<?php

namespace Drupal\media\OEmbed;

use Drupal\Component\Datetime\TimeInterface;
use Drupal\Component\Serialization\Json;
use Drupal\Core\Cache\CacheBackendInterface;
use Drupal\Core\Cache\UseCacheBackendTrait;
use Drupal\Core\Config\ConfigFactoryInterface;
use GuzzleHttp\ClientInterface;
use GuzzleHttp\Exception\RequestException;

/**
 * Retrieves and caches information about oEmbed providers.
 */
class ProviderRepository implements ProviderRepositoryInterface {

  use UseCacheBackendTrait;

  /**
   * How long the provider data should be cached, in seconds.
   *
   * @var int
   */
  protected $maxAge;

  /**
   * The HTTP client.
   *
   * @var \GuzzleHttp\Client
   */
  protected $httpClient;

  /**
   * URL of a JSON document which contains a database of oEmbed providers.
   *
   * @var string
   */
  protected $providersUrl;

  /**
   * The time service.
   *
   * @var \Drupal\Component\Datetime\TimeInterface
   */
  protected $time;

  /**
   * Constructs a ProviderRepository instance.
   *
   * @param \GuzzleHttp\ClientInterface $http_client
   *   The HTTP client.
   * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
   *   The config factory service.
   * @param \Drupal\Component\Datetime\TimeInterface $time
   *   The time service.
   * @param \Drupal\Core\Cache\CacheBackendInterface $cache_backend
   *   (optional) The cache backend.
   * @param int $max_age
   *   (optional) How long the cache data should be kept. Defaults to a week.
   */
  public function __construct(ClientInterface $http_client, ConfigFactoryInterface $config_factory, TimeInterface $time, CacheBackendInterface $cache_backend = NULL, $max_age = 604800) {
    $this->httpClient = $http_client;
    $this->providersUrl = $config_factory->get('media.settings')->get('oembed_providers_url');
    $this->time = $time;
    $this->cacheBackend = $cache_backend;
    $this->maxAge = (int) $max_age;
  }

  /**
   * {@inheritdoc}
   */
  public function getAll() {
    $cache_id = 'media:oembed_providers';

    $cached = $this->cacheGet($cache_id);
    if ($cached) {
      return $cached->data;
    }

    try {
      $response = $this->httpClient->request('GET', $this->providersUrl);
    }
    catch (RequestException $e) {
      throw new ProviderException("Could not retrieve the oEmbed provider database from $this->providersUrl", NULL, $e);
    }

    $providers = Json::decode((string) $response->getBody());

    if (!is_array($providers) || empty($providers)) {
      throw new ProviderException('Remote oEmbed providers database returned invalid or empty list.');
    }

    $keyed_providers = [];
    foreach ($providers as $provider) {
      try {
        $name = (string) $provider['provider_name'];
        $keyed_providers[$name] = new Provider($provider['provider_name'], $provider['provider_url'], $provider['endpoints']);
      }
      catch (ProviderException $e) {
        // Just skip all the invalid providers.
        // @todo Log the exception message to help with debugging.
      }
    }

    $this->cacheSet($cache_id, $keyed_providers, $this->time->getCurrentTime() + $this->maxAge);
    return $keyed_providers;
  }

  /**
   * {@inheritdoc}
   */
  public function get($provider_name) {
    $providers = $this->getAll();

    if (!isset($providers[$provider_name])) {
      throw new \InvalidArgumentException("Unknown provider '$provider_name'");
    }
    return $providers[$provider_name];
  }

}