// @ts-check

const {z} = require("zod")
const {randomUUID} = require("crypto")
const {defineEventHandler, getValidatedQuery, sendRedirect, readValidatedBody, useSession, createError, getRequestHeader, H3Event} = require("h3")
const {LRUCache} = require("lru-cache")

const {as, db} = require("../../passthrough")
const {reg} = require("../../matrix/read-registration")

const {sync} = require("../../passthrough")
const assert = require("assert").strict
/** @type {import("../pug-sync")} */
const pugSync = sync.require("../pug-sync")

const schema = {
	form: z.object({
		mxid: z.string()
	}),
	token: z.object({
		token: z.string()
	})
}

/**
 * @param {H3Event} event
 * @returns {import("../../matrix/api")}
 */
function getAPI(event) {
	/* c8 ignore next */
	return event.context.api || sync.require("../../matrix/api")
}

/** @type {LRUCache<string, string>} token to mxid */
const validToken = new LRUCache({max: 200})

/*
	1st request, GET, they clicked the button, need to input their mxid
	2nd request, POST, they input their mxid and we need to send a link
	3rd request, GET, they clicked the link and we need to set the session data (just their mxid)
*/

as.router.get("/log-in-with-matrix", defineEventHandler(async event => {
	const parsed = await getValidatedQuery(event, schema.token.safeParse)

	if (!parsed.success) {
		// We are in the first request and need to tell them to input their mxid
		return pugSync.render(event, "log-in-with-matrix.pug", {})
	}

	const userAgent = getRequestHeader(event, "User-Agent")
	if (userAgent?.match(/bot/)) throw createError({status: 400, data: "Sorry URL previewer, you can't have this URL."})

	const token = parsed.data.token
	if (!validToken.has(token)) return sendRedirect(event, `${reg.ooye.bridge_origin}/log-in-with-matrix`, 302)

	const session = await useSession(event, {password: reg.as_token})
	const mxid = validToken.get(token)
	assert(mxid)
	validToken.delete(token)

	const matrixGuilds = db.prepare("SELECT guild_id FROM guild_space INNER JOIN member_cache ON space_id = room_id WHERE mxid = ? AND power_level >= 50").pluck().all(mxid)

	await session.update({mxid, matrixGuilds})

	return sendRedirect(event, "./", 302) // open to homepage where they can see they're logged in
}))

as.router.post("/api/log-in-with-matrix", defineEventHandler(async event => {
	const api = getAPI(event)
	const {mxid} = await readValidatedBody(event, schema.form.parse)
	let roomID = null

	// Don't extend a duplicate invite for the same user
	for (const alreadyInvited of validToken.values()) {
		if (mxid === alreadyInvited) {
			return sendRedirect(event, "../ok?msg=We already sent you a link on Matrix. Please click it!", 302)
		}
	}

	// See if we can reuse an existing room from account data
	let directData = {}
	try {
		directData = await api.getAccountData("m.direct")
	} catch (e) {}
	const rooms = directData[mxid] || []
	for (const candidate of rooms) {
		// Check that the person is/still in the room
		let member
		try {
			member = await api.getStateEvent(candidate, "m.room.member", mxid)
		} catch (e) {}
		if (!member || member.membership === "leave") {
			// We can reinvite them back to the same room!
			await api.inviteToRoom(candidate, mxid)
			roomID = candidate
		} else {
			// Member is in this room
			roomID = candidate
		}
		if (roomID) break	// no need to check other candidates
	}

	// No candidates available, create a new room and invite
	if (!roomID) {
		roomID = await api.createRoom({
			invite: [mxid],
			is_direct: true,
			preset: "trusted_private_chat"
		})
		// Store the newly created room in account data (Matrix doesn't do this for us automatically, sigh...)
		;(directData[mxid] ??= []).push(roomID)
		await api.setAccountData("m.direct", directData)
	}

	const token = randomUUID()
	validToken.set(token, mxid)

	console.log(`web log in requested for ${mxid}`)
	const body = `Hi, this is Out Of Your Element! You just clicked the "log in" button on the website.\nOpen this link to finish: ${reg.ooye.bridge_origin}/log-in-with-matrix?token=${token}\nThe link can be used once.`
	await api.sendEvent(roomID, "m.room.message", {
		msgtype: "m.text",
		body
	})

	return sendRedirect(event, "../ok?msg=Please check your inbox on Matrix!&spot=SpotMailXL", 302)
}))