<?php

/**
 *
 */
function tripal_ws_rest() {

  global $base_url;
  $ws_args = func_get_args();

  // The web services should never be cached.
  drupal_page_is_cacheable(FALSE);

  // Set some initial variables.
  $response = array();
  $status = 'success';
  $version = 'v0.1';
  $message = '';
  $api_url = $base_url . '/ws/' . $version;
  $page_limit = 25;
  $pager_id = 0;

  // Set some defaults for the response.
  $response['@context'] =  array();

  // Lump everything ito a try block so that if there is a problem we can
  // throw an error and have that returned in the response.
  try {

    // The services is the first argument
    $service = (count($ws_args) > 0) ? $ws_args[0] : '';

    switch ($service) {
      case 'doc':
        tripal_ws_handle_doc_service($api_url, $response);
        break;
      case 'content':
        tripal_ws_handle_content_service($api_url, $response, $ws_args);
        break;
      case 'vocab':
        tripal_ws_handle_vocab_service($api_url, $response, $ws_args);
        break;
      default:
        tripal_ws_handle_no_service($api_url, $response);
    }
  }
  catch (Exception $e) {
    watchdog('tripal_ws', $e->getMessage(), array(), WATCHDOG_ERROR);
    $message = $e->getMessage();
    $status = 'error';
  }

  // The responses follow a similar format as the AGAVE API with a
  // status, message, version and all data in the 'result' object.
/*   $response['status']  = $status;
  $response['message'] = $message;
  $response['api_version'] = $version;
  $response['source'] = array(
    'site_name' => variable_get('site_name', 'Unspecified'),
    'site_url' => $base_url,
    'site_slogan' => variable_get('site_slogan', 'Unspecified'),
    'site_email' =>  variable_get('site_mail', 'Unspecified'),
  ); */

  // Rather than use the drupal_json_output() funciton we manually specify
  // content type because we want it to be 'ld+json'.
  drupal_add_http_header('Content-Type', 'application/ld+json');
  print drupal_json_encode($response);
}


/**
 *
 * @param $api_url
 * @param $response
 * @param $ws_args
 */
function tripal_ws_handle_content_service($api_url, &$response, $ws_args) {

  // Get the content type.
  $ctype     = (count($ws_args) > 1) ? $ws_args[1] : '';
  $entity_id = (count($ws_args) > 2) ? $ws_args[2] : '';

  // If we have no content type then list all of the available content types.
  if (!$ctype) {
    tripal_ws_get_content_types($api_url, $response);
  }
  // If we don't have an entity ID then show a paged list of entities with
  // the given type.
  else if ($ctype and !$entity_id) {
    tripal_ws_get_content_type($api_url, $response, $ws_args, $ctype);
  }
  // If we have a content type and an entity ID then show the entity
  else {
    tripal_ws_get_content($api_url, $response, $ws_args, $ctype, $entity_id);
  }
}
/**
 *
 * @param $api_url
 * @param $response
 * @param $ws_args
 */
function tripal_ws_handle_vocab_service($api_url, &$response, $ws_args) {

  // Get the vocab name.
  $namespace = (count($ws_args) > 1) ? $ws_args[1] : '';
  $accession = (count($ws_args) > 2) ? $ws_args[2] : '';

  // If we have no $namespace type then list all of the available vocabs.
  if (!$namespace) {
    tripal_ws_get_vocabs($api_url, $response);
  }
  // If we don't have a $namespace then show a paged list of terms.
  else if ($namespace and !$accession) {
  }
  // If we have a content type and an entity ID then show the entity
  else {
  }
}

/**
 *
 * @param $api_url
 * @param $response
 */
function tripal_ws_get_vocabs($api_url, &$response) {
  // First, add the vocabularies used into the @context section.
  $response['@context']['rdfs'] = 'http://www.w3.org/1999/02/22-rdf-syntax-ns#';
  $response['@context']['hydra'] = 'http://www.w3.org/ns/hydra/core#';

  // Next add in the ID for tihs resource.
  $response['@id'] = $api_url . '/vocab';

  // Start the list.
  $response['@type'] = 'Collection';
  $response['totalItems'] = 0;
  $response['label'] = 'Content Types';
  $response['member'] = array();

  // TODO: determine how to get the list of in-house terms that are used
  // on the site.  This should really only include terms that are used
  // as TripalEntity bundle types and that aren't part of another published
  // vocabulary.


