feat(ott-provider): retrieve poster from ott backend (#43)

OTT backend does not have in his response single poster URL value, but an array of images.
I'm checking if this array exists and in case it does, I'm parsing his first url and removing the width and height values (the player handles it according to his size in kaltura player).

src/k-provider/ott/provider-parser.js

@@ -49,11 +49,13 @@ export default class OTTProviderParser extends BaseProviderParser {
     const playbackContext = assetResponse.playBackContextResult;
     const mediaAsset = assetResponse.mediaDataResult;
     const kalturaSources = playbackContext.sources;
-    mediaEntry.name = mediaAsset.name;
-    mediaEntry.id = mediaAsset.id;
-    const metaData = {description: mediaAsset.description};
+    const metaData = {};
+    metaData.description = mediaAsset.description;
+    metaData.poster = OTTProviderParser._getPoster(mediaAsset.pictures);
     Object.assign(metaData, mediaAsset.metas);
     Object.assign(metaData, mediaAsset.tags);
+    mediaEntry.name = mediaAsset.name;
+    mediaEntry.id = mediaAsset.id;
     mediaEntry.metadata = metaData;
     const filteredKalturaSources = OTTProviderParser._filterSourcesByFormats(kalturaSources, requestData.formats);
     mediaEntry.sources = OTTProviderParser._getParsedSources(filteredKalturaSources);
@@ -64,6 +66,26 @@ export default class OTTProviderParser extends BaseProviderParser {
     return mediaEntry;
   }
 
+  /**
+   * Gets the poster url without width and height.
+   * @param {Array<Object>} pictures - Media pictures.
+   * @returns {string | Array<Object>} - Poster base url or array of poster candidates.
+   * @private
+   */
+  static _getPoster(pictures: Array<Object>): string | Array<Object> {
+    if (pictures && pictures.length > 0) {
+      const picObj = pictures[0];
+      const url = picObj.url;
+      // Search for thumbnail service
+      const regex = /.*\/thumbnail\/.*(?:width|height)\/\d+\/(?:height|width)\/\d+/;
+      if (regex.test(url)) {
+        return url;
+      }
+      return pictures.map(pic => ({url: pic.url, width: pic.width, height: pic.height}));
+    }
+    return '';
+  }
+
   /**
    * Gets the media type (LIVE/VOD)
    * @param {Object} mediaAssetData - The media asset data.