cached markup to render it in a different mode.
  unset($citation_data['#markup']);
  unset($citation_data['#children']);

  $citation_data['#data']['mode'] = 'citation';
  $link = Link::fromTextAndUrl(render($citation_data), $url)->toRenderable();
  unset($variables['fn']['fn']);
  $variables['fn']['fn'] = $link;
//  $variables['fn']['fn'][] = $link;
}

/**
 * Implementation of hook_inline_entity_form_entity_form_alter().
 *
 * Force all entities to be saved once they are created.
 *
 * @TODO: Add cleanup batch task for orphaned References.
 *
 * @param $form
 * @param \Drupal\Core\Form\FormStateInterface $form_state
 */
function bibcite_footnotes_inline_entity_form_entity_form_alter(&$form, FormStateInterface &$form_state) {
  $form['#save_entity'] = TRUE;
}

/**
 * Implementation of hook_form_node_form_alter().
 *
 * This function populates the Reference list drop-down in the CKEditor drop-down.
 * It gathers all referenced entities of type bibcite_reference and puts them
 * into a JavaScript setting under drupalSettings.bibcite_footnotes.references.
 *
 * @param $form
 * @param \Drupal\Core\Form\FormStateInterface $form_state
 */
function bibcite_footnotes_form_node_form_alter(&$form, FormStateInterface &$form_state) {
  $ief = $form_state->get('inline_entity_form');
  if ($ief) {
    // Inline entity storage uses hashes to separate out the field instances.
    $bibcite_references = [];
    foreach ($ief as $ief_instance) {
      /**
       * @var FieldConfig $field_config
       */
      $field_config = $ief_instance['instance'];

      // Check if this is a bibcite_reference field type.
      if ($field_config->getSetting('handler') == 'default:bibcite_reference') {
        $field_name = $field_config->get('field_name');
        if (!empty($ief_instance['entities'])) {

          foreach ($ief_instance['entities'] as $entity_wrapper) {
            /**
             * @var \Drupal\core\Entity\EntityInterface $entity
             */
            $entity = $entity_wrapper['entity'];
            if ($entity->getEntityTypeId() == 'bibcite_reference') {
              list($citation_text, $citation_key) = bibcite_footnotes_get_ckeditor_select_item($entity);
              $bibcite_references[] = [$citation_text, $citation_key];
            }
          }
        }
      }
    }

    $triggering_element = $form_state->getTriggeringElement();
    if (!$triggering_element) {
      $form['#attached']['drupalSettings']['bibcite_footnotes']['references'] = $bibcite_references;
    }
    else {
      $form[$triggering_element['#parents'][0]]['widget']['#attached']['library'][] = 'bibcite_footnotes/replace_citations';
      $form[$triggering_element['#parents'][0]]['widget']['#attached']['drupalSettings']['bibcite_footnotes']['references'] = $bibcite_references;
    }
  }
  else {
    // Not using Inline Entity Form, get the references if they exist
    $entity = $form_state->getFormObject()->getEntity();
    $fields = $entity->getFields();
    $reference_field = FALSE;
    foreach ($fields as $field) {
      $type = $field->getFieldDefinition();
      if ($type->getType() == 'entity_reference') {
        if ($type->getSetting('handler') == 'default:bibcite_reference') {
          $referenced_entities = $field->referencedEntities();
          $bibcite_references = [];
          foreach ($referenced_entities as $referenced_entity) {
            list($citation_text, $citation_key) = bibcite_footnotes_get_ckeditor_select_item($referenced_entity);
            $bibcite_references[] = [$citation_text, $citation_key];
          }
          $form['#attached']['drupalSettings']['bibcite_footnotes']['references'] = $bibcite_references;
        }
      }
    }
  }
}

/**
 * Construct an item to go into the CKEditor Reference drop-down list.
 *
 * @param $entity
 *
 * @return array
 *   The form of the array is ["Citation string", [reference entity id].
 */
function bibcite_footnotes_get_ckeditor_select_item($entity): array {
  $serializer = \Drupal::service('serializer');

  $data = $serializer->normalize($entity, 'csl');
  $build = ['#theme' => 'bibcite_citation', '#data' => $data];
  $citation_text = trim(strip_tags(render($build)));
  // Attempt to match up pre-saved entities with the eventual saved ones.
  $citation_key = $entity->id->first()->getValue()['value'];
  return [$citation_text, $citation_key];
}