spacebar/api/src/routes/users/@me/relationships.ts

import {
	RelationshipAddEvent,
	User,
	PublicUserProjection,
	RelationshipType,
	RelationshipRemoveEvent,
	emitEvent,
	Relationship,
	Config
} from "@fosscord/util";
import { Router, Response, Request } from "express";
import { HTTPError } from "lambert-server";
import { DiscordApiErrors } from "@fosscord/util";
import { route } from "@fosscord/api";

const router = Router();

const userProjection: (keyof User)[] = ["relationships", ...PublicUserProjection];

router.get("/", route({}), async (req: Request, res: Response) => {
	const user = await User.findOneOrFail({ where: { id: req.user_id }, relations: ["relationships", "relationships.to"] });

	//TODO DTO
	const related_users = user.relationships.map(r => {
		return {
			id: r.to.id,
			type: r.type,
			nickname: null,
			user: r.to.toPublicUser(),
		}
	})

	return res.json(related_users);
});

export interface RelationshipPutSchema {
	type: RelationshipType;
}

router.put("/:id", route({ body: "RelationshipPutSchema" }), async (req: Request, res: Response) => {
	return await updateRelationship(
		req,
		res,
		await User.findOneOrFail({ id: req.params.id }, { relations: ["relationships", "relationships.to"], select: userProjection }),
		req.body.type
	);
});

export interface RelationshipPostSchema {
	discriminator: string;
	username: string;
}

router.post("/", route({ body: "RelationshipPostSchema" }), async (req: Request, res: Response) => {
	return await updateRelationship(
		req,
		res,
		await User.findOneOrFail({
			relations: ["relationships", "relationships.to"],
			select: userProjection,
			where: {
				discriminator: String(req.body.discriminator,).padStart(4, '0'), //Discord send the discriminator as integer, we need to add leading zeroes
				username: req.body.username
			}
		}),
		req.body.type
	);
});

router.delete("/:id", route({}), async (req: Request, res: Response) => {
	const { id } = req.params;
	if (id === req.user_id) throw new HTTPError("You can't remove yourself as a friend");

	const user = await User.findOneOrFail({ id: req.user_id }, { select: userProjection, relations: ["relationships"] });
	const friend = await User.findOneOrFail({ id: id }, { select: userProjection, relations: ["relationships"] });

	const relationship = user.relationships.find((x) => x.to_id === id);
	const friendRequest = friend.relationships.find((x) => x.to_id === req.user_id);

	if (!relationship) throw new HTTPError("You are not friends with the user", 404);
	if (relationship?.type === RelationshipType.blocked) {
		// unblock user

		await Promise.all([
			Relationship.delete({ id: relationship.id }),
			emitEvent({
				event: "RELATIONSHIP_REMOVE",
				user_id: req.user_id,
				data: relationship.toPublicRelationship()
			} as RelationshipRemoveEvent)
		]);
		return res.sendStatus(204);
	}
	if (friendRequest && friendRequest.type !== RelationshipType.blocked) {
		await Promise.all([
			Relationship.delete({ id: friendRequest.id }),
			await emitEvent({
				event: "RELATIONSHIP_REMOVE",
				data: friendRequest.toPublicRelationship(),
				user_id: id
			} as RelationshipRemoveEvent)
		]);
	}

	await Promise.all([
		Relationship.delete({ id: relationship.id }),
		emitEvent({
			event: "RELATIONSHIP_REMOVE",
			data: relationship.toPublicRelationship(),
			user_id: req.user_id
		} as RelationshipRemoveEvent)
	]);

	return res.sendStatus(204);
});

export default router;

async function updateRelationship(req: Request, res: Response, friend: User, type: RelationshipType) {
	const id = friend.id;
	if (id === req.user_id) throw new HTTPError("You can't add yourself as a friend");

	const user = await User.findOneOrFail(
		{ id: req.user_id },
		{ relations: ["relationships", "relationships.to"], select: userProjection }
	);

	var relationship = user.relationships.find((x) => x.to_id === id);
	const friendRequest = friend.relationships.find((x) => x.to_id === req.user_id);

	// TODO: you can add infinitely many blocked users (should this be prevented?)
	if (type === RelationshipType.blocked) {
		if (relationship) {
			if (relationship.type === RelationshipType.blocked) throw new HTTPError("You already blocked the user");
			relationship.type = RelationshipType.blocked;
			await relationship.save();
		} else {
			relationship = await new Relationship({ to_id: id, type: RelationshipType.blocked, from_id: req.user_id }).save();
		}

		if (friendRequest && friendRequest.type !== RelationshipType.blocked) {
			await Promise.all([
				Relationship.delete({ id: friendRequest.id }),
				emitEvent({
					event: "RELATIONSHIP_REMOVE",
					data: friendRequest.toPublicRelationship(),
					user_id: id
				} as RelationshipRemoveEvent)
			]);
		}

		await emitEvent({
			event: "RELATIONSHIP_ADD",
			data: relationship.toPublicRelationship(),
			user_id: req.user_id
		} as RelationshipAddEvent);

		return res.sendStatus(204);
	}

	const { maxFriends } = Config.get().limits.user;
	if (user.relationships.length >= maxFriends) throw DiscordApiErrors.MAXIMUM_FRIENDS.withParams(maxFriends);

	var incoming_relationship = new Relationship({ nickname: undefined, type: RelationshipType.incoming, to: user, from: friend });
	var outgoing_relationship = new Relationship({
		nickname: undefined,
		type: RelationshipType.outgoing,
		to: friend,
		from: user
	});

	if (friendRequest) {
		if (friendRequest.type === RelationshipType.blocked) throw new HTTPError("The user blocked you");
		if (friendRequest.type === RelationshipType.friends) throw new HTTPError("You are already friends with the user");
		// accept friend request
		incoming_relationship = friendRequest;
		incoming_relationship.type = RelationshipType.friends;
	}

	if (relationship) {
		if (relationship.type === RelationshipType.outgoing) throw new HTTPError("You already sent a friend request");
		if (relationship.type === RelationshipType.blocked) throw new HTTPError("Unblock the user before sending a friend request");
		if (relationship.type === RelationshipType.friends) throw new HTTPError("You are already friends with the user");
		outgoing_relationship = relationship;
		outgoing_relationship.type = RelationshipType.friends;
	}

	await Promise.all([
		incoming_relationship.save(),
		outgoing_relationship.save(),
		emitEvent({
			event: "RELATIONSHIP_ADD",
			data: outgoing_relationship.toPublicRelationship(),
			user_id: req.user_id
		} as RelationshipAddEvent),
		emitEvent({
			event: "RELATIONSHIP_ADD",
			data: {
				...incoming_relationship.toPublicRelationship(),
				should_notify: true
			},
			user_id: id
		} as RelationshipAddEvent)
	]);

	return res.sendStatus(204);
}