import { AppError, notFound } from "@autoscholar/core";
import { papers, paperVersions } from "@autoscholar/db";
import { publicArtifactKey } from "@autoscholar/storage";
import { and, eq } from "drizzle-orm";
import { handler } from "@/lib/server/api";
import { db, storage } from "@/lib/server/db";

export const runtime = "nodejs";

/** Public artifact delivery: only files listed in the published version's artifact set; immutable; integrity header. */
export const GET = handler(async (req, { params }) => {
  const { publicId, version, path } = (await params) as { publicId: string; version: string; path: string[] };
  const vn = Number(version.replace(/^v/, ""));
  if (!Number.isInteger(vn) || vn < 1) throw notFound("version");
  const rel = path.map(decodeURIComponent).join("/");
  if (rel.includes("..") || rel.startsWith("/")) throw new AppError("invalid", "bad path", 400);
  const d = db();
  const [row] = await d
    .select({ p: papers, v: paperVersions })
    .from(papers)
    .innerJoin(paperVersions, and(eq(paperVersions.paperId, papers.id), eq(paperVersions.versionNo, vn)))
    .where(eq(papers.publicId, publicId.toUpperCase()))
    .limit(1);
  if (!row) throw notFound("paper version");
  if (process.env.STAGING_MODE !== "1" && row.p.synthetic) throw notFound("paper version");
  if ((row.v.metadata as { artifactsWithdrawn?: boolean }).artifactsWithdrawn)
    return new Response("Artifacts withdrawn. See the paper page for the notice.", {
      status: 410,
      headers: { "content-type": "text/plain" },
    });
  const entry = row.v.artifactSet.find((a) => a.path === rel);
  if (!entry) throw notFound("artifact");
  const key = publicArtifactKey(row.p.publicId, vn, rel);
  const st = storage();
  const head = await st.head(key);
  if (!head) throw notFound("artifact object");
  if (head.sha256 !== entry.sha256) throw new AppError("integrity", "artifact integrity check failed", 500);
  const stream = await st.stream(key);
  const inline =
    /^(application\/pdf|image\/|text\/)/.test(entry.contentType) &&
    new URL(req.url).searchParams.get("download") !== "1";
  const filename = rel.split("/").pop() ?? "file";
  const disp = `${inline ? "inline" : "attachment"}; filename="${row.p.publicId}-v${vn}-${filename}"`;
  const webStream = (await import("node:stream")).Readable.toWeb(stream) as ReadableStream;
  return new Response(webStream, {
    headers: {
      "content-type": entry.contentType,
      "content-length": String(entry.bytes),
      "content-disposition": disp,
      "x-artifact-sha256": entry.sha256,
      "cache-control": "public, max-age=31536000, immutable",
      "accept-ranges": "none",
      ...(entry.contentType.startsWith("text/") || entry.contentType === "application/json"
        ? { "content-security-policy": "sandbox" }
        : {}),
    },
  });
});