Implemented DMs and group DMs

19 files changed, 342 insertions, 79 deletions

diff --git a/api/src/routes/channels/#channel_id/index.ts b/api/src/routes/channels/#channel_id/index.ts
index 02ac9884..e836622b 100644
--- a/api/src/routes/channels/#channel_id/index.ts
+++ b/api/src/routes/channels/#channel_id/index.ts
@@ -1,6 +1,7 @@
-import { ChannelDeleteEvent, Channel, ChannelUpdateEvent, emitEvent, ChannelType, ChannelPermissionOverwriteType } from "@fosscord/util";
-import { Router, Response, Request } from "express";
+import { Channel, ChannelDeleteEvent, ChannelPermissionOverwriteType, ChannelService, ChannelType, ChannelUpdateEvent, emitEvent, Recipient } from "@fosscord/util";
+import { Request, Response, Router } from "express";
 import { route } from "@fosscord/api";
+
 const router: Router = Router();
 // TODO: delete channel
 // TODO: Get channel
@@ -16,14 +17,27 @@ router.get("/", route({ permission: "VIEW_CHANNEL" }), async (req: Request, res:
 router.delete("/", route({ permission: "MANAGE_CHANNELS" }), async (req: Request, res: Response) => {
 	const { channel_id } = req.params;
 
-	const channel = await Channel.findOneOrFail({ id: channel_id });
+	const channel = await Channel.findOneOrFail({ where: { id: channel_id }, relations: ["recipients"] });
 
-	// TODO: Dm channel "close" not delete
-	const data = channel;
+	if (channel.type === ChannelType.DM) {
+		const recipient = await Recipient.findOneOrFail({ where: { channel_id: channel_id, user_id: req.user_id } })
+		recipient.closed = true
+		await Promise.all([
+			recipient.save(),
+			emitEvent({ event: "CHANNEL_DELETE", data: channel, user_id: req.user_id } as ChannelDeleteEvent)
+		]);
 
-	await Promise.all([emitEvent({ event: "CHANNEL_DELETE", data, channel_id } as ChannelDeleteEvent), Channel.delete({ id: channel_id })]);
+	} else if (channel.type === ChannelType.GROUP_DM) {
+		await ChannelService.removeRecipientFromChannel(channel, req.user_id)
+	} else {
+		//TODO messages in this channel should be deleted before deleting the channel
+		await Promise.all([
+			Channel.delete({ id: channel_id }),
+			emitEvent({ event: "CHANNEL_DELETE", data: channel, channel_id } as ChannelDeleteEvent)
+		]);
+	}
 
-	res.send(data);
+	res.send(channel);
 });
 
 export interface ChannelModifySchema {
diff --git a/api/src/routes/channels/#channel_id/messages/#message_id/ack.ts b/api/src/routes/channels/#channel_id/messages/#message_id/ack.ts
index 97d1d19e..786e4581 100644
--- a/api/src/routes/channels/#channel_id/messages/#message_id/ack.ts
+++ b/api/src/routes/channels/#channel_id/messages/#message_id/ack.ts
@@ -26,7 +26,7 @@ router.post("/", route({ body: "MessageAcknowledgeSchema" }), async (req: Reques
 		data: {
 			channel_id,
 			message_id,
-			version: 496
+			version: 3763
 		}
 	} as MessageAckEvent);
 
diff --git a/api/src/routes/channels/#channel_id/messages/index.ts b/api/src/routes/channels/#channel_id/messages/index.ts
index ec93649e..bb610a6a 100644
--- a/api/src/routes/channels/#channel_id/messages/index.ts
+++ b/api/src/routes/channels/#channel_id/messages/index.ts
@@ -1,9 +1,8 @@
 import { Router, Response, Request } from "express";
-import { Attachment, Channel, ChannelType, Embed, getPermission, Message } from "@fosscord/util";
+import { Attachment, Channel, ChannelType, DmChannelDTO, Embed, emitEvent, getPermission, Message, MessageCreateEvent } from "@fosscord/util";
 import { HTTPError } from "lambert-server";
-import { route } from "@fosscord/api";
+import { handleMessage, postHandleMessage, route } from "@fosscord/api";
 import multer from "multer";
-import { sendMessage } from "@fosscord/api";
 import { uploadFile } from "@fosscord/api";
 import { FindManyOptions, LessThan, MoreThan } from "typeorm";
 
