import {
  CanActivate,
  ExecutionContext,
  ForbiddenException,
  Injectable,
  Type,
  UnauthorizedException,
} from '@nestjs/common';
import type { TCurrentUser } from '@tria-plc/api-common/modules/auth/types/current-user.type';

import { hasFreightPermission, isSuperAdmin } from './freight-permission.util';

// String literals on purpose (same reasoning as login-audience.middleware.ts):
// the values are wire-format constants from iam.users.user_type, and importing
// the vendored enum couples us to its package layout for no gain.
const CUSTOMER_USER_TYPES = ['individual', 'external_organization'];

const userTypeOf = (user: TCurrentUser): string | undefined =>
  (user as { userType?: string }).userType;

/** Staff routes are employee-only; a missing userType (stale session) also fails. */
const isEmployee = (user: TCurrentUser): boolean =>
  userTypeOf(user) === 'employee' || isSuperAdmin(user);

export function FreightPermissionGuard(
  permissions: string[],
): Type<CanActivate> {
  @Injectable()
  class FreightPermissionsGuard implements CanActivate {
    canActivate(context: ExecutionContext): boolean {
      const request = context.switchToHttp().getRequest<{ user?: TCurrentUser }>();
      const user = request.user;

      if (!user) {
        throw new UnauthorizedException('Authentication required');
      }
      if (!isEmployee(user)) {
        throw new ForbiddenException('Staff account required');
      }

      if (!permissions?.length) return true;
      if (permissions.some((p) => hasFreightPermission(user, p))) {
        return true;
      }

      throw new ForbiddenException(
        `Missing permission. Required one of: ${permissions.join(', ')}`,
      );
    }
  }

  return FreightPermissionsGuard;
}

/** Portal routes: customer accounts only (individual / external organization). */
@Injectable()
export class PortalCustomerGuard implements CanActivate {
  canActivate(context: ExecutionContext): boolean {
    const request = context.switchToHttp().getRequest<{ user?: TCurrentUser }>();
    const user = request.user;

    if (!user) {
      throw new UnauthorizedException('Authentication required');
    }
    if (!CUSTOMER_USER_TYPES.includes(userTypeOf(user) ?? '')) {
      throw new ForbiddenException('Customer account required');
    }
    return true;
  }
}

/**
 * Routes both audiences legitimately call (contract sign, shared document
 * reads, warehouse handover). Staff callers must hold one of the given
 * permissions; customer callers pass here and are scoped by the service's
 * ownership checks.
 */
export function MixedAudienceGuard(permissions: string[]): Type<CanActivate> {
  @Injectable()
  class MixedAudiencesGuard implements CanActivate {
    canActivate(context: ExecutionContext): boolean {
      const request = context.switchToHttp().getRequest<{ user?: TCurrentUser }>();
      const user = request.user;

      if (!user) {
        throw new UnauthorizedException('Authentication required');
      }
      if (CUSTOMER_USER_TYPES.includes(userTypeOf(user) ?? '')) {
        return true;
      }
      if (!isEmployee(user)) {
        throw new ForbiddenException('Unrecognized account type');
      }
      if (
        !permissions?.length ||
        permissions.some((p) => hasFreightPermission(user, p))
      ) {
        return true;
      }
      throw new ForbiddenException(
        `Missing permission. Required one of: ${permissions.join(', ')}`,
      );
    }
  }

  return MixedAudiencesGuard;
}