import axios from "axios";
import {Request, Response, NextFunction} from "express";
import * as mm from "micromatch";

const Module: {new (): any} = module.constructor as any;

function getProxys(proxyMap: {[key: string]: any} | Array<{context: string[] | string}> | Function) {
  if (typeof proxyMap === "function") {
    proxyMap = proxyMap();
  }
  if (Array.isArray(proxyMap)) {
    proxyMap = proxyMap.reduce((pre, cur) => {
      const url = cur.context;
      if (typeof url === "string") {
        pre[url] = true;
      } else {
        for (const key of url) {
          pre[key] = true;
        }
      }
      return pre;
    }, {});
  }
  return Object.keys(proxyMap);
}

export default function middleware(enable: boolean, proxyMap: {[key: string]: any} | Array<{context: string[] | string}> | Function = {}) {
  if (!enable) {
    return function(req: Request, res: Response, next: NextFunction) {
      next();
    };
  }
  const passUrls = [...getProxys(proxyMap), "/index.html", "/server/**", "/client/**", "/sockjs-node/**", "**/*.hot-update.*"];
  return (req: Request, res: Response, next: NextFunction) => {
    if (passUrls.some(reg => mm.isMatch(req.url, reg))) {
      next();
    } else {
      const errorHandler = (err: any) => {
        if (err.code === "301" || err.code === "302") {
          if (res.headersSent) {
            res.write(`<a data-type="${parseInt(err.code, 10)}" href="${err.detail}">跳转中。。。</a></body><script>window.location.href="${err.detail}"</script></html>`);
            res.end();
          } else {
            res.redirect(parseInt(err.code, 10), err.detail);
          }
        } else {
          console.error(err);
          if (res.headersSent) {
            res.write(`<h1 style="font-size:16px;top:0;left:0;position:fixed;z-index:999999;color:red">${err.message || "服务器错误！"}</h1></body></html>`);
            res.end();
          } else {
            res.send(err.message || "服务器错误！");
          }
        }
      };
      try {
        Promise.all([axios.get(`${req.protocol}://${req.headers.host}/server/main.js`), axios.get(`${req.protocol}://${req.headers.host}/index.html`)])
          .then(([main, tpl]) => {
            const arr = tpl.data.match(/<!--\s*{react-coat-init-env}\s*-->\s*<script>\s*function\s+(\w+)\s*\(([^)]+)\)[^{]+{([\s\S]+)}\s*<\/script>/m);
            global[arr[1]] = new Function(arr[2], arr[3]);
            const htmlChunks = tpl.data.split(/<!--\s*{react-coat-response-chunk}\s*-->/);
            if (htmlChunks[1]) {
              res.write(htmlChunks[0]);
            }
            const mainModule = new Module();
            mainModule._compile(main.data, "main.js");
            return mainModule.exports.default(req.url).then((result: {ssrInitStoreKey: string; data: any; html: string}) => {
              const {ssrInitStoreKey, data, html} = result;
              if (res.headersSent) {
                res.write(htmlChunks[1].replace(/[^>]*<!--\s*{react-coat-html}\s*-->[^<]*/m, `${html}`).replace(/<!--\s*{react-coat-script}\s*-->/, `<script>window.${ssrInitStoreKey} = ${JSON.stringify(data)};</script>`));
                res.end();
              } else {
                res.send(htmlChunks[0].replace(/[^>]*<!--\s*{react-coat-html}\s*-->[^<]*/m, `${html}`).replace(/<!--\s*{react-coat-script}\s*-->/, `<script>window.${ssrInitStoreKey} = ${JSON.stringify(data)};</script>`));
              }
            });
          })
          .catch(errorHandler);
      } catch (err) {
        errorHandler(err);
      }
    }
  };
}