/*
    i really should split this up into different modules
*/

import bodyParser from "body-parser"
import multer, {memoryStorage} from "multer"
import Discord, { IntentsBitField, Client } from "discord.js"
import express from "express"
import fs from "fs"
import axios, { AxiosResponse } from "axios"

import Files from "./lib/files"
require('dotenv').config()

let pkg = require(`${process.cwd()}/package.json`)

let app = express()

const multerSetup = multer({storage:memoryStorage()})

let config = require(`${process.cwd()}/config.json`)
app.use("/static",express.static("assets"))
app.use(bodyParser.text({limit:(config.maxDiscordFileSize*config.maxDiscordFiles)+1048576,type:["application/json","text/plain"]}))
let files:{[key:string]:{filename:string,mime:string,messageids:string[]}} = {}

// funcs

function ThrowError(response:express.Response,code:number,errorMessage:string) {
    fs.readFile(__dirname+"/../pages/error.html",(err,buf) => {
        if (err) {response.sendStatus(500);console.log(err);return}
        response.status(code)
        response.send(buf.toString().replace(/\$ErrorCode/g,code.toString()).replace(/\$ErrorMessage/g,errorMessage).replace(/\$Version/g,pkg.version))
    })
}

// init data

if (!fs.existsSync(__dirname+"/../.data/")) fs.mkdirSync(__dirname+"/../.data/")

fs.readFile(__dirname+"/../.data/files.json",(err,buf) => {
    if (err) {console.log(err);return}
    files = JSON.parse(buf.toString() || "{}")
})

// discord

let client = new Client({intents:[
    IntentsBitField.Flags.GuildMessages,
    IntentsBitField.Flags.MessageContent
],rest:{timeout:config.requestTimeout}})

let uploadChannel:Discord.TextBasedChannel

app.get("/", function(req,res) {
    fs.readFile(__dirname+"/../pages/base.html",(err,buf) => {
        if (err) {res.sendStatus(500);console.log(err);return}
        res.send(
            buf.toString()
                .replace("$MaxInstanceFilesize",`${(config.maxDiscordFileSize*config.maxDiscordFiles)/1048576}MB`)
                .replace(/\$Version/g,pkg.version)
                .replace(/\$Handler/g,"upload_file")
                .replace(/\$UploadButtonText/g,"Upload file")
                .replace(/\$otherPath/g,"/clone")
                .replace(/\$otherText/g,"clone from url...")
                .replace(/\$FileNum/g,Object.keys(files).length.toString())
        )
    })
})

app.get("/clone", function(req,res) {
    fs.readFile(__dirname+"/../pages/base.html",(err,buf) => {
        if (err) {res.sendStatus(500);console.log(err);return}
        res.send(
            buf.toString()
                .replace("$MaxInstanceFilesize",`${(config.maxDiscordFileSize*config.maxDiscordFiles)/1048576}MB`)
                .replace(/\$Version/g,pkg.version)
                .replace(/\$Handler/g,"clone_file")
                .replace(/\$UploadButtonText/g,"Input a URL")
                .replace(/\$otherPath/g,"/")
                .replace(/\$otherText/g,"upload file...")
                .replace(/\$FileNum/g,Object.keys(files).length.toString())
        )
    })
})

app.post("/upload",multerSetup.single('file'),async (req,res) => {
    if (req.file) {
        try {
            uploadFile({name:req.file.originalname,mime:req.file.mimetype,uploadId:req.header("monofile-upload-id")},req.file.buffer)
                .then((uID) => res.send(uID))
                .catch((stat) => {res.status(stat.status);res.send(`[err] ${stat.message}`)})
        } catch {
            res.status(400)
            res.send("[err] bad request")
        }
    } else {
        res.status(400)
        res.send("[err] bad request")
    }
})

app.post("/clone",(req,res) => {
    try {
        let j = JSON.parse(req.body)
        if (!j.url) {
            res.status(400)
            res.send("[err] invalid url")
        }
        axios.get(j.url,{responseType:"arraybuffer"}).then((data:AxiosResponse) => {
            uploadFile({name:req.body.split("/")[req.body.split("/").length-1] || "generic",mime:data.headers["content-type"],uploadId:j.uploadId},Buffer.from(data.data))
                .then((uID) => res.send(uID))
                .catch((stat) => {res.status(stat.status);res.send(`[err] ${stat.message}`)})
        }).catch((err) => {
            res.status(400)
            res.send(`[err] failed to fetch data`)
        })
    } catch {
        res.status(500)
        res.send("[err] an error occured")
    }
})

app.get("/download/:fileId",(req,res) => {
    if (files[req.params.fileId]) {
        let file = files[req.params.fileId]

        fs.readFile(__dirname+"/../pages/download.html",(err,buf) => {
            if (err) {res.sendStatus(500);console.log(err);return}
            res.send(buf.toString().replace(/\$FileName/g,file.filename).replace(/\$FileId/g,req.params.fileId).replace(/\$Version/g,pkg.version))
        })
    } else {
        ThrowError(res,404,"File not found.")
    }
})

app.get("/file/:fileId",async (req,res) => {
    if (files[req.params.fileId]) {
        let file = files[req.params.fileId]
        let bufToCombine = []

        for (let i = 0; i < file.messageids.length; i++) {
            let msg = await uploadChannel.messages.fetch(file.messageids[i]).catch(() => {return null})
            if (msg?.attachments) {
                let attach = Array.from(msg.attachments.values())
                for (let i = 0; i < attach.length; i++) {
                    let d = await axios.get(attach[i].url,{responseType:"arraybuffer"}).catch((e:Error) => {console.error(e)})
                    if (d) {
                        bufToCombine.push(d.data)
                    } else {
                        res.sendStatus(500);return
                    }
                }
            }
        }

        let nb:Buffer|null = Buffer.concat(bufToCombine)

        res.setHeader('Content-Type',file.mime)
        res.send(nb)

        nb = null

    } else {
        res.sendStatus(404)
    }
})

app.get("/server",(req,res) => {
    res.send(JSON.stringify({...config,version:pkg.version}))
})

app.get("*",(req,res) => {
    ThrowError(res,404,"Page not found.")
})

client.on("ready",() => {
    console.log("Discord OK!")

    client.guilds.fetch(config.targetGuild).then((g) => {
        g.channels.fetch(config.targetChannel).then((a) => {
            if (a?.isTextBased()) {
                uploadChannel = a
            }
        })
    })
})

app.listen(3000,function() {
    console.log("Web OK!")
})

client.login(process.env.TOKEN)