@@ -62,9 +61,9 @@ router.get("/", async (req: Request, res: Response) => {
 	if (!channel) throw new HTTPError("Channel not found", 404);
 
 	isTextChannel(channel.type);
-	const around = `${req.query.around}`;
-	const before = `${req.query.before}`;
-	const after = `${req.query.after}`;
+	const around = req.query.around ? `${req.query.around}` : undefined;
+	const before = req.query.before ? `${req.query.before}` : undefined;
+	const after = req.query.after ? `${req.query.after}` : undefined;
 	const limit = Number(req.query.limit) || 50;
 	if (limit < 1 || limit > 100) throw new HTTPError("limit must be between 1 and 100");
 
@@ -151,10 +150,12 @@ router.post(
 				return res.status(400).json(error);
 			}
 		}
+		//TODO querying the DB at every message post should be avoided, caching maybe?
+		const channel = await Channel.findOneOrFail({ where: { id: channel_id }, relations: ["recipients", "recipients.user"] })
 
 		const embeds = [];
 		if (body.embed) embeds.push(body.embed);
-		const data = await sendMessage({
+		let message = await handleMessage({
 			...body,
 			type: 0,
 			pinned: false,
@@ -162,9 +163,36 @@ router.post(
 			embeds,
 			channel_id,
 			attachments,
-			edited_timestamp: undefined
+			edited_timestamp: undefined,
+			timestamp: new Date()
 		});
 
-		return res.json(data);
+		message = await message.save()
+
+		await channel.assign({ last_message_id: message.id }).save()
+
+		if (channel.isDm()) {
+			const channel_dto = await DmChannelDTO.from(channel)
+
+			for (let recipient of channel.recipients!) {
+				if (recipient.closed) {
+					await emitEvent({
+						event: "CHANNEL_CREATE",
+						data: channel_dto.excludedRecipients([recipient.user_id]),
+						user_id: recipient.user_id
+					})
+				}
+			}
+
+			await Promise.all(channel.recipients!.map(async r => {
+				r.closed = false;
+				return await r.save()
+			}));
+		}
+
+		await emitEvent({ event: "MESSAGE_CREATE", channel_id: channel_id, data: message } as MessageCreateEvent)
+		postHandleMessage(message).catch((e) => {}); // no await as it shouldnt block the message send function and silently catch error
+
+		return res.json(message);
 	}
 );
diff --git a/api/src/routes/channels/#channel_id/recipients.ts b/api/src/routes/channels/#channel_id/recipients.ts
index ea6bc563..d88b38f3 100644
--- a/api/src/routes/channels/#channel_id/recipients.ts
+++ b/api/src/routes/channels/#channel_id/recipients.ts
@@ -1,5 +1,57 @@
-import { Router, Response, Request } from "express";
+import { Request, Response, Router } from "express";
+import { Channel, ChannelRecipientAddEvent, ChannelService, ChannelType, DiscordApiErrors, DmChannelDTO, emitEvent, PublicUserProjection, Recipient, User } from "@fosscord/util";
+
 const router: Router = Router();
-// TODO:
+
+router.put("/:user_id", async (req: Request, res: Response) => {
+	const { channel_id, user_id } = req.params;
+	const channel = await Channel.findOneOrFail({ where: { id: channel_id }, relations: ["recipients"] });
+
+	if (channel.type !== ChannelType.GROUP_DM) {
+		const recipients = [
+			...channel.recipients!.map(r => r.user_id),
+			user_id
+		].unique()
+
+		const new_channel = await ChannelService.createDMChannel(recipients, req.user_id)
+		return res.status(201).json(new_channel);
+	} else {
+		if (channel.recipients!.map(r => r.user_id).includes(user_id)) {
+			throw DiscordApiErrors.INVALID_RECIPIENT //TODO is this the right error?
+		}
+
+		channel.recipients!.push(new Recipient({ channel_id: channel_id, user_id: user_id }));
+		await channel.save()
+
+		await emitEvent({
+			event: "CHANNEL_CREATE",
+			data: await DmChannelDTO.from(channel, [user_id]),
+			user_id: user_id
+		});
+
+		await emitEvent({
+			event: "CHANNEL_RECIPIENT_ADD", data: {
+				channel_id: channel_id,
+				user: await User.findOneOrFail({ where: { id: user_id }, select: PublicUserProjection })
+			}, channel_id: channel_id
+		} as ChannelRecipientAddEvent);
+		return res.sendStatus(204);
+	}
+});
+
+router.delete("/:user_id", async (req: Request, res: Response) => {
+	const { channel_id, user_id } = req.params;
+	const channel = await Channel.findOneOrFail({ where: { id: channel_id }, relations: ["recipients"] });
+	if (!(channel.type === ChannelType.GROUP_DM && (channel.owner_id === req.user_id || user_id === req.user_id)))
+		throw DiscordApiErrors.MISSING_PERMISSIONS
+
+	if (!channel.recipients!.map(r => r.user_id).includes(user_id)) {
+		throw DiscordApiErrors.INVALID_RECIPIENT //TODO is this the right error?
+	}
+
+	await ChannelService.removeRecipientFromChannel(channel, user_id)
+
+	return res.sendStatus(204);
+});
 
