import Moment from "moment"

import {
   Catch,
   HttpException,
   ExceptionFilter,
   ArgumentsHost,
} from "@nestjs/common"

import {
   Request,
   Response
} from "express"

import { HttpResponseBody } from "../interface"

export interface HttpExceptionFilterHandler {
   (request:Request,response:Response):void | Promise<void>
}

@Catch()
export class HttpExceptionFilter implements ExceptionFilter<HttpException> {
   private readonly handlerList:HttpExceptionFilterHandler[] = []

   async catch(exception:HttpException,context:ArgumentsHost) {
      try {
         var httpContext = context.switchToHttp();
         var request = httpContext.getRequest<Request>();
         var response = httpContext.getResponse<Response>();
         var exceptionStatus = exception.getStatus();
         var exceptionResponse = exception.getResponse();
      } catch(e) {
         console.log(exception)
         exceptionStatus = 400
         exceptionResponse = {
            message:"Node异常触发",
            data:exception.message
         }
      }

      for ( let handler of this.handlerList.values() ) {
         await handler(request,response)
      }

      let exceptionBody:HttpResponseBody = {
         code:exceptionStatus,
         status:false,
         message:"",
         data:{},
         path: request.url,
         timestamp:Moment().format("X")
      }

      if ( typeof exceptionResponse === "string" ) {
         exceptionBody.message = exceptionResponse
      } else {
         exceptionBody.message = exceptionResponse["message"]
         if (exceptionResponse["data"]) exceptionBody.data = exceptionResponse["data"]
      }
      
      response.status(exceptionStatus)
      response.json(exceptionBody)
   }


   public addHandler(handler:HttpExceptionFilterHandler):this {
      this.handlerList.push(handler)
      return this
   }
}