1 files changed, 242 insertions, 36 deletions

diff --git a/src/purgatory/sync/throttle.rs b/src/purgatory/sync/throttle.rs
index 94056b5..a310a91 100644
--- a/src/purgatory/sync/throttle.rs
+++ b/src/purgatory/sync/throttle.rs
@@ -8,12 +8,22 @@
 //!
 //! The `ThrottleManager` owns all `DomainThrottle` instances and provides the
 //! interface for checking throttle status and managing identifier queues.
+//!
+//! ## Trigger-based Processing
+//!
+//! When capacity frees up (via `complete_request`) or a new identifier is enqueued
+//! (via `enqueue_identifier`), the manager automatically spawns tasks to process
+//! queued identifiers. This is trigger-based, not polling-based.
 
 use dashmap::DashMap;
 use indexmap::IndexMap;
 use std::collections::{HashSet, VecDeque};
-use std::sync::Mutex;
+use std::sync::{Arc, Mutex, OnceLock};
 use std::time::{Duration, Instant};
+use tracing::debug;
+
+use super::context::SyncContext;
+use super::functions::{sync_identifier_from_url, sync_identifier_next_url};
 
 /// State for an identifier waiting in a domain's queue.
 ///
@@ -240,9 +250,7 @@ impl DomainThrottle {
 /// - Throttle status checking for `sync_identifier_next_url`
 /// - Identifier queue management
 /// - Request tracking (start/complete)
-///
-/// Note: Trigger-based queue processing (`set_context`, `process_queued_identifier`)
-/// will be added in Phase 6 after `SyncContext` is available.
+/// - Trigger-based queue processing when capacity frees up
 pub struct ThrottleManager {
     /// Per-domain throttle state.
     /// Uses DashMap for concurrent access from multiple sync tasks.
@@ -253,6 +261,10 @@ pub struct ThrottleManager {
 
     /// Maximum requests per minute per domain.
     max_per_minute_per_domain: u32,
+
+    /// Sync context for processing queued identifiers.
+    /// Set once at startup via `set_context()`.
+    ctx: OnceLock<Arc<dyn SyncContext>>,
 }
 
 impl ThrottleManager {
@@ -266,38 +278,54 @@ impl ThrottleManager {
             throttles: DashMap::new(),
             max_concurrent_per_domain: max_concurrent,
             max_per_minute_per_domain: max_per_minute,
+            ctx: OnceLock::new(),
         }
     }
 
+    /// Set the sync context (called once at startup).
+    ///
+    /// The context is used for processing queued identifiers when capacity
+    /// becomes available. Must be called before any trigger-based processing
+    /// can occur.
+    ///
+    /// # Arguments
+    /// * `ctx` - The sync context implementation
+    pub fn set_context(&self, ctx: Arc<dyn SyncContext>) {
+        let _ = self.ctx.set(ctx);
+    }
+
     /// Check if a domain is currently throttled (at capacity).
     ///
     /// Returns true if the domain has no capacity for another request,
     /// either due to concurrent limit or rate limit.
     pub fn is_throttled(&self, domain: &str) -> bool {
-        self.throttles
-            .get(domain)
-            .map_or(false, |entry| {
-                let throttle = entry.lock().unwrap();
-                !throttle.has_capacity()
-            })
+        self.throttles.get(domain).map_or(false, |entry| {
+            let throttle = entry.lock().unwrap();
+            !throttle.has_capacity()
+        })
     }
 
     /// Get or create a throttle for a domain.
-    fn get_or_create_throttle(&self, domain: &str) -> dashmap::mapref::one::Ref<'_, String, Mutex<DomainThrottle>> {
+    fn get_or_create_throttle(
+        &self,
+        domain: &str,
+    ) -> dashmap::mapref::one::Ref<'_, String, Mutex<DomainThrottle>> {
         // First, try to get existing
         if let Some(entry) = self.throttles.get(domain) {
             return entry;
         }
-        
+
         // Create new throttle
-        self.throttles.entry(domain.to_string()).or_insert_with(|| {
-            Mutex::new(DomainThrottle::new(
-                domain.to_string(),
-                self.max_concurrent_per_domain,
-                self.max_per_minute_per_domain,
-            ))
-        });
-        
+        self.throttles
+            .entry(domain.to_string())
+            .or_insert_with(|| {
+                Mutex::new(DomainThrottle::new(
+                    domain.to_string(),
+                    self.max_concurrent_per_domain,
+                    self.max_per_minute_per_domain,
+                ))
+            });
+
         // Return the entry (we know it exists now)
         self.throttles.get(domain).unwrap()
     }
@@ -311,39 +339,193 @@ impl ThrottleManager {
         throttle.start_request();
     }
 
