<?php

namespace Drupal\content_migrate\Plugin\migrate_plus\data_parser;

use Drupal\migrate\MigrateException;
use Drupal\migrate_plus\Plugin\migrate_plus\data_parser\Json;
use Drupal\Component\Utility\UrlHelper;
use Drupal\Core\Url;

/**
 * Obtain JSON data for migration.
 *
 * @DataParser(
 *   id = "jsonapi",
 *   title = @Translation("JSON:API")
 * )
 */
class Jsonapi extends Json {

  /**
   * Iterator over the JSON data.
   *
   * @var \Iterator
   */
  protected $dataIterator;

  /**
   * Iterator over the JSON data.
   *
   * @var \Iterator
   */
  protected $includedIterator;


  /**
   * {@inheritdoc}
   */
  public function __construct(array $configuration, $plugin_id, $plugin_definition) {
    if (!isset($configuration['urls']) || empty($configuration['urls']) || empty($configuration['urls'][0])) {
      if (isset($configuration['jsonapi_endpoint']) && !empty(getenv('MIGRATE_JSONAPI_SOURCE'))) {
        // get from parameter or envs
        $configuration['urls'] = [ getenv('MIGRATE_JSONAPI_SOURCE') . $configuration['jsonapi_endpoint']];
      }
      else {
        throw new MigrateException('Missing MIGRATE_JSONAPI_SOURCE env configuration');
      }
    }
    parent::__construct($configuration, $plugin_id, $plugin_definition);
  }

  /**
   * Retrieves the JSON data and returns it as an array.
   *
   * @param string $url
   *   URL of a JSON feed.
   *
   * @return array
   *   The selected data to be iterated.
   *
   * @throws \GuzzleHttp\Exception\RequestException
   */
  protected function getSource($url) {
    $response = $this->getDataFetcherPlugin()->getResponseContent($url);

    // Convert objects to associative arrays.
    $source= json_decode($response, TRUE);

    // If json_decode() has returned NULL, it might be that the data isn't
    // valid utf8 - see http://php.net/manual/en/function.json-decode.php#86997.
    if (is_null($source)) {
      $utf8response = utf8_encode($response);
      $source = json_decode($utf8response, TRUE);
    }

    return $source;
  }

  /**
   * Retrieves the JSON data and returns it as an array.
   *
   * @param string $url
   *   URL of a JSON feed.
   *
   * @return array
   *   The selected data to be iterated.
   *
   * @throws \GuzzleHttp\Exception\RequestException
   */
  protected function getSourceData($source) {
    $data = [];

    $selectors = explode('/', trim('data/', '/'));
    foreach ($selectors as $selector) {
      if (!empty($selector)) {
        $data = $source[$selector];
      }
    }

    return $data;
  }

  /**
   * Retrieves the JSON data and returns it as an array.
   *
   * @param string $url
   *   URL of a JSON feed.
   *
   * @return array
   *   The selected data to be iterated.
   *
   * @throws \GuzzleHttp\Exception\RequestException
   */
  protected function getSourceIncluded($source) {
    if (!isset($source['included'])) {
      return [];
    }

    $included = [];

    // todo
    $selectors = explode('/', trim('included/', '/'));
    foreach ($selectors as $selector) {
      if (!empty($selector)) {
        $included = $source[$selector];
      }
    }

    return $included;
  }

  /**
   * {@inheritdoc}
   */
  protected function openSourceUrl($url) {
    // extract all relationship definition and add to URL as included
    $relationships = [];
    foreach ($this->configuration['fields'] as $field) {
      if (isset($field['relationship'])) {
        $relationships[] = $field['relationship'];
      }
    }
    if (!empty($relationships)) {
      $parts = UrlHelper::parse($url);
      if (isset($parts['include'])) {
        $include = explode(',', $parts['include']);
        $include = array_flip($include);
      }
      else {
        $include = [];
      }
      foreach ($relationships as $relationship) {
        $include[$relationship] = 1;
      }
      $path = $parts['path'];
      $options['query'] = $parts['query'];
      $options['fragment'] = $parts['fragment'];
      $options['query']['include'] = implode(',', array_keys($include));
      $url = Url::fromUri($path, $options)->toString();
    }

    drush_print($url);

    // (Re)open the provided URL.
    $source= $this->getSource($url);
    $this->dataIterator = new \ArrayIterator($this->getSourceData($source));
    $this->includedIterator = new \ArrayIterator($this->getSourceIncluded($source));
    if (isset($source['links']['next'])) {
      $this->urls[] = $source['links']['next'];
    }
    return TRUE;
  }

  /**
   * {@inheritdoc}
   */
  protected function fetchNextRow() {
    $current = $this->dataIterator->current();
    if ($current) {
      foreach ($this->fieldSelectors() as $field_name => $field_info) {
        if (
          isset($field_info['relationship']) &&
          isset($current['relationships'][$field_info['relationship']])
        ) {
          $field_data= [];

          $relationships = [];
          $relationship_data = $current['relationships'][$field_info['relationship']]['data'];

          if (empty($relationship_data)) {
            $field_data = null;
          }
          else {
            if (isset($relationship_data['type'])) {
              $relationships[] = $relationship_data;
            }
            else {
              $relationships = $relationship_data;
            }
            foreach ($relationships as $relationship) {
              foreach ($this->includedIterator as $included) {
                if ($included['type'] == $relationship['type'] && $included['id'] == $relationship['id']) {
                  if (isset($relationship['meta'])) {
                    $included['meta'] = $relationship['meta'];
                  }
                  $field_data[] = $included;
                }
              }
            }
            if (isset($field_info['multiple']) && $field_info['multiple']) {
              $field_data = $field_data;
            }
            else {
              $field_data = array_shift($field_data);
            }
          }
        }
        else {
          $field_data = $current;
        }

        if (!is_null($field_data)) {
          $selector = $field_info['selector'];
          $field_selectors = explode('/', trim($selector, '/'));
          if (isset($field_info['multiple']) && $field_info['multiple']) {
            foreach ($field_selectors as $field_selector) {
              array_walk($field_data, function (&$v) use ($field_selector) {
                if (is_array($v) && array_key_exists($field_selector, $v)) {
                  $v = $v[$field_selector];
                }
              });
            }
          }
          else {
            foreach ($field_selectors as $field_selector) {
              if (is_array($field_data) && array_key_exists($field_selector, $field_data)) {
                $field_data = $field_data[$field_selector];
              }
              else {
                $field_data = '';
              }
            }
          }
        }
        $this->currentItem[$field_name] = $field_data;
      }
      if (!empty($this->configuration['include_raw_data'])) {
        $this->currentItem['raw'] = $current;
      }
      $this->dataIterator->next();
    }
  }

  /**
   * Return the selectors used to populate each configured field.
   *
   * @return string[]
   *   Array of selectors, keyed by field name.
   */
  protected function fieldSelectors() {
    $fields = [];
    foreach ($this->configuration['fields'] as $field_info) {
      if (isset($field_info['selector'])) {
        $fields[$field_info['name']] = $field_info;
      }
    }
    return $fields;
  }

}