import type { Attachment } from "@/lib/types";

type MessageImageSource = {
  parts?: unknown[] | null;
  attachments?: unknown[] | null;
};

function normalizeImageContentType(value: unknown) {
  const contentType = String(value || "").trim().toLowerCase();
  return contentType.startsWith("image/") ? contentType : "image/jpeg";
}

export function getMessageImagePartUrl(part: unknown) {
  const value = part as Record<string, any> | null;
  if (!value) return "";

  const imageUrl = value.image_url;
  const candidate =
    value.type === "image_url"
      ? typeof imageUrl === "string"
        ? imageUrl
        : imageUrl?.url || value.url
      : value.type === "image" || value.type === "input_image"
        ? value.image || value.url || value.data
        : value.type === "file"
          ? value.url || value.data
          : "";

  return typeof candidate === "string" ? candidate.trim() : "";
}

export function collectMessageImageAttachments(
  message: MessageImageSource | null | undefined
): Attachment[] {
  if (!message) return [];

  const result: Attachment[] = [];
  const seen = new Set<string>();
  const append = (value: unknown, fallbackIndex: number, fromPart: boolean) => {
    const item = value as Record<string, any> | null;
    if (!item) return;

    const url = fromPart
      ? getMessageImagePartUrl(item)
      : typeof item.url === "string"
        ? item.url.trim()
        : "";
    if (!url || seen.has(url)) return;

    const explicitContentType = String(
      item.contentType || item.mediaType || item.mimeType || ""
    ).trim();
    if (explicitContentType && !explicitContentType.startsWith("image/")) {
      return;
    }

    seen.add(url);
    result.push({
      name: String(item.name || item.filename || item.alt || `图片${fallbackIndex + 1}`),
      url,
      contentType: normalizeImageContentType(explicitContentType),
      assetId:
        typeof item.assetId === "string" && item.assetId.trim()
          ? item.assetId.trim()
          : undefined,
      width: Number.isFinite(Number(item.width)) ? Number(item.width) : undefined,
      height: Number.isFinite(Number(item.height)) ? Number(item.height) : undefined,
    });
  };

  (Array.isArray(message.parts) ? message.parts : []).forEach((part, index) => {
    append(part, index, true);
  });
  (Array.isArray(message.attachments) ? message.attachments : []).forEach(
    (attachment, index) => {
      append(attachment, result.length + index, false);
    }
  );

  return result;
}