backend/src/guards/permissions.guard.ts

import {
  Injectable,
  ExecutionContext,
  UnauthorizedException,
} from '@nestjs/common';
import { AuthGuard } from '@nestjs/passport';
import { Reflector } from '@nestjs/core';
import { RolePermissions } from '@app/common/constants/role-permissions';
import { RoleType } from '@app/common/constants/role.type.enum';

@Injectable()
export class PermissionsGuard extends AuthGuard('jwt') {
  constructor(private reflector: Reflector) {
    super();
  }

  async canActivate(context: ExecutionContext): Promise<boolean> {
    // First, run the AuthGuard logic to validate the JWT
    const isAuthenticated = await super.canActivate(context);
    if (!isAuthenticated) {
      return false;
    }

    // Authorization logic
    const requiredPermissions = this.reflector.get<string[]>(
      'permissions',
      context.getHandler(),
    );

    if (!requiredPermissions) {
      return true; // Allow if no permissions are specified
    }

    const request = context.switchToHttp().getRequest();
    const user = request.user; // User is now available after AuthGuard

    const userRole = user?.role?.type as RoleType;
    if (!userRole || !RolePermissions[userRole]) {
      throw new UnauthorizedException({
        message: `Only ${this.getAllowedRoles(requiredPermissions)} role(s) can access this route.`,
      });
    }

    const userPermissions = RolePermissions[userRole];
    const hasRequiredPermissions = requiredPermissions.every((perm) =>
      userPermissions.includes(perm),
    );

    if (!hasRequiredPermissions) {
      throw new UnauthorizedException({
        message: `Only ${this.getAllowedRoles(requiredPermissions)} role(s) can access this route.`,
      });
    }

    return true;
  }

  private getAllowedRoles(requiredPermissions: string[]): string {
    const allowedRoles = Object.entries(RolePermissions)
      .filter(([, permissions]) =>
        requiredPermissions.every((perm) => permissions.includes(perm)),
      )
      .map(([role]) => role);

    return allowedRoles.join(', ');
  }
}