1 files changed, 181 insertions, 0 deletions
diff --git a/src/connections/Twitch/index.ts b/src/connections/Twitch/index.ts
new file mode 100644
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--- /dev/null
+++ b/src/connections/Twitch/index.ts
@@ -0,0 +1,181 @@
+/*
+	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 {
+	ConnectedAccount,
+	ConnectedAccountCommonOAuthTokenResponse,
+	ConnectionCallbackSchema,
+	ConnectionLoader,
+	DiscordApiErrors,
+} from "@spacebar/util";
+import wretch from "wretch";
+import RefreshableConnection from "../../util/connections/RefreshableConnection";
+import { TwitchSettings } from "./TwitchSettings";
+
+interface TwitchConnectionUserResponse {
+	data: {
+		id: string;
+		login: string;
+		display_name: string;
+		type: string;
+		broadcaster_type: string;
+		description: string;
+		profile_image_url: string;
+		offline_image_url: string;
+		view_count: number;
+		created_at: string;
+	}[];
+}
+
+export default class TwitchConnection extends RefreshableConnection {
+	public readonly id = "twitch";
+	public readonly authorizeUrl = "https://id.twitch.tv/oauth2/authorize";
+	public readonly tokenUrl = "https://id.twitch.tv/oauth2/token";
+	public readonly userInfoUrl = "https://api.twitch.tv/helix/users";
+	public readonly scopes = [
+		"channel_subscriptions",
+		"channel_check_subscription",
+		"channel:read:subscriptions",
+	];
+	settings: TwitchSettings = new TwitchSettings();
+
+	init(): void {
+		this.settings = ConnectionLoader.getConnectionConfig(
+			this.id,
+			this.settings,
+		) as TwitchSettings;
+	}
+
+	getAuthorizationUrl(userId: string): string {
+		const state = this.createState(userId);
+		const url = new URL(this.authorizeUrl);
+
+		url.searchParams.append("client_id", this.settings.clientId!);
+		url.searchParams.append("redirect_uri", this.getRedirectUri());
+		url.searchParams.append("response_type", "code");
+		url.searchParams.append("scope", this.scopes.join(" "));
+		url.searchParams.append("state", state);
+		return url.toString();
+	}
+
+	getTokenUrl(): string {
+		return this.tokenUrl;
+	}
+
+	async exchangeCode(
+		state: string,
+		code: string,
+	): Promise<ConnectedAccountCommonOAuthTokenResponse> {
+		this.validateState(state);
+
+		const url = this.getTokenUrl();
+
+		return wretch(url.toString())
+			.headers({
+				Accept: "application/json",
+				"Content-Type": "application/x-www-form-urlencoded",
+			})
+			.body(
+				new URLSearchParams({
+					grant_type: "authorization_code",
+					code: code,
+					client_id: this.settings.clientId!,
+					client_secret: this.settings.clientSecret!,
+					redirect_uri: this.getRedirectUri(),
+				}),
+			)
+			.post()
+			.json<ConnectedAccountCommonOAuthTokenResponse>()
+			.catch((e) => {
+				console.error(e);
+				throw DiscordApiErrors.GENERAL_ERROR;
+			});
+	}
+
+	async refreshToken(
+		connectedAccount: ConnectedAccount,
+	): Promise<ConnectedAccountCommonOAuthTokenResponse> {
+		if (!connectedAccount.token_data?.refresh_token)
+			throw new Error("No refresh token available.");
+		const refresh_token = connectedAccount.token_data.refresh_token;
+
+		const url = this.getTokenUrl();
+
+		return wretch(url.toString())
+			.headers({
+				Accept: "application/json",
+				"Content-Type": "application/x-www-form-urlencoded",
+			})
+			.body(
+				new URLSearchParams({
+					grant_type: "refresh_token",
+					client_id: this.settings.clientId!,
+					client_secret: this.settings.clientSecret!,
+					refresh_token: refresh_token,
+				}),
+			)
+			.post()
+			.unauthorized(async () => {
+				// assume the token was revoked
+				await connectedAccount.revoke();
+				return DiscordApiErrors.CONNECTION_REVOKED;
+			})
+			.json<ConnectedAccountCommonOAuthTokenResponse>()
+			.catch((e) => {
+				console.error(e);
+				throw DiscordApiErrors.GENERAL_ERROR;
+			});
+	}
+
+	async getUser(token: string): Promise<TwitchConnectionUserResponse> {
+		const url = new URL(this.userInfoUrl);
+
+		return wretch(url.toString())
+			.headers({
+				Authorization: `Bearer ${token}`,
+				"Client-Id": this.settings.clientId!,
+			})
+			.get()
+			.json<TwitchConnectionUserResponse>()
+			.catch((e) => {
+				console.error(e);
+				throw DiscordApiErrors.GENERAL_ERROR;
+			});
+	}
+
+	async handleCallback(
+		params: ConnectionCallbackSchema,
+	): Promise<ConnectedAccount | null> {
+		const userId = this.getUserId(params.state);
+		const tokenData = await this.exchangeCode(params.state, params.code!);
+		const userInfo = await this.getUser(tokenData.access_token);
+
+		const exists = await this.hasConnection(userId, userInfo.data[0].id);
+
+		if (exists) return null;
+
+		return await this.createConnection({
+			token_data: { ...tokenData, fetched_at: Date.now() },
+			user_id: userId,
+			external_id: userInfo.data[0].id,
+			friend_sync: params.friend_sync,
+			name: userInfo.data[0].display_name,
+			type: this.id,
+		});
+	}
+}