import {
  Injectable,
  NestInterceptor,
  ExecutionContext,
  CallHandler,
  Logger,
} from '@nestjs/common';
import { Request } from 'express';
import { Observable } from 'rxjs';
import { tap } from 'rxjs/operators';
// import dayjs = require('dayjs');
// dayjs().format('{YYYY} MM-DDTHH:mm:ss')

@Injectable()
export class LoggingInterceptor implements NestInterceptor {
  private readonly logger = new Logger('request'); // 实例化日志记录器

  intercept(context: ExecutionContext, next: CallHandler): Observable<any> {
    const start = Date.now(); // 请求开始时间

    return next.handle().pipe(
      tap(() => {
        // 调用完handle()后得到RxJs响应对象，使用tap可以得到路由函数的返回值
        const host = context.switchToHttp();
        const request = host.getRequest<Request>();
        // 打印请求方法，请求链接，处理时间和响应数据
        this.logger.log(
          `${request.method} ${request.url} ${Date.now() - start} ms`,
        );
      }),
    );
  }
}