 export default router;
diff --git a/api/src/routes/users/#id/profile.ts b/api/src/routes/users/#id/profile.ts
index d60c4f86..06d5c38c 100644
--- a/api/src/routes/users/#id/profile.ts
+++ b/api/src/routes/users/#id/profile.ts
@@ -19,6 +19,7 @@ router.get("/", route({ response: { body: "UserProfileResponse" } }), async (req
 		connected_accounts: user.connected_accounts,
 		premium_guild_since: null, // TODO
 		premium_since: null, // TODO
+		mutual_guilds: [], // TODO {id: "", nick: null} when ?with_mutual_guilds=true
 		user: {
 			username: user.username,
 			discriminator: user.discriminator,
diff --git a/api/src/routes/users/@me/channels.ts b/api/src/routes/users/@me/channels.ts
index da33f204..bd7af18c 100644
--- a/api/src/routes/users/@me/channels.ts
+++ b/api/src/routes/users/@me/channels.ts
@@ -1,15 +1,21 @@
-import { Router, Request, Response } from "express";
-import { Channel, ChannelCreateEvent, ChannelType, Snowflake, trimSpecial, User, emitEvent, Recipient } from "@fosscord/util";
-import { HTTPError } from "lambert-server";
+import { Request, Response, Router } from "express";
+import { PublicUserProjection, Recipient, User, ChannelService } from "@fosscord/util";
 import { route } from "@fosscord/api";
-import { In } from "typeorm";
 
 const router: Router = Router();
 
 router.get("/", route({}), async (req: Request, res: Response) => {
-	const recipients = await Recipient.find({ where: { user_id: req.user_id }, relations: ["channel"] });
+	const recipients = await Recipient.find({ where: { user_id: req.user_id }, relations: ["channel", "user"] });
 
-	res.json(recipients.map((x) => x.channel));
+	//TODO check if this is right
+	const aa = await Promise.all(recipients.map(async (x) => {
+		return {
+			...(x.channel),
+			recipients: await User.findOneOrFail({ where: { id: x.user_id }, select: PublicUserProjection }),
+		}
+	}))
+
+	res.json(aa);
 });
 
 export interface DmChannelCreateSchema {
@@ -19,30 +25,7 @@ export interface DmChannelCreateSchema {
 
 router.post("/", route({ body: "DmChannelCreateSchema" }), async (req: Request, res: Response) => {
 	const body = req.body as DmChannelCreateSchema;
-
-	body.recipients = body.recipients.filter((x) => x !== req.user_id).unique();
-
-	const recipients = await User.find({ where: body.recipients.map((x) => ({ id: x })) });
-
-	if (recipients.length !== body.recipients.length) {
-		throw new HTTPError("Recipient/s not found");
-	}
-
-	const type = body.recipients.length === 1 ? ChannelType.DM : ChannelType.GROUP_DM;
-	const name = trimSpecial(body.name);
-
-	const channel = await new Channel({
-		name,
-		type,
-		// owner_id only for group dm channels
-		created_at: new Date(),
-		last_message_id: null,
-		recipients: [...body.recipients.map((x) => new Recipient({ user_id: x })), new Recipient({ user_id: req.user_id })]
-	}).save();
-
-	await emitEvent({ event: "CHANNEL_CREATE", data: channel, user_id: req.user_id } as ChannelCreateEvent);
-
-	res.json(channel);
+	res.json(await ChannelService.createDMChannel(body.recipients, req.user_id, body.name));
 });
 
