import Path from "path";
import fs from "fs";

export default (opts) => {
  let { app, rules = [] } = opts;
  if (!app) {
    throw new Error("the app params is necessary!");
  }

  app.router = {};
  const appKeys = Object.keys(app);
  rules.forEach((item) => {
    let { path, name } = item;
    if (appKeys.includes(name)) {
      throw new Error(`the name of ${name} already exists!`);
    }
    let content = {};
    //readdirSync: 方法将返回一个包含“指定目录下所有文件名称”的数组对象。
    //extname: 返回path路径文件扩展名，如果path以 ‘.' 为结尾，将返回 ‘.'，如果无扩展名 又 不以'.'结尾，将返回空值。
    //basename: path.basename(p, [ext]) p->要处理的path ext->要过滤的字符
    fs.readdirSync(path).forEach((filename) => {
      let extname = Path.extname(filename);
      if (extname === ".js") {
        let name = Path.basename(filename, extname);
        content[name] = require(Path.join(path, filename));
        content[name].filename = name;
      }
    });
    app[name] = content;
  });
};