feat: Enable real-time loading of beacons

graphql/resolvers.js

@@ -325,6 +325,19 @@ const resolvers = {
                 groupLeader: group.leader,
             });
 
+            // Publish beacon update for real-time loading
+            pubsub.publish("BEACON_UPDATE", {
+                beaconUpdate: {
+                    beacon: newBeacon,
+                    groupId: groupID,
+                    type: "CREATED",
+                },
+                groupID: groupID,
+                groupMembers: group.members,
+                groupLeader: group.leader,
+                creatorID: user.id,
+            });
+
             return newBeacon;
         },
 
@@ -408,6 +421,19 @@ const resolvers = {
                 groupLeader: beacon.group.leader.toString(),
             });
 
+            // Publish beacon update for real-time loading
+            pubsub.publish("BEACON_UPDATE", {
+                beaconUpdate: {
+                    beacon: beacon,
+                    groupId: beacon.group.id,
+                    type: "UPDATED",
+                },
+                groupID: beacon.group.id,
+                groupMembers: beacon.group.members,
+                groupLeader: beacon.group.leader.toString(),
+                creatorID: user.id,
+            });
+
             return beacon;
         },
 
@@ -462,14 +488,17 @@ const resolvers = {
         },
 
         deleteBeacon: async (_parent, { id }, { user, pubsub }) => {
-            const beacon = await Beacon.findById(id);
+            const beacon = await Beacon.findById(id).populate("leader followers");
             if (!beacon) {
                 return new UserInputError("No beacon exists with this id!");
             }
 
-            if (beacon.leader.toString() !== user.id)
+            if (beacon.leader._id.toString() !== user.id)
                 return new Error("Beacon leader is allowed to delete the beacon!");
 
+            // Store beacon data before deletion for subscription payload
+            const beaconData = beacon.toObject();
+
             await User.updateOne({ _id: user.id }, { $pull: { beacons: id } });
 
             const group = await Group.findById(beacon.group);
@@ -485,7 +514,7 @@ const resolvers = {
                 groupUpdate: {
                     newUser: null,
                     newBeacon: null,
-                    deletedBeacon: deletedBeacon,
+                    deletedBeacon: beaconData,
                     updatedBeacon: null,
                     groupId: group.id,
                 },
@@ -494,6 +523,19 @@ const resolvers = {
                 groupLeader: group.leader.toString(),
             });
 
+            // Publish beacon update for real-time loading
+            pubsub.publish("BEACON_UPDATE", {
+                beaconUpdate: {
+                    beacon: beaconData,
+                    groupId: group.id,
+                    type: "DELETED",
+                },
+                groupID: group.id,
+                groupMembers: group.members,
+                groupLeader: group.leader.toString(),
+                creatorID: user.id,
+            });
+
             return deletedBeacon !== null;
         },
 
@@ -795,6 +837,37 @@ const resolvers = {
                     }
                 ),
             },
+            // Subscription for real-time beacon loading
+            beaconUpdate: {
+                subscribe: withFilter(
+                    (_, __, { pubsub }) => pubsub.asyncIterator(["BEACON_UPDATE"]),
+                    (payload, variables, { user }) => {
+                        const { groupID, groupMembers, groupLeader, creatorID, beaconUpdate } = payload;
+                        const { beacon, groupId, type } = beaconUpdate;
+
+                        // Don't notify the user who created/updated/deleted the beacon
+                        if (creatorID === user.id) {
+                            return false;
+                        }
+
+                        // Check if the beacon's group is in the subscribed groupIds
+                        if (!variables.groupIds.includes(groupID)) {
+                            return false;
+                        }
+
+                        // Check if user is part of the group
+                        const isGroupLeader = groupLeader === user.id.toString();
+                        const isGroupMember = groupMembers.some(memberId => memberId.toString() === user.id.toString());
+
+                        // Parse beacon object for proper serialization
+                        if (beacon != null) {
+                            payload.beaconUpdate.beacon = parseBeaconObject(beacon);
+                        }
+
+                        return (isGroupLeader || isGroupMember) && variables.groupIds.includes(groupId);
+                    }
+                ),
+            },
         },
     }),
 };

graphql/schema.js

@@ -122,6 +122,33 @@ const typeDefs = gql`
         updatedBeacon: Beacon
     }
 
+    """
+    Enum representing the type of beacon update event
+    """
+    enum BeaconUpdateType {
+        CREATED
+        UPDATED
+        DELETED
+    }
+
+    """
+    Payload for real-time beacon updates subscription
+    """
+    type BeaconPayload {
+        """
+        The beacon that was created, updated, or deleted
+        """
+        beacon: Beacon!
+        """
+        The ID of the group this beacon belongs to
+        """
+        groupId: ID!
+        """
+        The type of update: CREATED, UPDATED, or DELETED
+        """
+        type: BeaconUpdateType!
+    }
+
     type BeaconLocationsPayload {
         userSOS: User
         route: [Location]
@@ -165,6 +192,11 @@ const typeDefs = gql`
         beaconLocations(id: ID!): BeaconLocationsPayload!
         JoinLeaveBeacon(id: ID!): JoinLeaveBeaconPayload!
         groupUpdate(groupIds: [ID!]): UpdatedGroupPayload!
+        """
+        Subscribe to real-time beacon updates (create, update, delete) for specified groups.
+        This enables instantaneous loading of beacons for a smoother user experience.
+        """
+        beaconUpdate(groupIds: [ID!]!): BeaconPayload!
     }
 
     schema {