app/frontend/src/utils.ts

import { AxiosError } from "axios"
import type { ApiError } from "./client"
import { offlineDetail } from "./lib/connectionStore"
import { ago } from "./lib/utils"

function extractErrorMessage(err: ApiError): string {
  // An unreachable instance is not a rejected action: say plainly that
  // nothing was delivered, so nobody is left wondering whether it half-landed.
  const offline = offlineDetail(err)
  if (offline) {
    return offline.lastSeen
      ? `Not delivered. The instance is offline (last seen ${ago(offline.lastSeen)})`
      : "Not delivered. The instance is offline"
  }

  if (err instanceof AxiosError) {
    return err.message
  }

  const errDetail = (err.body as any)?.detail
  if (Array.isArray(errDetail) && errDetail.length > 0) {
    return errDetail[0].msg
  }
  return errDetail || "Something went wrong."
}

export const handleError = function (
  this: (msg: string) => void,
  err: ApiError,
) {
  const errorMessage = extractErrorMessage(err)
  this(errorMessage)
}