 export default router;
diff --git a/api/src/routes/users/@me/relationships.ts b/api/src/routes/users/@me/relationships.ts
index 58d2e481..1d72f11a 100644
--- a/api/src/routes/users/@me/relationships.ts
+++ b/api/src/routes/users/@me/relationships.ts
@@ -18,9 +18,19 @@ 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"] });
+	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(user.relationships);
+	return res.json(related_users);
 });
 
 export interface RelationshipPutSchema {
@@ -48,7 +58,10 @@ router.post("/", route({ body: "RelationshipPostSchema" }), async (req: Request,
 		await User.findOneOrFail({
 			relations: ["relationships", "relationships.to"],
 			select: userProjection,
-			where: req.body as { discriminator: string; username: string }
+			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
 	);
diff --git a/gateway/src/opcodes/Identify.ts b/gateway/src/opcodes/Identify.ts
index f6a4478f..d91cd7f2 100644
--- a/gateway/src/opcodes/Identify.ts
+++ b/gateway/src/opcodes/Identify.ts
@@ -88,20 +88,17 @@ export async function onIdentify(this: WebSocket, data: Payload) {
 	const user_guild_settings_entries = members.map((x) => x.settings);
 
 	const recipients = await Recipient.find({
-		where: { user_id: this.user_id },
+		where: { user_id: this.user_id, closed: false },
 		relations: ["channel", "channel.recipients", "channel.recipients.user"],
 		// TODO: public user selection
 	});
 	const channels = recipients.map((x) => {
 		// @ts-ignore
 		x.channel.recipients = x.channel.recipients?.map((x) => x.user);
-		// @ts-ignore
-		users = users.concat(x.channel.recipients);
-		if (x.channel.type === ChannelType.DM) {
-			x.channel.recipients = [
-				// @ts-ignore
-				x.channel.recipients.find((x) => x.id !== this.user_id),
-			];
+		//TODO is this needed? check if users in group dm that are not friends are sent in the READY event
+		//users = users.concat(x.channel.recipients);
+		if (x.channel.isDm()) {
+			x.channel.recipients = x.channel.recipients!.filter((x) => x.id !== this.user_id);
 		}
 		return x.channel;
 	});
@@ -111,16 +108,19 @@ export async function onIdentify(this: WebSocket, data: Payload) {
 	});
 	if (!user) return this.close(CLOSECODES.Authentication_failed);
 
-	const public_user = {
-		username: user.username,
-		discriminator: user.discriminator,
-		id: user.id,
-		public_flags: user.public_flags,
-		avatar: user.avatar,
-		bot: user.bot,
-		bio: user.bio,
-	};
-	users.push(public_user);
+	for (let relation of user.relationships) {
+		const related_user = relation.to
+		const public_related_user = {
+			username: related_user.username,
+			discriminator: related_user.discriminator,
+			id: related_user.id,
+			public_flags: related_user.public_flags,
+			avatar: related_user.avatar,
+			bot: related_user.bot,
+			bio: related_user.bio,
+		};
+		users.push(public_related_user);
+	}
 