  //$response['totalItems'] = $i;

  // Lastly, add in the terms used into the @context section.
  $response['@context']['Collection'] = 'hydra:Collection';
  $response['@context']['totalItems'] = 'hydra:totalItems';
  $response['@context']['member'] = 'hydra:member';
  $response['@context']['label'] = 'rdfs:label';
  $response['@context']['description'] = 'hydra:description';
}
/**
 * Provides a collection (list) of all of the content types.
 *
 * @param $api_url
 * @param $response
 */
function tripal_ws_get_content_types($api_url, &$response) {

  // First, add the vocabularies used into the @context section.
  $response['@context']['rdfs'] = 'http://www.w3.org/1999/02/22-rdf-syntax-ns#';
  $response['@context']['hydra'] = 'http://www.w3.org/ns/hydra/core#';

  // Next add in the ID for tihs resource.
  $response['@id'] = $api_url . '/content';

  // Start the list.
  $response['@type'] = 'Collection';
  $response['totalItems'] = 0;
  $response['label'] = 'Content Types';
  $response['member'] = array();

  // Get the list of published terms (these are the bundle IDs)
  $bundles = db_select('tripal_bundle', 'tb')
    ->fields('tb')
    ->orderBy('tb.label', 'ASC')
    ->execute();
  $terms = array();

  // Iterate through the terms and add an entry in the collection.
  $i = 0;
  while ($bundle = $bundles->fetchObject()) {
    $entity =  entity_load('TripalTerm', array('id' => $bundle->term_id));
    $term = reset($entity);
    $vocab = $term->vocab;

    if (!array_key_exists($vocab->namespace, $response['@context'])) {
      // If there is no URL prefix then use this API's vocabulary API
      if ($term->urlprefix) {
        $response['@context'][$vocab->namespace] = $term->urlprefix;
      }
      else {
        $response['@context'][$vocab->namespace] = $api_url . '/vocab/' . $vocab->namespace . '/';
      }
    }
    // Get the bundle description. If no description is provided then
    // use the term definition
    $description = tripal_get_bundle_variable('description', $bundle->id);
    if (!$description) {
      $description = $term->definition;
    }
    // Add the bundle as a content type.
    $response['member'][] = array(
      '@id' => $api_url . '/content/' . $bundle->label,
      '@type' => $vocab->namespace . ':' . $term->accession,
      'label' => $bundle->label,
      'description' => $description,
    );
    $i++;
  }
  $response['totalItems'] = $i;

  // Lastly, add in the terms used into the @context section.
  $response['@context']['Collection'] = 'hydra:Collection';
  $response['@context']['totalItems'] = 'hydra:totalItems';
  $response['@context']['member'] = 'hydra:member';
  $response['@context']['label'] = 'rdfs:label';
  $response['@context']['description'] = 'hydra:description';
}

/**
 *
 * @param $api_url
 * @param $response
 * @param $ws_args
 */
function tripal_ws_get_content_type($api_url, &$response, $ws_args, $ctype) {

  // First, add the vocabularies used into the @context section.
  $response['@context']['rdfs'] = 'http://www.w3.org/1999/02/22-rdf-syntax-ns#';
  $response['@context']['hydra'] = 'http://www.w3.org/ns/hydra/core#';
  $response['@context']['schema'] = 'https://schema.org/';

  // Next add in the ID for tihs resource.
  $response['@id'] = $api_url . '/content/' . $ctype;

  // Get the TripalBundle, TripalTerm and TripalVocab type for this type.
  $bundle = tripal_load_bundle_entity(array('label' => $ctype));
  $term = entity_load('TripalTerm', array('id' => $bundle->term_id));
  $term = reset($term);
  $vocab = $term->vocab;

  if (!array_key_exists($vocab->namespace, $response['@context'])) {
    // If there is no URL prefix then use this API's vocabulary API
    if ($term->urlprefix) {
      $response['@context'][$vocab->namespace] = $term->urlprefix;
    }
    else {
      $response['@context'][$vocab->namespace] = $api_url . '/vocab/' . $vocab->namespace . '/';
    }
  }

