package org.example;

import com.alibaba.druid.spring.boot.autoconfigure.DruidDataSourceAutoConfigure;
import com.alibaba.druid.spring.boot.autoconfigure.properties.DruidStatProperties;
import com.alibaba.druid.util.Utils;
import org.springframework.boot.autoconfigure.AutoConfigureAfter;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

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

/**
 * Druid广告配置
 *
 * @author zzp
 */
@Configuration
@ConditionalOnWebApplication
@AutoConfigureAfter(DruidDataSourceAutoConfigure.class)
@ConditionalOnProperty(
        name = "spring.datasource.druid.stat-view-servlet.enabled",
        havingValue = "true",
        matchIfMissing = true)
public class DruidAdConfig {

    /**
     * 去除监控页面底部广告
     *
     * @param properties
     * @return org.springframework.boot.web.servlet.FilterRegistrationBean
     */
    @Bean
    public FilterRegistrationBean removeDruidAdFilterRegistrationBean(
            DruidStatProperties properties) {
        // 获取web监控页面的参数
        DruidStatProperties.StatViewServlet config = properties.getStatViewServlet();
        // 提取common.js的配置路径
        String pattern = config.getUrlPattern() != null ? config.getUrlPattern() : "/druid/*";
        String commonJsPattern = pattern.replaceAll("\\*", "js/common.js");

        final String filePath = "support/http/resources/js/common.js";

        // 创建filter进行过滤
        Filter filter =
                new Filter() {
                    @Override
                    public void init(FilterConfig filterConfig) throws ServletException {}

                    @Override
                    public void doFilter(
                            ServletRequest request, ServletResponse response, FilterChain chain)
                            throws IOException, ServletException {
                        chain.doFilter(request, response);
                        // 重置缓冲区，响应头不会被重置
                        response.resetBuffer();
                        // 获取common.js
                        String text = Utils.readFromResource(filePath);
                        // 正则替换banner, 除去底部的广告信息
                        text = text.replaceAll("<a.*?banner\"></a><br/>", "");
                        text = text.replaceAll("powered.*?shrek.wang</a>", "");
                        response.getWriter().write(text);
                    }

                    @Override
                    public void destroy() {}
                };
        FilterRegistrationBean registrationBean = new FilterRegistrationBean();
        registrationBean.setFilter(filter);
        registrationBean.addUrlPatterns(commonJsPattern);
        return registrationBean;
    }
}