import { CanActivate, ExecutionContext, ForbiddenException, Injectable } from '@nestjs/common';
import { Reflector } from '@nestjs/core';
import { ROLES_KEY } from '../decorators/roles.decorator';
import type { AuthenticatedUser } from '../strategies/jwt.strategy';

/**
 * Role-based access control. Applied globally: any authenticated user
 * reaching a protected route must hold the ADMIN role unless the route
 * declares a wider set with @Roles(...). Routes without a JwtAuthGuard
 * (public endpoints) have no `request.user` and are skipped here — their
 * openness is decided by the controller's own guards.
 */
@Injectable()
export class RolesGuard implements CanActivate {
  constructor(private readonly reflector: Reflector) {}

  canActivate(context: ExecutionContext): boolean {
    const request = context.switchToHttp().getRequest<{
      user?: AuthenticatedUser;
    }>();
    if (!request.user) {
      return true; // public route — no JwtAuthGuard in front
    }
    const required = this.reflector.getAllAndOverride<string[]>(ROLES_KEY, [
      context.getHandler(),
      context.getClass(),
    ]) ?? ['ADMIN'];
    if (!required.includes(request.user.role)) {
      throw new ForbiddenException('Insufficient role');
    }
    return true;
  }
}