feat: make billing cycle optional in usage response (#2054)

Author: oddgrd

common/src/models/user.rs

@@ -224,20 +224,29 @@ pub struct UpdateAccountTierRequest {
     pub account_tier: AccountTier,
 }
 
-/// Response for the /user/me/usage backend endpoint
+/// Sub-Response for the /user/me/usage backend endpoint
 #[derive(Debug, Default, Deserialize, Serialize, Clone)]
 #[cfg_attr(feature = "utoipa", derive(utoipa::ToSchema))]
 #[typeshare::typeshare]
-pub struct UserUsageResponse {
+pub struct UserBillingCycle {
     /// Billing cycle start, or monthly from user creation
     /// depending on the account tier
     pub start: NaiveDate,
 
     /// Billing cycle end, or end of month from user creation
     /// depending on the account tier
     pub end: NaiveDate,
+}
+
+/// Response for the /user/me/usage backend endpoint
+#[derive(Debug, Default, Deserialize, Serialize, Clone)]
+#[cfg_attr(feature = "utoipa", derive(utoipa::ToSchema))]
+#[typeshare::typeshare]
+pub struct UserUsageResponse {
+    /// Billing cycle for user, will be None if no usage data exists for user.
+    pub billing_cycle: Option<UserBillingCycle>,
 
-    /// HashMap of project related metrics for this cycle
-    /// keyed by project_id
+    /// HashMap of project related metrics for this cycle keyed by project_id. Will be empty
+    /// if no project usage data exists for user.
     pub projects: HashMap<String, ProjectUsageResponse>,
 }