package com.gkhy.assess.framework.shiro.filter;

import com.alibaba.fastjson.JSONObject;
import com.gkhy.assess.common.api.CommonResult;
import com.gkhy.assess.common.api.ResultCode;
import com.gkhy.assess.common.utils.JwtTokenUtil;
import com.gkhy.assess.common.domain.JwtToken;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.apache.shiro.subject.Subject;
import org.apache.shiro.web.filter.authc.BasicHttpAuthenticationFilter;
import org.apache.shiro.web.util.WebUtils;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.RequestMethod;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.PrintWriter;

@Slf4j
public class JwtFilter extends BasicHttpAuthenticationFilter {

    /**
     * 默认开启跨域设置（使用单体）
     * 微服务情况下，此属性设置为false
     */
    private boolean allowOrigin = true;

    public JwtFilter(){}

    public JwtFilter(boolean allowOrigin){
        this.allowOrigin=allowOrigin;
    }

    /**
     * 前置拦截处理
     * @param request
     * @param response
     * @return
     * @throws Exception
     */
    @Override
    protected boolean preHandle(ServletRequest request, ServletResponse response) throws Exception {
        //servlet请求与响应的转换
        HttpServletRequest httpServletRequest = WebUtils.toHttp(request);
        HttpServletResponse httpServletResponse = WebUtils.toHttp(response);
        if(allowOrigin){
            this.fillCorsHeader(WebUtils.toHttp(request), WebUtils.toHttp(response));
        }
        //跨域时会首先发送一个option请求，这里我们给option请求直接返回正常状态
        if(httpServletRequest.getMethod().equals(RequestMethod.OPTIONS.name())){
            httpServletResponse.setStatus(HttpStatus.OK.value());
            return false;
        }
        return super.preHandle(request, response);
    }



    /**
     * 过滤器拦截请求的入口方法,所有请求都会进入该方法
     * 返回true则允许访问
     * @param request
     * @param response
     * @param mappedValue
     * @return
     */
    @Override
    protected boolean isAccessAllowed(ServletRequest request, ServletResponse response, Object mappedValue) {
        try{
            //检测header里的JWT Token内容是否正确，尝试使用token进行登录
            this.executeLogin(request,response);
            return true;
        } catch (Exception e){ //未找到token
            log.error(e.getMessage());
            JwtTokenUtil.responseError(response,e.getMessage());
        }
        return false;
    }

    /**
     * 身份验证，检查JWT token是否合法
     * @param request
     * @param response
     * @return
     * @throws Exception
     */
    @Override
    protected boolean executeLogin(ServletRequest request, ServletResponse response) throws Exception {
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        String jwtToken = httpServletRequest.getHeader(JwtTokenUtil.USER_LOGIN_TOKEN);
        JwtToken token=new JwtToken(jwtToken);
        Subject subject = getSubject(request,response);
        subject.login(token);
        return true;
    }


    /**
     * isAccessAllowed()方法返回false,会进入该方法，表示拒绝访问
     * @param request
     * @param response
     * @return
     * @throws Exception
     */
    @Override
    protected boolean onAccessDenied(ServletRequest request, ServletResponse response) throws Exception {
        HttpServletResponse httpServletResponse = WebUtils.toHttp(response);
        httpServletResponse.setCharacterEncoding("UTF-8");
        httpServletResponse.setContentType("application/json;charset=UTF-8");
        httpServletResponse.setStatus(HttpStatus.OK.value());

        PrintWriter writer = httpServletResponse.getWriter();

        writer.write(JSONObject.toJSONString(CommonResult.failed(ResultCode.UNAUTHORIZED)));

        return false;
    }


    //跨域请求的解决方案之一
    protected void fillCorsHeader(HttpServletRequest request, HttpServletResponse response){
        response.setHeader(HttpHeaders.ACCESS_CONTROL_ALLOW_ORIGIN, request.getHeader(HttpHeaders.ORIGIN));
        // 允许客户端请求方法
        response.setHeader(HttpHeaders.ACCESS_CONTROL_ALLOW_METHODS, "GET,POST,OPTIONS,HEAD,PUT,DELETE");
        // 允许客户端提交的Header
        String requestHeaders = request.getHeader(HttpHeaders.ACCESS_CONTROL_REQUEST_HEADERS);
        if (StringUtils.isNotEmpty(requestHeaders)) {
            response.setHeader(HttpHeaders.ACCESS_CONTROL_ALLOW_HEADERS, requestHeaders);
        }
        // 允许客户端携带凭证信息(是否允许发送Cookie)
        response.setHeader(HttpHeaders.ACCESS_CONTROL_ALLOW_CREDENTIALS, "true");
    }

}