import { getAsset } from "@/lib/server/data-store";
import { jsonError } from "@/lib/server/api";
import { requireAppUser } from "@/lib/server/auth/current-user";
import { readAssetForDownload } from "@/lib/server/storage";

export const runtime = "nodejs";

export async function GET(_request: Request, context: { params: Promise<{ id: string }> }) {
  try {
    const user = await requireAppUser();
    const { id } = await context.params;
    const asset = await getAsset(id);
    if (!asset || asset.ownerId !== user.id) return jsonError("资产不存在", 404);
    const file = await readAssetForDownload(asset);
    if (!file) return jsonError("资产文件不可下载", 404);
    return new Response(new Uint8Array(file.bytes), {
      headers: {
        "Content-Type": file.contentType,
        "Content-Length": String(file.bytes.length),
        "Content-Disposition": contentDisposition(asset.name || `${asset.id}${extensionForContentType(file.contentType)}`),
        "Cache-Control": "private, no-store"
      }
    });
  } catch (error) {
    return jsonError(error, 500);
  }
}

function contentDisposition(fileName: string): string {
  const clean = fileName.replace(/[\r\n/\\]/g, "_").trim() || "download";
  const ascii = clean.replace(/[^\x20-\x7E]/g, "_").replace(/"/g, "_");
  return `attachment; filename="${ascii}"; filename*=UTF-8''${encodeURIComponent(clean)}`;
}

function extensionForContentType(contentType: string): string {
  const normalized = contentType.split(";")[0]?.trim().toLowerCase();
  if (normalized === "image/png") return ".png";
  if (normalized === "image/jpeg") return ".jpg";
  if (normalized === "image/webp") return ".webp";
  if (normalized === "image/svg+xml") return ".svg";
  if (normalized === "video/mp4") return ".mp4";
  if (normalized === "audio/mpeg") return ".mp3";
  return "";
}