package com.dsideal.gw.Handler;

import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.dsideal.gw.GwApplication;
import com.jfinal.handler.Handler;
import com.jfinal.upload.MultipartRequest;
import com.jfinal.upload.UploadFile;
import okhttp3.*;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.util.Enumeration;
import java.util.List;
import java.util.Objects;

/**
 * 测试用例：
 * GET
 * http://10.10.21.20:8000/dsBase/dm/getDmSchoolProperty
 * http://10.10.21.20:8000/dsBase/global/getGlobalList?page=1&limit=10
 * POST
 * http://10.10.21.20:8000/dsBase/global/testPost?a=100
 * 上传文件
 * http://10.10.21.20:8000/dsBase/global/testUpload
 * form-data
 * upfile --->参数值：选择一个文件 类型：file
 */

public class RouterHandler extends Handler {
    //OkHttp的实例，单例模式
    private static final OkHttpClient OK_HTTP_CLIENT = new OkHttpClient();

    /**
     * 功能：输出JSON文本串
     *
     * @param res
     * @param jo
     */
    public void renderJson(HttpServletResponse res, JSONObject jo) {
        res.setHeader("Access-Control-Allow-Origin", "*");
        res.setHeader("Cache-Control", "no-cache");
        res.setCharacterEncoding("UTF-8");
        res.setContentType("application/json");
        try {
            res.getWriter().println(jo);
            res.getWriter().flush();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    //OkHttp的回调函数，同步执行
    private void executeRequest(Request request, HttpServletResponse res) throws IOException {
        Response response = OK_HTTP_CLIENT.newCall(request).execute();
        if (response.isSuccessful()) {
            String responseBody = null;
            if (response.body() != null) {
                responseBody = response.body().string();
            }
            JSONObject jo = Objects.requireNonNull(JSONUtil.parseObj(responseBody).put("success", true)).put("code", response.code());
            renderJson(res, jo);
        } else {
            JSONObject jo = new JSONObject();
            jo.put("message", "请求失败！");
            jo.put("code", response.code());
            renderJson(res, jo);
        }
    }

    public static RequestBody createRequestBody(HttpServletRequest req) {
        FormBody.Builder formBodyBuilder = new FormBody.Builder();
        // 遍历请求中的参数
        Enumeration<String> parameterNames = req.getParameterNames();
        while (parameterNames.hasMoreElements()) {
            String paramName = parameterNames.nextElement();
            String paramValue = req.getParameter(paramName);
            formBodyBuilder.add(paramName, paramValue);
        }
        // 构建RequestBody
        return formBodyBuilder.build();
    }

    @Override
    public void handle(String target, HttpServletRequest req, HttpServletResponse res, boolean[] isHandled) {
        //可以正确获取到URL的完整路径
        String servletPath = req.getServletPath();
        String queryString = req.getQueryString();
        //对于根目录的访问，放行
        if (servletPath.equals("/")) {
            next.handle(target, req, res, isHandled);
            return;
        }
        //如果是白名单，不检查jwt,否则需要检查jwt
        if (GwApplication.whiteSet.contains(servletPath)) {
            // TODO
            System.out.println("白名单内链接，不检查jwt!");
        } else {
            System.out.println("不包含在白名单内链接，检查jwt!");
        }

        //路由到哪个微服务
        int xie1 = servletPath.indexOf('/'); // 找到第一个 '/' 的索引
        int xie2 = servletPath.indexOf('/', xie1 + 1); // 从第一个 '/' 之后开始找第二个 '/' 的索引

        //action名称
        String action = servletPath.substring(xie2 + 1);
        if (xie1 == -1 || xie2 == -1) {
            JSONObject jo = new JSONObject();
            jo.put("success", false);
            jo.put("message", "输入的字符串格式不正确，没有找到两个 '/'。");
            renderJson(res, jo);
            isHandled[0] = true; //停止filter
            return;
        }