  // Start the list.
  $response['@type'] = 'Collection';
  $response['totalItems'] = 0;
  $response['label'] = $bundle->label . " collection";

  // Get the list of entities for this bundle.
  $query = new EntityFieldQuery;
  $query->entityCondition('entity_type', 'TripalEntity')
    ->entityCondition('bundle', $bundle->name)
    ->propertyOrderBy('title', 'DESC')
    ->pager(10);

  // Iterate through the entities and add them to the list.
  $results = $query->execute();
  $i = 0;
  if (isset($results['TripalEntity'])) {
    $entities = entity_load('TripalEntity', array_keys($results['TripalEntity']));
    foreach ($entities as $entity) {
      $response['member'][] = array(
        '@id' => $api_url . '/content/' . $ctype . '/' .  $entity->id,
        '@type' => $vocab->namespace . ':' . $term->accession,
        'label' => $entity->title,
        'itemPage' => url('/bio-data/' . $entity->id, array('absolute' => TRUE)),
      );
      $i++;
    }
  }
  $response['totalItems'] = $i;

  // Lastly, add in the terms used into the @context section.
  $response['@context']['Collection'] = 'hydra:Collection';
  $response['@context']['totalItems'] = 'hydra:totalItems';
  $response['@context']['member'] = 'hydra:member';
  $response['@context']['label'] = 'rdfs:label';
  $response['@context']['itemPage'] = 'schema:itemPage';

}

/**
 *
 * @param $api_url
 * @param $response
 * @param $ws_args
 */
function tripal_ws_get_content($api_url, &$response, $ws_args, $ctype, $entity_id) {

  // First, add the vocabularies used into the @context section.
  $response['@context']['rdfs'] = 'http://www.w3.org/1999/02/22-rdf-syntax-ns#';
  $response['@context']['hydra'] = 'http://www.w3.org/ns/hydra/core#';
  $response['@context']['schema'] = 'https://schema.org/';

  // Get the TripalBundle, TripalTerm and TripalVocab type for this type.
  $bundle = tripal_load_bundle_entity(array('label' => $ctype));
  $term = entity_load('TripalTerm', array('id' => $bundle->term_id));
  $term = reset($term);
  $vocab = $term->vocab;

  if (!array_key_exists($vocab->namespace, $response['@context'])) {
    // If there is no URL prefix then use this API's vocabulary API
    if ($term->urlprefix) {
      $response['@context'][$vocab->namespace] = $term->urlprefix;
    }
    else {
      $response['@context'][$vocab->namespace] = $api_url . '/vocab/' . $vocab->namespace . '/';
    }
  }

  // Get the TripalEntity and attach all the fields.
  $entity = entity_load('TripalEntity', array('id' => $entity_id));
  field_attach_load('TripalEntity', $entity);
  $entity = reset($entity);


  // Next add in the ID and Type for this resources.
  $response['@id'] = $api_url . '/content/' . $ctype . '/' . $entity_id;
  $response['@type'] = $vocab->namespace . ':' . $term->accession;
  $response['label'] = $entity->title;
  $response['itemPage'] = url('/bio-data/' . $bundle->id, array('absolute' => TRUE));

  // Get information about the fields attached to this bundle and sort them
  // in the order they were set for the display.
  // TODO: should we allow for custom ordering of fields for web services
  // or use the default display ordering?
  $fields = field_info_instances('TripalEntity', $bundle->name);
  uasort($fields, function($a, $b) {
    $a_weight = (is_array($a) && isset($a['display']['default']['weight'])) ? $a['display']['default']['weight'] : 0;
    $b_weight = (is_array($b) && isset($b['display']['default']['weight'])) ? $b['display']['default']['weight'] : 0;

    if ($a_weight == $b_weight) {
      return 0;
    }
    return ($a_weight < $b_weight) ? -1 : 1;
  });

  // Iterate throught the fields and add each value to the response.
  //$response['fields'] = $fields;
  foreach ($fields as $field_name => $field) {
    $field_value = $entity->$field_name;

    // Get the semantic web settings for this field
    $field_type = '';
    if (array_key_exists('semantic_web', $field['settings'])) {
      $field_type = $field['settings']['semantic_web']['type'];
      if ($field_type) {
        $ns = $field['settings']['semantic_web']['ns'];
        $nsurl = $field['settings']['semantic_web']['nsurl'];
        $response['@context'][$ns] = $nsurl;
        $response['@context'][$field['label']] = $ns . ':' .$field_type;
      }
    }

    // TODO: need a way to hide fields.

