"use strict";

const crypto = require("crypto");
const Redis = require("ioredis");

function AuthToken(redisdb, defaultExpiresSeconds) {
  this.tokenDB = redisdb;
  this.defaultExpiresSeconds = defaultExpiresSeconds;
}

// 创建一条Redis记录，并生成Token
AuthToken.prototype.gen = async function ({ uid, appid }) {
  let userToken = '';

  try {
    // 生成系统内部的user token
    let hash = crypto.createHash("md5");
    hash.update(uid + Date() + Math.random());
    userToken = hash.digest("hex");

    // 缓存到redis
    let tokenData = {
      uid,
      appids: [appid],
      ts: Math.floor(Date.now() / 1000),
      ttl: this.defaultExpiresSeconds,
    };

    let ret = await this.tokenDB.set(userToken, JSON.stringify(tokenData), "EX", this.defaultExpiresSeconds);
    if (ret != 'OK') {
      console.log('set token to redis db fail:' + ret);
    }
  } catch (err) {
    console.log(err)
  }

  return userToken;
};

// 更新Token数据
AuthToken.prototype.update = async function (userToken, { appid }) {
  try {
    let tokenData = await this.tokenDB.get(userToken).then(function (data) {
      return JSON.parse(data);
    });

    if (tokenData) {
      if (appid && !(appid in tokenData.appids)) {
        tokenData.appids.push(appid);
      }
      let ret = await this.tokenDB.set(userToken, JSON.stringify(tokenData), "EX", this.defaultExpiresSeconds);
      if (ret != 'OK') {
        console.log('set token to redis db fail:' + ret);
      }
      return tokenData;
    }
  } catch (err) {
    console.log(err)
  }

  return null;
};

// 删除Token记录
AuthToken.prototype.del = async function (userToken) {
  let tokenData = await this.tokenDB.get(userToken).then(function (data) {
    return JSON.parse(data);
  });

  if (tokenData) {
    this.tokenDB.del(userToken);
  }

  return tokenData;
};

// 检查Token是否存在
AuthToken.prototype.check = async function (userToken, updateExpire = true) {
  try {
    if (updateExpire) {
      if (await this.tokenDB.expire(userToken, this.defaultExpiresSeconds) >= 1) {
        return true;
      }
    } else {
      if (await this.tokenDB.exists([userToken]) >= 1) {
        return true;
      }
    }
  } catch (err) {
    console.log(err);
  }
  return false;
};

// 获取Token数据
AuthToken.prototype.get = async function (userToken) {
  let tokenData = await this.tokenDB.get(userToken).then(function (data) {
    return JSON.parse(data);
  });

  // token不存在
  if (!tokenData) {
    return null;
  }

  return tokenData;
};

AuthToken.prototype.koaRequest = async function (ctx, next) {
  let token = ctx.request.body.token;
  if (!token) token = ctx.header["authorization"];
  if (!token) token = ctx.header["token"];

  if (!token) {
    ctx.body = { code: 401, msg: "Need user token.", data: {} };
    return;
  }

  let ret = await this.check(token);
  if (!ret) {
    ctx.body = { code: 401, msg: "User token not exist.", data: {} };
    return;
  }

  ctx.authToken = this;

  return next();
};

let tokenInstance = null;
module.exports = function getTokenInstance(redisdb, defaultExpiresSeconds) {
  if (!tokenInstance) {
    tokenInstance = new AuthToken(redisdb, defaultExpiresSeconds);
  }
  return tokenInstance;
};