feat(#375): emit SubscriptionCancelled event on subscription cancella…

contract/contracts/hello-world/src/autoshare_logic.rs

@@ -1,15 +1,12 @@
 use crate::base::errors::Error;
 use crate::base::events::{
-    AdminTransferred, AuthorizationFailure, AutoshareCreated, AutoshareUpdated, CategoryRegistered,
-    ContractPaused, ContractUnpaused, GroupActivated, GroupDeactivated, NotificationCategory,
-    NotificationDelivered, NotificationExpired, NotificationExtended, NotificationLimitsConfigured,
-    NotificationPriority, NotificationRecalled, NotificationRevoked, NotificationScheduled,
-    ScheduledNotificationCancelled, Withdrawal,
-    AdminTransferred, AuthorizationFailure, AutoshareCreated, AutoshareUpdated, ContractPaused,
-    ContractUnpaused, GroupActivated, GroupDeactivated, NotificationAcknowledged,
-    NotificationCategory, NotificationExpired, NotificationPriority, NotificationRevoked,
-    NotificationScheduled, ScheduledNotificationCancelled, Withdrawal,
     AdminTransferred, AuditAction, AuditRecordAppended, AuthorizationFailure, AutoshareCreated,
+    AutoshareUpdated, BatchNotificationsCreated, BatchProcessingCompleted, CategoryRegistered,
+    ContractPaused, ContractUnpaused, GroupActivated, GroupDeactivated, NotificationAccessed,
+    NotificationAcknowledged, NotificationCategory, NotificationDelivered, NotificationExpired,
+    NotificationExtended, NotificationLimitsConfigured, NotificationPriority, NotificationRecalled,
+    NotificationRevoked, NotificationScheduled, ScheduledNotificationCancelled,
+    SchemaVersionSet, SubscriptionCancelled, Withdrawal,
     AutoshareUpdated, BatchNotificationsCreated, CategoryRegistered, ContractPaused,
     ContractUnpaused, GroupActivated, GroupDeactivated, NotificationCategory, NotificationExpired,
     NotificationPriority, NotificationRevoked, NotificationScheduled, OwnershipTransferInitiated,
@@ -751,6 +748,72 @@ pub fn topup_subscription(
     Ok(())
 }
 
+/// Cancels an active notification subscription for a group and emits a
+/// [`SubscriptionCancelled`] event so off-chain consumers can track the full
+/// subscription lifecycle.
+///
+/// The subscriber must be the group's creator or an authorised member of the
+/// group. Cancellation marks the group as inactive (deactivates it) and zeroes
+/// out the remaining usage count so no further notifications can be dispatched
+/// against the subscription.
+///
+/// # Errors
+/// - [`Error::ContractPaused`]   – the contract is currently paused.
+/// - [`Error::NotFound`]         – `id` does not correspond to a known group.
+/// - [`Error::Unauthorized`]     – `subscriber` is neither the creator nor a
+///                                 member of the group.
+/// - [`Error::GroupInactive`]    – the group is already inactive (subscription
+///                                 already cancelled or never active).
+pub fn cancel_subscription(
+    env: Env,
+    id: BytesN<32>,
+    subscriber: Address,
+) -> Result<(), Error> {
+    subscriber.require_auth();
+
+    if get_paused_status(&env) {
+        return Err(Error::ContractPaused);
+    }
+
+    let key = DataKey::AutoShare(id.clone());
+    let mut details: AutoShareDetails = env
+        .storage()
+        .persistent()
+        .get(&key)
+        .ok_or(Error::NotFound)?;
+
+    // Only the creator or a current member may cancel the subscription.
+    let is_creator = details.creator == subscriber;
+    let is_member = details.members.iter().any(|m| m.address == subscriber);
+
+    if !is_creator && !is_member {
+        publish_authorization_failure(&env, &subscriber, "cancel_subscription");
+        return Err(Error::Unauthorized);
+    }
+
+    if !details.is_active {
+        return Err(Error::GroupInactive);
+    }
+
+    // Deactivate the group and clear remaining usages.
+    details.is_active = false;
+    details.usage_count = 0;
+    env.storage().persistent().set(&key, &details);
+
+    let cancelled_at = env.ledger().timestamp();
+
+    SubscriptionCancelled {
+        group_id: id,
+        subscriber,
+        category: NotificationCategory::Group,
+        priority: NotificationPriority::Medium,
+        cancelled_at,
+    }
+    .publish(&env);
+
+    Ok(())
+}
+
 // ============================================================================
 // Payment History
 // ============================================================================

contract/contracts/hello-world/src/base/events.rs

@@ -469,6 +469,21 @@ pub struct NotificationAcknowledged {
     pub timestamp: u64,
 }
 
+/// Emitted when a subscriber cancels an active notification subscription.
+///
+/// Off-chain consumers can key off `(group_id, subscriber)` to track the full
+/// subscription lifecycle. The `group_id` identifies the AutoShare group whose
+/// subscription was cancelled; `subscriber` is the address that initiated the
+/// cancellation.
+#[contractevent(data_format = "single-value")]
+#[derive(Clone)]
+pub struct SubscriptionCancelled {
+    /// The group whose subscription was cancelled.
+    #[topic]
+    pub group_id: BytesN<32>,
+    /// The address that cancelled the subscription.
+    #[topic]
+    pub subscriber: Address,
 /// Emitted when the current owner initiates a two-step ownership transfer by
 /// nominating a `pending_owner`. The transfer is not final until the pending
 /// owner calls `accept_ownership`.
@@ -499,5 +514,7 @@ pub struct OwnershipTransferred {
     pub category: NotificationCategory,
     #[topic]
     pub priority: NotificationPriority,
+    /// Ledger timestamp (seconds) when the cancellation occurred.
+    pub cancelled_at: u64,
     pub new_owner: Address,
 }

contract/contracts/hello-world/src/lib.rs

@@ -275,6 +275,16 @@ impl AutoShareContract {
             .unwrap();
     }
 
+    /// Cancels an active notification subscription for a group.
+    ///
+    /// The `subscriber` must be the group's creator or a current member. On
+    /// success the group is deactivated, its remaining usage count is zeroed, and
+    /// a `SubscriptionCancelled` event is emitted so off-chain consumers can
+    /// track the full subscription lifecycle.
+    pub fn cancel_subscription(env: Env, id: BytesN<32>, subscriber: Address) {
+        autoshare_logic::cancel_subscription(env, id, subscriber).unwrap();
+    }
+
     // ============================================================================
     // Payment History
     // ============================================================================
@@ -712,4 +722,7 @@ mod tests {
 
     #[path = "../tests/access_log_test.rs"]
     mod access_log_test;
+
+    #[path = "../tests/subscription_cancellation_test.rs"]
+    mod subscription_cancellation_test;
 }