'use strict';

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

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

AuthToken.prototype.genToken = async function (userData, userkey, expiresSeconds) {
  // 生成系统内部的user token
  let hash = crypto.createHash('md5');
  hash.update(JSON.stringify(userData) + Date() + Math.random());
  let userToken = hash.digest('hex');

  // 缓存到redis
  let tokenData = {
    userData: userData,
    userkey: userkey,
    expires: { ttl: expiresSeconds, ts: Math.floor(Date.now() / 1000) }
  };
  await this.tokenDB.set(userToken, JSON.stringify(tokenData), 'EX', expiresSeconds);

  return userToken;
};

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

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

AuthToken.prototype.checkToken = async function (userToken, userKey, checkKey = false, updateExpire = true) {
  let tokenData = await this.tokenDB.get(userToken).then(function (data) {
    return JSON.parse(data);
  });

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

  if (checkKey && userKey != tokenData.userkey) {
    return null;
  }

  if (updateExpire) {
    tokenData.expires.ts = Math.floor(Date.now() / 1000);
    this.tokenDB.set(userToken, JSON.stringify(tokenData), 'EX', tokenData.expires.ttl);
  }

  return tokenData;
};

AuthToken.prototype.getTokenData = 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.checkTokenKoaRequest = async function (ctx, userkey, checkKey, next) {
  let token = ctx.request.body.token
  if (!token) token = ctx.header['authorization']
  if (!token) token = token = ctx.header['token']

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

  let tokenData = await this.checkToken(token, userkey, checkKey);
  if (!ret) {
    ctx.body = {
      result: 'fail', error: { code: 401, msg: 'User token error.' }, data: {}
    };
    return;
  }
  
  ctx.userData = tokenData.userData;

  return next();
};

/*
AuthToken.prototype.checkTokenKoaRequestByAgent = async function (ctx, next) {
  return this.checkTokenKoaRequest(ctx, ctx.userAgent.source, true, next);
};
*/


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