const fetch = require("node-fetch")
const {render} = require("pinski/plugins")
const db = require("../utils/db")
const {getToken, getUser} = require("../utils/getuser")
const pug = require("pug")
const converters = require("../utils/converters")

class InstanceError extends Error {
	constructor(error, identifier) {
		super(error)
		this.identifier = identifier
	}
}

function formatOrder(format) {
	// most significant to least significant
	// key, max, order, transform
	// asc: lower number comes first, desc: higher number comes first
	const spec = [
		["second__height", 8000, "desc", x => x ? Math.floor(x/96) : 0],
		["fps", 100, "desc", x => x ? Math.floor(x/10) : 0],
		["type", " ".repeat(60), "asc", x => x.length],
	]
	let total = 0
	for (let i = 0; i < spec.length; i++) {
		const s = spec[i]
		let diff = s[3](format[s[0]])
		if (s[2] === "asc") diff = s[3](s[1]) - diff
		total += diff
		if (i+1 < spec.length) {
			s2 = spec[i+1]
			total *= s2[3](s2[1])
		}
	}
	return -total
}

module.exports = [
	{
		route: "/watch", methods: ["GET"], code: async ({req, url}) => {
			const id = url.searchParams.get("v")
			const user = getUser(req)
			const settings = user.getSettingsOrDefaults()
			const outURL = `${settings.instance}/api/v1/videos/${id}`
			try {
				const video = await fetch(outURL).then(res => res.json())
				if (!video) throw new Error("The instance returned null.")
				if (video.error) throw new InstanceError(video.error, video.identifier)
				// video data additional processing
				for (const format of video.formatStreams.concat(video.adaptiveFormats)) {
					if (!format.second__height && format.resolution) format.second__height = +format.resolution.slice(0, -1)
					if (!format.second__order) format.second__order = formatOrder(format)
				}
				for (const rec of video.recommendedVideos) {
					if (!rec.second__lengthText && rec.lengthSeconds > 0) {
						rec.second__lengthText = converters.lengthSecondsToLengthText(rec.lengthSeconds)
					}
				}
				const subscribed = user.isSubscribed(video.authorId)
				return render(200, "pug/video.pug", {video, subscribed})
			} catch (e) {
				let message = pug.render("pre= error", {error: e.stack || e.toString()})
				if (e instanceof fetch.FetchError) {
					const template = `
p The selected instance, #[code= instance], did not respond correctly.
p Requested URL: #[a(href=url)= url]
`
					message = pug.render(template, {instance: settings.instance, url: outURL})
				} else if (e instanceof InstanceError) {
					const template = `
p #[strong= error.message]
if error.identifier
	p #[code= error.identifier]
p That error was generated by #[code= instance].
`
					message = pug.render(template, {instance: settings.instance, error: e})
				}
				return render(500, "pug/video.pug", {video: {videoId: id}, error: true, message})
			}
		}
	}
]