import * as Effect from "effect/Effect";
import { OAuthError } from "./errors.ts";
import { bodyBytes } from "../server/http.ts";

const privateHeaders = {
  "Cache-Control": "no-store",
  "Referrer-Policy": "no-referrer",
  "X-Content-Type-Options": "nosniff",
  "Content-Security-Policy":
    "frame-ancestors 'none'; base-uri 'self'; form-action 'self' https://dash.cloudflare.com",
};
export function privateResponse(response: Response) {
  const result = new Response(response.body, response);
  for (const [key, value] of Object.entries(privateHeaders))
    result.headers.set(key, value);
  return result;
}
export function json(body: unknown, status = 200) {
  return privateResponse(Response.json(body, { status }));
}
export function redirect(path: string, cookies: string[] = []) {
  const response = new Response(null, {
    status: 303,
    headers: { Location: path },
  });
  for (const value of cookies) response.headers.append("Set-Cookie", value);
  return privateResponse(response);
}
export function checkOrigin(request: Request, origin: string) {
  return Effect.gen(function* () {
    if (
      new URL(request.url).origin !== origin ||
      request.headers.get("Origin") !== origin
    )
      return yield* new OAuthError("forbidden");
  });
}
export function form(request: Request) {
  return Effect.gen(function* () {
    if (
      !request.headers
        .get("Content-Type")
        ?.startsWith("application/x-www-form-urlencoded") ||
      Number(request.headers.get("Content-Length")) > 2048
    )
      return yield* new OAuthError("invalid_request");
    if (!request.body) return new URLSearchParams();
    const bytes = yield* bodyBytes(
      new Response(request.body),
      2048,
      new OAuthError("invalid_request"),
    );
    return new URLSearchParams(new TextDecoder().decode(bytes));
  });
}