/*
	Spacebar: A FOSS re-implementation and extension of the Discord.com backend.
	Copyright (C) 2023 Spacebar and Spacebar Contributors

	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU Affero General Public License as published
	by the Free Software Foundation, either version 3 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU Affero General Public License for more details.

	You should have received a copy of the GNU Affero General Public License
	along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/

import {
	getDatabase,
	getPermission,
	GuildMembersChunkEvent,
	Member,
	Presence,
	RequestGuildMembersSchema,
	Session,
} from "@spacebar/util";
import { WebSocket, Payload, OPCODES, Send } from "@spacebar/gateway";
import { check } from "./instanceOf";
import { FindManyOptions, ILike, In } from "typeorm";

export async function onRequestGuildMembers(this: WebSocket, { d }: Payload) {
	// Schema validation can only accept either string or array, so transforming it here to support both
	if (!d.guild_id) throw new Error('"guild_id" is required');
	d.guild_id = Array.isArray(d.guild_id) ? d.guild_id[0] : d.guild_id;

	if (d.user_ids && !Array.isArray(d.user_ids)) d.user_ids = [d.user_ids];

	check.call(this, RequestGuildMembersSchema, d);

	const {
		presences,
		nonce,
		query: requestQuery,
	} = d as RequestGuildMembersSchema;
	let { limit, user_ids, guild_id } = d as RequestGuildMembersSchema;

	// some discord libraries send empty string as query when they meant to send undefined, which was leading to errors being thrown in this handler
	const query = requestQuery != "" ? requestQuery : undefined;

	guild_id = guild_id as string;
	user_ids = user_ids as string[] | undefined;

	if ("query" in d && (!limit || Number.isNaN(limit)))
		throw new Error('"query" requires "limit" to be set');
	if ("query" in d && user_ids)
		throw new Error('"query" and "user_ids" are mutually exclusive');

	// TODO: Configurable limit?
	if ((query || (user_ids && user_ids.length > 0)) && (!limit || limit > 100))
		limit = 100;

	const permissions = await getPermission(this.user_id, guild_id);
	permissions.hasThrow("VIEW_CHANNEL");

	const memberCount = await Member.count({
		where: {
			guild_id,
		},
	});

	const memberFind: FindManyOptions = {
		where: {
			guild_id,
		},
		relations: ["user", "roles"],
	};
	if (limit) memberFind.take = Math.abs(Number(limit || 100));

	let members: Member[] = [];

	if (memberCount > 75000) {
		// since we dont have voice channels yet, just return the connecting users member object
		members = await Member.find({
			...memberFind,
			where: {
				...memberFind.where,
				user: {
					id: this.user_id,
				},
			},
		});
	} else if (memberCount > this.large_threshold) {
		// find all members who are online, have a role, have a nickname, or are in a voice channel, as well as respecting the query and user_ids
		const db = getDatabase();
		if (!db) throw new Error("Database not initialized");
		const repo = db.getRepository(Member);
		const q = repo
			.createQueryBuilder("member")
			.where("member.guild_id = :guild_id", { guild_id })
			.leftJoinAndSelect("member.roles", "role")
			.leftJoinAndSelect("member.user", "user")
			.leftJoinAndSelect("user.sessions", "session")
			.andWhere(
				"',' || member.roles || ',' NOT LIKE :everyoneRoleIdList",
				{ everyoneRoleIdList: "%," + guild_id + ",%" },
			)
			.addOrderBy("user.username", "ASC")
			.limit(memberFind.take);

		if (query && query != "") {
			q.andWhere(`user.username ILIKE :query`, {
				query: `${query}%`,
			});
		} else if (user_ids) {
			q.andWhere(`user.id IN (:...user_ids)`, { user_ids });
		}

		members = await q.getMany();
	} else {
		if (query) {
			// @ts-expect-error memberFind.where is very much defined
			memberFind.where.user = {
				username: ILike(query + "%"),
			};
		} else if (user_ids && user_ids.length > 0) {
			// @ts-expect-error memberFind.where is still very much defined
			memberFind.where.id = In(user_ids);
		}

		members = await Member.find(memberFind);
	}

	const baseData = {
		guild_id,
		nonce,
	};

	const chunkCount = Math.ceil(members.length / 1000);

	let notFound: string[] = [];
	if (user_ids && user_ids.length > 0)
		notFound = user_ids.filter(
			(id) => !members.some((member) => member.id == id),
		);

	const chunks: GuildMembersChunkEvent["data"][] = [];
	while (members.length > 0) {
		const chunk: Member[] = members.splice(0, 1000);

		const presenceList: Presence[] = [];
		if (presences) {
			for await (const member of chunk) {
				const session = await Session.findOne({
					where: { user_id: member.id },
				});
				if (session)
					presenceList.push({
						user: member.user.toPublicUser(),
						status: session.status,
						activities: session.activities,
						client_status: session.client_status,
					});
			}
		}

		chunks.push({
			...baseData,
			members: chunk.map((member) => member.toPublicMember()),
			presences: presences ? presenceList : undefined,
			chunk_index: chunks.length,
			chunk_count: chunkCount,
		});
	}

	if (chunks.length == 0) {
		chunks.push({
			...baseData,
			members: [],
			presences: presences ? [] : undefined,
			chunk_index: 0,
			chunk_count: 1,
		});
	}

	if (notFound.length > 0) {
		chunks[0].not_found = notFound;
	}

	chunks.forEach((chunk) => {
		Send(this, {
			op: OPCODES.Dispatch,
			s: this.sequence++,
			t: "GUILD_MEMBERS_CHUNK",
			d: chunk,
		});
	});
}