 	const session_id = genSessionId();
 	this.session_id = session_id; //Set the session of the WebSocket object
@@ -201,7 +201,7 @@ export async function onIdentify(this: WebSocket, data: Payload) {
 		// @ts-ignore
 		experiments: experiments, // TODO
 		guild_join_requests: [], // TODO what is this?
-		users: users.unique(), // TODO
+		users: users.unique(),
 		merged_members: merged_members,
 		// shard // TODO: only for bots sharding
 		// application // TODO for applications
diff --git a/gateway/src/opcodes/index.ts b/gateway/src/opcodes/index.ts
index a6d13bfb..c4069589 100644
--- a/gateway/src/opcodes/index.ts
+++ b/gateway/src/opcodes/index.ts
@@ -21,5 +21,6 @@ export default {
 	8: onRequestGuildMembers,
 	// 9: Invalid Session
 	// 10: Hello
+	// 13: Dm_update
 	14: onLazyRequest,
 };
diff --git a/util/src/dtos/DmChannelDTO.ts b/util/src/dtos/DmChannelDTO.ts
new file mode 100644
index 00000000..8b7a18fd
--- /dev/null
+++ b/util/src/dtos/DmChannelDTO.ts
@@ -0,0 +1,35 @@
+import { MinimalPublicUserDTO } from "./UserDTO";
+import { Channel, PublicUserProjection, User } from "../entities";
+
+export class DmChannelDTO {
+	icon: string | null;
+	id: string;
+	last_message_id: string | null;
+	name: string | null;
+	origin_channel_id: string | null;
+	owner_id?: string;
+	recipients: MinimalPublicUserDTO[];
+	type: number;
+
+	static async from(channel: Channel, excluded_recipients: string[] = [], origin_channel_id?: string) {
+		const obj = new DmChannelDTO()
+		obj.icon = channel.icon || null
+		obj.id = channel.id
+		obj.last_message_id = channel.last_message_id || null
+		obj.name = channel.name || null
+		obj.origin_channel_id = origin_channel_id || null
+		obj.owner_id = channel.owner_id
+		obj.type = channel.type
+		obj.recipients = (await Promise.all(channel.recipients!.filter(r => !excluded_recipients.includes(r.user_id)).map(async r => {
+			return await User.findOneOrFail({ where: { id: r.user_id }, select: PublicUserProjection })
+		}))).map(u => new MinimalPublicUserDTO(u))
+		return obj
+	}
+
+	excludedRecipients(excluded_recipients: string[]): DmChannelDTO {
+		return {
+			...this,
+			recipients: this.recipients.filter(r => !excluded_recipients.includes(r.id))
+		}
+	}
+}
\ No newline at end of file
diff --git a/util/src/dtos/UserDTO.ts b/util/src/dtos/UserDTO.ts
new file mode 100644
index 00000000..f09b5f4e
--- /dev/null
+++ b/util/src/dtos/UserDTO.ts
@@ -0,0 +1,17 @@
+import { User } from "../entities";
+
+export class MinimalPublicUserDTO {
+	avatar?: string | null;
+	discriminator: string;
+	id: string;
+	public_flags: number;
+	username: string;
+
+	constructor(user: User) {
+		this.avatar = user.avatar
+		this.discriminator = user.discriminator
+		this.id = user.id
+		this.public_flags = user.public_flags
+		this.username = user.username
+	}
+}
\ No newline at end of file
diff --git a/util/src/dtos/index.ts b/util/src/dtos/index.ts
new file mode 100644
index 00000000..13702342
--- /dev/null
+++ b/util/src/dtos/index.ts
@@ -0,0 +1,2 @@
+export * from "./DmChannelDTO";
+export * from "./UserDTO";
\ No newline at end of file
diff --git a/util/src/entities/Channel.ts b/util/src/entities/Channel.ts
index fc954f63..6eac19ca 100644
--- a/util/src/entities/Channel.ts
+++ b/util/src/entities/Channel.ts
@@ -1,7 +1,6 @@
-import { Column, Entity, JoinColumn, JoinTable, ManyToMany, ManyToOne, OneToMany, RelationId } from "typeorm";
+import { Column, Entity, JoinColumn, ManyToOne, OneToMany, RelationId } from "typeorm";
 import { BaseClass } from "./BaseClass";
 import { Guild } from "./Guild";
-import { Message } from "./Message";
 import { User } from "./User";
 import { HTTPError } from "lambert-server";
 import { emitEvent, getPermission, Snowflake } from "../util";
@@ -31,6 +30,9 @@ export class Channel extends BaseClass {
 	@Column({ nullable: true })
 	name?: string;
 
+	@Column({ nullable: true })
+	icon?: string;
+
 	@Column({ type: "simple-enum", enum: ChannelType })
 	type: ChannelType;
 
@@ -38,13 +40,8 @@ export class Channel extends BaseClass {
 	recipients?: Recipient[];
 
