import {
  CallHandler,
  ExecutionContext,
  Injectable,
  NestInterceptor,
} from '@nestjs/common';
import { Observable } from 'rxjs';
import { map } from 'rxjs/operators';

export function filterDeletedItems(data) {
  const { isArray } = Array;
  if (isArray(data)) {
    const filtered = data.filter(
      item => !('deletedAt' in item && !!item.deletedAt),
    );
    filtered.forEach(item => {
      Object.keys(item)
        .filter(key => isArray(item[key]))
        .forEach(
          children => (item[children] = filterDeletedItems(item[children])),
        );
    });
    return filtered;
  } else {
    const r = filterDeletedItems([data]);
    return r.length === 1 ? r[0] : undefined;
  }
}

@Injectable()
export class FilterDeletedItemsInterceptor implements NestInterceptor {
  intercept(context: ExecutionContext, next: CallHandler): Observable<any> {
    return next.handle().pipe(map(filterDeletedItems));
  }
}