Add ability to specify enqueueing behavior (#13)

Author: paulirwin

README.md

@@ -68,11 +68,7 @@ resulting log entries (which is up to you to implement), and then for each one,
 calling the `ISyncService.SyncEntityIfEligible` method to process just that one 
 entity. This allows you to break down large synchronization operations into
 smaller, manageable pieces, while still keeping track of the overall synchronization 
-state of the entity. Note that this currently will not consider eligibility
-when determining whether to enqueue the entity, because that will be done when
-the `SyncEntityIfEligible` method is called. This means that you can enqueue
-entities that are not currently eligible for synchronization, and in case they
-become eligible before the next sync run, they will be processed as part of that run.
+state of the entity.
 
 ## Installation
 

Syncerbell/ISyncQueueService.cs

@@ -17,13 +17,15 @@ public interface ISyncQueueService
     /// details in the sync log.
     /// </remarks>
     /// <param name="syncTrigger">The type of trigger that initiated this sync operation (e.g., manual, timer).</param>
+    /// <param name="behavior">Specifies whether to queue all entities or only those that are eligible for sync.</param>
     /// <param name="cancellationToken">A cancellation token to cancel the operation if needed.</param>
     /// <returns>
     /// A read-only list of sync log entries that were created and queued for processing.
     /// Each entry represents a sync operation that needs to be performed by a distributed worker.
     /// </returns>
     /// <exception cref="OperationCanceledException">Thrown when the operation is cancelled via the cancellation token.</exception>
     Task<IReadOnlyList<ISyncLogEntry>> CreateAllQueuedSyncEntries(SyncTriggerType syncTrigger,
+        QueueBehavior behavior = QueueBehavior.QueueEligibleOnly,
         CancellationToken cancellationToken = default);
 
     /// <summary>

Syncerbell/QueueBehavior.cs

@@ -0,0 +1,20 @@
+namespace Syncerbell;
+
+/// <summary>
+/// Specifies the behavior for determining which entities should be queued for sync processing.
+/// </summary>
+public enum QueueBehavior
+{
+    /// <summary>
+    /// Queue all entities regardless of their eligibility status.
+    /// This will create sync entries for every registered entity without checking sync eligibility strategies.
+    /// </summary>
+    QueueAll,
+
+    /// <summary>
+    /// Queue only entities that are eligible for sync according to their configured eligibility strategies.
+    /// This respects sync eligibility rules such as interval-based strategies or custom eligibility logic.
+    /// </summary>
+    QueueEligibleOnly
+
+}

Syncerbell/SyncQueueService.cs

@@ -13,6 +13,7 @@ public class SyncQueueService(
 {
     /// <inheritdoc />
     public async Task<IReadOnlyList<ISyncLogEntry>> CreateAllQueuedSyncEntries(SyncTriggerType syncTrigger,
+        QueueBehavior behavior = QueueBehavior.QueueEligibleOnly,
         CancellationToken cancellationToken = default)
     {
         var entities = await entityResolver.ResolveEntities(cancellationToken);
@@ -38,6 +39,23 @@ public async Task<IReadOnlyList<ISyncLogEntry>> CreateAllQueuedSyncEntries(SyncT
                     continue;
                 }
 
+                // Check eligibility if behavior requires it
+                if (behavior == QueueBehavior.QueueEligibleOnly)
+                {
+                    var trigger = new SyncTrigger
+                    {
+                        TriggerType = syncTrigger,
+                        PriorSyncInfo = acquireResult.PriorSyncInfo
+                    };
+
+                    var isEligible = await entity.Eligibility.IsEligibleToSync(trigger, entity, cancellationToken);
+                    if (!isEligible)
+                    {
+                        logger.LogDebug("Entity {EntityName} is not eligible for sync. Skipping queue creation.", entity.Entity);
+                        continue;
+                    }
+                }
+
                 // Mark the entry as queued
                 logEntry.SyncStatus = SyncStatus.Pending;
                 logEntry.QueuedAt = currentTime;