-    /// Record that a request completed for a domain.
+    /// Record that a request completed for a domain (internal, no trigger).
     ///
     /// Decrements in-flight count and cleans up old timestamps.
-    ///
-    /// Note: Trigger-based processing (spawning tasks when capacity frees)
-    /// will be added in Phase 6 after `SyncContext` is available.
-    pub fn complete_request(&self, domain: &str) {
+    /// Does not trigger processing of queued identifiers.
+    fn complete_request_internal(&self, domain: &str) {
         if let Some(entry) = self.throttles.get(domain) {
             let mut throttle = entry.lock().unwrap();
             throttle.complete_request();
         }
     }
 
-    /// Add an identifier to a domain's waiting queue.
+    /// Record that a request completed for a domain.
+    ///
+    /// Decrements in-flight count, cleans up old timestamps, and triggers
+    /// processing of queued identifiers if capacity is available.
+    ///
+    /// # Arguments
+    /// * `domain` - The domain that completed a request
+    pub fn complete_request(self: &Arc<Self>, domain: &str) {
+        let should_trigger = {
+            if let Some(entry) = self.throttles.get(domain) {
+                let mut throttle = entry.lock().unwrap();
+                throttle.complete_request();
+                throttle.has_capacity() && throttle.has_queued_work()
+            } else {
+                false
+            }
+        };
+
+        if should_trigger {
+            self.try_process_next(domain);
+        }
+    }
+
+    /// Add an identifier to a domain's waiting queue (internal, no trigger).
     ///
     /// If the identifier is already queued for this domain, merges the tried_urls sets.
+    /// Does not trigger processing.
+    fn enqueue_identifier_internal(
+        &self,
+        domain: &str,
+        identifier: String,
+        tried_urls_for_domain: HashSet<String>,
+    ) {
+        let entry = self.get_or_create_throttle(domain);
+        let mut throttle = entry.lock().unwrap();
+        throttle.enqueue_identifier(identifier, tried_urls_for_domain);
+    }
+
+    /// Add an identifier to a domain's waiting queue.
     ///
-    /// Note: Trigger-based processing (spawning tasks when capacity available)
-    /// will be added in Phase 6 after `SyncContext` is available.
+    /// If the identifier is already queued for this domain, merges the tried_urls sets.
+    /// Triggers processing if capacity is available.
     ///
     /// # Arguments
     /// * `domain` - The domain to queue for
     /// * `identifier` - The repository identifier
     /// * `tried_urls_for_domain` - URLs from this domain that have already been tried
     pub fn enqueue_identifier(
-        &self,
+        self: &Arc<Self>,
         domain: &str,
         identifier: String,
         tried_urls_for_domain: HashSet<String>,
     ) {
-        let entry = self.get_or_create_throttle(domain);
-        let mut throttle = entry.lock().unwrap();
-        throttle.enqueue_identifier(identifier, tried_urls_for_domain);
+        let should_trigger = {
+            let entry = self.get_or_create_throttle(domain);
+            let mut throttle = entry.lock().unwrap();
+            throttle.enqueue_identifier(identifier, tried_urls_for_domain);
+            throttle.has_capacity()
+        };
+
+        if should_trigger {
+            self.try_process_next(domain);
+        }
+    }
+
+    /// Try to process the next queued identifier for a domain.
+    ///
+    /// This is called when capacity becomes available (either via `complete_request`
+    /// or when a new identifier is enqueued). Spawns a task to process the next
+    /// ready identifier if one exists.
+    fn try_process_next(self: &Arc<Self>, domain: &str) {
+        // Get next ready identifier (not in_progress)
+        let identifier = {
+            if let Some(entry) = self.throttles.get(domain) {
+                let mut throttle = entry.lock().unwrap();
+                throttle.next_ready_identifier()
+            } else {
+                None
+            }
+        };
+
+        if let Some(identifier) = identifier {
+            let manager = self.clone();
+            let domain = domain.to_string();
+
+            tokio::spawn(async move {
+                manager.process_queued_identifier(&domain, &identifier).await;
+            });
+        }
+    }
+
+    /// Process a single identifier from a domain's queue.
+    ///
+    /// This function:
+    /// 1. Gets the next URL to try for this identifier on this domain
+    /// 2. If a URL is found, fetches from it and marks it as tried
+    /// 3. If no URL is found, removes the identifier from this domain's queue
+    /// 4. Triggers processing of the next identifier if capacity is available
+    async fn process_queued_identifier(self: &Arc<Self>, domain: &str, identifier: &str) {
+        let ctx = match self.ctx.get() {
+            Some(ctx) => ctx,
+            None => {
+                debug!(
+                    domain = %domain,
+                    identifier = %identifier,
+                    "No sync context set - cannot process queued identifier"
+                );
+                // Mark not in progress so it can be retried
+                if let Some(entry) = self.throttles.get(domain) {
+                    let mut throttle = entry.lock().unwrap();
+                    throttle.mark_identifier_not_in_progress(identifier);
+                }
+                return;
+            }
+        };
+
+        // Get tried URLs for this identifier on this domain
+        let tried_urls = {
+            self.throttles
+                .get(domain)
+                .map(|entry| {
+                    let throttle = entry.lock().unwrap();
+                    throttle.get_tried_urls(identifier)
+                })
+                .unwrap_or_default()
+        };
+
+        // Get next URL for this identifier on this specific domain
+        let url = sync_identifier_next_url(
+            ctx.as_ref(),
+            identifier,
+            Some(domain),
+            &tried_urls,
+            self,
+        )
+        .await;
+
+        match url {
+            Some(url) => {
+                debug!(
+                    domain = %domain,
+                    identifier = %identifier,
+                    url = %url,
+                    "Processing queued identifier - fetching from URL"
+                );
+
+                // Fetch from this URL
+                sync_identifier_from_url(ctx.as_ref(), identifier, &url, self).await;
+
+                // Record URL as tried and mark not in_progress
+                if let Some(entry) = self.throttles.get(domain) {
+                    let mut throttle = entry.lock().unwrap();
+                    throttle.mark_url_tried(identifier, url);
+                    throttle.mark_identifier_not_in_progress(identifier);
+                }
+
+                // complete_request was already called by sync_identifier_from_url,
+                // which will trigger try_process_next if capacity is available
+            }
+            None => {
+                debug!(
+                    domain = %domain,
+                    identifier = %identifier,
+                    "No more URLs for identifier on this domain - removing from queue"
+                );
+
+                // No more URLs for this identifier on this domain - remove from queue
+                if let Some(entry) = self.throttles.get(domain) {
+                    let mut throttle = entry.lock().unwrap();
+                    throttle.remove_identifier(identifier);
+                }
+
+                // Try next identifier since we didn't use any capacity
+                self.try_process_next(domain);
+            }
+        }
     }
 }
 
