const express = require('express');
const router = express.Router();
const crypto = require('crypto');
const events = require('events');
const db = require('../common/mysqlConnection');

router.post('/', (req, res, next) => {
    if (req.session.signinStatus) {
        res.send({
            status: 'signedin',
            info: '已登录',
            url: '#/index'
        });
    } else {
        if (!req.body) {
            res.send({
                status: 'error',
                info: '参数错误，请重试'
            });
        } else {
            let captchaCode = req.body.captcha;
            if (req.session.captcha !== captchaCode) {
                res.status(200).send({
                    status: 'error',
                    info: '验证码错误'
                });
            } else {
                let emitter = new events.EventEmitter(),
                    userId = req.body.userId,
                    password = req.body.password;
    
                emitter.on('ok', () => {
                    //更改登录状态
                    req.session.signinId = userId;
                    req.session.signinStatus = true;

                    res.send({
                        status: 'signedin',
                        info: '登陆成功',
                        url: '#/index'
                    });
                });
    
                emitter.on('err', (err, errInfo) => {
                    res.json({
                        status: 'error',
                        info: errInfo,
                        error: err
                    });
    
                });

                //从User表中取对应ID的密码和盐值
                emitter.on('selectUserPasswordAndSaltFromUserTable', () => {
                    //定义SQL语句查询
                    let pool = db.pool.adminDatabasePool;
                        sqlString = 'SELECT password, salt FROM CloudSqlAdmin_Users WHERE userId = ?',
                        value = [userId];
    
                    db.queryArgs(pool, sqlString, value, (err, results, fields) => {
                        if (err) {
                            emitter.emit('err', err.err, '数据库查询出错');
                        } else {
                            let passwordHashOnDb = results[0].password,
                                salt = results[0].salt;
    
                            emitter.emit('checkUserPassword', passwordHashOnDb, salt);
                        }
                    });
                })
    
                //检测用户密码是否正确
                emitter.on('checkUserPassword', (passwordHashOnDb, salt) => {
                    crypto.pbkdf2(password, salt, 4096, 256, 'SHA256', (err, hash) => {
                        if (err) {
                            emitter.emit('err', err, '后端逻辑出错，请联系管理员修复该问题');
                            throw err;
                        }
                        hash = hash.toString('hex'); //生成密文
    
                        if (hash != passwordHashOnDb) {
                            emitter.emit('err', null, '用户名/邮箱或密码错误，请重试。');
                        } else {
                            emitter.emit('ok')
                        }
                    })
                });

                emitter.emit('selectUserPasswordAndSaltFromUserTable');
            }
        }
    }
});

module.exports = router