package com.xiaopeng.payment.config;


import lombok.extern.slf4j.Slf4j;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;


/**
 * 修复 multipart 文件上传被 ReplaceRequestFilter 破坏的问题。
 * <p>
 * ReplaceRequestFilter（来自 request-wrapper jar，logan-starter-core 传递依赖）
 * 会读取 request 的 InputStream 来包装请求体，导致后续 Spring 解析 multipart 时
 * 抛出 "Stream closed" 异常。
 * <p>
 * 解决方案：注册一个高优先级 Filter，对 multipart 请求提前触发 Servlet 容器的
 * multipart 解析（通过调用 request.getParts()），使文件数据被缓存到临时文件中。
 * 这样即使后续 ReplaceRequestFilter 消费了 InputStream，multipart 数据仍然可用。
 */
@Slf4j
@Configuration
public class MultipartFilterConfig {

    private static final String MULTIPART = "multipart/";
    @Bean
    public FilterRegistrationBean<Filter> earlyMultipartParsingFilter() {
        FilterRegistrationBean<Filter> registration = new FilterRegistrationBean<>();
        registration.setFilter(new EarlyMultipartParsingFilter());
        registration.addUrlPatterns("/*");
        // 确保在 ReplaceRequestFilter 之前执行
        registration.setOrder(Integer.MIN_VALUE + 10);
        registration.setName("earlyMultipartParsingFilter");
        return registration;
    }
    /**
     * 在 filter 链最前面对 multipart 请求提前解析，
     * 让 Tomcat 将文件数据缓存到磁盘，避免后续 filter 消费 InputStream 导致 Stream closed。
     */
    static class EarlyMultipartParsingFilter implements Filter {
        @Override
        public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
                throws IOException, ServletException {
            if (request instanceof HttpServletRequest) {
                HttpServletRequest httpRequest = (HttpServletRequest) request;
                String contentType = httpRequest.getContentType();
                if (contentType != null && contentType.toLowerCase().startsWith(MULTIPART)) {
                    // 提前触发 multipart 解析，Tomcat 会将 parts 缓存
                    try {
                        httpRequest.getParts();
                    } catch (Exception e) {
                        log.warn("Early multipart parsing failed, will retry later: {}", e.getMessage());
                    }
                }
            }
            chain.doFilter(request, response);
        }
    }

}