🌿 introduce OAuth configuration

.fernignore

@@ -1 +1,4 @@
 # Specify files that shouldn't be modified by Fern
+src/wrapper/
+src/core/auth/OAuthTokenProvider.ts
+src/index.ts

src/core/auth/OAuthTokenProvider.ts

@@ -0,0 +1,57 @@
+/**
+ * This file was auto-generated by Fern from our API Definition.
+ */
+
+import * as core from "../../core";
+import { Auth } from "../../api/resources/auth/client/Client";
+
+/**
+ * The OAuthTokenProvider retrieves an OAuth access token, refreshing it as needed.
+ * The access token is then used as the bearer token in every authenticated request.
+ */
+export class OAuthTokenProvider {
+    private readonly BUFFER_IN_MINUTES = 2;
+    private readonly _clientId: core.Supplier<string>;
+    private readonly _clientSecret: core.Supplier<string>;
+    private readonly _authClient: Auth;
+    private _accessToken: string | undefined;
+    private _expiresAt: Date;
+
+    constructor({
+        clientId,
+        clientSecret,
+        authClient,
+    }: {
+        clientId: core.Supplier<string>;
+        clientSecret: core.Supplier<string>;
+        authClient: Auth;
+    }) {
+        this._clientId = clientId;
+        this._clientSecret = clientSecret;
+        this._authClient = authClient;
+        this._expiresAt = new Date();
+    }
+
+    public async getToken(): Promise<string> {
+        if (this._accessToken && this._expiresAt > new Date()) {
+            return this._accessToken;
+        }
+        return this.refresh();
+    }
+
+    private async refresh(): Promise<string> {
+        const tokenResponse = await this._authClient.getToken({
+            clientId: await core.Supplier.get(this._clientId),
+            clientSecret: await core.Supplier.get(this._clientSecret),
+        });
+
+        this._accessToken = tokenResponse.accessToken;
+        this._expiresAt = this.getExpiresAt(tokenResponse.expiresIn, this.BUFFER_IN_MINUTES);
+        return this._accessToken;
+    }
+
+    private getExpiresAt(expiresInSeconds: number, bufferInMinutes: number): Date {
+        const now = new Date();
+        return new Date(now.getTime() + expiresInSeconds * 1000 - bufferInMinutes * 60 * 1000);
+    }
+}

src/index.ts

@@ -1,4 +1,4 @@
 export * as Chariot from "./api";
-export { ChariotClient } from "./Client";
 export { ChariotEnvironment } from "./environments";
 export { ChariotError, ChariotTimeoutError } from "./errors";
+export { ChariotClient } from "./wrapper/ChariotClient";

src/wrapper/ChariotClient.ts

@@ -0,0 +1,30 @@
+import { Auth } from "api/resources/auth/client/Client";
+import { ChariotClient as FernClient } from "../Client";
+import * as core from "../core";
+import * as environments from "../environments";
+import { OAuthTokenProvider } from "core/auth/OAuthTokenProvider";
+
+export declare namespace ChariotClient {
+
+    interface Options {
+        environment?: core.Supplier<environments.ChariotEnvironment | string>;
+        clientId: core.Supplier<string>;
+        clientSecret: core.Supplier<string>;
+    }
+}
+
+export class ChariotClient extends FernClient {
+    constructor(protected readonly _options: ChariotClient.Options) {
+        const _oauthTokenProvider = new OAuthTokenProvider({
+            clientId: _options.clientId,
+            clientSecret: _options.clientSecret,
+            authClient: new Auth({
+                environment: _options.environment,
+            }),
+        });
+        super({
+            ..._options,
+            token: async () => await _oauthTokenProvider.getToken(),
+        })
+    }
+}