import {
  Injectable,
  NestInterceptor,
  ExecutionContext,
  CallHandler,
  StreamableFile,
} from '@nestjs/common';
import { Observable } from 'rxjs';
import { map } from 'rxjs/operators';
import { DEFAULT_SUCCESS_MSG } from 'src/share/constans';

export interface Response<T> {
  statusCode: number;
  message: string;
  data: T;
}

@Injectable()
export class TransformResponseInterceptor<T>
  implements NestInterceptor<T, Response<T> | StreamableFile>
{
  intercept(
    context: ExecutionContext,
    next: CallHandler,
  ): Observable<Response<any> | StreamableFile> {
    return next.handle().pipe(
      map((data) => {
        if (data instanceof StreamableFile) {
          return data;
        }
        return {
          statusCode:
            <number>data?.statusCode ||
            <number>context.switchToHttp().getResponse().statusCode,
          message: <string>data?.message || DEFAULT_SUCCESS_MSG,
          data: data,
        };
      }),
    );
  }
}