@@ -523,8 +705,8 @@ mod tests {
         // Should now be throttled
         assert!(manager.is_throttled("example.com"));
 
-        // Complete one request
-        manager.complete_request("example.com");
+        // Complete one request (using internal method for non-Arc test)
+        manager.complete_request_internal("example.com");
 
         // Should have capacity again
         assert!(!manager.is_throttled("example.com"));
@@ -540,8 +722,8 @@ mod tests {
         // Domain doesn't exist yet
         assert!(!manager.throttles.contains_key("example.com"));
 
-        // Enqueue an identifier
-        manager.enqueue_identifier("example.com", "repo1".to_string(), HashSet::new());
+        // Enqueue an identifier (using internal method for non-Arc test)
+        manager.enqueue_identifier_internal("example.com", "repo1".to_string(), HashSet::new());
 
         // Domain throttle should now exist
         assert!(manager.throttles.contains_key("example.com"));
@@ -560,4 +742,28 @@ mod tests {
         // Domain throttle should now exist
         assert!(manager.throttles.contains_key("example.com"));
     }
+
+    #[test]
+    fn has_queued_work_reflects_queue_state() {
+        let manager = ThrottleManager::new(5, 100);
+
+        // Initially no queued work
+        let has_work = manager
+            .throttles
+            .get("example.com")
+            .map(|e| e.lock().unwrap().has_queued_work())
+            .unwrap_or(false);
+        assert!(!has_work);
+
+        // Enqueue an identifier
+        manager.enqueue_identifier_internal("example.com", "repo1".to_string(), HashSet::new());
+
+        // Now should have queued work
+        let has_work = manager
+            .throttles
+            .get("example.com")
+            .map(|e| e.lock().unwrap().has_queued_work())
+            .unwrap_or(false);
+        assert!(has_work);
+    }
 }