/**
 * Turns errors thrown while handling a request into `APIFailure` responses.
 *
 * @module
 */

import { Context, Next } from "@oak/oak";

import { APIErrorCode, APIFailure } from "../../shared/api.ts";
import { APIException } from "../lib/api-exception.ts";

/**
 * Answers an {@link APIException} with its status and code, and anything else
 * with a 500 `SERVER_ERROR`, logging both.
 */
export async function errorMiddleware(
  ctx: Context,
  next: Next,
): Promise<void> {
  try {
    await next();
  } catch (err) {
    if (err instanceof APIException) {
      const responseBody: APIFailure = {
        success: false,
        error: {
          code: err.code,
          message: err.message,
        },
      };

      ctx.response.status = err.status;
      ctx.response.body = responseBody;

      console.log(responseBody);
    } else {
      console.error(err);

      const responseBody: APIFailure = {
        success: false,
        error: {
          code: APIErrorCode.SERVER_ERROR,
          message: "Unexpected server error",
        },
      };

      ctx.response.status = 500;
      ctx.response.body = responseBody;
    }
  }
}