/**
 * Response interceptor.
 * @file 统一响应结构拦截器
 * @module interceptor/response.interceptor
 * @author zhxiao1124
 */

import { CallHandler, ExecutionContext, Injectable, NestInterceptor } from "@nestjs/common";
import { Reflector } from "@nestjs/core";
import { Request } from "express";
import { map, Observable } from "rxjs";
import { SUCCESS_MESSAGE } from "@constants/text.constant";
import { API_MESSAGE_METADATA } from "@app/decorators/api-message.decorator";
import { getRequestCost } from "@app/utils/request-context.util";

@Injectable()
export class ResponseInterceptor implements NestInterceptor {
    constructor(private readonly reflector = new Reflector()) {}

    intercept(context: ExecutionContext, next: CallHandler): Observable<unknown> {
        const request = context.switchToHttp().getRequest<Request & { requestId?: string }>();
        const message = this.reflector.get<string>(API_MESSAGE_METADATA, context.getHandler()) ?? SUCCESS_MESSAGE;

        return next.handle().pipe(
            map((data) => ({
                code: 0,
                data: data ?? {},
                message,
                timestamp: Date.now(),
                requestId: request.requestId,
                cost: `${getRequestCost(request)}ms`,
            })),
        );
    }
}