        String prefix = servletPath.substring(xie1 + 1, xie2); // 截取两个 '/' 之间的内容
        if (!GwApplication.routeList.containsKey(prefix)) {
            JSONObject jo = new JSONObject();
            jo.put("success", false);
            jo.put("message", prefix + "前缀没有找到合适的路由表，请检查是否请求正确！");
            renderJson(res, jo);
            isHandled[0] = true; //停止filter
            return;
        }
        //路由到哪个微服务
        String FORWARD_URL = GwApplication.routeList.get(prefix) + "/" + prefix + "/" + action;

        //1、如果是上传文件
        if (req.getMethod().equals("POST") && req.getContentType() != null && req.getContentType().startsWith("multipart/form-data")) {
            // 指定文件类型
            MediaType mediaType = MediaType.parse("multipart/form-data");
            MultipartRequest mp = new MultipartRequest(req);
            List<UploadFile> files = mp.getFiles();
            if (files.isEmpty()) {
                JSONObject jo = new JSONObject();
                jo.put("success", false);
                jo.put("message", "没有上传文件！");
                renderJson(res, jo);
                isHandled[0] = true;//停止filter
                return;
            }
            UploadFile uploadFile = files.getFirst();

            // 获取文件流
            RequestBody requestBody = RequestBody.create(uploadFile.getFile(), mediaType);
            // 构建MultipartBody
            MultipartBody body = new MultipartBody.Builder()
                    .setType(MultipartBody.FORM)
                    .addFormDataPart("file", uploadFile.getFileName(), requestBody)
                    .build();
            // 构建Request
            Request request = new Request.Builder()
                    .url(FORWARD_URL)
                    .post(body)
                    .build();
            try {
                executeRequest(request, res);
                isHandled[0] = true;//停止filter
                return;
            } catch (Exception e) {
                JSONObject jo = new JSONObject();
                jo.put("success", false);
                jo.put("message", "请求失败！" + e);
                renderJson(res, jo);
                isHandled[0] = true;//停止filter
                return;
            }
        }

        //2、处理GET请求
        if (req.getMethod().equals("GET")) {
            //参数:queryString
            Request request;
            if (queryString != null) {
                request = new Request.Builder().url(FORWARD_URL + "?" + queryString)
                        .addHeader("Authorization", req.getHeader("Authorization"))
                        .addHeader("Accept", "application/json;odata=verbose")
                        .get().build();
            } else {
                request = new Request.Builder()
                        .url(FORWARD_URL)
                        .addHeader("Authorization", req.getHeader("Authorization"))
                        .addHeader("Accept", "application/json;odata=verbose")
                        .get().build();
            }
            try {
                executeRequest(request, res);
                isHandled[0] = true;//停止filter
                return;
            } catch (IOException e) {
                JSONObject jo = new JSONObject();
                jo.put("success", false);
                jo.put("message", "请求失败！" + e);
                renderJson(res, jo);
                isHandled[0] = true;//停止filter
                return;
            }
        }

        //3、处理POST请求
        if (req.getMethod().equals("POST")) {
            RequestBody body = createRequestBody(req);
            Request request;
            if (queryString != null) {
                request = new Request.Builder().url(FORWARD_URL + "?" + queryString)
                        .addHeader("Authorization", req.getHeader("Authorization"))
                        .addHeader("Accept", "application/json;odata=verbose")
                        .post(body).build();
            } else {
                request = new Request.Builder().url(FORWARD_URL)
                        .addHeader("Authorization", req.getHeader("Authorization"))
                        .addHeader("Accept", "application/json;odata=verbose")
                        .post(body).build();
            }
            try {
                executeRequest(request, res);
                isHandled[0] = true;//停止filter
                return;
            } catch (IOException e) {
                JSONObject jo = new JSONObject();
                jo.put("success", false);
                jo.put("message", "请求失败！" + e);
                renderJson(res, jo);
                isHandled[0] = true;//停止filter
                return;
            }
        }

        //4、其它的OPTIONS
        JSONObject jo = new JSONObject();
        jo.put("success", false);
        jo.put("message", "系统只支持GET,POST，其它的OPTIONS不支持！文件上传请使用S3协议进行直传，不通过JAVA处理，JAVA只处理授权！");
        renderJson(res, jo);
        //停止filter
        isHandled[0] = true;
    }
}