import { ForbiddenException, Injectable, NestMiddleware } from '@nestjs/common';
import { InjectDataSource } from '@nestjs/typeorm';
import { DataSource } from 'typeorm';
import { NextFunction, Request, Response } from 'express';

export const CLIENT_APP_HEADER = 'x-client-app';

// EUserType values from @tria-plc/api-common, duplicated here to avoid
// pulling in the full enum just for this string comparison.
const ALLOWED_USER_TYPES_BY_CLIENT: Record<string, string[]> = {
  backoffice: ['employee'],
  portal: ['individual', 'external_organization'],
};

/**
 * Blocks EDRFREIGHT-415: /auth/login and /auth/mfa-verify match credentials
 * against email/username/phone_number only (see vendor
 * findUserForLogin), with no check that the account's userType belongs on
 * the app that's asking. A backoffice (employee) client presenting a
 * customer's credentials — or vice versa — must not get a session.
 */
@Injectable()
export class LoginAudienceMiddleware implements NestMiddleware {
  constructor(@InjectDataSource() private readonly dataSource: DataSource) {}

  async use(req: Request, _res: Response, next: NextFunction) {
    const clientApp = req.header(CLIENT_APP_HEADER);
    const allowedUserTypes = clientApp
      ? ALLOWED_USER_TYPES_BY_CLIENT[clientApp]
      : undefined;
    if (!allowedUserTypes) {
      throw new ForbiddenException(
        `Missing or unrecognized ${CLIENT_APP_HEADER} header`,
      );
    }

    const identifier: unknown = req.body?.email;
    if (typeof identifier !== 'string' || !identifier) {
      // No identifier to look up — the vendor DTO validation rejects the
      // request on its own.
      return next();
    }

    const [user] = await this.dataSource.query(
      `SELECT user_type AS "userType" FROM iam.users
       WHERE email = $1 OR username = $1 OR phone_number = $1 LIMIT 1`,
      [identifier],
    );

    if (user && !allowedUserTypes.includes(user.userType)) {
      throw new ForbiddenException(
        `This account cannot sign in through the ${clientApp} application`,
      );
    }

    next();
  }
}