import { withUser, ApiError } from "@/lib/api";
import { exportConversation, EXPORT_FORMATS, type ExportFormat } from "@/lib/conversations/service";
import { APP_URL } from "@/lib/env";

export const dynamic = "force-dynamic";
type P = { id: string };

/**
 * GET /api/conversations/[id]/export?format=json|markdown|txt|html[&download=1][&print=1]
 *
 * - `download=1` → `Content-Disposition: attachment` (default for json/markdown/txt)
 * - html without `download` renders inline (opened in a new tab by the client for "PDF (print)");
 *   `print=1` embeds a tiny script that opens the print dialog on load.
 */
export const GET = withUser<P>(
  async ({ req, user }, { id }) => {
    const sp = new URL(req.url).searchParams;
    const format = (sp.get("format") ?? "markdown") as ExportFormat;
    if (!(EXPORT_FORMATS as readonly string[]).includes(format)) throw new ApiError(400, `Unknown format. Use one of: ${EXPORT_FORMATS.join(", ")}`, "BAD_FORMAT");
    const print = sp.get("print") === "1";
    const inline = format === "html" && sp.get("download") !== "1";
    const out = await exportConversation(user.id, id, format, { print, appUrl: APP_URL });
    return new Response(out.body, {
      headers: {
        "Content-Type": out.contentType,
        "Cache-Control": "private, no-store",
        "X-Robots-Tag": "noindex",
        ...(inline ? {} : { "Content-Disposition": `attachment; filename="${out.filename}"` }),
      },
    });
  },
  { limit: { max: 40, windowMs: 60_000, key: "conv-export" } },
);