var express = require("express");
require("express-async-errors");
var morgan = require("morgan");
var fs = require("fs/promises");
var getVideoLength = v => require('video-length')(v, {bin: "mediainfo"});

var app = module.exports.app = express();
app.set("env", process.env.NODE_ENV || "production");
app.set("trust proxy", ["loopback","linklocal","uniquelocal","173.245.48.0/20","103.21.244.0/22","103.22.200.0/22","103.31.4.0/22","141.101.64.0/18","108.162.192.0/18","190.93.240.0/20","188.114.96.0/20","197.234.240.0/22","198.41.128.0/17","162.158.0.0/15","104.16.0.0/13","104.24.0.0/14","172.64.0.0/13","131.0.72.0/22","2400:cb00::/32","2606:4700::/32","2803:f800::/32","2405:b500::/32","2405:8100::/32","2a06:98c0::/29","2c0f:f248::/32"]);
module.exports.server = app.listen(process.env.PORT || 8080, process.env.ADDR);

app.use(morgan(`:date[iso] :remote-addr :method :url ":req[user-agent]" :referrer`));

app.use("/videos/", express.static("videos"));

app.get("/playlist", async (req, res) => {
	res.send(await getPlaylist());
});

app.use(express.static("public"));

require("./mousie-server");





var currentPlaylist;

async function getPlaylist() {
	if (!currentPlaylist || Date.now() > currentPlaylist.timestamp + currentPlaylist.totalDuration*1000) {
		currentPlaylist = await generatePlaylist();
	}
	return currentPlaylist;
}

async function generatePlaylist() {
	var videofiles = await fs.readdir("videos");

	var videos = [];

	for (let name of videofiles) {
		let metadata = await getMetadata(name);
		if (!metadata.duration) {
			console.warn("missing duration:", name);
			continue;
		};
		videos.push({
			name,
			duration: metadata.duration,
			source: metadata.source || inferSource(name)
		});
	}

	shuffle(videos);

	return {
		videos,
		timestamp: Date.now(),
		totalDuration: videos.reduce((td, v) => td + v.duration, 0)
	}
}

async function getMetadata(video) {
	var videopath = `videos/${video}`;
	var metadatapath = `metadata/${video}.json`;
	try {
		var metadata = JSON.parse(await fs.readFile(metadatapath, "utf8"));
	} catch (error) {
		var metadata = {
			duration: null
		};
		try {
			metadata.duration = await getVideoLength(videopath);
		} catch(error) {
			console.error("get video length:", error.message);
		};
		await fs.writeFile(metadatapath, JSON.stringify(metadata));
	}
	return metadata;
}

function inferSource(name) {
	var youtube_id = name.match(/\[([A-Za-z0-9_-]{11})\]/);
	if (youtube_id) 
		return `https://www.youtube.com/watch?v=${youtube_id[1]}`;

	var niconico_id = name.match(/\[(sm\d+)\]/);
	if (niconico_id)
		return `https://www.nicovideo.jp/watch/${niconico_id[1]}`;
}




function shuffle(array) {
    for (let i = array.length - 1; i > 0; i--) {
        const j = Math.floor(Math.random() * (i + 1));
        [array[i], array[j]] = [array[j], array[i]];
    }
}