PM-20532 - SendAccessToken model first draft

libs/common/src/auth/send-access/models/send-access-token.ts

@@ -0,0 +1,32 @@
+export class SendAccessToken {
+  constructor(
+    /**
+     * The access token string
+     */
+    readonly token: string,
+    /**
+     * The time (in milliseconds since the epoch) when the token expires
+     */
+    readonly expiresAt: number,
+  ) {}
+
+  /**
+   * Builds an instance from our Identity token response data
+   * @param accessToken The `access_token` string
+   * @param expiresInSeconds The `expires_in` value (in seconds)
+   */
+  static fromResponseData(accessToken: string, expiresInSeconds: number): SendAccessToken {
+    const expiresAtTimeStamp = Date.now() + expiresInSeconds * 1000;
+    return new SendAccessToken(accessToken, expiresAtTimeStamp);
+  }
+
+  /** Returns whether the send access token is expired or not */
+  isExpired(): boolean {
+    return Date.now() >= this.expiresAt;
+  }
+
+  /** Returns how many full seconds remain until expiry. Returns 0 if expired. */
+  timeUntilExpirySeconds(): number {
+    return Math.max(0, Math.floor((this.expiresAt - Date.now()) / 1_000));
+  }
+}