import {
  CallHandler,
  ExecutionContext,
  Injectable,
  NestInterceptor,
} from '@nestjs/common';
import { map, Observable } from 'rxjs';
import { ApiResponse } from '../types/api-response';

@Injectable()
export class ResponseInterceptor<T> implements NestInterceptor<T, ApiResponse<T>> {
  intercept(_: ExecutionContext, next: CallHandler): Observable<ApiResponse<T>> {
    return next.handle().pipe(
      map((data: T) => ({
        success: true,
        data: this.serialize(data) as T,
        error: null,
      })),
    );
  }

  private serialize(value: unknown): unknown {
    if (typeof value === 'bigint') return value.toString();
    if (value instanceof Date) return value.toISOString();
    if (
      value &&
      typeof value === 'object' &&
      'toNumber' in value &&
      typeof value.toNumber === 'function'
    ) {
      return value.toNumber();
    }
    if (Array.isArray(value)) return value.map((item) => this.serialize(item));
    if (value && typeof value === 'object') {
      return Object.fromEntries(
        Object.entries(value).map(([key, item]) => [key, this.serialize(item)]),
      );
    }
    return value;
  }
}