import Request from 'request'

/**
 * @class
 * Provide Snapshot functionaity for cameras.
 * <h3>Functions</h3>
 * {@link Snapshot#getSnapshot},
 * <br><br>
 * <h3>Overview</h3>
 * Use the Snapshot::getSnapshot() method to retrieve a snapshot from the ONVIF-compliant camera.
 */
export default class Snapshot {
  private snapshotUri = ''
  private username?: string
  private password?: string

  init(snapshotUri: string, username?: string, password?: string) {
    this.snapshotUri = snapshotUri
    this.username = username
    this.password = password
  }

  /**
   * Retrieves a snapshot from the specified camera
   * @example
   * OnvifManager.connect('10.10.1.60', 80, 'username', 'password')
   *   .then(results => {
   *     let camera = results
   *     // calling add method will automatically initialize snapshot
   *     // with the defaultProfile's snapshotUri
   *     camera.add('snapshot')
   *     camera.snapshot.getSnapshot()
   *       .then(results => {
   *         let mimeType = results.mimeType
   *         let rawImage = results.image
   *         let prefix = 'data:' + mimeType + ';base64,'
   *         let base64Image = Buffer.from(rawImage, 'binary').toString('base64')
   *         let image = prefix + base64Image
   *         // 'image' is now ready to be displayed on a web page
   *         // ...
   *       })
   *     }
   *   })
   */
  getSnapshot() {
    return new Promise((resolve, reject) => {
      const params: Request.RequiredUriUrl & Request.CoreOptions = {
        method: 'GET',
        uri: this.snapshotUri,
        gzip: true,
        encoding: 'binary'
      }

      if (typeof this.username === 'string' && typeof this.password === 'string') {
        // Authentication is required only when 'username' and 'password' are provided
        params.auth = {
          user: this.username,
          pass: this.password,
          sendImmediately: false
        }
      }

      Request(params, (error, response, body) => {
        if (error) {
          reject(error)
          return
        }

        if (response.statusCode === 200) {
          const mimeType = response.headers['content-type']
          const data = {
            mimeType: mimeType,
            image: Buffer.from(body, 'binary')
          }
          resolve(data)
        } else {
          reject(response)
        }
      })
    })
  }
}