import { as_type } from './crud.types'

export function crud_upload(type, id, fd, dispatch) {
  return new Promise( (resolve, reject) => {
    const xhr = new XMLHttpRequest()
    xhr.upload.addEventListener("progress", uploadProgress, false)
    xhr.addEventListener("load", uploadComplete, false)
    xhr.addEventListener("error", uploadFailed, false)
    xhr.addEventListener("abort", uploadCanceled, false)
    xhr.open("POST", '/' + type + '/' + id + '/upload/')
    xhr.send(fd)

    dispatch && dispatch({ type: as_type(type, 'upload_loading')})

    function uploadProgress (e) {
      if (e.lengthComputable) {
        dispatch && dispatch({
          type: as_type(type, 'upload_progress'),
          percent: Math.round(e.loaded * 100 / e.total),
          [type]: id,
        })
      }
      else {
        dispatch && dispatch({
          type: as_type(type, 'upload_error'),
          error: 'unable to compute upload progress',
          [type]: id,
        })
      }
    }

    function uploadComplete (e) {
      try {
        const data = JSON.parse(e.target.responseText)
      } catch (e) {
        dispatch && dispatch({
          type: as_type(type, 'upload_error'),
          error: 'upload failed',
          [type]: id,
        })
        return
      }
      dispatch && dispatch({
        type: as_type(type, 'upload_complete'),
        data,
        [type]: id,
      })
    }

    uploadFailed = function (evt) {
      dispatch && dispatch({
        type: as_type(type, 'upload_error'),
        error: 'upload failed',
        [type]: id,
      })
    }

    uploadCancelled  = function (evt) {
      dispatch && dispatch({
        type: as_type(type, 'upload_error'),
        error: 'upload cancelled',
        [type]: id,
      })
    }
  })
}

export const upload_action = (type, id, fd) => dispatch => crud_upload(type, id, fd, dispatch)