 	@Column({ nullable: true })
-	@RelationId((channel: Channel) => channel.last_message)
 	last_message_id: string;
 
-	@JoinColumn({ name: "last_message_id" })
-	@ManyToOne(() => Message)
-	last_message?: Message;
-
 	@Column({ nullable: true })
 	@RelationId((channel: Channel) => channel.guild)
 	guild_id?: string;
@@ -162,6 +159,10 @@ export class Channel extends BaseClass {
 
 		return channel;
 	}
+
+	isDm() {
+		return this.type === ChannelType.DM || this.type === ChannelType.GROUP_DM
+	}
 }
 
 export interface ChannelPermissionOverwrite {
diff --git a/util/src/entities/Recipient.ts b/util/src/entities/Recipient.ts
index 2a27b29f..bb280588 100644
--- a/util/src/entities/Recipient.ts
+++ b/util/src/entities/Recipient.ts
@@ -19,5 +19,8 @@ export class Recipient extends BaseClass {
 	@ManyToOne(() => require("./User").User)
 	user: import("./User").User;
 
+	@Column({ default: false })
+	closed: boolean;
+
 	// TODO: settings/mute/nick/added at/encryption keys/read_state
 }
diff --git a/util/src/entities/User.ts b/util/src/entities/User.ts
index 736704f8..cef88777 100644
--- a/util/src/entities/User.ts
+++ b/util/src/entities/User.ts
@@ -124,7 +124,7 @@ export class User extends BaseClass {
 	flags: string; // UserFlags
 
 	@Column()
-	public_flags: string;
+	public_flags: number;
 
 	@JoinColumn({ name: "relationship_ids" })
 	@OneToMany(() => Relationship, (relationship: Relationship) => relationship.from)
diff --git a/util/src/index.ts b/util/src/index.ts
index f3bd9e9b..538bfdd1 100644
--- a/util/src/index.ts
+++ b/util/src/index.ts
@@ -4,6 +4,8 @@ import "reflect-metadata";
 export * from "./util/index";
 export * from "./interfaces/index";
 export * from "./entities/index";
+export * from "./services/index";
+export * from "./dtos/index";
 
 // import Config from "../util/Config";
 // import db, { MongooseCache, toObject } from "./util/Database";
diff --git a/util/src/interfaces/Event.ts b/util/src/interfaces/Event.ts
index aff50300..03099bbb 100644
--- a/util/src/interfaces/Event.ts
+++ b/util/src/interfaces/Event.ts
@@ -127,6 +127,22 @@ export interface ChannelPinsUpdateEvent extends Event {
 	};
 }
 
