import type { MessageBlock } from "@rakazo/contracts";

export const TURN_ATTACHMENT_UNAVAILABLE =
  "An attachment in this message could not be loaded. Tell the user the attachment was unavailable and do not guess its contents.";
export const STEERING_ATTACHMENT_UNAVAILABLE = TURN_ATTACHMENT_UNAVAILABLE;

export function missingTurnImagesInstruction(
  blocks: MessageBlock[] | undefined,
  images: { length: number } | undefined,
): string {
  const expected = blocks?.filter((block) => block.kind === "image").length ?? 0;
  const loaded = images?.length ?? 0;
  return expected > 0 && loaded < expected ? TURN_ATTACHMENT_UNAVAILABLE : "";
}

export async function settleSteeringAttachmentLoads<TImage, TFile>(
  images: Promise<TImage[] | undefined>,
  files: Promise<TFile[]>,
  blocks?: MessageBlock[],
  signal?: AbortSignal,
): Promise<{
  images: TImage[] | undefined;
  files: TFile[];
  unavailableInstruction: string;
}> {
  const [loadedImages, loadedFiles] = await Promise.allSettled([images, files]);
  if (signal?.aborted) {
    if (loadedImages.status === "rejected") throw loadedImages.reason;
    if (loadedFiles.status === "rejected") throw loadedFiles.reason;
  }
  const expectedImageCount = blocks?.filter((block) => block.kind === "image").length ?? 0;
  const loadedImageCount =
    loadedImages.status === "fulfilled" ? (loadedImages.value?.length ?? 0) : 0;
  const unavailable =
    loadedImages.status === "rejected" ||
    loadedFiles.status === "rejected" ||
    loadedImageCount < expectedImageCount;
  return {
    images: loadedImages.status === "fulfilled" ? loadedImages.value : undefined,
    files: loadedFiles.status === "fulfilled" ? loadedFiles.value : [],
    unavailableInstruction: unavailable ? STEERING_ATTACHMENT_UNAVAILABLE : "",
  };
}