import {DownloadConfig, DownloadMetadata} from 'types';

class DownloadService {
  constructor(private player: KalturaPlayerTypes.Player) {}

  private isPlatformSupported() {
    const userAgent = navigator.userAgent || '';
    return !(userAgent.includes('Tizen') || userAgent.includes('Web0S'));
  }

  private isEntrySupported() {
    return !(this.player.isLive() || this.player.getVideoElement().mediaKeys || this.player.isImage());
  }

  private isContentTypeSupported(response: Response) {
    if (response.ok) {
      const contentType = response.headers.get('content-type');
      return !!(contentType && contentType.toLowerCase().includes('video'));
    }
    return false;
  }

  private getFilename(response: Response) {
    const responseUrlSplit = response.url.split('/');
    return responseUrlSplit[responseUrlSplit.indexOf('fileName') + 1];
  }

  private getDownloadUrl(config: DownloadConfig) {
    const {flavorId, flavorParamId} = config;
    const {
      provider: {
        partnerId,
        env: {cdnUrl}
      }
    } = this.player;
    const {
      session: {ks},
      sources: {id}
    } = this.player.config;

    const partnerPart = `/p/${partnerId}`;
    const entryIdPart = `/entryId/${id}`;
    const flavorParamIdPart = flavorParamId !== null ? `/flavorParamId/${flavorParamId}` : '';
    const flavorIdPart = flavorId !== null ? `/flavorId/${flavorId}` : '';
    const ksPart = ks ? `/ks/${ks}` : '';
    const protocolPart = `/protocol/${location.protocol.split(':')[0]}`;

    return `${cdnUrl}${partnerPart}/playManifest${entryIdPart}${protocolPart}${ksPart}${flavorParamIdPart}${flavorIdPart}/format/download`;
  }

  async getDownloadMetadata(config: DownloadConfig): Promise<DownloadMetadata> {
    if (!(this.isPlatformSupported() || this.isEntrySupported())) {
      return null;
    }

    const requestUrl = this.getDownloadUrl(config);

    try {
      const response = await fetch(requestUrl, {method: 'HEAD'});
      if (!response.ok) {
        return null;
      }

      const downloadUrl = response.url;

      const isContentTypeSupported = this.isContentTypeSupported(response);
      const fileName = this.getFilename(response);

      if (isContentTypeSupported && fileName) {
        return {
          downloadUrl,
          fileName
        };
      }
    } catch (e: any) {}

    return null;
  }

  downloadFile(downloadUrl: string, fileName: string) {
    const aElement = document.createElement('a');
    aElement.href = downloadUrl;
    aElement.hidden = true;
    aElement.download = fileName;
    aElement.target = '_blank';
    aElement.rel = 'noopener noreferrer';
    aElement.click();
  }
}

export {DownloadService};