+export interface ChannelRecipientAddEvent extends Event {
+	event: "CHANNEL_RECIPIENT_ADD";
+	data: {
+		channel_id: string;
+		user: User;
+	};
+}
+
+export interface ChannelRecipientRemoveEvent extends Event {
+	event: "CHANNEL_RECIPIENT_REMOVE";
+	data: {
+		channel_id: string;
+		user: User;
+	};
+}
+
 export interface GuildCreateEvent extends Event {
 	event: "GUILD_CREATE";
 	data: Guild & {
@@ -436,6 +452,8 @@ export type EventData =
 	| ChannelUpdateEvent
 	| ChannelDeleteEvent
 	| ChannelPinsUpdateEvent
+	| ChannelRecipientAddEvent
+	| ChannelRecipientRemoveEvent
 	| GuildCreateEvent
 	| GuildUpdateEvent
 	| GuildDeleteEvent
@@ -482,6 +500,8 @@ export enum EVENTEnum {
 	ChannelUpdate = "CHANNEL_UPDATE",
 	ChannelDelete = "CHANNEL_DELETE",
 	ChannelPinsUpdate = "CHANNEL_PINS_UPDATE",
+	ChannelRecipientAdd = "CHANNEL_RECIPIENT_ADD",
+	ChannelRecipientRemove = "CHANNEL_RECIPIENT_REMOVE",
 	GuildCreate = "GUILD_CREATE",
 	GuildUpdate = "GUILD_UPDATE",
 	GuildDelete = "GUILD_DELETE",
@@ -525,6 +545,8 @@ export type EVENT =
 	| "CHANNEL_UPDATE"
 	| "CHANNEL_DELETE"
 	| "CHANNEL_PINS_UPDATE"
+	| "CHANNEL_RECIPIENT_ADD"
+	| "CHANNEL_RECIPIENT_REMOVE"
 	| "GUILD_CREATE"
 	| "GUILD_UPDATE"
 	| "GUILD_DELETE"
diff --git a/util/src/services/ChannelService.ts b/util/src/services/ChannelService.ts
new file mode 100644
index 00000000..7cded10f
--- /dev/null
+++ b/util/src/services/ChannelService.ts
@@ -0,0 +1,88 @@
+import { Channel, ChannelType, PublicUserProjection, Recipient, User } from "../entities";
+import { HTTPError } from "lambert-server";
+import { emitEvent, trimSpecial } from "../util";
+import { DmChannelDTO } from "../dtos";
+import { ChannelRecipientRemoveEvent } from "../interfaces";
+
+export function checker(arr: any[], target: any[]) {
+	return target.every(v => arr.includes(v));
+}
+
+export class ChannelService {
+	public static async createDMChannel(recipients: string[], creator_user_id: string, name?: string) {
+		recipients = recipients.unique().filter((x) => x !== creator_user_id);
+		const otherRecipientsUsers = await User.find({ where: recipients.map((x) => ({ id: x })) });
+
+		if (otherRecipientsUsers.length !== recipients.length) {
+			throw new HTTPError("Recipient/s not found");
+		}
+
+		const type = recipients.length === 1 ? ChannelType.DM : ChannelType.GROUP_DM;
+
+		let channel = null;
+
+		const channelRecipients = [...recipients, creator_user_id]
+
+		const userRecipients = await Recipient.find({ where: { user_id: creator_user_id }, relations: ["channel", "channel.recipients"] })
+
+		for (let ur of userRecipients) {
+			let re = ur.channel.recipients!.map(r => r.user_id)
+			if (re.length === channelRecipients.length) {
+				if (checker(re, channelRecipients)) {
+					if (channel == null) {
+						channel = ur.channel
+						await ur.assign({ closed: false }).save()
+					}
+				}
+			}
+		}
+
+		if (channel == null) {
+			name = trimSpecial(name);
+
+			channel = await new Channel({
+				name,
+				type,
+				owner_id: (type === ChannelType.DM ? undefined : creator_user_id),
+				created_at: new Date(),
+				last_message_id: null,
+				recipients: channelRecipients.map((x) => new Recipient({ user_id: x, closed: !(type === ChannelType.GROUP_DM || x === creator_user_id) })),
+			}).save();
+		}
+
+
+		const channel_dto = await DmChannelDTO.from(channel)
+
+		if (type === ChannelType.GROUP_DM) {
+
+			for (let recipient of channel.recipients!) {
+				await emitEvent({
+					event: "CHANNEL_CREATE",
+					data: channel_dto.excludedRecipients([recipient.user_id]),
+					user_id: recipient.user_id
+				})
+			}
+		} else {
+			await emitEvent({ event: "CHANNEL_CREATE", data: channel_dto, user_id: creator_user_id });
+		}
+
+		return channel_dto.excludedRecipients([creator_user_id])
+	}
+
+	public static async removeRecipientFromChannel(channel: Channel, user_id: string) {
+		await Recipient.delete({ channel_id: channel.id, user_id: user_id })
+
+		await emitEvent({
+			event: "CHANNEL_DELETE",
+			data: await DmChannelDTO.from(channel, [user_id]),
+			user_id: user_id
+		});
+
+		await emitEvent({
+			event: "CHANNEL_RECIPIENT_REMOVE", data: {
+				channel_id: channel.id,
+				user: await User.findOneOrFail({ where: { id: user_id }, select: PublicUserProjection })
+			}, channel_id: channel.id
+		} as ChannelRecipientRemoveEvent);
+	}
+}
\ No newline at end of file
diff --git a/util/src/services/index.ts b/util/src/services/index.ts
new file mode 100644
index 00000000..c012a208
--- /dev/null
+++ b/util/src/services/index.ts
@@ -0,0 +1 @@
+export * from "./ChannelService";