const {koaBody} = require('koa-body');
const Koa = require('koa');
const fs = require('fs');
const path = require('path');
const { spawn } = require('child_process')
const router = require('koa-router')()
    , os = require('os')
    , iconv = require("iconv-lite")
const moment = require('moment')

const { DATABASELIST, SERVER_PORT} = require('./config')

//  备份间隔时间
const mintues = 60 * 24;// minute



// web服务
function server(){
    const app = new Koa();
    app.use(koaBody({
        multipart: true, // 支持文件上传
        formidable: {
            maxFieldsSize: 500 * 1024 * 1024, // 最大文件为2兆
            multipart: true // 是否支持 multipart-formdate 的表单
        }
    }));
    router.post('/putfile', async ctx => {
        const fileList = await getFileList()
        console.log('请求备份', fileList)
        if(fileList.length == 0){
            ctx.body = [{state:false,filename:'无备份文件'}]
        }else{
            const bunneryList = await readFile(fileList)
            ctx.body =  bunneryList
            deleteFile(fileList)
        }
    });
    app.use(router.routes(), router.allowedMethods())
    app.listen(SERVER_PORT, () => {
        console.log('=> 备份服务已启动! http://127.0.0.1:' + SERVER_PORT)
    });
}

// 本分服务
function back(){
    /**
     * 数据库备份程序
     * */
    function backSQL(host, user, passwd, database){
        return new Promise(rec => {
            const cout = os.platform() == 'win32' ? '-r' : '>'
                , filename = `back/BACKUP_${ database }_${ moment().format("YYYY_MM_DD_HH_mm_ss") }.sql`
            const backProcess = spawn('mysqldump',['-u'+user, '-p'+passwd, database, cout + filename]);
            backProcess.stdout.on('data', data => console.log('Data : ', out(data)))
            backProcess.stderr.on('data', data => console.log('Error: ', out(data)))
            backProcess.on('close', code => {
                console.log('Exit :', code.toString())
                rec(filename)
            })
        })
    }

//  开始备份数据库
    function startBackSQL(){
        //  数据库信息
        let host = "localhost"
            , user = "root"
            , passwd = "root"
            , database = "develop"
        backSQL(host, user, passwd, database)
        const outTime = getT() - new Date().getTime()
        for(let item in DATABASELIST){
            const i = DATABASELIST[item];
            database = i;
            setTimeout(() => {
                setInterval(() => {
                    backSQL(host, user, passwd, database)
                }, 1000 * 60 * mintues)
            },outTime)
        }
    }
    /**
     * 根据系统类型，读取编码格式
     * */
    function out(data){
        if(os.platform() == 'win32'){
            return iconv.decode(data, 'GBK')
        }else{
            return data
        }
    }

//  读取文件目录
    function getFileList(){
        return new Promise((rec, res) => {
            fs.readdir(__dirname + '/back', (err, fileList) => {
                if(err){
                    res(err)
                }else{
                    rec(fileList)
                }
            })
        })
    }

//  读取文件
    function readFile(fileList){
        return new Promise(rec => {
            const list = []
            for(let i in fileList){
                fs.readFile(__dirname + '/back/' + fileList[i],'utf8',function(err,datastr){
                    if(err){
                        list.push({
                            state:false,
                            filename:fileList[i]
                        })
                    }else{
                        list.push({
                            state:true,
                            filename:fileList[i],
                            file:datastr
                        })
                    }
                    if(i == fileList.length -1){
                        rec(list)
                    }
                })
            }
        })
    }

//  删除文件
    function deleteFile(filelist){
        for(let filename of filelist){
            fs.unlink(__dirname + '/back/' + filename, (e, data) => {
                if(e){
                    console.log('删除文件失败：', filename)
                }else{
                    console.log('删除文件成功：', filename)
                }
            })
        }
    }

    // 获取明天凌晨时间
    function  getT(){
        const temore = new Date().getTime() + 1000 * 60 * 60 * 24
        const now = new Date(temore)
        let year = now.getFullYear(); //得到年份
        let month = now.getMonth();//得到月份
        let date = now.getDate();//得到日期
        return new Date(year + "-" + month + "-" + date).getTime()
    }


//  启动本地备份
    startBackSQL()
}

server()
back()