    // Get the values based on cardinality
    $items = field_get_items('TripalEntity', $entity, $field_name);
    $values = '';
    if (array_key_exists('und', $field_value) and count($field_value['und']) == 1) {
      $values = $field_value['und'][0]['value'];
    }
    // If cardinality is greater than 1 then the value should be an array
    else {
      $values = array();
      for ($i = 0; $i < count($field_value); $i++) {
        $values[] = $field_value['und'][$i]['value'];
      }
    }
    $response[$field['label']] = $values;
  }

 //$response['fields'] = $fields;

  // Lastly, add in the terms used into the @context section.
  $response['@context']['label'] = 'rdfs:label';
  $response['@context']['itemPage'] = 'schema:itemPage';
}


/**
 * Provides the Hydra compatible apiDocumentation page that describes this API.
 *
 * @param $api_url
 * @param $response
 */
function tripal_ws_handle_doc_service($api_url, &$response) {
  // First, add the vocabularies used into the @context section.
  $response['@context']['rdfs'] = 'http://www.w3.org/1999/02/22-rdf-syntax-ns#';
  $response['@context']['hydra'] = 'http://www.w3.org/ns/hydra/core#';

  // Next add in the ID for tihs resource.
  $site_name = variable_get('site_name', '');
  $response['@id'] = $api_url . '/doc/';
  $response['title'] =  $site_name . ": RESTful Web Services API";
  $response['entrypoint'] = $api_url;
  $response['description'] = "A fully queryable REST API using JSON-LD and " .
      "discoverable using the WC3 Hydra specification.";

  // Lastly, add in the terms used into the @context section.
  $response['@context']['title'] = 'hydra:title';
  $response['@context']['entrypoint'] = array(
    "@id" => "hydra:entrypoint",
    "@type" => "@id",
  );
  $response['@context']['description'] = 'hydra:description';
}

/**
 * This function specifies the types of resources avaiable via the API.
 *
 * @param $api_url
 * @param $response
 * @param $ws_args
 */
function tripal_ws_handle_no_service($api_url, &$response) {

  // First, add the vocabularies used into the @context section.
  $response['@context']['rdfs'] = 'http://www.w3.org/1999/02/22-rdf-syntax-ns#';
  $response['@context']['hydra'] = 'http://www.w3.org/ns/hydra/core#';
  $response['@context']['dc'] = 'http://purl.org/dc/dcmitype/';
  $response['@context']['schema'] = 'https://schema.org/';

  // Next add in the ID for tihs resource.
  $response['@id'] = $api_url;


  // Start the list.
  $response['@type'] = 'Collection';
  $response['totalItems'] = 0;
  $response['label'] = 'Services';
  $response['member'] = array();

  // Start the list.
  $response['member'][] = array(
    '@id' => $api_url . '/content/',
    '@type' => 'Service',
    'label' => 'Content Types',
    'description' => 'Provides acesss to the biological and ' .
      'ancilliary data available on this site. Each content type ' .
      'represents biological data that is defined in a controlled vocabulary '.
      '(e.g. Sequence Ontology term: gene (SO:0000704)).',
  );
  $response['member'][] = array(
    '@id' => $api_url . '/doc/',
    '@type' => 'Service',
    'label' => 'API Documentation',
    'description' => 'The WC3 Hydra compatible documentation for this API.',
  );
  $response['member'][] = array(
    '@id' => $api_url . '/vocab/',
    '@type' => 'Service',
    'label' => 'Vocabulary',
    'description' => 'Defines in-house locally defined vocabulary terms that ' .
      'have been added specifically for this site.  These terms are typically ' .
      'added because no other appropriate term exists in another community-vetted '.
      'controlled vocabulary.',
  );

  $response['totalItems'] = count($response['member']);

  $response['@context']['Collection'] = 'hydra:Collection';
  $response['@context']['totalItems'] = 'hydra:totalItems';
  $response['@context']['member'] = 'hydra:member';
  $response['@context']['Service'] = 'dc:Service';
  $response['@context']['label'] = 'rdfs:label';
  $response['@context']['description'] = 'hydra:description';
}