import type { Feature } from "@stc/contracts";
import { badRequest, body, json } from "./http";

const MAX = 200_000;
const ts = new Bun.Transpiler({ loader: "ts", target: "browser" });

/** Type-strips TypeScript for the in-browser runner (the worker itself runs plain JavaScript). */
export function transpileTs(code: string): string {
  return ts.transformSync(code);
}

export function transpileRoutes(): Feature["routes"] {
  return {
    "/api/learner/transpile": {
      POST: async (req) => {
        const b = await body<{ code?: string }>(req);
        if (!b || typeof b.code !== "string") return badRequest("code is required");
        if (b.code.length > MAX) return badRequest("code is too long");
        try {
          return json({ code: transpileTs(b.code) });
        } catch (e) {
          return json({ error: (e as Error).message }, 422);
        }
      },
    },
  };
}