require("dotenv").config();
var {MongoClient, GridFSBucket} = require("mongodb");
var express = require("express");
var app = express();
app.set("trust proxy", "127.0.0.1");
var dbclient = new MongoClient(process.env.DB_URI);
dbclient.connect().then(async () => {
	var db = dbclient.db("mikudb");
	var collection = db.collection("illustration_collection");
	var bucket = new GridFSBucket(db);
	var idlist = require("./idlist.json");
	var ipa_lastload_map = {};
	let redirectRandom = (req, res) => {
		let random_id = idlist[Math.floor(Math.random() * idlist.length)];
		res.redirect(`/https://www.pixiv.net/en/artworks/${random_id}`);
	};
	app.get('/', redirectRandom);
	app.get("/https://www.pixiv.net/en/artworks/:id", async (req, res) => {
		//if (req.headers["cache-control"] == "max-age=0") { // this indicates a reload in chrome
		// but chrome still sends it after redirect
		if (ipa_lastload_map[req.ip] == req.params.id && req.query.noredirect == null) {
			return redirectRandom(req, res); 
		} else ipa_lastload_map[req.ip] = req.params.id;
		console.log(new Date().toLocaleString(), req.ip, req.params.id);
		var asdf = await collection.findOne({_id: req.params.id}, {downloaded_images: 1});
		if (!asdf) return res.sendStatus(404);
		var filename = Object.keys(asdf.downloaded_images)[0];
		res.type(filename.split('.').pop());
		res.header("Content-Disposition", `filename=${filename}`);
		var gfsid = Object.values(asdf.downloaded_images)[0];
		bucket.openDownloadStream(gfsid).pipe(res);
	});
	app.listen(39);
	console.log("server ready");
});