require('dotenv').config()
const HOST = process.env.HOST || 'localhost'
const PORT = process.env.PORT || '3000'
const MONGODB_URL = process.env.MONGODB_URL || 'mongodb+srv://test:It6E1HC5p5K83bS8@test.ekqr7.azure.mongodb.net/test?retryWrites=true&w=majority'
const UPLOAD_SIZE_LIMIT = process.env.UPLOAD_SIZE_LIMIT || 102400
const UPLOAD_TEMP_PATH = process.env.UPLOAD_TEMP_PATH || '/tmp'
const UPLOAD_SAVE_PATH = process.env.UPLOAD_SAVE_PATH || 'upload'

const fs = require('fs')
const path = require('path')
const md5file = require('md5-file')
const filesize = require('filesize')
const { hash, compare } = require('bcryptjs')

const mongoose = require('mongoose')
mongoose.connect(MONGODB_URL, { useNewUrlParser: true }).catch(error => console.error(error))
mongoose.connection.on('connected', () => console.info('mongodb is connected'))
mongoose.connection.on('error', (error) => console.error(error))
const Filesharing = require('./models/Filesharing')

const CronJob = require('cron').CronJob
const job = new CronJob(
    '0 * * * * *',
    async () => {
        const files = await Filesharing.find({ createdAt: { $lt: new Date(Date.now() - 24 * 3600 * 1000) } })
        for (let file of files) {
            const id = file.id
            await Filesharing.findByIdAndDelete(id)
            console.log(`删除共享 ${id}`)
            const ref_number = await Filesharing.countDocuments({ md5: file.md5 })
            if (ref_number == 0) {
                const file_path = path.join(__dirname, UPLOAD_SAVE_PATH, file.md5)
                fs.unlinkSync(file_path)
                console.log(`删除文件 ${file_path}`)
            }
        }
    },
    null,
    true
)

const express = require('express')
const app = express()
app.use(express.static('public'))
app.set('view engine', 'pug')
app.use(express.urlencoded({ extended: false }))
app.use(express.json())
app.locals.moment = require('moment')
app.locals.moment.locale('zh-cn')
app.locals.filesize = filesize.partial({ base: 2, standard: 'jedec' })
app.get('/', async (req, res) => {
    const files = await Filesharing.find().sort({ createdAt: -1 })
    res.render('index', { title: '文件分享', files })
})
app.get('/upload', async (req, res) => {
    res.render('upload', { title: '文件上传' })
})

const multer = require('multer')
const upload = multer({ dest: UPLOAD_TEMP_PATH, limits: { fileSize: UPLOAD_SIZE_LIMIT } })
app.post('/upload', upload.single('file'), async (req, res) => {
    const file_temp_path = path.join(UPLOAD_TEMP_PATH, req.file.filename)
    const md5 = await md5file(file_temp_path)
    const file_save_path = path.join(__dirname, UPLOAD_SAVE_PATH, md5)
    if (!fs.existsSync(file_save_path)) {
        fs.cpSync(file_temp_path, file_save_path) // 复制临时文件到UPLOAD_PATH
    }
    fs.unlinkSync(file_temp_path) // 删除临时文件
    // 写入数据库
    const file = await Filesharing.create({
        md5,
        size: req.file.size,
        encoding: req.file.encoding,
        mimetype: req.file.mimetype,
        // 解决了multer将中文文件名错误编码的问题
        filename: Buffer.from(req.file.originalname, 'latin1').toString('utf8'),
        password: req.body.password ? await hash(req.body.password, 16) : '',
    })
    console.log(`上传文件 ${file.filename}`)
    res.status(201).render('upload', { title: '文件上传', file })
})
app.get('/download/:id', async (req, res) => {
    try {
        if (!req.params.id.match(/^[0-9a-fA-F]{24}$/)) throw '格式错误的ObjectId'
        const file = await Filesharing.findById(req.params.id)
        if (!file) throw '试图下载不存在的文件'
        res.render('download', { title: '文件下载', file })
    } catch (error) {
        console.error(error)
        res.sendStatus(404)
    }
})
app.post('/download/:id', async (req, res) => {
    try {
        if (!req.params.id.match(/^[0-9a-fA-F]{24}$/)) throw '格式错误的ObjectId'
        const file = await Filesharing.findById(req.params.id)
        if (!file) throw '试图下载不存在的文件'
        if (file.password == '' || (await compare(req.body.password, file.password)) == true) {
            await Filesharing.findByIdAndUpdate(req.params.id, { $inc: { downloads: 1 } })
            console.log(`下载文件 ${file.filename}`)
            res.status(200).download(path.join(UPLOAD_SAVE_PATH, file.md5), file.filename)
        } else {
            res.sendStatus(401)
        }
    } catch (error) {
        console.error(error)
        res.sendStatus(404)
    }
})
app.get('/file/:md5', async (req, res) => {
    try {
        const file = await Filesharing.findOne({ md5: req.params.md5 })
        if (!file) throw '试图下载不存在的文件'
        if (file.password != '') throw '访问的文件需要密码'
        res.sendFile(path.join(__dirname, UPLOAD_SAVE_PATH, req.params.md5))
    } catch (error) {
        console.error(error)
        res.sendStatus(404)
    }
})

app.listen(PORT, HOST, () => {
    console.info(`server is running at http://${HOST}:${PORT}`)
})