feat(api): initial implementation of the auth system (#30)

Adds the auth system but does not add all required features. They will be handled in other tickets

server/api/plextv.ts

@@ -0,0 +1,62 @@
+import axios, { AxiosInstance } from 'axios';
+
+interface PlexAccountResponse {
+  user: PlexUser;
+}
+
+interface PlexUser {
+  id: number;
+  uuid: string;
+  email: string;
+  joined_at: string;
+  username: string;
+  title: string;
+  thumb: string;
+  hasPassword: boolean;
+  authToken: string;
+  subscription: {
+    active: boolean;
+    status: string;
+    plan: string;
+    features: string[];
+  };
+  roles: {
+    roles: string[];
+  };
+  entitlements: string[];
+}
+
+class PlexTvAPI {
+  private authToken: string;
+  private axios: AxiosInstance;
+
+  constructor(authToken: string) {
+    this.authToken = authToken;
+    this.axios = axios.create({
+      baseURL: 'https://plex.tv',
+      headers: {
+        'X-Plex-Token': this.authToken,
+        'Content-Type': 'application/json',
+        Accept: 'application/json',
+      },
+    });
+  }
+
+  public async getUser(): Promise<PlexUser> {
+    try {
+      const account = await this.axios.get<PlexAccountResponse>(
+        '/users/account.json'
+      );
+
+      return account.data.user;
+    } catch (e) {
+      console.error(
+        'Something broke when getting account from plex.tv',
+        e.message
+      );
+      throw new Error('Invalid auth token');
+    }
+  }
+}
+
+export default PlexTvAPI;