// @ts-check

const assert = require("assert")
const reg = require("../../matrix/read-registration")

const passthrough = require("../../passthrough")
const { discord, sync, db } = passthrough
/** @type {import("../../matrix/api")} */
const api = sync.require("../../matrix/api")
/** @type {import("../../matrix/file")} */
const file = sync.require("../../matrix/file")
/** @type {import("../converters/user-to-mxid")} */
const userToMxid = sync.require("../converters/user-to-mxid")

/**
 * A sim is an account that is being simulated by the bridge to copy events from the other side.
 * @param {import("discord-api-types/v10").APIUser} user
 * @returns mxid
 */
async function createSim(user) {
	// Choose sim name
	const simName = userToMxid.userToSimName(user)
	const localpart = reg.ooye.namespace_prefix + simName
	const mxid = "@" + localpart + ":cadence.moe"

	// Save chosen name in the database forever
	// Making this database change right away so that in a concurrent registration, the 2nd registration will already have generated a different localpart because it can see this row when it generates
	db.prepare("INSERT INTO sim (discord_id, sim_name, localpart, mxid) VALUES (?, ?, ?, ?)").run(user.id, simName, localpart, mxid)

	// Register matrix user with that name
	try {
		await api.register(localpart)
	} catch (e) {
		// If user creation fails, manually undo the database change. Still isn't perfect, but should help.
		// (A transaction would be preferable, but I don't think it's safe to leave transaction open across event loop ticks.)
		db.prepare("DELETE FROM sim WHERE discord_id = ?").run(user.id)
		throw e
	}
	return mxid
}

/**
 * Ensure a sim is registered for the user.
 * If there is already a sim, use that one. If there isn't one yet, register a new sim.
 * @param {import("discord-api-types/v10").APIUser} user
 * @returns {Promise<string>} mxid
 */
async function ensureSim(user) {
	let mxid = null
	const existing = db.prepare("SELECT mxid FROM sim WHERE discord_id = ?").pluck().get(user.id)
	if (existing) {
		mxid = existing
	} else {
		mxid = await createSim(user)
	}
	return mxid
}

/**
 * Ensure a sim is registered for the user and is joined to the room.
 * @param {import("discord-api-types/v10").APIUser} user
 * @param {string} roomID
 * @returns {Promise<string>} mxid
 */
async function ensureSimJoined(user, roomID) {
	// Ensure room ID is really an ID, not an alias
	assert.ok(roomID[0] === "!")

	// Ensure user
	const mxid = await ensureSim(user)

	// Ensure joined
	const existing = db.prepare("SELECT * FROM sim_member WHERE room_id = ? and mxid = ?").get(roomID, mxid)
	if (!existing) {
		await api.inviteToRoom(roomID, mxid)
		await api.joinRoom(roomID, mxid)
		db.prepare("INSERT INTO sim_member (room_id, mxid) VALUES (?, ?)").run(roomID, mxid)
	}
	return mxid
}

/**
 * @param {import("discord-api-types/v10").APIUser} user
 * @param {Omit<import("discord-api-types/v10").APIGuildMember, "user">} member
 */
async function memberToStateContent(user, member, guildID) {
	let displayname = user.username
	if (member.nick && member.nick !== displayname) displayname = member.nick + " | " + displayname // prepend nick if present

	const content = {
		displayname,
		membership: "join",
		"moe.cadence.ooye.member": {
		},
		"uk.half-shot.discord.member": {
			bot: !!user.bot,
			displayColor: user.accent_color,
			id: user.id,
			username: user.discriminator.length === 4 ? `${user.username}#${user.discriminator}` : `@${user.username}`
		}
	}

	if (member.avatar || user.avatar) {
		// const avatarPath = file.userAvatar(user) // the user avatar only
		const avatarPath = file.memberAvatar(guildID, user, member) // the member avatar or the user avatar
		content["moe.cadence.ooye.member"].avatar = avatarPath
		content.avatar_url = await file.uploadDiscordFileToMxc(avatarPath)
	}

	return content
}

function calculateProfileEventContentHash(content) {
	return `${content.displayname}\u0000${content.avatar_url}`
}

/**
 * @param {import("discord-api-types/v10").APIUser} user
 * @param {Omit<import("discord-api-types/v10").APIGuildMember, "user">} member
 */
async function syncUser(user, member, guildID, roomID) {
	const mxid = await ensureSimJoined(user, roomID)
	const content = await memberToStateContent(user, member, guildID)
	const profileEventContentHash = calculateProfileEventContentHash(content)
	const existingHash = db.prepare("SELECT profile_event_content_hash FROM sim_member WHERE room_id = ? AND mxid = ?").pluck().get(roomID, mxid)
	// only do the actual sync if the hash has changed since we last looked
	if (existingHash !== profileEventContentHash) {
		await api.sendState(roomID, "m.room.member", mxid, content, mxid)
		db.prepare("UPDATE sim_member SET profile_event_content_hash = ? WHERE room_id = ? AND mxid = ?").run(profileEventContentHash, roomID, mxid)
	}
}

async function syncAllUsersInRoom(roomID) {
	const mxids = db.prepare("SELECT mxid FROM sim_member WHERE room_id = ?").pluck().all(roomID)

	const channelID = db.prepare("SELECT channel_id FROM channel_room WHERE room_id = ?").pluck().get(roomID)
	assert.ok(typeof channelID === "string")
	/** @ts-ignore @type {import("discord-api-types/v10").APIGuildChannel} */
	const channel = discord.channels.get(channelID)
	const guildID = channel.guild_id
	assert.ok(typeof guildID === "string")

	for (const mxid of mxids) {
		const userID = db.prepare("SELECT discord_id FROM sim WHERE mxid = ?").pluck().get(mxid)
		assert.ok(typeof userID === "string")

		/** @ts-ignore @type {Required<import("discord-api-types/v10").APIGuildMember>} */
		const member = await discord.snow.guild.getGuildMember(guildID, userID)
		/** @ts-ignore @type {Required<import("discord-api-types/v10").APIUser>} user */
		const user = member.user
		assert.ok(user)

		console.log(`[user sync] to matrix: ${user.username} in ${channel.name}`)
		await syncUser(user, member, guildID, roomID)
	}
}

module.exports._memberToStateContent = memberToStateContent
module.exports.ensureSim = ensureSim
module.exports.ensureSimJoined = ensureSimJoined
module.exports.syncUser = syncUser
module.exports.syncAllUsersInRoom = syncAllUsersInRoom