/**
 * Copyright (c) 2018 人人开源 All rights reserved.
 *
 * https://www.renren.io
 *
 * 版权所有，侵权必究！
 */

package io.renren.common.xss;

import cn.hutool.core.io.IoUtil;
import cn.hutool.core.util.StrUtil;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;

import javax.servlet.ReadListener;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.LinkedHashMap;
import java.util.Map;


/**
 * XSS过滤处理
 *
 * @author Mark sunlightcs@gmail.com
 * @since 1.0.0
 */
public class XssHttpServletRequestWrapper extends HttpServletRequestWrapper {
    HttpServletRequest orgRequest;

    public XssHttpServletRequestWrapper(HttpServletRequest request) {
        super(request);
        orgRequest = request;
    }

    @Override
    public ServletInputStream getInputStream() throws IOException {
        //非json类型，直接返回
        if(!checkContentTypeIsJson()){
            return super.getInputStream();
        }

        //为空，直接返回
        String json = IoUtil.readUtf8(super.getInputStream());
        if (StrUtil.isBlank(json)) {
            return super.getInputStream();
        }

        //xss过滤
        json = xssEncode(json);
        final ByteArrayInputStream bis = new ByteArrayInputStream(json.getBytes(StandardCharsets.UTF_8));
        return new ServletInputStream() {
            @Override
            public boolean isFinished() {
                return true;
            }

            @Override
            public boolean isReady() {
                return true;
            }

            @Override
            public void setReadListener(ReadListener readListener) {

            }

            @Override
            public int read() {
                return bis.read();
            }
        };
    }

    @Override
    public String getParameter(String name) {
        String value = super.getParameter(xssEncode(name));
        if (StrUtil.isNotBlank(value)) {
            value = xssEncode(value);
        }
        return value;
    }

    @Override
    public String[] getParameterValues(String name) {
        String[] parameters = super.getParameterValues(name);
        if (parameters == null || parameters.length == 0) {
            return null;
        }

        for (int i = 0; i < parameters.length; i++) {
            parameters[i] = xssEncode(parameters[i]);
        }
        return parameters;
    }

    @Override
    public Map<String,String[]> getParameterMap() {
        Map<String,String[]> map = new LinkedHashMap<>();
        Map<String,String[]> parameters = super.getParameterMap();
        for (String key : parameters.keySet()) {
            String[] values = parameters.get(key);
            for (int i = 0; i < values.length; i++) {
                values[i] = xssEncode(values[i]);
            }
            map.put(key, values);
        }
        return map;
    }

    @Override
    public String getHeader(String name) {
        String value = super.getHeader(xssEncode(name));
        if (StrUtil.isNotBlank(value)) {
            value = xssEncode(value);
        }
        return value;
    }

    private String xssEncode(String input) {
        return XssUtils.filter(input);
    }

    /**
     * 获取最原始的request
     */
    public HttpServletRequest getOrgRequest() {
        return orgRequest;
    }

    /**
     * 获取最原始的request
     */
    public static HttpServletRequest getOrgRequest(HttpServletRequest request) {
        if (request instanceof XssHttpServletRequestWrapper) {
            return ((XssHttpServletRequestWrapper) request).getOrgRequest();
        }

        return request;
    }
    /**
     * 判断是否是json请求，以前缀的方式
     */
    private boolean checkContentTypeIsJson()
    {
        String header = super.getHeader(HttpHeaders.CONTENT_TYPE);
        return StrUtil.startWithIgnoreCase(header, MediaType.APPLICATION_JSON_VALUE);
    }
}