import { Request, Response } from 'express';
import { OAuth2Error, ServerError } from '../model/error';
import { OAuth2TokenResponse } from '../model/model';

interface ErrorResponseData {
  [x: string]: string | undefined;
  error: string;
  error_description: string;
  state?: string;
}

function dataRes(req: Request, res: Response, code: number, data: any): void {
  res.header('Cache-Control', 'no-store');
  res.header('Pragma', 'no-cache');
  res.status(code).send(data);
  console.debug('Response:', data);
}

function redirect(req: Request, res: Response, redirectUri: string): void {
  res.header('Location', redirectUri);
  res.status(302).end();
  console.debug('Redirecting to', redirectUri);
}

export function error(req: Request, res: Response, err: OAuth2Error, redirectUri?: string): void {
  // Transform unknown error
  if (!(err instanceof OAuth2Error)) {
    console.error((err as Error).stack);
    err = new ServerError('Uncaught exception');
  } else {
    console.error('Exception caught', err.stack);
  }

  if (redirectUri) {
    const obj: ErrorResponseData = {
      error: err.code,
      error_description: err.message
    };

    if (req.query.state) {
      obj.state = req.query.state as string;
    }

    redirectUri += '?' + (new URLSearchParams(obj as Record<string, string>).toString());
    redirect(req, res, redirectUri);
    return;
  }

  dataRes(req, res, err.status, { error: err.code, error_description: err.message });
}

export function data(
  req: Request,
  res: Response,
  obj: OAuth2TokenResponse,
  redirectUri?: string,
  fragment: boolean = false
): void {
  if (redirectUri) {
    redirectUri += fragment
      ? '#'
      : (redirectUri.indexOf('?') === -1 ? '?' : '&');

    if (req.query.state) {
      obj.state = req.query.state as string;
    }

    redirectUri += new URLSearchParams(obj as Record<string, string>).toString();
    redirect(req, res, redirectUri);
    return;
  }

  dataRes(req, res, 200, obj);
}