packages/ui/src/preview/assistant-preview-validation.ts

// Adapted from ZCode assistantPreviewCardValidation.ts (Apache-2.0), commit 872ad960.
// See licenses/third-party-notices.txt and docs/internals/previews.md.
import {
  ASSISTANT_PREVIEW_CARD_CANDIDATE_LIMIT,
  ASSISTANT_PREVIEW_CARD_VISIBLE_LIMIT,
  type AssistantPreviewCard,
  type AssistantPreviewCardFileStatService,
  getAssistantPreviewCardFilePath,
  isValidAssistantPreviewWebsiteUrl,
  requiresAssistantPreviewCardFileStat,
} from "./assistant-preview-cards.ts";

export function getAssistantPreviewCardsValidationSignature(cards: readonly AssistantPreviewCard[]): string {
  return cards
    .map((card) => {
      if (card.type === "website") {
        return [card.id, card.type, card.title, card.subtitleId, card.url, card.filePath ?? ""].join(
          "\u0000",
        );
      }

      return [card.id, card.type, card.kind, card.title, card.subtitleId, card.path].join("\u0000");
    })
    .join("\u0001");
}

export function resolveAssistantPreviewCardsWithoutFileStat(
  cards: readonly AssistantPreviewCard[],
): AssistantPreviewCard[] | null {
  if (cards.some(requiresAssistantPreviewCardFileStat)) {
    return null;
  }

  return cards
    .filter((card) => card.type === "website" && isValidAssistantPreviewWebsiteUrl(card.url))
    .slice(0, ASSISTANT_PREVIEW_CARD_VISIBLE_LIMIT);
}

export async function resolveValidatedAssistantPreviewCards(
  cards: readonly AssistantPreviewCard[],
  fileService: AssistantPreviewCardFileStatService,
): Promise<AssistantPreviewCard[]> {
  const statFreeCards = resolveAssistantPreviewCardsWithoutFileStat(cards);
  if (statFreeCards) {
    return statFreeCards;
  }

  const candidates = cards.slice(0, ASSISTANT_PREVIEW_CARD_CANDIDATE_LIMIT);
  const paths = candidates
    .map(getAssistantPreviewCardFilePath)
    .filter((path): path is string => path !== null);
  const results = await fileService.checkFilesExist({ paths });
  const existingPaths = new Set(results.filter((result) => result.exists).map((result) => result.path));

  return candidates
    .filter((card) => {
      if (card.type === "website" && !isValidAssistantPreviewWebsiteUrl(card.url)) {
        return false;
      }
      const path = getAssistantPreviewCardFilePath(card);
      return path === null || existingPaths.has(path);
    })
    .slice(0, ASSISTANT_PREVIEW_CARD_VISIBLE_LIMIT);
}