package com.xjrsoft.common.xss;

import cn.hutool.core.collection.ListUtil;
import cn.hutool.core.util.StrUtil;
import org.apache.commons.io.IOUtils;
import org.apache.commons.lang.StringUtils;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.util.AntPathMatcher;

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.List;
import java.util.Map;

/**
 * XSS过滤处理
 *
 * @author tzx
 */
public class XssHttpServletRequestWrapper extends HttpServletRequestWrapper {
    /**
     * 没被包装过的HttpServletRequest（特殊场景，需要自己过滤）
     */
    HttpServletRequest orgRequest;

    public static final String HTTP_METHOD_OVERRIDE = "x-http-method-override";

    private String method;

    private final List<String> ignoreXssUrl = ListUtil.toList("/magic-api/**", "/magic/web/**", "/workflow/execute/*", "/oa/wfMeetingApply/update_meetingSummary", "/base/baseClassDynamics");
    //html过滤
    private final static HTMLFilter HTML_FILTER = new HTMLFilter();

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

        // 判断请求方式是否需要转换
        String methodOverride = this.getHeader(HTTP_METHOD_OVERRIDE);
        this.method = request.getMethod();
        if (StrUtil.isNotBlank(methodOverride) && (methodOverride.equals("PUT") || methodOverride.equals("DELETE"))) {
            method = methodOverride;
        }
    }

    @Override
    public ServletInputStream getInputStream() throws IOException {
        //非json类型，直接返回
        if (!MediaType.APPLICATION_JSON_VALUE.equalsIgnoreCase(super.getHeader(HttpHeaders.CONTENT_TYPE))) {
            return super.getInputStream();
        }

        //为空，直接返回
        String json = IOUtils.toString(super.getInputStream(), StandardCharsets.UTF_8);
        if (StringUtils.isBlank(json)) {
            return super.getInputStream();
        }
        AntPathMatcher matcher = new AntPathMatcher();

        if (ignoreXssUrl.stream().noneMatch(url -> matcher.matchStart(url, orgRequest.getRequestURI()))) {
            //xss过滤 orgRequest.getRequestURI()
            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() throws IOException {
                return bis.read();
            }
        };
    }

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

    @Override
    public String getMethod() {
        return method;
    }

    private String xssEncode(String input) {
        return HTML_FILTER.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;
    }

}